Alexander GlaserWWS556dPrinceton UniversityFebruary 26, 2007

MakingHighly Enriched Uranium

Revision 4

1

Natanz Site, Iran, 2007

Sep 2002

200 meters

(FEP)

FuelEnrichment

Plant

(FEP)

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What is HEU?

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Highly Enriched Uranium(visually)

Natural uranium0.7% U-235

Low-enriched uraniumtypically 3-5%,

but less than 20% U-235

U-235

U-238Uranium

Highly enriched uranium Weapon-grade uranium20% U-235 and above more than 90% U-235

HEU(weapon-usable)

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LEU HEU

Critical Mass of Uranium

Enrichment [wt%]

Criti

cal M

ass [

kg]

0 20 40 60 80 1000

50

100

150

200

250

300

144 kg

12 kg

(for a beryllium-reflected metallic sphere)

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Characteristics ofHighly Enriched Uranium

Easy to handleEasy to use in nuclear weapon or nuclear explosive device

Difficult/Impossible to detect

Difficult to produce

Conventionalchemical

propellant

Sub-critical pieces of uranium-235 combined

Plutonium core compressed

High-explosive lenses

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Why Make HEU Anyway?(if there is so much of it around)

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Global HEU Inventory 2007

China 22 MT____ ____ ± 25%

France 33 MT____ ____± 20%

India 0.2 MT____ ____ ± 50%

Pakistan 1.4 MT____ ____ ± 15%

Russia 770 MT____ ____ ± 300 MT

United Kingdom 24 MT____ ____ declared

United States 467 MT____ ____ declared

Non-nuclear states 10 MT____

TOTAL (rounded) 1325 MT____ ____ ± 310 MT

Country National Stockpile (estimate)

(civilian and military combined)

Estimates from IPFM Global Fissile Material Report 2006, updated partially based on D. Albright (ISIS)

(total world-inventory of HEU is enough for 50,000-100,000 nuclear weapons)

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Global Distribution of Civilian HEU

1,000 -100 -

10 -1 -

10,000 kg1,000 kg

100 kg10 kg

More than 10,000 kg

Less than 1 kg (cleared)

Estimated total civilian inventory: about 50 metric tons

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Production of Enriched Uranium(Uranium Enrichment)

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Global Enrichment Picture 2007

Brazil Resende Commercial Under construction GC 120____

ChinaLanhou 2 Commercial Under construction GC 500____

Shaanxi Commercial In operation GC 500____

FranceGeorge Besse Commercial In operation GD 10800____

George Besse II Commercial Planned GC 7500____

Germany Urenco Deutschland Commercial In operation GC 1800 (+2700)____

India Rattehalli Military In operation GC 4-10____

Iran Natanz Commercial Under construction GC 100-250____

Japan Rokkasho Commercial In operation GC 1050____

Netherlands Urenco Nederland Commercial In operation GC 2500 (+1000)____

Pakistan Kahuta Military In operation GC 15-20____

Russia

Angarsk Commercial In operation GC 2350____

Novouralsk Commercial In operation GC 12160____

Zelenogorsk Commercial In operation GC 7210____

Seversk Commercial In operation GC 3550____

U.K. Capenhurst Commercial In operation GC 4000____

USA

Paducah Commercial In operation GD 11300____

Piketon (USEC/DOE) Commercial Planned GC 3500____

Eunice (LES) Commercial Planned GC 3000____

Country Name/Location Type Status Process Capacity [tSWU/yr]

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Comparison of Enrichment Capacities

Feed Product Time

150,000 kg U(nat) at 0.71% 20,000 kg LEU at 4%(Tails at 0.20%)

1 year

Material and separative work required to fuel a 1000 MWe light-water reactor

Feed Product Time

150,000 kg U(nat) at 0.71% 654 kg(25-50 bombs)

HEU at 93%(Tails at 0.30%)

1 year

Material and separative work required to produce enough HEU for several bombs per year

150,000 kg U(nat) at 0.71% 100 kg (4-8 bombs)

HEU at 93%(Tails at 0.65%)

40 days

Values for a reference facility with a capacity of 130 tSWU/yr

020,000 kg LEU at 4% 100 kg (4-8 bombs)

HEU at 93%(Tails at 3.55%)

08 days

Additional time is needed before HEU can be produced in a facility that previously produced LEU becausethe “old” uranium gas has to be “flushed out” from the equipment and the facility may have to be reconfigured

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The Case of the Gas Centrifuge

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Centrifuges for Uranium Enrichment

Depleted uranium

Enriched uranium

rotor

bottom bearing

bottom scoop

baffle

top scoop

electromagnetic motor

casing

tails

feed

product

center post

Source: IPFM 2006 Report

Source: Presentation by Mohammad Saeidi (AEOI)

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SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

SeparatingUnit

Feed

Tails

Product

Stage 1 Stage 2 Stage 3 Stage 4

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Genealogy of the Gas Centrifuge

Original centrifuge R&D (pre-commercial, “Zippe-connection”)

Technology transfer (confirmed or planned)

Independent development or unconfirmed foreign assistance

Status or achievement unclearLast revision: 02/2007

(Libya)

N. Korea

Pakistan

(Iraq)

Iran

Japan

India

Australia

ChinaFrance

Brazil

USA

Russia

Germany

U.K.

