CATALOG OF NUCLEAR RrEACTOR CONCEPTS I

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ANL-7 180 Reactor Technology (TID-4500) ,

AEC Research and Development Report

CFSTl PRICES ARGONNE NATIONAL LABORATORY

9700 South Cass Avenue & H*C* $ 3 4 0 ; MN ,*' ' Argonne, I l l i n o i s 60439 - -

CATALOG OF NUCLEAR REACTOR CONCEPTS

P a r t I. Homogeneous and Quasi-homogeneous Reac tors

S e c t i o n V. Reac tors ~ u e l e d ' w i t h Uranium Hexafluoride, Gases, o r Plasmas

. Char les E. Tee t e r , James A. Lecky, and John H. Martens

Technica l P u b l i c a t i o n s Depar tmen t

March 1966

Operated by The U n i v e r s i t y of Chicago under

Coatrac t W-31- 109-eng-38 w i t h the

U. S. Atomic Energy Commission

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TABLE OF CONTENTS

P a g e

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P r e f a c e 5

P l a n of C a t a l o g of N u c l e a r R e a c t o r C o n c e p t s . . . . . . . . . . . . . . . 6

L i s t of R e a c t o r C o n c e p t s . . . . . . . . . . . . . . . . . . . . . . . . . . 7

SECTION V . REACTORS FUELED WITH URANIUM HEXAFLUORIDE. GASES. OR PLASMAS . . . . . . . . . . . . . . . . . . . . . . 9

C h a p t e r 1 . I n t r o d u c t i o n . . . . . . . . . . . . . . . . . . . . . . . 9

. . . . . . . C h a p t e r 2 . R e a c t o r s Fueled w i t h U r a n i u m H e x a f l u o r i d e 13

C h a p t e r 3 . R e a c t o r s Fueled w i t h G a s e s o r P l a s m a s . . . . . . . . . 3 7

LEFT BLANK

< . . PREFACE

This r e p o r t i s an a d d i t i o n a l s e c t i o n i n t h e Catalog of Nuclear Reactor

Concepts t h a t was begun wi th ANL-6892 and cont inued i n ANL-6909, ANL-7092, and

ANL-7138, A s i n t h e previous r e p o r t s , t h e m a t e r i a l i s di;ided i n t o c h a p t e r s ,

each wi th t e x t and r e f e r e n c e s , p lus d a t a s h e e t s t h a t cover t h e ind iv idua l

concepts . The p lan of t h e c a t a l o g , wi th t h e r e p o r t numbers f o r t h e s e c t i o n s

a l r eady i s sued , i s given on t h e next page, which i s . f o l l o w e d by pages l i s t i n g

t h e concepts included i n t h i s s e c t i o n .

D r . Charles E. T e e t e r , formerly employed by t h e Chicago Operat ions Of f i ce

a t Argonne, I l l i n o i s , i s now a f f i l i a t e d wi th t h e Southeas te rn Massachusetts

Technological I n s t i t u t e , New Bedford, Mass. Through a consu l t an t sh ip a r range-

ment wi th Argonne Nat iona l Laboratory, he is cont inuing . t o he lp guide the

o rgan iza t ion and compilat ion of t h i s c a t a l o g .

We wish t o acknowledge t h e a s s i s t a n c e of M i s s E l l e n Thro i n t h e prepara-

t i o n of t h i s s e c t i o n .

J. H. M.

March, 1966

PLAN OF CATALOG OF REACTOR CONCEPTS

General Introduction

Part I. . Homogeneous and Quasi-homogeneous Reactors

Section I. Particulate-fueled Reactors ANL-6892

Section 11. Reactors Fueled with Homogeneous Aqueous Solutions and Slurries ANL-6909

Section 111. Reactors' Fueled with Molten-salt Solut ions ANL-7092

. Section IV. Reactors Fueled with Liquid Metals ANL-7138

Section V. Reactors FueLed with Uranium Hexa- fluoride, Gases, or Plasmas This report

Section VI. Solid Homogeneous Kcactors

Part 11. Heterogeneous Reactors

Section 1. Reactors Cooled by Liquid Metals

Section 11. Gas -cooled Reactors

Section 111. Organic-cooled Reactors

Section IV. Boiling Reactors

Section V. Reactors Cooled by Supercritical Fluids

Section VI. Water-cooled Reactors

Sectinn VII. . Reacllurs Cooled by Other Fluids

Section VIII. Boiling-waLer Reactors

Section IX. Pressurized-water Reactors

Part 111. Miscellaneous Reactor Concepts

REACTOR CONCEPTS DESCRIBED I N THIS REPORT

Name of Reac to r Chapter No. Data Shee t No. Page

H e x a f l u o r i d e Thermal P i l e

Uranium Hexaf luor ide Thermal P i l e

Uranium H e x a f l u o r i d e Thermal P i l e 2

L i q u i d Hexaf luor ide P i l e 2

Proposed Hanford C i r c u l a t e d - H e x a f l u o r i d e Thermal P i l e

u~~~ H e x a f l u o r i d e Breeder

Hex P-9 P i l e (UF6-D20 P i l e ) 2 7

~ o m o ~ e n e b u s , C i r c u l a t i n g L i q u i d UF6 Fue led P i l e

C i r c u l a t i n g L i q u i d UF6 P i l e 2 9

Gaseous UF6 F u e l e d , Gas Cooled Power P i l e

Gaseous UF6 Fue led , Gas Cooled Power P i l e

Water:Cooled, High F l u x , UF6 . .

Fue led P i l e 2 12

C i r c u l a t i n g Gaseous U F 6 Fue led P i l e

Homogeneous, C i r c u l a t i n g Gaseous UF6 F u e l e d P i l e

Gaseous UF6-Fueled Reac to r 2 15

D i r e c t Expansion UFg-Fueled Reac to r

D i r e c t Expansion UF6-Fueled React o r

UF6-Fueled R e a c t o r f o r Locomotive P r o p u l s i o n

. Gaseous UF6 R e a c t o r

UF6 Gas Phase Reac to r

Gaseous-Fuel P a s t Breeder Reac to r

Gaseous R e a c t o r f o r Rocket P r o p u l s i o n

C a v i t y R e a c t o r

F i s s ion-p lasma R e a c t o r

Plasma Core R e a c t o r

F i z z l e r R e a c t o r

F i z z l e r R e a c t o r f o r Rocket P r o p u l s i o n

REACTOR CONCEPTS DESCRIBED IN THIS ' REPORT (Cont . )

Name of Reactor

Gas-Solid Fueled Reac tor , S e r i e s f o r Rocket Propuls ion

Cavity Reactor

Gaseous Propuls ion Reactor

Vortex React o r

Coaxial Flow Reactor

Homogeneous Gas Phase Magnetu- hydrodynamic Nuclear Reactor

Chapter No. Data Sheet No. Page

PART I. HOMOGENEOUS AND QUASI-HOMOGENEOUS REACTORS

SECTION V . REACTORS FUELED WITH URANIUM HEXAFLUORIDE, GASES, OR PLASMAS

Chapter 1. . In t roduc t ion :

This s e c t i o n covers r e a c t o r s fue l ed wi th uranium hexa f luo r ide , e i t h e r a s

a gas o r a l i q u i d , and those fue l ed wi th o t h e r gases (such a s vaporized f i s -

s i l e meta ls ) o r wi th plasmas ( ion ized gases ) . Although uranium hexa f luo r ide 1

i s normally a s o l i d o r a gas ( i t sublimes a t 56.4OC under atmospheric p re s su re )

i t s use a s a l i q u i d by keeping t h e system under p re s su re has been proposed.

The l i q u i d phase appears above t h e t r i p l e poin t of 147.3OF and 22 p s i a . The

c r i t i c a l po in t i s a t P 45 .5 atm; and T 4 4 6 0 ~ . ~ The r e a c t o r s fue l ed w i t h c , c ,

UF a r e included i n Chapter 2. Reactors fue l ed wi th o t h e r gases o r wi th 6

plasmas a r e i n Chapter 3 ; i n some of t h e s e , uranium hexaf luor ide is t h e

o r i g i n a l form of t h e f u e l .

The UF - fue l ed r e a c t o r s might be considered f a i r l y convent iona l , i n t h a t 6

t h e l i q u i d o r gaseous f u e l is i n a r e a c t o r system resembling those p rev ious ly

descr ibed f o r r e a c t o r s fue l ed wi th molten s a l t s o r meta ls . The f u e l may

e i t h e r c i r c u l a t e f o r coo l ing o r be cooled by another m a t e r i a l . I n t h e r e a c t o r s

fue l ed wi th gaseous meta ls o r wi th plasmas, on t h e o t h e r hand, t h e gaseous f u e l ,

a t extremely h igh tempera tures , mixes wi th a gas t h a t i s both a rocke t propel -

l a n t and the r e a c t o r coo lan t . Soph i s t i ca t ed means a r e needed both t o con ta in

and l a t e r t o s e p a r a t e t h e two gases . Most of t h e concepts i n t h i s s e c t i o n a r e

f o r thermal r e a c t o r s . Another moderator i s t h e r e f o r e needed because w i t h

f l u o r i n e a lone a s a moderator t h e c r i t i c a l mass would be exces s ive .

The advantages of UF a s r e a c t o r f u e l s were recognized e a r l y i n t h e war- 6

t ime atomic energy program. It has a low c ros s s e c t i o n f o r p a r a s i t i c neut ron

cap tu re . Like o t h e r f l u i d f u e l s , UF can be used i n simple r e a c t o r systems 6

and can be c i r c u l a t e d t o g ive hea t t o a b o i l e r o r o t h e r hea t o u t l e t . Fuel

f a b r i c a t i o n i s not necessary , and both f i s s i o n products and bred f i s s i l e

m a t e r i a l can be removed by s imple means. The gaseous f u e l s have t h e added

advantage t h a t t hey a r e not l i m i t e d by s t r u c t u r a l p r o p e r t i e s t o any minimum

ten~perakure . There a r e , however, d i f f i c u l t i e s w i t h t h e systems descr ibed i n

t h i s s e c t i o n . Such problems a s p o s s i b l e i n s t a b i l i t y , co r ros iveness , and

Iissiori-producr: deposition w i t h UF and t h e need f o r s p e c i a l containment 6

methods f o r gases and plasmas a t extremely h igh tempera tures w i l l be covered

i n Chapters 2 and 3 . Two d i f f i c u l t i e s common t o both types of gaseous r e a c t o r s

a r e t h a t gases a r e poor conductors of hea t and extremely l a r g e volumes a r e

needed t o o b t a i n a c r i t i c a l mass because of t h e low dens i ty of gases .

An e a r l y sugges t ion f o r t h e use of uranium hexa f luo r ide a s a r e a c t o r f u e l 3

was i n t h e concept by Anderson and Brown i n 1942. They proposed us ing l i q u i d

UF6. Seve ra l o t h e r concepts were advanced dur ing World War I1 and s h o r t l y

t h e r e a f t e r . Concepts have been publ ished i n t e r m i t t e n t l y s i n c e then , a l though

no p r a c t i c a l development has occured i n t h e United S t a t e s . Some of t he

sugges t ions publ i shed a r e t o o incomplete f o r d a t a s h e e t s t o be made. I n

Russ i a , a low-power exper imenta l r e a c t o r fue l ed wi th gaseous UF began opera- 4 6

t i o n i n 1957.

The r e a c t o r s fue l ed w i t h high-temperature gases , such a s t h e vo r t ex and

t h e plasma r e a c t o r s , f i r s t r ece ived a t t e n t i o n s h o r t l y a t t e r t h e war, e s p e c i a l l y

f o r rocke t propuls ion . Seve ra l concepts have been pubLished; much of t h i s

work d e a l s wi th t h e problem of s e p a r a t i n g t h e gaqeous f u e l and t h e p rope l l an t

gas . Work i s con t inu ing i n t h i s f i e l d , but d e t a i l s of some developments a r e 5 no t a v a i l a b l e .

References

1. W.D. Wilkinson, Uranium M e t a l l u r g y , Vol. 1, Uranium Process M e t a l l u r g y ,

p. 553, I n t e r s c i e n c e P u b l i s h e r s , 1962.

2 . J . W . Arend t , E.W. Powell , and H.W. S a y l o r , comps. and e d s . , A B r i e f

Guide t o UF Handl ing, K-1323, Union Carb ide Nuc lea r Co., Feb. 1 8 , 1957. 6

3 . H.L. Anderson and H.S. Brown, L i q u i d UF6 P l a n t f o r t h e P r o d u c t i o n of

Element 94, CN-362, M e t a l l u r g i c a l L a b o r a t o r y , U n i v e r s i t y of Chicago,

Nov. 27, 1942.

4. I . K . K iko in , V.A. Dmitr ievsky, Y.T. Glazkov, I . S . G r i g o r i e v , B.G. Bubovsky,

and S.V. Kersnovsky, Exper imental Reac to r w i t h Gaseous F i s s i o n a b l e Sub-

s t a n c e (UF6), P roc . 2nd U. N. I n t . Conf. on P e a c e f u l Uses o f Atorni.2

Energy, 2, p p . 528-534, Uni ted N a t i o n s , N . Y . , 1958.

5. R.S. Cooper, . . Adv,anced . . Nuclear P r o p u l s i o n , Nuclgar News, 1, No. 11, p p . 40-

41, Nov. 1964.

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Chapter 2. Reactors Fueled With Uranium Hexafluoride

Most of t h e concepts i n t h i s chapter a r e f o r thermal r e a c t o r s . Use of

uranium hexaf luor ide alone i s not p r a c t i c a l , and a moderator must be used wi th

i t . Gaseous (hel ium), l i q u i d (heavy water o r f luorocarbons) , and s o l i d (be ry l -

l ium o r g raph i t e ) moderators have been suggested.

The e a r l y concepts f o r UF a s a f u e l employed e i t h e r l i q u i d o r gaseous 6

forms. L a t e r , use of t h e gaseous f u e l predominated. The advantages of a gas

a s f u e l have been given i n Chapter 1.

Some problems appear t o need f u r t h e r i n v e s t i g a t i o n : s t a b i l i t y of t h e

compound under i r r a d i a t i o n ; co r ros ion of containment m a t e r i a l s , e s p e c i a l l y

under i r r a d i a t i o n ; s e t t l i n g out i n t h e r e a c t o r of s o l i d UF f i s s i o n products , 6 '

o r co r ros ion products ; and t h e use of a moderator f o r which a r e a c t o r of r e a -

sonable s i z e i s poss ib le : f o r example, i f heavy water were t o be used a s has

been sugges ted , a very l a r g e amount would be needed.

The only r e a c t o r r epo r t ed t o have a c t u a l l y opera ted wi th UF a s f u e l was 6

a Russian r e a c t o r ' t h a t opera ted a t low temperature (90°C) and low power (1.5 kW). 1

The Russian i n v e s t i g a t o r s , Kikoin e t a l . , f ound t h a t t h e decomposition of t h e

UF could be hindered by adding c h l o r i n e t r i f l u o r i d e . No exper ience on t h e 6

s t a b i l i t y under r a d i a t i o n a t temperatures u sua l i n power r e a c t o r s has been

r epor t ed .

