LA-UR- 0 /1- P) o9&Approved forpublic relea s e;distribution is unlimited.

Title:

Author(s) :

Submitted to:

Re lease of MCNP5_RSICC_ 1 .30

Tim Goorley , Jeff Bull , Forrest Brown , et . al .MCNP Monte Carlo Team , X-5Los Alamos National Laborato ry

American Nuclear Society Winter MeetingWashington , D .C .Nov. 14-18 , 2004 .

~0 Los AlamosNATIONAL LABORATOR Y

Los A lamo s National Labo ratory, an aff i rmat ive a c ti on/eq ua l oppor tunity employer, is op erated by th e U niversity of Cali forni a fo r th e U.S .Depa rtm ent of En ergy under contrac t W-7405- ENG -36 . By a cc eptance of th is a rticl e , the p u blisher recogn izes that the U. S . Governmen tretai ns a non exctusive , royal ty-free l icense to pub lish or reprod uce the publish ed for m of this contri but ion, o r to all ow othe rs to do s o, for U .S .Government p urpose s . LosAlamo s Nat i ona l Laboratory reques ts that the p ub lishe r i de nt ify th i s a rticle as work performed under theauspices of the U. S . D epartment of Ene rgy. Los Al amos National Laborato ry st rongly s uppo rtsacad emi c freedom anda resea rcher's ri ght topublish ; as an in sti tut ion , however, the Laboratory d oes not endorse the v iewpoint of a pu blicati on o r guarantee i ts techn ica l cor rectness .

Form 836 ( 8/00)

For submission to the Fall/Win ter 2004 ANS meet ing in DC

Release of MCNP5_RSICC_ 1 .30

T im Goorley, Jeffery S . Bull , Forrest B . B rown, Thomas E . Booth, H. Grady Hughes, Russel l D . Mosteller, R . ArthurForster, Susan E . Post, Richard E . Prael, Elizabeth C . Selcow, Avneet Sood, Jeremy E. Sweezy

Diagnostic Applications Group(X-5) Los Ala mos National Laboratory, P.O . Box 1663 MS F663, Los Alamos, NM, 87545 .mcnp@lanl.gov, http ://www-xdiv.lanl.gov/x5/MCNP/

INTRODUCTION

In July of 2004, an updated version of MCNP5 TM(IvICNPS RS 1CC ] .30) was release d to the RadiationShield i ng Information Computational Center .1,Z T h isupdated version has three new features, thirtee n bug fixesand several minor coding improvements. The newfeatures are : support for 8 byte integers, special ized tallytreatment of large lattices, and mesh ta l ly enhancements .Of the thirteen bug fixes, only four resulted in incorrectanswers in specific circumstances . In add i tio n to thestandard RSICC distribution of the MCNP5 source,executables and patches, the patch file (only) is availableon the MCNP we bsite : http ://www-xd i v .tan l .gov/x5/MCNP/theresources .htm l

NEW FEATURE S

The three new MCNP5 features are d iscussed in th efollowing paragraph s . Several new imp rovements havealso been made to the manual and developmentenvironment. All of the features, bug fixes, codingimprovement issues and re lated documentation are nowmaintained in Sourceforge' . Fortran and C source codeand regression test problems are now under versioncontrol with CVS.

8 Byte Integer Support

There have been occasional requests on the mcnp-forum from users who wish to run more than 2 . 1 billionparticles to improve their tally statistics. In the updatedversion of MCNP5, twenty-five integer variables are nowexplicitly declared as 8 byte integers . Most of t hesevariables are re l ated to NPS, the number ofh istories, andallow users to run more than 2 . 1 b i l lion so urce particles.Besides the N PS card in the MCNP input dec k , the othercards which allow some 8 byte integer entries are:PRDMP, RAND, PTRAC and MPLOT. These entriescontrol how frequently file dumps and parallelcommunication rendezvous occur, random numberparameters, particle track fi le generation, and tally plotfrequencies, respectively. Additiona l ly, format stateme n ts

in the output files were expanded to print al lowed 8 byteintegers in fields of twelve characters, or up to 999billion. Since longer MCNP runs can cause larger ptracfiles to be created, ptrac fi les larger than 250 Gigabyteswere created and tested .

Lattice Tally Enhancements

In some medical physics radiation transportapplications, lattices, often based on CT images, are usedto represent human geometry . These calculations,particularly for large lattices, are very time consuming .Lattice tally enhancements included in this release ofMCNP5 reduce wall-clock runtimes by orders ofmagnitude4 for these specific problems. MCNPS also hasthe capability of determining if the input deck meetsstringent requirements necessary to use the lattice speedtally treatment . If so, MCNP5 will issue a warning andwill automatically use the enhancement . A new card,SPDTL, can also be used to turn this treatment on or off,and to print out which requirements are not fulfilled, ifany

. Mesh Tally Enhancements

The original release of MCNPS in June 2003contained support for mesh tallies, or a 3-D grid whichcalculates volume-averaged fluxes in each voxel in thatgrid . Included with this feature was the ability to use theta lly multip l ier card (F M card) in comb ination with amesh tally . On the FM card , the user must specify thematerial whose data are used to calculate the tally values.These data were used over the entire mesh, even if theparticle was trave l ing in a material other than thatidentified on the FM card. This prevented the calcu lationof material dependen t quantities such as kff and particleproduction rates in mesh tallies that range over severalmaterials. Thi s drawback has been rectified in this newversion of MCNP S . I f zero is entered as the materialnumber on an FM card containing a multiplier set, thereaction data for the material in whic h the particle istraveling is used to calculate the tally values.