The Netherlands

Urenco

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Why Are Centrifuges Different?

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Crude Breakout Scenario(using an early-generation machine)

Stage number

Num

ber o

f mac

hine

s in

sta

ge

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2160

40

20

0

20

40

60

21 40 56 71 84 96 106 91 79 67 57 48 40 34 27 22 17 13 9 6 3

Total number of machines in cascade: 987

Assumed characteristics of P-2-type machine

peripheral velocity =rotor diameter =

rotor height =separative power =

48515

1005

m/scmcmSWU/yr

Source: Urenco

of UF6 w/ natural uraniumof UF6 w/ 4.4%-enriched uranium

Feed =Product =

32.4 kg/d3.3 kg/d

Performance of reference LEU-cascade

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Simple Breakout Scenario(using an early-generation machine)

(compare to equilibrium time for gaseous diffusion process, which is on the order of months)

Time [hours]

Enric

hmen

t [w

t%]

-2 0 2 4 6 8 10 120

20

40

60

80

100

Simple batch operation:1 cascade usingpre-enriched feed-stock

Serial batch operation:10 cascades feedinto 1 additional cascade

26%

86%

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Detection of Undeclared Facilities

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240 meters

200

met

ers

GRONAU centrifuge enrichment facility, GermanyCurrent capacity: 1,800,000 SWU/a (to be expanded to 4,500,000 SWU/yr)Footprint of facility: 200 meters x 240 meters

Specific capacity of facility: 37.5 SWU/yr per square meter

Minimum capacity of facility to produce 25 kg of HEU annually: about 6,000 SWU/yrHypothetical footprint: 160 square meters (42 ft x 42 ft)

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Detectability of Undeclared Facilities

Reactor

Reprocessing

Yes Yes No

No No (Yes)

Detectability (Selected Criteria)

IdentifiableStructure

ThermalSignature Effluents

Calutron/EMIS

Gaseous diffusion

No Yes Yes

Yes Yes Yes

PlutoniumProduction

Centrifuge No No No

UraniumEnrichment

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What Are Our Options?

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• Increase the effectiveness of (and the confidence in) safeguards

• Increase the ability to detect undeclared facilities

• Contain technology to existing or selected producers

• Focus on the demand side (i.e. “devalue” nuclear weapons)

Possible Strategies to Limit the Front-End Proliferation Risks of the Nuclear Fuel Cycle

Preclude covert misuse

Motivation

Deter clandestine activities

TARGET/OBJECTIVESTRATEGY

Know-how held by “trusted users”

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Global Nuclear Expansion Scenario(1500 GWe in 58 countries, based on 2003 MIT study)

More than 10 GWe installed

At least 1 GWe installed

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Enrichment Demand and Distribution(for 1500 GWe Global Nuclear Expansion Scenario)

Global enrichment capacity: 1,500 x 150 tSWU/yr (225,000 tSWU/yr)

12,750

4,800

2,250

5,100

27,750

24,450

5,400

2,8503,150

2,850

36,600

20,850

37,200

11,050

10,300

17,650

tSWU/yr Total SWU-production in country

Combined SWU-demand of countries importing alltheir enrichment services: 11,850 tSWU/yr

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Containment Strategies

Black Box approaches with or without “Poison Pills” and combined with multinational operation of facilities

Have and have-not approachesBush Proposal (2004) or other “criteria-based” proposals

Export ControlsDeter, delay, detect procurement efforts

But to what extent are they durable?Underlying assumption that indigenous R&D efforts are irrelevant/insufficient

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Timeline of Centrifuge Programs

(arrows indicate uncertain dates of respective events or milestones)

1960 1970 1980 1990 2000 2010

Japan

India

U.K.

Netherlands

Iran

Germany R&D as part of URENCO/ETC

Pakistan

Australia

Brazil

R&D as part of URENCO/ETC

R&D as part of URENCO/ETC

R&D

Machineat least 2-5 SWU/yr

Test cascadeat least 100 machines

Pilot plantand further developments

DRAFT version, August 2006 - by Alexander Glaser, Princeton University

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• Increase the effectiveness of (and the confidence in) safeguards

• Increase the ability to detect undeclared facilities

• Contain technology to existing or selected producers

• Focus on the demand side (i.e. “devalue” nuclear weapons)

Possible Strategies to Limit the Front-End Proliferation Risks of the Nuclear Fuel Cycle

Preclude covert misuse

Motivation

Deter clandestine activities

TARGET/OBJECTIVESTRATEGY

Know-how held by “trusted users”

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