The c o r r o s i v i t y of UF toward meta ls has been i n v e s t i g a t e d , bu t appa ren t ly 6

not under cond i t i ons of i r r a d i a t i o n . Heymann and elli in^^ found t h a t t h e co r -

ro s ion r a t e s a t 80°C a r e low f o r n i c k e l , copper , Monel, aluminum, a l l o y s t e e l s ,

and t i t a n i u m a l l o y s . For use a t h igh tempera tures , h i g h - p u r i t y n i c k e l and

Monel appear t o be b e s t . ~ a n ~ l o i s ~ s t u d i e d co r ros ion by UF a t h igh tempera- 6

t u r e s . High-puri ty n i c k e l has t h e lowest co r ros ion r a t e s above 800°C, and

t h e s e r a t e s a r e compatible w i t h i n d u s t r i a l uses . Between 550' and 700°C,

however, co r ros ion of n i c k e l and Monel by p e n e t r a t i o n along c r y s t a l l i n e bound-

a r i e s p ro t l i b i t s t h e use of t h e s e meta ls i n t h i s temperature range. Nickel of

t h e h ighes t p u r i t y , i n which i m p u r i t i e s r e spons ib l e f o r i n t e r g r a n u l a r a t t a c k

a r e e l imina ted , should have g r e a t l y improved c o r r o s i o n r e s i s t a n c e . Dry UF6

is normally conta ined i n n i c k e l o r Monel. ~ a n e ~ p o i n t s ou t t h a t t h e s t a b i l i t y

under i r r a d i a t i o n of t h e p r o t e c t i v e f i l m on t h e s e metals has not been i n v e s t i -

ga ted . 5

I n 1947, Hull descr ibed s e v e r a l concepts and d i scussed d i f f e r e n t a s p e c t s

of us ing UF as f u e l . He l i s t e d many advantages, most of which have been given 6

he re a l r eady . Others he noted a re : remote ope ra t ion permi ts low-decontamination

s e p a r a t i o n , w i th consequent s i m p l i f i e d process ing; and e l imina t ion of cool ing

permi ts a low inventory . He suggested hydrogen f luo r ide . (b .p . , 19.4OC),

deuter ium f l u o r i d e , and f luorocarbons a s l i q u i d solvent-moderators f o r homo-

geneous r e a c t o r s . Helium o r f luorocarbons would be coo lan t s ; water o r l i q u i d

meta ls would have t o be kept s e p a r a t e from t h e UF because of t h e vigorous 6

r e a c t i o n s t h a t would occur on con tac t between them and t h e f u e l . Graphi te

r e a c t s s o v igo rous ly wi th UF t h a t i t a l s o would have t o be sepa ra t ed . For 6

containment m a t e r i a l s , he suggested bery l l ium o r n i c k e l ; aluminum o r magnesium

could be used i f t he problem of a t t a c k by UF could be so lved . Areas i n which 6

he thought i n v e s t i g a t i o n was needed a re : co r ros ion of metals by u r a l ~ l u ~ u Ilexa-

f l u o r i d e and f l u o r i n e ; decomposition of UF by f i s s ion -p roduc t f l u o r i d e s , wiLh 6

o r wi thout s o l v e n t s ; and hea t t r a n s t c r by r ad iae ion and conducLiull t l ~ r o u g l ~

gaseous UF A p o s s i b l e problem wi th l i q u i d UF6 i s formation of gas bubbles 6 '

t h a t might cause i n s t a b i l i t y . 6

I n 1962, Wethington proposed t h a t r e s e a r c h be c a r r i e d out on a r e a c t o r

fue l ed w i t h a s o l u t i o n of uranium hexa f luo r ide i n a f luorocarbon. He c i t e d

t h e 'Russian exper ience and t h e work of o t h e r s t o show t h a t a l though t h e r e

would be some decomposition of UF under r a d i a t i o n it could be c o n t r o l l e d and 6

i t would be no worse t h a ~ l that: uf o t h e r compounds used i n r e a c t o r technol.ogy.

The f luorocarbons were suggested a s promising moderators because publ ished

informat ion i n d i c a t e s t h a t they have good r a d i a t i o n - s t a b i l i t y . More i n v e s t i -

g a t i o n , however, would be needed on Lhe cullcept.

As ~uent ioned i n P a r t I , Sec t ion I , of t h i s c a t a l o g , Kerce has suggested

t h a t CaF p a r t i c l e s might be f l u i d i z e d wi th a mixture of uranium hexaf luor ide 2

and te t ra f luoromethane (CF ) t o g ive a gaseous suspension. The f e a s i b i l i t y of 4

such a system would depend upon t h e mixture having s u f f i c i e n t moderating pro-

perLies .

Another concept w i t h uranium hexa f luo r ide a s a gaseous f u e l Itas been d i s -

cussed i n Pa r t I , Sec t ion I. Hal ik e t a l . proposed f l u i d i z i n g t i n e p a r t i c l e s

of be ry l l i um oxide moderator by t h e f u e l gas.

Reactors Fueled With Liquid Uranium Hexafluoride

I n 1942, Anderson and ~ r o w n , ~ ' ~ of t h e Meta l lu rg i ca l Laboratory of t h e

Un ive r s i t y of Chicago, suggested a r e a c t o r fue l ed wi th l iqu ' id uranium hexa-

f l u o r i d e , a s we l l as two v a r i a n t s of t h e o r i g i n a l des ign . The r e a c t o r would

be a breeder f o r producing plutonium. I n t h e o r i g i n a l des ign , t h e f u e l -

c o o l a n t - f e r t i l e m a t e r i a l i s n a t u r a l o r enr iched l i q u i d UF The f u e l c i r c u l a t e s 6'

through tubes i n a moderator of g r a p h i t e o r heavy water and goes t o an e x t e r n a l

heat exchanger. The tubes a r e of uranium l i n e d wi th n i c k e l o r o the r co r ros ion -

r e s i s t a n t metal of low neut ron-absorp t ion c ros s s e c t i o n . A power of more than

100 MW(t) was expected. In t h e f i r s t v a r i a n t , t h e c e n t r a l po r t ion of t h e -

g r a p h i t e mat r ix con ta ins uranium rods , which a r e cooled by helium pass ing be.-

tween t h e rods . A t t h e per iphery of t h e mat r ix a r e aluminum tubes con ta in ing

l i q u i d UF which passes t o an e x t e r n a l hea t exchanger. Breeding occurs i n t h i s 6 '

o u t e r reg ion , which a l s o se rves a s a r e f l e c t o r f o r t h e inne r s e c t i o n of rods .

I n t h e second v a r i a n t , t h e r e i s a c e n t r a l s p h e r i c a l vo id , f i l l e d wi th heavy

water , i n t h e g raph i t e mat r ix . The UF c i r c u l a t e s through tubes t h a t a r e i m - 6

bedded i n t h e graphice and pass through t h e heavy water . A power of more than

100 MW(t) was expected.

Two 1943 concepts from t h e Meta l lu rg i ca l Laboratory, Univers i ty of Chicago,

a r e a Liquid Hexafluoride P i l e and the Proposed Hanford Ci rcu la ted-Hexaf luor ide ,

Thermal p i l e . ' Both a r e r a t e d a t 390 MW(t). I n t h e f i r s t , t h e l i q u i d UF 6

c i r c u l a t e s through tubes of aluminum i n a g r a p h i t e moderator and out t o a hea t

exchanger. This concept i s a burner . I n t h e second concept , t he f u e l c i r c u -

l a t e s through tubes, immersed i n 25 tons of heavy water surrounded by a g r a p h i t e

r e f l e c t o r , t o an e x t e r n a l hea t exchanger. It i s a b reede r , w i t h t h e f u e l and

f e r t i l e m a t e r i a l being n a t u r a l uranium moderated by heavy wa te r .

I n t h e u~~~ Hexafluoride I3reeder , lo suggested by Meta l lu rg i ca l LaboratOry

s t a f f members i n 1944, a f luorocarbon i s u t i l i z e d t o d i s s o l v e U 233 .

F6, and

thorium is t h e r e f l e c t o r - b r e e d i n g b lanket . The f u e l c i r c u l a t e s i n tubes through

the c y l i n d r i c a l co re . The power is 100 t o 200 MW(t).

A 1944 concept by Anderson i s t h e Hex P-9 P i l e (UF -D 0 p i l e ) . 8,11,12

6 2 This

would r e q u i r e 686 tons of l i q u i d UF ("Hex"), probably h igh ly enr iched f o r a 6

burner and n a t u r a l uranium f o r a b reede r , w i t h 63 tons of heavy water ("P-9")

a s moderator. The f u e l c i r c u l a t e s through tubes i n t h e moderator and out t h e

top t o a hea t exchanger. Temperature l i m i t s t o prevent bo th s o l i d i f i c a t i o n

and v a p o r i z a t i o n of t h e UF a r e 75OC minimum and 150°C maximum. 6

Among the concepts descr ibed by Hull i n 1 9 4 7 ~ were two f o r l i q u i d UF 6 f u e l . I n one, t h e f u e l i s . l i q u i d UF d i s so lved i n e i t h e r a l i q u i d f luorocarbon

6 o r deuterium f l u o r i d e . The f u e l c i r c u l a t e s f o r hea t exchange and removal of

f i s s i o n products . It has thorium t e t r a f l u o r i d e a s f e r t i l e m a t e r i a l . I n t h e

second concept , t h e f e r t i l e m a t e r i a l , thorium t e t r a f l u o r i d e , i s p re sen t as a

f i n e powder w i th in bery l l ium c y l i n d e r s i n a g r a p h i t e bed.

Reactors Fueled With Gaseous Uranium Hexafluoride . . 5

I n 1947, Hull desc r ibed t h e use of gaseous uranium hexaf.luoride, po in t ing

ou t t h e advantages of t h e f l u i d f u e l , and he descr ibed concepts o r i g i n a t e d by

s t a f f members of t h e C l in ton Labora to r i e s (now Oak Ridge National Laboratory) .

A pre l imina ry s tudy on such p i l e s had been publ ished e a r l i e r i n t h e same year

by Hull and Miles. 13

I n one des ign , t h e f u e l , u~~~ o r U 235 i n UF6, i s contained i n porous

be ry l l i um tubes surrounded by impervious bery l l ium tubes . The pores a r e f o r

t r a p p i n g f i s s i o n products . The tubes a r e w i t h i n a g raph i t e moderator core t h a t

i s e i t h e r i n the form ok rods i n t h e c e n t e r ~f a t r i a n g u l a r l a t t i c e of i u e l

t ubes o r a s annular tubes around them. The coo lan t , helium, c i r c u l a t e s through

rhe spaces i n t he core and out t o a heat exchanger. A blanket of thorium

powder i n be ry l l i um tubes w i t h i n a g r a p h i t e bed is t h e f e r t i l e ma te r i a l . Bred

E i s s i l e m a t e r i a l i s leached out of t h e f u e l by slowly c i r c u l a t i n g f l u o r i n e

through t h e bed. The porous design of t h e f u e l t ubes , intended t o f a c i l i t a t e

t r a p p i n g of f i s s i o n products , a l lows t h e products t o be removed from t h e UF 6 without chemical process ing . This design was f o r a power of 96 MW(t).

I n a mod i f i ca t ion of t h i s des ign , t he f u e l c i r c u l a t e s slowly through

aluminum tubes o u t s i d e t h e r e a c t o r . These tubes have l a r g e pores t h a t do not

t r a p t h e f i s s i o n products . Thus removal of f i s s i o n products is cont inuous,

p e r m i t t i n g b e t t e r neut ron cconomy. Bccausc of t h c i r low c o s t , t h c s c aluminum

tubes can be d iscarded i n s t e a d of being reprocessed , but t h e i r use r e s u l t s i n

lower power p o t e n t i a l . The power i s 50 MW(t).

I n a h igh - f lux p i l e , t h e water coolant flows i n an annulus between porous

aluminum rods and be ry l l i um c y l i n d e r s . The rods con ta in u~~~ o r u~~~ as

gaseous uranium hexa f luo r ide . Water coo l ing of t h e rods , according t o t h e

a u t h o r , g ives a h igh power output--32 MW(t)--but a t a temperature t o o low f o r

economic va lue i n gene ra t ion of e l e c t r i c a l power. The moderator would be e i t h e r

water o r beryl l ium. A r e f l e c t o r - b l a n k e t , l i k e t h a t i n t h e previous des ign ,

permi ts breeding.

The o r i g i n a t o r s be l i eved t h a t t h e uranium bred i n t h e r e a c t o r could be

removed f a i r l y simply from t h e b lanket of t h e f i n e l y powdered thorium f l u o r i d e

conta ined i n bery l l ium tubes . A hot mixture of helium and f l u o r i n e flowing

through t h e powder would conver t t h e products t o f l u o r i d e s . I f t h e powder were

f i n e enough and t h e temperature high enough, t h e PaF and UF could d i f f u s e 5 6

through t h e bery l l ium, be v o l a t i l i z e d a t t h e s u r f a c e , and be c a r r i e d away by

c i r c u l a t i n g gas. The UF could be sepa ra t ed i n a f r a c t i o n a t i n g column con- 6

233 t i n u o u s l y a s soon a s t h e proact inium decays t o U

Two o t h e r concepts descr ibed were f o r r e a c t o r s i n which gaseous UF c . i r - 6 .

c u l a t e s ou t s ide t h e r e a c t o r f o r removal of f i s s i o n products and, presumably,

f o r hea t exchange. Both would ope ra t e a t 230°C o r h igher . This temperature

would avoid t h e need f o r excess ive p re s su re . I n one des ign , t h e f u e l c i r c u -

l a t e s through ho le s i n a c y l i n d e r of bery l l ium moderator. The au tho r s . . s t a t e d

t h a t f i s s i o n products would s e t t l e out of t h e gas onto s u r f a c e s w i t h i n the

r e a c t o r , bu t us ing t h e gaseous form of UF avoids t h e problem of gas .bubbles 6

t h a t would occur w i th l i q u i d UF I n t h e o t h e r des ign , t h e r e a c t o r is homo- 6 '

geneous, w i t h t h e moderator being a gas , helium o r carbon t e t r a f l u o r i d e

( te t ra f luoromethane) . The ope ra t ing p re s su re i s 100 afm. The au thors s p e c i f y

a s p h e r i c a l r e a c t o r wi th a diameter of 1 7 meters , but they s t a t e d t h a t i t was

t o o l a r g e t o be cons idered a t t h a t t ime. Breeding w i t h a b lanket would be

p o s s i b l e , but t h e b lanket would have t o be extremely l a r g e .

A 1947 sugges t ion by ~ o o d m a n ' ~ f o r a r e a c t o r fue l ed w i t h gaseous UF 6

included t h e use of f l u o r i n e t o s t a b i l i z e t h e UF and t o a c t a s a d d i t i o n a l 6

moderator. The f u e l e i t h e r c i r c u l a t e s t o an e x t e r n a l hea t exchanger o r r e -

mains f i x e d and i s cooled by a coolan t such a s l i q u i d metal pass ing through

c o i l s .

I n 1953 Kerner proposed t h e use of t h e d i r e c t expansion of UF i n an 6

internal-combust ion engine , a t u r b i n e , o r a r e c i p r o c a t o r . l5 The gas i s

b r i e f l y compressed t o s u p e r c r i t i c a l i t y w i th a p i s t o n ; it h e a t s up , and pushes

back t h e p i s t o n . The gas r e t u r n s t o t he core through a hea t exchanger and a

Pump

Reactor concepts i n which t h i s d i r e c t expansion were u t i l i z e d were ad-

vanced i n 1953 by ~ o r t e s c u e ' ~ and i n 19'57 by Clasen. l7 I n t h e 1953 concept, .

t h e moderator i s molten be ry l l i um f l u o r i d e surrounding f u e 1 , t u b e s i n a c y l i n -

d r i c a l n i c k e l c a l a n d r i a . The r e a c t o r i s under a p re s su re of 20 atm. Cadium

absorbers i n t h e hea t exchangers were suggested f o r c o n t r o l of c r i t i c a l i t y

o u t s i d e t h e core. I n t h e 1957 concept , t h e f u e l is w i t h i n a be ry l l i um core ;

t h e t u r b i n e a l s o i s t o be made of be ry l l i um a s much a s poss ib l e . A g r a p h i t e

r e f l e c t o r surrounds core and t u r b i n e . A blanket of u ~ ~ ~ F ~ i s suggested i f

breeding i s des i r ed . A f a s t r e a c t o r i s suggested a s an a l t e r n a t i v e , but no

d e t a i l s a r e given.

The expansion of gaseous u ~ ~ ~ F i s t he b a s i s f o r another r e a c t o r , f o r 6

which few d e t a i l s are g iven , i n which a p i s t o n compresses t h e gas f u e l i n each

end of a c y l i n d e r . 1'8-20 The compression causes c r i t i c a l i t y , and t h e gas ex-

pands t o d r i v e t h e p i s t o n t o t h e oppos i t e end, where t h e gas a t t h a t end ex-

pands. Thus a r e c i p r o c a t i n g a c t i o n of t h e p i s t o n r e s u l t s . Each end of t h e

c y l i n d e r i s surrounded by a moderator and r e f l e c t o r . Di rec t conversion of t h e

p i s t o n motion i n t o e l e c t r i c a l a c t i o n by use of e lec t romagnet ic i nduc t ion was

proposed. The a p p l i c a t i o n of t he concept t o locomotives has been sugges ted , and

i n 1955 t h e USAEC awarded a c o n t r a c t f o r t h e s tudy of a nuclear-powered r ec ip ro -

c a t i n g engine f o r locomotive propuls ion t o t h e Baldwin-Lima-Hamilton Corporat ion

and t h e Denver & Rio Grande ail road.^' The ch ie f problems v i s u a l i z e d were i n

s t a r t u p and i n handl ing UF 6

The only UF - fue l ed r e a c t o r t o be b u i l t and opera ted i s t h e Russian low- 6

power [1.5 k ~ ( t ) ] experimental r e a c t o r , fue l ed wi th gaseous UF It went 1 ,21

6 ' c r i t i c a l i n i957. ~ u s s i a n i n v e s t i g a t o r s r epo r t ed t h a t t h e r e a c t o r opera ted

s a t i s f a c t o r i l y . There was a p re s su re drop and a decrease i n r e a c t i v i t y a t a

h ighe r power l e v e l , which was a t t r i b u t e d t o d i s s o c i a t i o n of t h e UF under ir- 6 r a d i a t i o n . Adding c h l o r i n e t r i f l u o r i d e permi t ted s t a b l e opera t ion . The f u e l

is h igh ly enr iched uranium hexa f luo r ide , t h e moderator is bery l l ium, and t h e

r e f l e c t o r i s g raph i t e . The f u e l i s w i t h i n channels formed from aluminum tubes .

C r i t i c a l i t y i s achieved by i n c r e a s i n g t h e pressure . Control rods a r e provided.

The au tho r s suggest t h a t improved methods of plutonium breeding might be pos-

s i b l e w i t h the UF r e a c t o r . Some plutonium f l u o r i d e s a r e not v o l a t i l e , and 6

plutonium hexa f luo r ide , which has a high vapor p re s su re , i s uns tab le . Thus

s p e c i a l t r a p s i n t h e fue l -coolant system might be used t o c o l l e c t plutonium

f l u o r i d e s . 2 2

A 1958 concept by Baron was f o r a c i r c u l a t i n g - f u e l conve r t e r u t i l i z i n g

s l i g h t l y enr iched uranium i n the gaseous f u e l a s both f u e l and f e r t i l e ma te r i a l .

The f u e l flows by n a t u r a l c i r c u l a t i o n through double-wall aluminum tubes s e t

w i t h i n g raph i t e blocks i n t h e core ; helium, t h e in t e rmed ia t e coo lan t , i s i n t h e

annulus between t h e tube w a l l s and i n an e x t e r n a l hea t exchanger t o which t h e

f u e l c i r c u l a t e s . The f u e l leaves t h e corc a t 900°F. To main ta in s u f f i c i e n t

f u e l c i r c u l a t i o n , a ' c o r e he igh t of ' .25 f e e t i s s p e c i f i e d . The power i s 35 MW(e).

amm mitt,'^ i n 1960, desc r ibed a concept f o r a f a s t b reeder r e a c t o r i n which

t h e UF f u e l and t h e sodium coolant flow through p a r a l l e l tubes made from a 6 n i c k e l a l l o y . A b lanket of f e r t i l e m a t e r i a l surrounds t h e co re . The power

given is 300 MW(tj.

S t a t u s

There appear t o have been no s u s t a i n e d developmental programs leading t o

r e a c t o r experiments f o r r e a c t o r s fue l ed wi th uranium hexaf luor ide . The e a r l y

i n t e r e s t i n uranium hexaf luor ide as a r e a c t o r f u e l has r e s u l t e d i n compara-

t i v e l y few concepts and, a s ide from t h e low-power Russian r e a c t o r , apparent ly

no p r a c t i c a l development. Recent concepts have been few. Questions of p r a c t i -

c a l r e a c t o r ope ra t ion , such a s s t a b i l i t y and c o r r o s i v i t y of UF under ope ra t ing 6

cond i t i ons of a power r e a c t o r , a r e not y e t c l a r i f i e d .

1 THIS , . PAGE

1 WASINTENTIONALLY. . . + . . I i . .

I i A LEFTBLANK

DATA SHEETS

REACTORS FUELED WITH URANIUM HEXAFLUORIDE

, :-? ; .,, < . . > .:-.., , .. : - < . ,.- f .:..7

! 6 ..... : .. ,. : . . .;. -: s ( ; . .,:. . ... .. .'

! . , .: . . . . . *

I - ; . : c ,.;:- , . ; !., ? : ~TH,~s.. . ' ,~AGE,.-:, , . . . .: . . , . . . . * . .' .. . . .

I

i I WAS .INTENTIONALLY . .,

I ! I LEFT BLANK i

No. 1 Hexafluoride Thermal P i l e

M e t a l l u r g i c a l Laboratory, Un ive r s i t y of Chicago

References: CN-362; U.S. P a t e n t 2,990,354.

O r i g i n a t o r s : H.L. Anderson and H.S. Brown.

S t a t u s : Proposa l , Novcrnber 1942; p a t e n t i s sued , 1961.

D e t a i l s : Thermal neut rons , s teady s t a t e , b r eede r , f o r p roduct ion of Pu. Fue l -

c o o l a n t - f e r t i l e m a t e r i a l : n a t u r a l o r enr iched U i n l i q u i d UF Moderator: 6 ' g r a p h i t e o r D 0 . Core arrangement: l i q u i d UF c i r c u l a t e s through tubes i n

2 6 moderator ma t r ix t o e x t e r n a l h e a t exchanger. I f moderator i s g r a p h i t e blocks,

tubes a r e of U l i n e d wi th N i o r o t h e r c o r r o s i o n - r e s i s t a n t meta l of low neutron-

abso rp t ion c r o s s s e c t i o n . I f moderator i s D 0, tubes a r e of U l i n e d wi th a l l o y s 2

of meta l s of low neut ron-absorp t ion c r o s s s e c t i o n , such a s N i , Be, o r Mg. With

D20, 223 tubes, 8 cm I D , i n c y l i n d r i c a l c o r e 3.31 m long, 3.6 m d iameter ; 1.082

reproduct ion f a c t o r . With g r a p h i t e , 1700 tubes , 4 cm I D , 8.30 cm long. Bred

Pu can be recyc led a s f u e l o r s epa ra t ed chemica l ly . Control : Cd o r boron

s t e e l rods . Power : probably more than 100 MW( t ) . Breeding- r a t i o : 1.029.

Code: 0312 - 12 31110 4 1 612 732 81x11 941 104

14 4 2 733 81x12

NO. 2 ' Uranium Hexaf luor ide Thermal P i l e

M e t a l l u r g i c a l Laboratory, Un ive r s i t y of Chicago

References: CN-362; U.S. P a t e n t 2,990,354.

Or ig ina to r s : H.L. Anderson and H.S. Brown.

S t a t u s : Proposa l , November 1942; p a t e n t i s sued , 1961.

D e t a i l s : Va r i an t of concept i n Data Shee t No. 1. C e n t r a l p o r t i o n of g r a p h i t e

ma t r ix c o n t a i n s U rods cooled by helium, which pas se s through spaces between

rods . A t pe r iphe ry of ma t r ix , A l tubes c o n t a i n c i r c u l a t i n g l i q u i d UF63 which

pas se s t o e x t e r n a l h e a t exchanger. .Outer graphite-UF system a c t s a s r e f l e c t o r 6 t o U-rod s e c t i o n and a l s o s e r v e s a s breeding s e c t i o n , from which Pu can be

e x t r a c t e d .

Code: 0312 - 12 31110 4 1 612 732 81x11 941 109

31716 42 7 3 3 81x12

No. 3 Uranium Hexafluoride Thermal P i l e

M e t a l l u r g i c a l Laboratory, Univers i ty of Chicago

References: CN-362; U.S. Pa ten t 2,990,354.

Or ig ina to r s : H.L. Anderson and H.S. Brown.

S t a t u s : Proposa l , November 1942; pa t en t i s sued , 1961.

D e t a i l s : Var ian t of concept i n Data Sheet No. 1. Graphite mat r ix has c e n t r a l

s p h e r i c a l vo id f i l l e d wi th D 0. A 1 o r U tubes imbedded i n g r a p h i t e pass 2

through D20. UF c i r c u l a t e s through tubes . 6

C n d ~ : 0?17 I ? ?1.1.1.Q 41 612 732 81x11 Y4L LUY

14 42 733 81x12

No. 4 Liquid Hexafluoride P i l e

M e t a l l u r g i c a l Laboratory, Un ive r s i t y of Chicago

Reference: Unpublished r e p o r t , 1943.

Or ig ina to r s : S t a f f members.

S t a t u s : Prel iminary proposa l , 1943.

D e t a i l s : Thermal neut rons , s t eady s t a t e , burner . Fuel-coolant : l i q u i d UF 6"

Modera tor - re f lec tor : g r a p h i t e . Fue l c i r c u l a t e s through 170 A 1 tubes surrounded

by g r a p h i t e t o e x t e r n a l hea t exchanger. Secondary coolant : H2O0 Moderator

would probably have t o be cooled by s u b s i d i a r y water cyc le . F r a c t i o n of f u e l

cont inuous ly withdrawn and put through evapora tor f o r removing f i s s i o n products .

Core r e q u i r e s 1 5 tons of UF and 25 tons of g raph i t e . Fuel temperature i n core: 6

1 9 4 ' ~ ; temperature r i s e i n c e n t e r tube: 108'F, Power: 390 MM(t).

Code: 0313 - 12 31110 44 612 7'11 8XXXX 921 104

No. 5 Proposed Hanford Circulated-Hexafluoride Thermal P i l e

Me ta l lu rg i ca l Laboratory, Univers i ty of Chicago

Reference: Unpublished r e p o r t , 1943.

Or ig ina to r s : S t a f f members.

S t a t u s : Proposal , 1943.

De ta i l s : Thermal neut roas , s teady s t a t e , breeder . Fuel-coolant - f e r t i l e

ma te r i a l : n a t u r a l U i n l i q u i d UF6, which c i r c u l a t e s t o e x t e r n a l hea t ex-

changer. ~u~~~ bred from u~~~~ Moderator: D20. Reactor: v e r t i c a l cy l inde r .

Fuel c i r c u l a t e s through core i n tubes of A l , Be, Mg, o r U. Tubes immersed i n

25 tons of D 0 surrounded by g raph i t e r e f l e c t o r . UF e n t e r s a t 176OF and 2 6

leaves a t 248OF. Operating pressure : 250 p s i a , Power: 390 MW(t).

Code: 0312 14 31110 41 612 732 8XXXX 921 104

No. 6 u~~~ Hexafluoride Breeder

Me ta l lu rg i ca l Laboratory, Univers i ty of Chicago

Reference: Unpublished r e p o r t , 1944.

Or ig ina to r s : S t a f f members.

S t a tus : Proposa l , 1944.

De ta i l s : Thermal neut rons , s teady s t a t e , breeder . Fuel-coolant-moderator:

u~~~ i n UF6 d isso lved in f luorocarbon; c i r c u l a t e s t o e x t e r n a l hea t exchanger.

F e r t i l e ma te r i a l : Th r e f l ec to r -b reed ing b lanket . Fuel c i r c u l a t e s through

tubes i n c y l i n d r i c a l r e a c t o r . Temperature r i s e , f u e l i n l e t t o o u t l e t : 90°F.

Power: 100 t o 200 MW(t).

Code: 0312 - 18 31209 45 622 7x6 8XXXX 931 101

No. 7 Hex P-9 P i l e (UF6-D20 P i l e )

M e t a l l u r g i c a l Laboratory, Univers i ty of Chicago

References: CE-1150; CE-1074; U.S. Pa ten t 2,990,354, June 27, 1961.

Or ig ina to r : H.L. Anderson.

S t a t u s : Pre l iminary des ign , 1944.

D e t a i l s : Thermal neut rons , s teady s t a t e , burner o r breeder . Fuel-coolant :

686 tons l i q u i d UF6 (465 tons U). U, probably h ighly enr iched i n u~~~ f o r

bu rne r , probably n a t u r a l f o r breeder . Bred Pu could be recyc led a s f u e l . u2 3 8

Moderator: 63 t o n s D20. F e r t i l e ma te r i a l : i n UF6. Core arrangement:

f u e l c i r c u l a t e d by thermal syphon i n t o r e a c t o r a t bottom, through p ipes i n

c o r e , and out a t - t o p t o e x t e r n a l hea t exchanger. Cold f l u i d r e tu rned t o

bottom of core. Maximum temperature: 150°C, t o avoid need f o r h igh p re s su re

t o keep UF6 l i q u i d ; minimum temperature: 75OC, t o prevent s o l i d i f i c a t i o n .

P re s su re : 150 p s i , t o prevent vapor i za t ion . Control: c o n t r o l rod and s a f e t y

rod of Cd o r boron s t e e l ; h igh r a t e of change of dens i ty and high temperature

c o e f f i c i e n t of expansion of UF Power: 600 W ( t ) . S p e c i f i c power: 1300- 6 '

1600 kw/ton UF6 a t AT of 75-130°C; 550-650 kw/ton UF6 a t AT of 75-105 '~ .

Code: 0312 14 31110 41 612 7 1 1 81x11 9XX 104

03 13 44 732 81x12

46 84689

No. 8 Homogeneous, C i r c u l a t i n g Liquid UF Fueled P i l e 6

Cl in ton L a b o r a t o r i e ~

Reference: MonN-336.

Or ig ina to r s : S t a f f members.

S t a t u s : Pre l iminary proposa l , 1947.

D e t a i l s : Thermal neut rons , s teady s t a t e , could be used f o r power product ion,

breeding , o r producing h igh f lux . Fuel-coolant -moderator: u~~~ i n l i q u i d UF 6 d i s so lved i n e i t h e r l i q u i d f luorocarbon o r DF. F e r t i l e ma te r i a l : ThF4. Fuel

s o l u t i o n c i r c u l a t e s f o r cont inuous removal of f i s s i o n products and f o r hea t

exchange. Reactor would ope ra t e a t 100°C and, w i th DF moderator, 15 atm. Con-

tainment m a t e r i a l would probably be N i r a t h e r than A 1 o r Mg, d e s p i t e t h e l o s s

i n breeding gain.

Code: 0311 17 31203 44 622 7x6 8XXXX 9X.X 101

0312 18 31213

No. 9 ' C i r c u l a t ing Liquid UF P i l e 6-

- Clin ton Labora tor ies

Reference: MonN-336.

Or ig ina to r s : S t a f f members.

S t a tus : Prel iminary concept , 1947.

De ta i l s : Thermal neut rons , s teady s t a t e , could be used f o r power product ion,

breeding, o r product ion of h igh f lux . Fuel-coolant : u~~~ i n l i q u i d UF 6 ;

could c i r c u l a t e t o e x t e r n a l hea t exchanger. Moderator: Be. Re f l ec to r -

breeding blanket : ThF a s f i n e powder i n Be cy l inde r s i n g r a p h i t e bed. Con- 4

tainment ma te r i a l s : Be, A l , o r Mg. Pressure: 4 atm. S p e c i f i c power: about

1 kW/kg UF6.

Code: 0311 15 31110 44 612 776 8XXXX 941 104 .

0312

No. 10 Gaseous UF Fueled, Gas Cooled Power P i l e 6 Cl in ton Labora to r i e s

Reference: MonN-336.

Or ig ina to r s : S t a f f members.

S t a t u s : Pre l iminary des ign , 1947.

D e t a i l s : Thermal neut rons , s teady s t a t e , could be used f o r power product ion ,

breeding , o r product ion of h igh f lux . Fuel: u~~~ o r U235 i n gaseous UF 6'

coolan t : helium. Moderator: g raph i t e . Ref l ec to r -b reed ing blanket : f i n e

powder of ThFk i n Be c y l i n d e r s i n g raph i t e bed. Bred f u e l removed by slow :.- l e ach ing ou t of PaF and UF' by slow c i r c u l a t i o n of F through the bed. Core

6 6 2 s t r u c t u r e : c y l i n d e r , 99 cm rad ius and 192 cm high. Fuel vo l : 5900 l i t e r s ,

w i t h 15 .8 kg u * ~ ~ . Fuel conta ined i n porous Be f u e l tubes , 1 cm diam., pro-

v i d i n g 75% voids ; each porous element core enclosed i n s o l i d Be s h e l l , 1.1 mm

t h i c k , which c l o s e s pores on ou t s ide . T o t a l f u e l tubes: 5151; each con ta in

3.07 g u ~ ~ ~ . Graphi te moderator e i t h e r of rods a t t h e c e n t e r of t r i a n g u l a r

l a t t i c e of f u e l tubes o r annular tubes around them. Helium c i r c u l a t e s through

vo ids i n core w i t h AT of 750°F and an o u t l e t temperature of 1250°F. Reactor

designed t o ope ra t e a t 800°C and 10 atm. Since f i s s i o n products become t rapped

i n fuel-element po res , they a r e removed from UF without chemical process ing , 6 Control : rods. Breeding r a t i o ; s l i g h t l y l e s s than 1 wi th u ~ ~ ~ , s l i g h t l y more

w i t h u ~ ~ ~ . . S p e c i f i c power: 6000 k ~ / k p u ~ ~ ~ . Power: 96 MW(t).

Code: 0311 - 12 31716 44 662 776 81XlX 941 106

0312 4 5

No. 11 ,Gaseous UF Fueled, Gas Cooled Power P i l e 6

Cl in ton Labora tor ies

Reference: MonN-336. . . . . .

Or ig ina to r s : S t a f f members.

S t a tus : Prel iminary concept , 1947.

~ e t a i l s : Variant of concept' i n Data. Sheet .No.. 10. Gas f u e l c i r c u l a t e s . s lowly

through porous A 1 f u e l tubes (90% voids) o u t s i d e r e a c t o r f o r cont inuous f i s s i o n -

product removal t h a t makes poss ib l e b e t t e r neut ron economy. Fuel tubes have

l a r g e pores t h a t do not t r a p f i s s i o n products a s small pores i n Be t u b e . d o . Use

of A l , which al lows tubes t o be d iscarded r a t h e r than reprocessed , causes lower

power p o t e n t i a l from r e a c t o r . Pressure : 10 atm. S p e c i f i c power: 2500 k ~ / k g u23 5

Power: 50 MW(t). . .

Code: 031.1 12 31716 44 662 776 81XlX 941 106 ,

0312 4 5

.. .

No. 12 Water-cooled, High Flux, UF, 'Fueled P i l e u

Clin ton Labora to r i e s

Reference: MonN-336.

Or ig ina to r s : S t a f f members.

S t a t u s : Conceptual des ign , 1947.

De ta i l s : Thermal neut rons , s t eady s t a t e , could be used f o r power product ion ,

breeding, o r product ion uf lligh f lux . Fuel: U233 o r u~~~ a s U F Coolant: b -

H 2 0 Moderator: H 0 o r Be. Ref lec tor -breeding blanket : ThF i n b lanket 2 4

s i m i l a r t o t h a t i n t h e concept i n Data Sheet No. 10. Core s t r u c t u r e : 240

l i t e r s of f u e l , con ta in ing 3.25 kg IJ235, w i t h i n porous A 1 rods encased i n Be

tubes . Fuel elements mounted i n hexagonal p a t t e r n ; i n t e r s t i c e s f i l l e d wi th

s o l i d Be, l eav ing 3-mm annulus around each f u e l element f o r H20 flow a t 17

f t / s e c . Containment: Be, A l , or Mg. Temperature: 260°C. Pressure : 50 atm.

S p e c i f i c power: 10 kg u~~~~ Power 32 MW(t).

Code: 0311 13 31101 44 662 776 8XXXX 941 106

03 12 15 4 5

No,. 13 C i r c u l a t i n p Gaseous UF Fueled P i l e 6

Cl in ton Labora to r i e s

Reference: MonN-336.

Or ig ina to r s : S t a f f members.

S t a t u s : Pre l iminary des ign , 1947.

D e t a i l s : Thermal neut rons , s t eady s t a t e , could be used f o r power product ion,

breeding , o r product ion of h igh f l u x . Fuel-coolant : u~~~ i n gaseous UF 6 ' Moderator: Be. Ref lec tor -breeding b lanket : ThF i n b lanket s i m i l a r t o t h a t 4 i n concept i n Data Sheet No. 10. Core s t r u c t u r e : Be c y l i n d e r wi th long i tud ina l

h o l e s through which f u e l c i r c u l a t e s . Containment: Be, A l , o r Mg. Pressure:

20 atm.

Code: 0311 1 5 31710 44 662 776 8XXXX 941 104

0312

No. 1 4 Homogeneous, C i r c u l a t i n g Gaseous UF Fueled P i l e 6

Cl in ton Labora to r i e s

Reference: Mod-336.

O r i g i n a t o r s : S t a f f members.

S t a t u s : Proposa l , 1947.

D e t a i l s : Thermal neut rons , s t eady s t a t e , could be used f o r power product ion ,

breeding , o r product ion of h igh f l u x . Fuel-coolant-moderator: u~~~ i n gaseous

UF mixed w i t h helium o r CF4 (moderating gas) . Ref lec tor -breeding b lanket : 6

ThF i n b lanket s i m i l a r t o t h a t i n t h e concept i n Data Sheet No. 10. Fuel 4

c i r c u l a t e s o u t s i d e r e a c t o r f o r removal of f i s s i o n products and hea t exchange.

Reactor v e s s e l : sphere , 17 m i n diameter . Pressure: 100 atm. Containment:

B e , A l , o r Mg.

Code: 0311 - 18 ' 31710 -44 662 776 8XXXX 941 101

0312 19

No. 15. Gaseous UF -Fueled Reactor 6

Reference: The Science and Enpineering of Nuclear Power, r, pp. 303-6.

Or ig ina tor : Clark Goodman.

S t a t u s : Proposal , 1947.

De ta i l s : Thermal neut rons , s t eady s t a t e , burner . Fuel-coolant-moderator:

enr iched UF wi th F added t o s t a b i l i z e molecular UF and t o a c t a s addi - 6 2 6

t i o n a l moderator. Gas e i t h e r c i r c u l a t e s t o e x t e r n a l hea t exchanger o r remains

w i t h i n r e a c t o r and i s cooled by a coo lan t , such a s l i q u i d meta l , pass ing

through c o i l s .

Code: 0313 1 X 31710 44 662 7 11 8XXXX 9XX 101

17 31106 105

No. 16. Di rec t Expansion UF -Fueled Reactor 6

UKAE A

References: B r i t i s h Pa ten t 799,575.

Or ig ina tor : P e t e r Fortescue.

S t a t u s : Conceptual design,. 1953; pa t en t i s sued , 1958.

De ta i l s : Thermal neut rons , s t eady s t a t e , burner o r b reede r , wi th d i r e c t expan-

s i o n of f u e l t o t u r b i n e . Fuel-coolant : u~~~ i n gaseous UF Moderator: Be 6 "

a s molten BeF Core s t r u c t u r e : moderator i n c y l i n d r i c a l N i c a l a n d r i a sub- 2 '

s t a n t i a l l y f i l l i n g Ni- l ined c y l i n d r i c a l p re s su re v e s s e l about 3 f e e t long.

Fuel fluws through c a l a n d r i a rubes. Heat produced by c r i t i c a l mass causes

f u e l t o expand d i r e c t l y t o t u r b i n e . Fuel t hen goes t o e x t e r n a l hea t exchanger

and is recyc led t o core . Pressure : 20 atm. Control : a s gas expands, r eac -

t i v i t y and h e a t decrease ; Cd absorbers can be included i n hea t exchangers t o

prevent c r i t i c a l i t y ou t s ide of core .

Code: 0312 15 31710 44 662 711 84699 9XX 104

03 13 81XX2

No. 17 Direc t Expansion UF -Fueled +Reactor 6

M e t a l l g e s e l l s c h a f t Ak t i engese l l s cha f t

References: United Kingdom Pa ten t 855,155; French ' ~ a t ' e n t 778,697; ~ e r m a n

Pa ten t 1,110,334.

Or ig ina t or : Hermann Clasen.

S t a t u s : Conceptual des ign , 1957; United Kingdom pa ten t i s sued , 1960. . .

D e t a i l s : Thermal o r f a s t neut rons , s t eady s t a t e , breeder o r burner wi th d i r e c t

expansion of f u e l t o t u r b i n e . Fuel-coolant : u~~~ or u~~~ i n gaseous UF 6'

Moderator: Be ; r e a c t o r core and t u r b i n e to be made of Be a s f a r a s ' pos s ib l e .

Re f l ec to r : g r a p h i t e around core and t u r b i n e . Fuel curltailled i n c o n i c a l co re ,

which se rves a s t u r b i n e housing. F i s s i o n of U, i n i t i a t e d by Ra-Be source ,

expands UF, d i r e c t l y t o r o t o r . Vapor is then r eco~~ ip res sed and recyc led t o V

core . I f breeding i s d e s i r e d , u ~ ~ ~ F ~ would surround tu rb ine . Pressure : 35

atm., h igh enough t o begin cha in r e a c t i o n . Containment: f o r thermal r e a c t o r ,

pure Be co re surrounded by s h i e l d i n g of Monel a l l o y , For f a s t r e a c t o r , core

and t u r b i n e of Ni-Cu a l l o y . Control : decrease i n p re s su re from expansion of

UF6.

Cod-e: 0112 1 5 31710 44 662 711 84699 921 104

0113 4 5 7x5

03 12

03 13

No. 1 8 UF -Fueled Reactor f o r Locomotive ~ r o ~ u l s i o n -6

Baldwin-Lima-Hamilton Corp. and,.benver & Rio Grande Western Rai lroad

References: Sovie t J. A t . Energy (Engl i sh T r a n s l . ) , 2, No. 5, p. 587 (1957);

Railway Age, 138, No. 14, p. 7; 141, No. 16, pp. 20-21.

O r i g i ~ ~ a t o l - s : S t a f f mcmbcro,

S t a t u s : Proposal , 1955.

D e t a i l s : Thermal neu t rons , pu lsed , burner . Fuel: u~~~ i n gaseous UF ' F u e l 6 '

conta ined i n two ends of c y l i n d e r having a p i s ton . Rec iproca t ing a c t i o n by

p i s t o n compresses gas i n each end a l t e r n a t e l y , caus ing c r i t i c a l i t y ; p i s t o n

pushed t o oppos i t e end of c y l i n d e r by expansion of f i s s i o n i n g f u e l . Each end

of c y l i n d e r surrounded by moderator and r e f l e c t o r .

Code: 0323 1 X 3XXXX 44 662 7 11 8XXXX 921 109

No. 19 Gaseous UF Reactor 6

I n s t i t u t e of Atomic Energy, Academy of Sc iences , USSR

References: Proc. 2nd U.N. I n t . Conf., 9 , pp. 528-534; AECL-1011.

Or ig ina to r s : I . K . Kikoin e t a l .

S t a tus : Experimental ope ra t ion , 1957.

De ta i l s : . Thermal neut rons , s teady s t a t e , burner . Fuel-coolant : 90%-enriched

U i n gaseous UF C1F could be added t o make UF s t a b l e under i r r a d i a t i o n . 6 ' 3 6

Moderator: Be'. Re f l ec to r : g r a p h i t e . Core s t r u c t u r e : f u e l . i n c y l i n d r i c a l

core wi th 148 square A 1 channels , 40 x 40 cm, i n square l a t t i c e under 1 . 3 atm.

Channels d iv ided i n t o s e c t i o n s connected t o main header coupled t o gas-pumping

system, al lowing simultaneous f i l l i n g of channels . T o t a l vo l : 3 1 4 . l i t e r s .

Graphi te r e f l e c t o r surrounding core i s 50 cm t h i c k on s i d e s and 60 cm on top

and bottom. C r i t i c a l i t y reached by h e a t i n g f u e l t o 80-90°C, t o cause a pro- . .

g r e s s i v e inc rease i n pressure . Containment: s ea l ed p r o t e c t i v e v e s s e l .

Asbestos i n space between r e f l e c t o r and t h i s v e s s e l t o prevent hea t l o s s .

Control: one h o r i z o n t a l and 4 v e r t i c a l channels f o r c o n t r o l and s a f e t y rods - -

s t e e l tubes f i l l e d wi th B C. Manual c o n t r o l : 2 t u b u l a r s t e e l rods f i l l e d 4

wi th B 4 C Power: about 1 . 5 kW(t).

Code: 0313 15 31110 44 662 7 11 81111 9 2 1 104

81211

No. 20 UF6 Gas Phase Reactor

Burns and Roe, Inc .

Reference: Nucleonics , l6, No. 8, pp. 128-133, IAug. 1958;.

Or ig ina to r : S Baron.

S t a t u s : Conceptual des ign , Aug. 1958.

D e t a i l s : Thermal neut rons , s t eady s t a t e , conve r t e r . F u e l - c o o l a n t - f e r t i l e

m a t e r i a l : 8%-enriched uranium i n gaseous UF wi th BrF added. Moderator: 6 3

g r a p h i t e . Re f l ec to r : g r a p h i t e . Core s t r u c t u r e : core diameter 7.5 f t ;

he igh t 25 f t . Fuel flows i n s i d e A 1 double-tube-wall channels ; in te rmedia te

coo lan t (helium) .in annulus between tube wa l l s and i n e x t e r n a l hea t exchanger.

Tubes s e t w i th in g r a p h i t e moderator blocks. Fue l , under 30 atm max. p re s su re ,

e n t e r s co re a t 450°F and l eaves a t 900°F. Fuel 'flows by n a t u r a l c i r c u l a t i o n ;

c o r e he ight of 25 f t necessary f o r maintenance of s u f f i c i e n t f u e l v e l o c i t y .

S ince f u e l i s 8% en r i ched , some Pu forms, bu t only a s i n c i d e n t a l product . .

Control : nega t ive temperature c o e f f i c i e n t . Power: 35 MW(e).

Code: 0311 12 31710 42 662 7x3 84699 9 2 1 104

No. 21 Gascous-Fuel Fas t Breeder Reactor

Worthington Corp.

Reference: Nucl. Power, 5, No. 47, pp. 125-126, March 1960. ,

O r i g i n a t o r s : F.G. Hamrnitt and David Aronson.

S t a t u s : Conceptual des ign , March 1960.

D e t a i l s : Fas t neut rons , s teady s t a t e , b reeder . Fuel: u~~~ i n gaseous UF 6'

Coolant: Na. Fuel and coolant flow through p a r a l l e l tubes made of N i a l l o y ,

such a s Inconel X. Containment: Inconel X. Radial breeding b lanket s u r -

rounds core . Control : nega t ive temperature c o e f f i c i e n t ; p re s su re of UF i n 6 t ubes c o n t r o l l e d . Power: 300 MW(t).

Code: 0112 11 31103 44 662 7XX 83699 9XX 109

84699

3 5

References

1. I . K . Kikoin, V.A. Dmitrievsky, Y.Y. Glazkov, I.S. Gr igor iev , B.G. Bubovsky,

and S.V. Kersnovsky, Experimental Reactor With Gaseous F i s s ionab le Sub-

s t ance (UF ), Proc. 2nd U.N. I n t . Conf. on Peaceful Uses of Atomic Energy, 6

9, pp. 528-534, United Nations, N . Y . , 1958.

2. D o Heymann and F.E..T. Ke l l i ng , Corrosion of Some Metals and Alloys i n

Uranium Hexafluoride, Corrosion Technol. , 5, pp. 148-151, 1958.

3. G. Langlo is , Corrosion of Me ta l l i c Ma te r i a l s by Uranium Hexafluoride a t

High ~ e m ~ e r a t u r e s , AEC-tr-6504, t r a n s . of CEA-2385, Serv ice d ' i t u d e de

Separa t ion des I so topes de llUranium, 1963.

4. J . A . Lane, Homogeneous Reactors and Thei r Development, i n F lu id Fuel

Reactors , J . A . Lane, H.G. MacPherson, and.Frank Maslan, e d s ? , p . 23,

Addison-Wesley Publ i sh ing Co., Inc . , Reading, Mass., 1958.

5. D.E. Hul l , Poss ib l e Appl ica t ions of UF i n P i l e s , MonN-336, Cl in ton 6

Labora to r i e s , Aug. 5 , 1947.

6. J .A . Wethington, Jr. , Research P e r t a i n i n g t o a Uranium (VI) F luo r ide -

Fluorocarbon Reactor . A Proposal t o t h e United S t a t e s Atomic Energy

Commission, Apr. 26, 1962.

7. H-L. Anderson and H.S. Brown, Liquid UF P l a n t f o r t h e Product ion of 6

Element 94, CN-362, Me ta l lu rg i ca l Laboratory, Un ive r s i t y of Chicago,

Nov. 27, 1942.

8. H.L. Anderson and H.S. Brown, Nuclear F i s s i o n Chain React ing System, U.S.

Pa ten t No. 2,990,354, June 27, 1961. F i l e d Mar. 24, 1945.

9 . Unpublished r e p o r t , MetalPurgical Laboratory, Un ive r s i t y of Chicago, 1943.

10. I b i d , 1944.

11. G.F. Quinn, Thermal Syphon f o r Hex P-9 P i l e , CE-1150, Me ta l lu rg i ca l

Laboratory, Un ive r s i t y of Chicago, Jan . 10, 1944. Decl . , Dec. 13, 1953.

12. C.F. Quinn, Thermal Syphon i n Homogeneous P i l e , CE-1074, Me ta l lu rg i ca l

Laboratory, Univers i ty of Chicago, Dec. 2 , 1943. Decl. , Dec. 13, 1955,

13. D.E. Hull and F.T. Miles , Pre l iminary Report on a Hex P i l e , MonN-240;

Cl in ton Labora to r i e s , Jan . 22, 1947.

14. Clark Goodman, Cons t ruc t ion of Nuclear Reactors , i n The Science and

Engineering of Nuclear Power, 1, Clark Goodman, e d . , Addison-Wesley

Publ i sh ing Co., Inc . , Reading, Mass., 2nd ed . , 1952 ( 1 s t ed . , 1947).

E.H. Kerner, letter, J. Appl. Phys., 24 , pp. 815-816, June 1953.

Peter Fortescue, Improvements In or Relating to Nuclear Power Plants,

United Kingdom Patent 799,575, Aug. 13, 1958. Filed Jan. 14, 1955,

application Oct. 17, 1953.

Hermann Clasen (Metallgesellschaft Aktiengesellschaft), .Improvements In

or Relating to Nuclear Reactors, United Kingdom Patent 855,155, Nov. 30,

1960. Filed Oct. 23, 1958, application Nov. 8, 1957.

Atomic Locomotives, Soviet J. At. Enerpy (English Transl.), . , 2, No. 5, p. 587, 1957

Ts Nuclear power Practicable?, Railway Age, 141, No. 16, pp. 20-21, Oct. 8,

1956.

Atomic Locomotive Study Authurized, Ibid., 138, No. 14, pa 7, Aprl.4, 1955.

Atomic Energy of Canada, Ltd., Survey of Soviet Reactors (Status According

to Published Reports up to September 15, 1958), AECL-1011. Translated

from ade ern& energie, 5, pp. 92-101, 1959.

S. Baron, Gaseous Fuel Reactor, Nucleonics, 16, No. 8, pp. 128-133, Aug. 1958.

F.GI Hammitt, A Gaseous-Fuel Fast Breeder Keactor, Nucl. Power, 5, No. 47, pp. 125-126, Mar. 1960.

Chapter 3 . .Reac to r s Fueled With Gases o r Plasmas,

Concepts i n t h i s chapter included those i n which t h e f u e l i s a nonionized

gas o r an ion ized gas (plasma) a t extremely high temperatures . Before oper-

a t i n g cond i t i ons a r e reached, t he f u e l may be a s o l i d o r l f q u i d . A concept

f o r such r e a c t o r s was descr ibed by Shepherd and Cleaver i n 1949.' The advan-

t age of a gaseous f u e l , i t s c a p a b i l i t y f o r a t t a i n i n g temperatures t oo high

f o r l i q u i d s o r s o l i d s , i s t h e b a s i s f o r t he suggested use of most of t h e s e

concepts f o r rocke t propulsion. I n rocke t propuls ion , t h e p rope l l an t gas would

a c t a s coolan t f o r t h e r e a c t o r . For i n t e r p l a n e t a r y f l i g h t s , t h e nuc lea r r eac -

t i o n would have t o r a i s e t he p rope l l an t temperature by r egene ra t ive hea t ing t o

about 10,OOOOR. The name "cav i ty r e a c t o r " was suggested by ~ a f o n o v * f o r those

r e a c t o r s i n which a core of uniformly d i s t r i b u t e d gaseous f u e l is surrounded

by a modera to r - r e f l ec to r of uniform dens i ty . They were s o named because t h e

f l u x d i s t r i b u t i o n s of d i l u t e f u e l s approach t h e f l a t d i s t r i b u t i o n of an empty

c a v i t y and because of t h e gaseous f u e l i s a t near-vacuum a s i t i s used i n t h e

system.

General

Iii:..the s imp les t kind of a c a v i t y r e a c t o r , t h e f u e l and coolant a r e fed

s e p a r a t e l y i n t o t h e core r eg ion , where they mix i n t i m a t e l y , and a r e expe l l ed

from the core . Separa t ion i s done e x t e r n a l l y . Because c o s t and weight must

be minimized i n a rocke t system, t h e f i s s i o n a b l e m a t e r i a l must be sepa ra t ed

from t h e coo lan t and conserved; y e t , t h e coo lan t , which is a l s o t h e rocket

p r o p e l l a n t , must be a b l e t o p ick up energy e f f i c i e n t l y from t h e f u e l f o r t h e

sysLem as a whole t o ope ra t e e f f e c t i v e l y . For t h i s reason , s e v e r a l s o p h i s t i -

c a t e d methods of achiev ing fue l - coo lan t s e p a r a t i o n have been cons idered . I n

some, t h e two f l u i d s a r e s epa ra t ed a f t e r mixing; i n o t h e r s , they a r e kept

s epa ra t ed i n t h e core.

Conf igura t ions t o keep t h e f u e l and coolant s epa ra t ed whi le they both a r e

i n t h e core reg ion inc lude (1) c o a x i a l flow, ( 2 ) magnetohydrodynamic means,

a11J ( 3 ) magnetic f i e l d s . 'I'hese methods of s e p a r a t i o n a r e d iscussed under t h e

concepts taken up i n t h i s chap te r .

I n many concepts , t h e f u e l i s a plasma, which r a i s e s problems of con ta in -

ment.

There a r e two ways of r e s t r i c t i n g t h e i n t e r a c t i o n between high-temperature

gases and ad jacent s o l i d ma te r i a l s : (1) l i m i t t h e i n t e r a c t i o n i n t ime; o r (2)

l i m i t t he i n t e r a c t i o n i n space by e l i m i n a t i n g a l l s o l i d m a t e r i a l i n . t h e v i c i n i t y

of t h e hot gas and r e p l a c i n g it w i t h an e lec t romagnet ic f i e l d .

el son^ has suggested t h a t , d e s p i t e t hese problems, plasmas should be

cons idered because of t h e i r advantages. A plasma can be confined e l e c t r o -

magne t i ca l ly , s e p a r a t i n g i t from t h e surrounding s o l i d ma te r i a l s with'.which

i t would o therwise r e a c t ; it can be a c c e l e r a t e d by e lec t romagnet ic means t o

g r e a t e r supe r son ic v e l o c i t i e s than a r e ob ta inab le wi th a nonionized gas ac-

c e l e r a t e d by means of f l u i d j e t s ; and i t can be sepa ra t ed from t h e nonionized

p r o p e l l a n t . The s i m p l i c i t y of t h e system r e l i e s on t h e f a c t t h a t t h e ion ized

f u e l i s confined by a f i e l d b a r r i e r , whereas t he r ~ o ~ l i o n i z e d hydrogen propel -

l a n t d i f f u s e s through t h e f i e l d . L imi t a t ions on t h e p r i n c i p a l system v a r i a b l e s 3

i n p lasma systems a r e g iven i n Table 1.

Table 1. L imi t a t ions on P r i n c i p a l System Var iab les

Var i ab le Lower Limit Upper LimiL

S i z e

Temperature

C r i t i c a l i t y W t of modera to r - r e f l ec to r Excessive f u e l inventory Excessive magnetic f i e l d

v o l Fab r i ca t ion d i f f i c u l t i e s

Fuel i o n i z a t ion temperature Radia t ive hea t t r a n s f e r t o wa l l s

P rope l l an t i o n i z a t i o n

Magnetic f i e l d Plasma confinement E l e c t r i c power r e q u i r e - s Lrel1g~11 Coot of maximum t o l e r a b l ~ ment s

f u e l 1033 by d i f f u s i o n Coil w t .

E l e c t r i c a l f i e l d Rota t ion of plasma t o o Supersonic-flow problems s t r e n g t h slow; thus i n s t a b i l i t y and Excessive vo l t age drop

i n t o l e r a b l e a x i a l d i f f u s i o n s ac ros s plasma /

P r o p e l l a n t flow r a t e Flow channel ac ros s s e c t i o n Excessive p re s su re excess ive (moderator t o o Helmholtz waves (propel- heavy) l a n t &wept through

nozzle)

Plasma r o t a t i o n a l Plasma i n s t a b i l i t y (maximum Shock waves and boundary- v e l o c i t y (homopolar permiss ib le propellant l aye r tu rbulence conf igu ra t ion ) * f low r a t e t oo slow) Ro ta t iona l k i n e t i c energy

Approaches d i f f u s i o n proper- wasted i n sp inning t i e s of s imple magnetic + , prope l l an t b o t t l e

Nelson suggested conf in ing plasma by e i t h e r a simple magnetic b o t t l e wi th

mi r ro r s a t each end o r a homopolar device , which provides more r e a c t o r c o n t r o l .

* ~ i s s i o n i n g p l a s m a ' r o t a t e s by be ing e l ec t romagne t i ca l ly pumped by c ros sed e l e c t r i c and magnetic f i e l d s . Cen t r i fuga l fo rce a s s o c i a t e d wi th t h e ro t a t iom tends t o keep t h e plasma away from regions where leakage would most l i k e l y occur .

I n r e a c t o r s such a s t h e vo r t ex r e a c t o r s , i n which t h e p rope l l an t and f u e l

mix i n t i m a t e l y , t h e cool ing mechanism i s e i t h e r r egene ra t ive hea t ing o r t h e

d i r e c t hea t ing of t h e gaseous p rope l l an t by t h e slowing down of f i s s i o n f r a g -

ments. I n systems'where t h e f u e l and p rope l l an t do not mix , - such a s i n t h e

magnetic containment of ion ized f u e l o r coax ia l flow, hea t t r a n s f e r from t h e

f u e l t o t h e p rope l l an t i s p r i n c i p a l l y by thermal r a d i a t i o n .

I n those systems i n which the primary ene rgy - t r ans fe r mechanism is thermal

r a d i a t i o n , t h e r a d i a t i o n must be a t t enua ted by t h e p rope l l an t gas before i t can

reach the c a v i t y wa l l s . Also, a t c e r t a i n tempera tures , t h e gases become t r a n s -

parent t o r a d i a t i o n . Hydrogen gas i s t r a n s p a r e n t between 5000°R and 12,000°R.

Graphi te dus t can be used t o "seed1' hydrogen f o r r a d i a t i o n absorp t ion but i t

sublimes a t 6800°R.

Concepts

I n Shepherd and Cleaver ' s 1949 concept f o r rocke t propuls ion , t h e f u e l

and- coolan t a r e f ed i n t o a core a r e a formed by t h e modera to r - r e f l ec to r . Here

they mix and the c r i t i c a l mass i s reached. The propel lan t -coolant must be

hea ted t o 3000-5000°K. The f u e l m a t e r i a l and moderator m a t e r i a l a r e not s p e c i -

f i e d , but t h e o r i g i n a l form of f u e l might be a powder, a l i q u i d suspension of a

powder, a wi re (extruded i n t o t h e chamber) o r a l i q u i d compound of f i s s i l e

m a t e r i a l . The coolant could b,e hydrogen,deuterium, helium, ammonia, o r steam. '

Control might be poss ib l e by vary ing t h e amount of f u e l f ed t o core. A s p e c i f i c

power of 100 MW per me t r i c t on was sought. 2

I n 1955 Safonov advanced a design f o r a c a v i t y r e a c t o r , w i th d i f f e r e n t

arrangements t o f i t d i f f e r e n t purposes. The gaseous f u e l , of low d e n s i t y a t

t he high ope ra t ing temperature o f t h e r e a c t o r , could be u~~~ o r U235, a s w e l l

a s plutonium. The f u e l is i n a reg ion surrounded by a modera to r - r e f l ec to r of

heavy water , bery l l ium, o r g raph i t e . This modera to r - r e f l ec to r reg ion could

con ta in f e r t i l e ma te r i a l f o r breeding and a thermal-absorbing m a t e r i a l f o r

c o n t r o l . The coo lan t , an unspec i f i ed gas , i s pumped around o r through t h e

f u e l . An inhe ren t s a f e t y f a c t o r i s s t a t e d t o be t h e prompt neut ron regenera-

t i o n t ime, which is a s long o r longer than t h a t f o r s o l i d - f u e l thermal r e a c t o r s .

The h igh neutron f l u x produced might make t h e r e a c t o r s u i t a b l e f o r eng inee r ing

t e s t i n g . Other modi f ica t ions a re : a gas- o r a i r - c o o l e d power r e a c t o r ; z i r -

conium tubes ca r ry ing l i qu id -me ta l coolant i n t h e c e n t e r and f i s s i l e m a t e r i a l

a t o r near t h e o u t e r s u r f a c e s ; l i q u i d metal t o c a r r y t h e f i s s i l e mater ia l ; o r

uranium hexaf luor ide f u e l . The gas- o r a i r - coo led and t h e UF - fue l ed r e a c t o r s 6

could be used t o ope ra t e a t u r b i n e ; t h e UF - fue l ed r e a c t o r would ope ra t e by 6

d i r e c t expansion. I n a l l , t h e f u e l would be gaseous i n r e a c t o r ope ra t ion .

The d i r e c t conversion of mechanical energy produced i n a pu ls ing plasma

t o e l e c t r i c a l energy i s proposed . in a 1957 concept by Colgate and Aamodt. 4

The gaseous f u e l , plutonium o r uranium, is p a r t i a l l y ion ized a t t h e tempera-

t u r e of ope ra t ion . A magnetic f i e l d compresses t h e gas a t one end of a

c y l i n d r i c a l g r a p h i t e f u e l con ta ine r , which i s blanketed by heavy water ( the

coo lan t -modera to r - r e f l ec to r ) . The b lanket i s contained i n aluminum o r z i r -

conium. As t he gas is compressed, c r i t i c a l i t y occurs t o r e l e a s e f i s s i o n

energy , which d r i v e s t h e gas t o t h e o t h e r end of t h e con ta ine r . Here it i s

aga in compressed and d r i v e n back by t h e f i s s i o n energy. The o s c i l l a t i o n of

t he gas between t h e two ends causes t he po r t ion of t h e gas d i r e c t l y behind

t h e shock f r o n t t o become h ighly ion lzed . AS rhis p l a s~na , acLillg as a c o n -

d u c t o r , moves through t h e magnetic f i e l d it induces an e l e c t r i c a l cu r r en t i n

an e x t e r n a l e l e c t r i c a l c i r c u i t . The power is 500 MW(e).

A high-temperature (15,000°K) r e a c t o r wi th e lec t romagnet ic confinement 233 235

of f u e l was descr ibed by Taylor i n 1957. The f u e l , a plasma of U , U , o r Pu239, i s i n a core surrounded by t h e modera to r - r e f l ec to r , heavy water o r

bery l l ium. The c o o l a n t - p r o p e l l a n t , hydrogen, passes through t h e co re , where

i t ga ins energy, and leaves t h e r e a c t o r . The f u e l i s r e t a i n e d i n t he core by

e x t e r n a l l y app l i ed e lec t romagnet ic f i e l d s , which do not r e t a i n t h e nonionized

p r o p e l l a n t .

A pre l iminary des ign f o r a r e a c t o r ul: high power, c a l l e d a "fizzier",

was publ i shed by Bussard and Uelauer i n 1 9 5 8 . ~ D r ~ i g ~ i r d t o producc 5000 MJ(t), Fuel (,,233, $35

t h i s r e a c t o r was intended f o r rocke t propuls ion . , o r

and coolant ( rocke t p r o p e l l a n t ) mix i n a core reg ion formed by t h e unspec i f i ed

modera to r - r e f l ec to r . Here c r i t i c a l i t y h e a t s t h e f u e l t o above i t s vapor iza-

t i o n temperature. The au thors conclude thae ar rhe operaLiu8 p ~ e s s ~ t r e can-

s i d e r e d reasonable (1000 p s i ) , g r e a t l y excess ive amounts of f u e l would be l o s t .

Two 1959 concepts by re^^ were f o r rocke t propuls ion; few d e t a i l s were

givcn. I n one, t h e "fizzier" r e a c t o r , t h e f u e l i s mixed i n a s o l i d w i th t h e

p r o p e l l a n t , which i s a l s o the moderator. Removal of a po r t ion of a cadmium

c o n t r o l rod causes c r i t i c a l i t y , which vapor izes t h e f u e l . The o t h e r concept

i s f o r a s e r i e s of s u b c r i t i c a l s o l i d - f u e l e d r e a c t o r s . They a r e made tempo:-

r a r i l y h igh ly s u p e r c r i t i c a l when p rope l l an t gas con ta in ing f i s s i l e m a t e r i a l i s

passed through them. The gas i nc reases i n temperature as it passes through

t h e s e r i e s of r e a c t o r s u n t i l i t comes out of t h e nozzle a t a very h igh tempera-

t u r e .

Meghreblian descr ibed two c a v i t y r e a c t o r s of s i m i l a r design t h a t were

in tended f o r rocke t propuls ion . I n both , two f u e l zones were used, one of .

s o l i d f u e l and one of gaseous. I n a c e n t r a l moderator mat r ix con ta ins

t h e gaseous f u e l and i s surrounded by a s o l i d f u e l zone. I n t h e o the r ,1° t h e

s o l i d i s i n t h e c e n t r a l po r t ion and t h e gaseous f u e l i n t h e moderator mat r ix

surrounds i t . A re f lec tor -mudera tor surrounds t h e core i n both . The c o o l a n t ,

which is the rocket p r o p e l l a n t , passes i n t o t h e co re , and p icks up h e a t , f i r s t

from t h e s o l i d - f u e l reg ion and then from t h e gaseous f u e l . No d e t a i l s of

m a t e r i a l s were s p e c i f i e d .

The concept f o r a vo r t ex r e a c t o r , 11-17. proposed by Kerrebrock and .

~ e ~ h r e b l . i a n , ~ ~ ' ~ * emphasized t h e s e p a r a t i o n of f u e l and p r o p e l l a n t , a f t e r

mixing, by t h e formation of a vo r t ex . The f u e l (gaseous uranium, plutonium,

o r t h e i r compounds, i n hydrogen) is contained a s a j e t - d r i v e n vo r t ex i n many

long t h i n tubes imbedded i n moderator m a t e r i a l (bery l l ium oxide o r g r a p h i t e ) .

Af t e r t he f u e l and coolant mix, t h e mixture s p i r a l s i n t o the c e n t e r of co re ,

i s drawn o f f a x i a l l y , and i s discharged. Be'cause of t h e r a d i a l p re s su re

g rad ien t w i t h i n the vo r t ex , t h e heav ie r f u e l molecules would be conta ined i n a

s t e a d y - s t a t e concen t r a t ion d i s t r i b u t i o n i n t he vo r t ex , while t h e l i g h t e r pro-

p e l l a n t gas would d i f f u s e through i t . I6 A core temperature of 10,OOOOR and a

power of 500 MM(t) were sought. I n a d d i t i o n t o t h e method descr ibed f o r a t -

t a i n i n g a v o r t e x , magnetic f i e l d s , magnetic m i r r o r s , o r magnetohydrodynamics

( e x t e r n a l l y imposed e l e c t r i c a l and magnetic f i e l d s ) might be used.

Certain va r i ab l e s - - tube d iameter , mass flow r a t e per u n i t tube l eng th ,

j e t i n j e c t i o n v e l o c i t y , and wa l l p r e s s u r e - - a f f e c t vo r t ex s t r e n g t h . l5 The

s t r e n g t h inc reases a s tube diameter decreases and a s mass flow r a t e i n c r e a s e s ,

and i t inc reases w i t h subsonic r a t h e r than sLpersonic i n j e c t i o n . Because vo r -

t i c e s develop t u r b u l e n t i n s t a b i l i t i e s , p a r t i c u l a r l y a t t h e per iphery , s e v e r a l

eonfiguratFons. designed t o produce a laminar flow by s t a b i l i z i n g t h e shea r

boundary l a y e r on a concave wa l l have been cons idered . They a re : (1) b leed-

o f f of t h e boundary l a y e r through a uniformly porous w a l l , ( 2 ) i n j e c t i o n of

heavy gas uniformly through a porous w a l l , ( 3 ) wal l coo l ing , and ( 4 ) bleeding

o f f some of t h e t o t a l flow a x i a l l y a t r a d i a l p o s i t i o n s between t h e tube .cen ter

and the wa l l s.0 t h a t t h e e x i t r a d i a l flow i s he ld t o an al lowable r a t e , based

on d i f f u s i o n cons ide ra t ions (b led-of f flow would be r e c i r c u l a t e d ) . 1 5

Three v a r i a n t s have been explored i n somewhat more detai.1,.

One v 'ar iant i n c l u d e s ' a r o t a t i n g porous w a l l through which t h e p rope l l an t

i s introduced.15 Turbulence i s reduced because t h e boundary l a y e r on the o u t e r

wa l l i s e f f e c t i v e l y e l imina ted . However, t o produce s i g n i f i c a n t t h r u s t l e v e l s ,

many sma'll tubes would s t i l l be r equ i r ed because mass flow p e r u n i t of vo r t ex

tube l e n g t h remains l i m i t e d by the d i f f u s i o n process . There i s a severe

mechanical problem i n combining h igh temperature, high speed, and many tubes .

I n another v a r i a n t , excess mass flow, which has been j e t - i n j e c t e d i n t o

t h e system and which causes t h e vo r t ex i n s t a b i l i t i e s , i s bled o f f and r e c i r -

c u l a t e d . The heavy mass could be helium + C F o r Freon-12 (CCL F ) . 15

8 16 2 2 The t h i r d v a r i a n t 1 7 i s based on t h e same p r i n c i p l e a s t h e vo r t ex r e a c t o r

except t h a t , t o reduce turbulence and t o d i s s i p a t e i n s t a b i l i t i e s , s e v e r a l

v o r t i c e s a r e generated i n a s i n g l e con ta ine r i n square a r r a y , by means of f l u i d

i n j e c t i o n from tubes loca t ed i n t h e c o n t a i n e r . The i n j e c t i o n and e x i t p a t t e r n

i s designed s o t h a t ad j acen t v o r t i c e s r o l l on one another , producing zero shear

a t t h e i n t e r f a c e s . This e l imina te s a major soufce of InsLabl l iLy , turbulence

a t t h e per iphery of t h e v o r t i c e s t h a t a r e l oca t ed i n t h e i n t e r i o r of t he mat r ix .

Also, s i n c e wal l a r e a per vo r t ex decreases a s t h e number of v o r t l c e s Inc reases ,

t h e wa l l a r e a per vo r t ex approaches the a r e a of a s i n g l e i n j e c t i o n tube a s t he

number of v o r t i c e s becomes i n f i n i t e . This g r e a t l y reduces t h e momentum removed

from t h e system by t h e a c t i o n of shea r f o r c e s , which i s p ropor t iona l t o t he

w a l l a r e a involved.

I n t he Coaxial Flow Reactor of Weinstein and Ragsdale, 18'19 the f u e l ,

f u l l y ion ized gaseous and t h e hydrogen coolant a r e f ed i n t o t h e c o r e ,

which i s surrounded by a moderator of g r a p h i t e , heavy water , o r bo th . Here

c r i t i c a l i t y occurs . 'I'he f u e l i s fed i n t o t h e c e n t e r of t he co re , and t h e

hydrogen e n t e r s around the per iphery a t a flow r a t e d i f f e r e n t from t h a t of t h e

f u e l . Because of t h e d i f f e r i n g a x i a l v e l o c i t i e s , t he two streams do not mix.

They a r e exhausted from the core through a nozz le . The average r e a c t o r tempera-

t u r e i s about 10,OOOOR. Heat t r a n s f e r frvrll t he f u e l a t t h i s tcmperature i s

p r i m a r i l y by r a d i a t i o n . The thermal energy mu6C be atLenuaLer1 lsy tlie propellant

t o avoid overhea t ing t h e w a l l s (maxirnum temperature 5000°R). Because hydrclgen

i s t r a n s p a r e n t t o r a d i a t i o n between 5000' and 12,000°R, "seeding" wi th an ab-

s o r b e r i s necessary f o r r a d i a t i v e hea t t r a n s f e r . So l id p a r t i c l e s , such a s

g r a p h i t e d u s t , might be adequate up t o t h e subl imat ion po in t of g raph i t e (6800JR).

A r ecen t des ign by s t a f f members a t t h e Hanford Atomic Products Operation

i s f o r a system t o produce e l e c t r i c a l power by a magnetohydrodynamic genera tor

and a secondary hea t exchangermt0 Both would de r ive t h e i r power from a r e a c t o r

f u e l e d wi th f i s s i o n a b l e gas such a s uranium hexaf luor ide . The gas flows i n n

t o r o i d a l con ta ine r a t a d e n s i t y below t h a t of c r i t i c a l i t y , except i n t h e core

r eg ion . Here it i s compressed t o g ive c r i t i c a l i t y , and the gaseous f u e l i s

i on ized . The plasma flows through a magnetohydrodynamic channel , which consisLs

of r a i l s ca r ry ing c u r r e n t , and two l a r g e cryogenic magnets, which supply t h e

c ros s -cu r ren t f i e l d . The plasma s t ream provides an emf t o genera te c u r r e n t

flow between t h e r a i l s . The gas flows t o 'a t u r b i n e and then t o a hea t ex-

changer t o produce steam from t h e remaining usable hea t . A f t e r p u r i f i c a t i o n ,

t h e gas is r e tu rned t o t h e system.

S t a t u s

A b r i e f summary of a conference he ld a t t h e Los Alamos S c i e n t i f i c

Laboratory i n Apr i l 1964 i n d i c a t e s r ecen t work on some gas- and plasma-

fue l ed r e a c t o r s , a l though few d e t a i l s a r e given. 2 1

Ragsdale r epo r t ed f u r t h e r work on the coaxia l - f low r e a c t o r descr ibed

e a r l i e r i n t h i s chapter . Research was r epo r t ed i n hea t t r a n s f e r , hydro-

dynamics, and nuc leonics . Larger flow a r e a , p lus h igher p rope l l an t v e l o c i t y ,

i s thought t o g ive an economic r a t i o of p rope l l an t t o f u e l i n t h e exhaust

gas . The r a t i o would be about 50.

I n t h e "Glo-Plug" r e a c t o r , t h e gaseous f u e l i s conta ined wi th in a double-

wal led t r a n s p a r e n t tube. Hydrogen flowing between the wa l l s cools t h e tube.

Heat t r a n s f e r i s by r a d i a t i o n through the tubes and coo lan t . The p r o p e l l a n t ,

seeded wi th m a t e r i a l t o make i t absorbent ; absorbs t h e r a d i a t i o n . Quartz was. -. being considered a s - m a t e r i a l f o r t h e tubes .

Stumpf and Rosenweig, i n r e p o r t i n g experiments on v o r t i c e s , d i scussed

t h e p o s s i b i l i t y of combining vo r t ex containment wi th o t h e r methods. For

example, f u e l might be contained i n some c e l l s of a mat r ix of v o r t i c e s and

p rope l l an t could flow through o t h e r s .

i WAS ?IrN~ENT~O:.NIALLY i I I

LEFT BLANK 1 ! I I

DATA SHEET

REACTORS FUELED WITH GASES OR PLASMAS

LEFT BLANK

No. 1 Gaseous Reactor f o r Rocket Propulsion

Reference: J. B r i t . I n t e r p l a n e t . - Soc. , 8, No. 1, pp. 23-37, ::Jan. 1949'.-, .,

' O r i g i n a t o r s : L.R. Shepherd and A.V. Cleaver .

S t a t u s : Pre l iminary concepts , 1949. . . . .

Deta i l s : Thermal neut rons , s teady s t a t e , burner , f o r rocke t -propulsion.

Fuel : m a t e r i a l ~ i o t s p e c i f i e d , but could be i n i n i t i a l form of': (1) powder;

(2) powder suspension i n l i q u i d ; ( 3 ) , w i r e extruded i n t o chamber; o r (4) l i q u i d

compound of f i s s i l e m a t e r i a l . Authors favor t he l a s t . Fuel would vapor ize a t

r e a c t o r ope ra t ing temperatures . Coolant: H o r D2; helium; ammonia, e i t h e r 1 C 2 -

NH o r N ~ ' D o r steam, e i t h e r H 0 o r D 0. Modera tor - re f lec tor : ex t ' e rna l , 3 3 ; 2 2

m a t e r i a l unspec i f ied . Fuel and coolant each f ed i n t o core a r e a formed by

modera to r - r e f l ec to r , where they mix i n t i m a t e l y and where: c r i t i c a 1 , m a s s is

formed. React ion must hea t coo lan t , which i s rocke t p r o p e l l a n t , t o 3000-

500O0K: Heated coolant i s exhausted through nozz le , Control: vary ing amount

of f u e l f ed i n t o t h e core. s p e c i f i c power: lOO.MW/metric ton.

Code: 0313 1 X 31701 4X 66X 711 83799 - 921 107

31702

No. 2 Cavity Reactor

Rand Corporat ion

Reference: RM-1520.

Or ig ina to r : George Safonov. . .

S t a t u s : Pre l iminary concept , 1955.

D e t a i l s : Thermal, poss ib ly ep i thermal neut rons , s t eady s t a t e , burner o r breeder .

Fue l : u~~~ o r u~~~ poss ib ly i n UF puZ3'. Coolant: unspec i f i ed gas . Moderator- 6 ;

r e f l e c t o r : . D 0 , Be, o r g r a p h i t e . F e r t i l e m a t e r i a l could be contained i n 2

modera to r - r e f l ec to r without a f f e c t i n g c r i t i c a l i t y of core reg ion . Core s t r u c -

t u r e : low-densi ty f u e l conta ined i n reg ion surrounded by modera to r - r e f l ec to r .

Coolant pumped through o r around f u e l . Fuel dens i ty (presumably a t ope ra t ing

c o n d i t i q n s ) between 0.05 and 0.10 l b / c u f t - - l e s s than molecular d e n s i t y of

gases under s t anda rd condi r foas . ConLrul: Ll~erulal-absorbing m a t c r i a l i n

modera to r - r e f l ec to r . Inhe ren t s a f e t y f a c t o r i s t h e prompt neut ron r egene ra t ion

t ime, which i s as long as o r longer than t h a t i n s o l i d - t u c l thermal r e a c t o r s . A

6 - f t diameter core i n Be o r g r a p h i t e would r e q u i r e 12-14 kg u~~~ f o r c r i t i c a l i t y ;

t h e same s i z e i n D O would r e q u i r e 2 kg u ~ ~ ~ . S n ~ a l l e r amounts of ~u~~~ o r U 233

2 would be r equ i r ed . I f neut rons i n t h e ep i thermal range were used, sma l l e r core

might be poss ib l e . The h igh neutron f l u x t h a t would be produced might make t h e

r e a c t o r s u i t a b l e f o r use i n engineer ing t e s t i n g . Author sugges ts t h e fol1,owing

p o s s i b i l i t i e s f o r r e a c t o r ~ d n f i ~ u r a t i o n s , w i th i n i t i a l form of f u e l ( i n opera-

t i o n , t h e f u e l would be gaseous):

1. Gas- o r a i r - coo led r e a c t o r ope ra t ing a t " r e spec t ab le s p e c i f i c power",

perhaps on a once-through b a s i s f o r running a gas t u r b i n e .

Code: 0312 12 31714 44 662 7XX 81XX8 9 2 1 1 0 7

0313 14 31719 4 5 66X 941 0212 15 46 02 13

2. Zirconium tubes c a r r y i n g f i s s i l e m a t e r i a l on o r near t h e i r o u t e r s u r f a c e s .

Liquid-metal coolan t would run through t h e c e n t e r of t he tube .

Code: 0312 12 31106 44 66X 7XX 81XX8 921 107 03 13 14 4 5 9 41 0212 15 46 0213

3 . F i s s i l e m a t e r i a l c a r r i e d by a c i r c u l a t i n g l i q u i d metal . T h i s would have

s e l f - s t a b i l i z i n g f e a t u r e s of l i qu id -me ta l f u e l . Code: 0312 12 31106 44 66X 7XX 81XX8 921 107

0313 14 4 5 84689" 941 0212 15 4 6 0213

2 3 5 ~ which could expand d i r e c t l y f q r running a t u r b i n e or 4. Fuel might be U 6 ,

a r e c i p r o c a t i n g engine.

Code: 0312 12 31710 44 662 7XX 81XX8 921 107 03 13 14 9 41 02 12 15

No. 3 Fission-Plasma Reactor

Radiat ion Laboratory, Un ive r s i t y of C a l i f o r n i a , Livermore, and LASL

Reference: Nucleonics, l5, No. 8 , pp. 50-55, :Aug. 1957;

Or ig ina to r s : S.A. Colgate and R.L. Aamodt . S t a t u s : Pre l iminary concept , Aug. 1957.

De ta i l s : Thermal neut rons , pu l s ing , burner , w i t h d i r e c t conversion t o e l e c - 239

t r i c a l energy f o r power product ion. Fuel: u~~~ o r Pu i n gaseous form,

o r gaseous UF Coolant -moderator-ref l e c t o r : D 0, which b lankets g r a p h i t e 6 ' 2

f u e l con ta ine r , t o cool g raph i t e and a c t a s neutron modera to r - r e f l ec to r .

Gaseous f u e l i s uniformly conta ined i n g r a p h i t e and A 1 o r Z r , which i s s u r -

rounded by D 0 b l anke t , a l s o contained i n A 1 o r Z r , and conc re t e s h i e l d i n g . 2

Magnetic ' f i e l d produced by Cu c o i l s l oca t ed i n D 0 blanket s e c t i o n compresses 2

f u e l a t one end of t h e c o n t a i n e r , causing c r i t i c a l i t y . D i rec t conversion i s

accomplished by having ion ized gas do work aga ins t t h e magnetic f i e l d . The

r e l e a s e d f i s s i o n energy c r e a t e s a shock wave which d r i v e s t h e gas towards t h e

o t h e r end of t h e con ta ine r . As the gas o s c i l l a t e s , t h e p o r t i o n ' d i r e c t l y be-

hind t h e shock f r o n t becomes h igh ly ion ized . This plasma a c t s as a conductor

moving i n a magnetic f i e l d . The plasma, a s i t moves through t h e magnetic

f i e l d , induces a c u r r e n t i n an e x t e r n a l e l e c t r i . c a 1 c i r c u i t . This conversion

of mechanical energy t o e l e c t r i c a l i s t h e b a s i s f o r t h e gene ra t ion of e l e c t r i -

c a l power--500 MW(e) . Code: 0323 1 4 31102 44 662 7 1 1 8XXXX 921 109

46 66X

No. 4 Plasma Core Reactor

Reference: Aerojet-General Corp., unpublished r e p o r t , 1957.

Or ig ina to r : Lawnie Taylor .

S t a t u s : Pre l iminary concept , 1957.

D e t a i l s : Thermal neut rons , s t eady s t a t e , burner f o r i n t e r p l a n e t a r y rocket

p ropu l s ion . Fuel: u ~ ~ ~ , u~~~ , o r ~u~~~ plasma. Coolant: H2. Moderator-

r e f l e c t o r : D20 o r Be. Core s t r u c t u r e : plasma-fuel core i s surrounded by

modera to r - r e f l ec to r . H c o o l a n t , which i s rocket p r o p e l l a n t , ga ins energy 2

by moving through c o r e , Modera tor - re f lec tor m a t e r i a l i s core .wal1 . Wall

t empera ture i s c a l c u l a t e d t o be 15,000°K o r h ighe r . Containment: f u e l con-

f i n e d w i t h i n core reg ion by e x t e r n a l l y app l i ed e lec t romagnet ic f i e l d s , by

e i t h e r (1) simple magnetic b o t t l e w i th mi r ro r s a t each end o r ( 2 ) homopolar

device providing a s t r o n g e l e c t r o s t a t i c f i e l d f o r which modera tor - re f lec tor

i s o u t e r e l e c t r o d e and plasma i s inne r e l e c t r o d e . Magnetic f i e l d con ta ins

i on ized f u e l but does not con ta in t h e noniorlized coo lan t . Control: a d d i t i o n

of poison t o coo lan t ; v a r i a t i o n of f u e l and coolant cons is tency and i n j e c t i o n

r a t e s ; v a r i a t i o n of moderator cons is tency; v a r i a t i o n of mir ror s e p a r a t i o n and 3

r a t i o ; v a r i a t i o n of f i e l d i n t e n s i t y . Power dens i ty : 12-27 kW/cm . Code: 0313. 14 34715 ' 44 661 7 1 1 8159X 921 107

15 4 5 83699

46 83799

84667

847 6 7

No. 5- F i z z l e r Reactor

Reference: Nuclear Rocket Propulsion, pp. 322-327.. . .. . . .

Orig ina tors : Bussard and DeLauer (based on c a l c u l a t i o n s of Safonov).

S t a t u s : Pre l iminary concept , 1958.

De ta i l s : Thermal neut rons , s t eady s t a t e , burner , f o r . r o c k e t propulsion. Fuel: 233 235

U , U , o r ~u~~~ i n i t i a l l y i n s o l i d , l i q u i d , o r gaseous form but u l t i m a t e l y

i n gaseous form. C.oolant : gas , no t s p e c i f i e d . ' Moderat o r - r e f l e c t o r : not

s p e c i f i e d . Fuel and coo lan t , which i s rocke t p r o p e l l a n t , mix i n core reg ion

formed by modera to r - r e f l ec to r , C r i t i c a l i t y r a i s e s f u e l above vapor i za t ion

temperature. Fue'l dens i ty needs t o be about 0.10 l b l c u f t . Power: 5000 MW(t).

Power dens i ty : 100 MW/cu f t . Drawback: a t ope ra t ing p re s su re of 1000 p s i ,

which au thors cons ider reasonable , 20,000 l b of f u e l would be l o s t . To l o s e

only 300 l b , which is c a l c u l a t e d t o be a maximum amount, p re s su re of 67,000 p s i

would be needed; t h i s i s imprac t i ca l .

Code: 0313 1 X 3X7XX 44 661 7 11 8XXXX 921 107

4 5

46

No. 6 F i z z l e r Reactor f o r Rocket ~ r o ~ u l s i o n

Reference: As t ronau t i c s , 4, pp. 23-25, 111-112,:'Oct. 1959:.

Or ig ina tor : J e r r y Grey.

SLaLus : Pre l iminary concept , 1959. . .

Deta i l s : Thermal neut rons , s t eady s t a t e , burner . F i s s i l e m a t e r i a l mixed i n

a s o l i d "grain" w i th moderating p rope l l an t . Control: Cd rod. Removal of a

p o r t i o n of c o n t r o l rod causes c r i t i c a l i t y i n fuel . . immediately a d j a c e n t , which

h e a t s t h e f u e l t o vapor i za t ion temperature. Heat from t h i s v a p o r i z a t i o n

t r a v e l s up the f u e l a x i s , reducing t h e neut ron-absorp t ion c ros s s e c t i o n of

Lhe c o n t r o l rod enough t o al low c r i t i c a l i t y , temperature r i s e , and vapor i za t ion

of a l l of t h e f u e l .

Code: 0313 1 X 3X7XX 4X 66X 711 81212 9XX 109

No. 7 Gas-Solid Fueled Reac tors , S e r i e s f o r Rocket Propulsion

Reference: As t ronau t i c s , 4, pp. 23-25, 111-112 ; :Oct. 1959.,

Or ig ina to r : J e r r y Grey.

S t a t u s : Pre l iminary concept , 1959.

D e t a i l s : Pulsed burner . A s e r i e s of s u b c r i t i c a l "conventiorial" ( so l id - fue l ed )

r e a c t o r s a r e temporar i ly rendered h igh ly s u p e r c r i t i c a l when a s l u g of propel -

l a n t gas con ta in ing some gaseous f i s s i o n a b l e ma te r i a l , passes through them. Gas

i s hea ted t o i n c r e a s i n g l y h igh temperatures a s i t passes through each succeeding

r e a c t o r , f i n a l l y coming out of nozzle a t very h igh temperature.

Code: OX23 1 X 3XXXX 4X 66X 711 8XXXX 9XX 109

No. 8 Cavity Reac to r '

J e t Propulsion Laboratory

References: JPL-TR 32-42; JPL-TR 32-94.

Or ig ina to r : R. V. Meghreblian.

S t a t u s : Pre l iminary concept , 1961; work cont inuing .

D e t a i l s : Thermal neut rons , s t eady s t a t e , burner , f o r rocke t propuls ion .

C e n t r a l moderator mat r ix con ta ins gaseous f u e l . This i s surrounded by s o l i d -

f u e l r eg ion . Reflector-moderator surrounds co re . Coolant , which i s rocker

p r o p e l l a n t , i s f e d i n t o core t a n g e n t i a l l y , f i r s t p ick ing up hea t ( r egene ra t ive

coo l ing ) from tempera ture- l imi ted s o l i d - f u e l reg ion , t hen from gaseous- fue l

r eg ion , which i s not tempera ture- l imi ted . Coolant mixes wi th gaseous f u e l and

then is exhausted from r e a c t o r . No d e t a i l s of m a t e r i a l s given.

Code: 0313 1 X 317XX 4X 5XXX 66X 711 8XXXX 921 109

No. 9 Gaseous Propulsion Reactor

J e t Propulsion Laboratory

Reference: . ~ u c l k o n i c s , l9, No. 4 , pp. 95-99, :;&re 1961:;.

Or ig ina tor : R. V. Meghrebl ian .

S t a t u s : Prel iminary concept , 1961.

De ta i l s : SYmilar t o r e a c t o r descr ibed i n Data Sheet No. 8: However, s o l i d

f u e l i s l oca t ed i n t h e c e n t e r of t h e core and i s surrounded by a moderator

ma t r ix , which con ta ins gaseous f u e l . Th i s , i n t u r n , i s surrounded by t h e

modera to r - r e f l ec to r . The coolant. , f ed i n t a n g e n t i a l l y , f i r s t p icks up hea t

from t h e s o l i d - f u e l r eg ion , then- from t h e gaseous-fuel reg ion . No m a t e r i a l s

i nd ica t ed .

Code: 0313 1 X 317XX 4X 5XXX 66X 7 1 1 8XXXX ' 9 2 1 109

No. 10 Vortex Reactor

References: AD-265961; CF-57-11-3; J. Aerospace S c i . , 28, No. 9 , pp. 710-

724,t:Sept. 1961:; NASA-TN-D-288; ORNL-2837; N-2865a; NP-10270.

Or ig ina to r s : J.L. Kerrebrock and R.V. Meghreblian.

S t a t u s : Concept, 1958; work cont inuing. .

De ta i l s : Thermal neut rons , s t eady s t a t e , burner , f o r rocke t propuls ion . Fuel :

U, Pu, o r ' t h e i r compounds, i n H2. Fuel e i t h e r gas o r a gas-car ry ing s o l i d .

Coolant: CH4, NH3, o r H2. Moderator: Be0 o r g r a p h i t e . Re f l ec to r : Be o r

D20. Fuel contained a s a j e t - d r i v e n vo r t ex i n many long , t h i n , d i s c r e t e tubes

imbedded i n moderator m a t e r i a l . Vortex can a l s o be genera ted by: (1) e x t e r -

n a l l y imposed e l e c t r i c a l and magnetic f i e l d s ; (2) r o t a t i n g magnetic f i e l d - - a

r a d i a l e l e c t r i c f i e l d between a p a i r of c y l i n d r i c a l e l e c t r o d e s combined wi th an . .

a x i a l magnetic f i e l d ; o r (3) magnetic mir ror i n a c y l i n d r i c a l con f igu ra t ion .

Fuel and coo lan t , which i s a l s o rocket p r o p e l l a n t , mix. As mixture s p i r a l s i n t o

c e n t e r it i s drawn o f f a x i a l l y and discharged through one end. I n t h e v o r t e x , a

s t r o n g r a d i a l p re s su re g rad ien t e x i s t s . With such a g r a d i e n t , t h e heavy f i s -

s ionab le gas i s contained i n a s t e a d y - s t a t e concen t r a t ion d i s t r i b u t i o n i n t h e

v o r t e x and t h e l i g h t e r p rope l l an t gas d i f f u s e s through i t . Reactor is r i g h t

c y l i n d e r of equal he ight and diameter . Gas e x i t p re s su re might be 100 atm. ,

core temperature 10 , OOOOR. Power: 500 MW(t).

Code: 0313 12 3x707 44 661 711 8XXXX 921 104

15 3x715 46 663 107

3x713

No. 11 Coaxial Flow Reactor

Nat iona l Aeronaut ics and Space Administrat ion

References: TID-7653 ( P t . l ) , pp. 110-114; ARS Paper No. 1518-60, 1960.

Or ig ina to r s : H. Weinstein and R.G. Ragsdale.

S t a t u s : Concept, 1960; work cont inuing .

D e t a i l s : Thermal neu t rons , s t e a d y s t a t e , burner , f o r rocke t propulsion. Fuel:

f u l l y i on ized gaseous Coolant: H seeded wi th something l i k e g raph i t e 2

d u s t . Modera tor - re f lec tor : g r a p h i t e o r D 0 a s e x t e r n a l r e f l ec to r -modera to r , 2

o r a two-region moderator w i t h g r a p h i t e i n s i d e and D 0 ou t s ide . Core s t r u c - 2

t u r e : c r i t i c a l i t y t akes p l ace i n c a v i t y (LO f r long, 10 IL diaul.) I o r ~ ~ ~ c d by

e x t e r n a l modera to r - r e f l ec to r . Fuel i s fed i n t o c e n t e r of co re ; f u e l r eg ion

about 10 f t diam. Coolant , which i s rocke t p r o p e l l a n t , i s fed i n t o core arourld

pe r iphe ry a t flow r a t e d i f f e r e n t from flow r a t e of f u e l . D i f f e r ing a x i a l

v e l o c i t i e s prevent two f l u i d s from mixing. Coolant and a small po r t ion of t h e

f u e l a r e exhausted from core reg ion through nozzle . Control: rotat ing-drum

c o n t r o l rods . One s tudy us ing both g raph i t e and D 0 a s modera to r - r e f l ec to r 2

has been based on t h e fo l lowing parameters: r e a c t o r overa. l : l . i s 16.6 f t long

and 16 .6 f t i n d iameter , cav i ty : 10 f t long, 10 f t krl d iameter ; moderator-

r e f l e c t o r : 3 .3 f t t h i c k . Fuel v e l o c i t y : 0 .2 f t / s e c . Coolant v e l o c i t y :

1 7 f t / s e c . Temperatures: f u e l , 2 0 , 0 0 0 ° ~ ; hydrogen, 10,OOOO~; g r a p h i t e ,

5 , 0 0 0 ° ~ ; D 0 , 70UR. Since hydrogen a t t hese Lemperatures i s t r anspa ren t t o a r a d i a t i o n , i t must be "seeded" wi th absorbing m a t e r i a l f o r hea t t r a n s f e r .

Graphi te d u s t might be s a t i s f a c t o r y up t o i t s subl imat ion po in t (680U0R).

Pressure : 2200 p s i a w i t h f u l l y ion ized f u e l .

Code: 0313 12 34715 46 661 7 11 8144X 9 2 1 1,07

14 109

No. 12 Homogeneous Gas Ph'ase Magnetohydrodynamic Nuclear Reactor

General E l e c t r i c Co., Hanford . .

Reference: Unpublished r e p o r t , 1965.

Or ig ina tors : S t a f f members.

S t a t u s : Concept, 1965.

De ta i l s : Steady s t a t e , burner . Fuel: gas , e .g . UF6. Gaseous f u e l flows i n

t o r o i d a l con ta ine r i n s u b c r i t i c a l d e n s i t y except i n core r eg ion , where i t i s

compressed t o c r i t i c a l i t y . Nuclear r e a c t i o n s and hea t cause i o n i z a t i o n of

f u e l . Ion ized s t ream passes through magnetohydrodynamic channel composed of

cu r r en t - ca r ry ing r a i l s and 2 cryogenic magnets t h a t provide a c r o s s - c u r r e n t

f i e l d . Ionized gas s t ream provides t h e e lec t romot ive fo rce t o genera te t h e

cu r r en t flow between t h e r a i l s . The gas could then expand d i r e c t l y t o a t u r -

b ine . Gas then proceeds through hea t exchanger f o r steam product ion and t o

u n i t f o r gas s e p a r a t i o n and p u r i f i c a t i o n . F i s s i o n products and wastes a r e

d iscarded , and p u r i f i e d gas p lus enough new f u e l t o keep c o n s i s t e n t l e v e l

c i r c u l a t e s aga in t o compressor.

Code: OX13 1 X 3x710 4X 662 7 11 84699 921 109

References .

1. L.R. Shepherd and A.V. Cleaver , The Atomic Rocket, J. B r i t . I n t e r p l a n e t .

Soc 8 , No. 1, pp. 23-37, Jan . 1949: , -

2. George Safonov, The C r i t i c a l i t y and Some P o t e n t i a l i t i e s of "Cavity

Reactors" , RM-1520, The Rand Corporat ion, J u l y 17, 1955. Decl . , Oct. 12 ,

3 . S,T. Nelson, The Plasma Core Reactor , TDR-594(1555-01)TN-1 (AD-258979),

Aerospace Corp., May 10 , 1961.

4. S.A. Colgate and R.L. AarnudL, Plasma Reactor Prnmises Uirecc E l e ~ r a i c

Pnwer, Nucleonics , l5, No. 8 , pp. 50-55, Aug. 1957:.0

5. Lawnie Taylor , unpublished r e p o r t , Aerojet-General Corp., 1957.

6. R.W. Bussard and R.D. DeLauer, Nuclear Rocket Propuls ion , pp. 322-327,

McGraw-Hill Book Co., I n c . , N . Y . , 1958.

7 . J e r r y Grey, Gaseous-Core Nuclear Reac tors , As t ronau t i c s , 4, pp. 23-25,

111-112, Oct. 1959.

8 . R.V. Meghtebl.ian, Gaseous F i s s i o n Reactors f o r Spacecraf t Propuls ion ,

J P Z - T R - ~ ~ - ~ ~ , J e t Propuls ion Laboratory, C a l i f o r n i a ' ~ n s t i t u t e of Tech-

nology, .T~l'l.y 6 , 1960.

9 . R.V. Meghreblian, Gaseous F i s s i o n Reactors f o r Booster Propuls ion , JPE-

TR-32-94, J e t Propuls ion Laboratory, C a l i f o r n i a I n s t i t u t e yL Technology,

Mar. 31, 1961.

10. R.V. Meghreblian, Gaseous Propuls ion Reactors , Nucleonics , l9, No. 4,

pp. 95-99, Apt. 1961.

11. J.L. Kerrebrock and R.V. Meghreblian, An Analysis of Vortex Tubes f o r

Combined as-Phase P i s a i o n Heat ing and Separa t ion of t h e F i s s ionab le

M a t e r i a l , CF-57-11-3, O~WL,:;.Apr;.:Il, 1958.

12. J.L. K e r r e b n ~ c k and R.V. Meghreblian, Vortex Containment f o r t h e Gaseous-

F i s s i o n Rocket, J. Aerospace SCi. , %, No. 9 , p p . 710-724, Sept . 1961.

13. M.L. Rosenzweig, Advanced Propuls ion S tud ie s . Summary of Research i n t he

F i e l d of Advanced Nuclear Propulsion. Semiannual Technical Report ,

January 1-June 30, 1961, AD-265961, Aerospace Corp.

14. R.G. Ragsdale, NASA Research on the Hydrodynamics of the Gaseous Vortex

Reactor, NASA-TN-D-288, National Aeronautics and Space Administration,

Sept. 1960.

15. J. J. Keyes, Jr., and R.E. Dial, An Experimental Study of Vortex Flow for

Application to Gas-Phase Fission Heating, ORNL-2837, ORNL, June 13, 1960.

Decl., Mar. 8, 1961.

16. M.L. Rosenzweig, The Vortex Matrix Approach to Gaseous Nuclear Propulsion,

N-2865a, Aerospace Corporation, 1961.

17. M.L. Rosenzweig, W.S. Lewellen, and J.L. Kerrebrock, The Feasibility of

Turbulent Vortex Containment in the Gaseous Fission Rocket, NP-10270,

Space ~ e c h n o l o ~ ~ Laboratories, Inc., Oct . 17, 1960. 18. H. Weinstein and R.G. Ragsdale, A Coaxial Flow Reactor--A Gaseous

Nuclear-Rocket Concept, Paper No. 1518-60, presented at the ARS 15th

Annual Meeting, Washington, D.C., Dec. 5-8, 1960. /

19. R.E. Hyland, Two-Dimensional Diffusion Calculations on Co-Axial Cavity

Reactors, pp. 103-109; R.G. Ragsdale and FOE. Rom, NASA Research on' the

Coaxial Flow Gaseous Nuclear-:Rocket, pp. 110-114 in Proceedings of Nuclear

Propulsion Conference, Naval Postgraduate School, August 15-17, 1962,

Monterey, California, TID-7653 (Pt.l), USAEC, July 1963.

20. Unpublished report, Hanford Atomic Products Operation, General Electric

Co., 1965.

21. Nuclear News, 7, No. 11, p. 41, Nov. 1964.