BUG FIXE S

r" MCNP is a trademark of the Regents of th eUniversity of Cal ifornia, Los Alamos NationalLaboratory.

Thirteen bugs were fixed in t he new update . Onlyfour of these bugs caused incorrect answers in specificcircumstances. These four bugs app ly to the use of

1 /2 11 /8 /2004 4 : 47 PM

For submission to the Fal l/Winter 2004 ANS meeting in DC

DXTRAN spheres in lattices, incorrect interpolation inDE DF cards appl ied to mesh tal lies, incorrect materialusage for FM cards with mesh tallies, and attenuator orspecial multiplier sets with the FM card and mesh ta l lies .Other bug fixes correct crashes resu lting fromtransforming macrobodies, reading runtpe filesincorrectly, and incorrect allocation of the variable ibnk.Two warning messages have also been corrected. A fullbug fix l ist is in the patch docume n tation2 .

CODING IMPROVEMENTS

S l ight changes have been made to the code and buildsystem to co n tinue to modernize MCNP . Support foroutdated Windows graphics interface, Winteracter, hasbeen removed . P lotti ng on all p l atforms is now on lysupported with X11 graph ics. More name d constants havebeen added and more real number constan ts have beenforced to double precision. Support for the I n te l 7 .1compiler in sequential p lot mo de on Windows PCs wasalso added .

FUTURE RELEASES

Currently under development is the next version ofMCNP, MCN P 6 . Th is version will contain chargedpartic le transport, magnetic field tracki ng, and other newfeatures . This version is not expecte d to be released for atleast another year . Patches with bug fixes and possib lynew features for MCNP5 will be released in themeantime .

REFERENCES

1 . X-5 Monte Carlo Team, "MCNP - A General MonteCarlo N-Partic le Transport Code, Version 5, Vo l . 1 "Los Alamos Nationa l Laboratory, LA-UR -03-198 7(April 2003) .

2 . X-5 Monte Carlo Team, "Patch to Update MCNP5version MCNPS RSICC 1 .20 to versionMCN P5_RSICC_ 1 .30," Los Alamos NationalLaboratory, LA-UR -04 -592 1 (August 2004) .

3 . http://sourceforge .nedindex .ph p4. T. GOORLEY, "MCNP5 Tally Enhancements fo r

Lattices," Los. Alamos Nationa l Laboratory, LAU R-04-3400 (May 2004) .

2 /2 11/8/2004 4 : 47 PM

MCNP5 RSICCRelease of

X-5 MCNP Team

Speaker: Tim Goorley

1 .3 0

Diagnostics ~Applications ~

~A lamosG roup (X-5) . . . . . . :

Release of MCNP5 RSICC 1 .3 0

• Introduction

• New Features- 8 byte Integer Support

- Lattice Tally Enhancements

- Mesh Tally Enhancements

• Bug Fixes

• New Data Library

• Future WorkDiagnostics /

IAppl ications ~Group (X -5) LasAlamos

Introduction

• MCNP - Monte Carlo N Particle - Genera lpurpose radiation (n,y,e) transport code .

• MCNP5 released April 200 3

- Initial Release RSICC 1 .1 4

- l st Patch - RSICC_ 1 .20 (Dec 2003 )

- 2nd Patch - RSICC_ 1 . 30 (Sept 2004)

Diagnost i csApplications ~AlamosGroup(X - 5) .~~, . . . .•

New Features

• 8 Byte Integer (> 2 .14 Billion) Support- 25 variables in code changed to 8 Byte

- More histories

- More infrequent rendezvous (for parallel calc .)

- More events in ptrac file (>250 Gigabytes)

- Input Cards :PRDMP, RAND, PTRAC, & MPLO T

• Support for Mac OS X

- Include LAM-MPI compiling options

DiagnosticsApplications

, ~i AiamosGroup (X-5) .

New Features

• Lattice Speed Tally Enhancements

- For problems with hexagonal geometric lattices& F4 tallies, exchanges capabilities for speed .

- Typically used for medical physics voxel models .

- Wall Clock speedups of -SOOx possible .

- Autodetect if possible, warning if used .

T. Goorley, MCNP5 Tally Enhancements for Lattices, LA-UR-04-3400 .

W .S . Kiger, et al ., Performance enhancements of MCNP4B . MCNP5, and MCNPXfor Monte Carlo Radiotherapy Planning Calculations in Lattice Geometries, 11 tnInternational Symposia for Neutron Capture Therapy, Boston USA, Oct 12-15 .

DiagnosticsAppiications j Lds AlamosGroup (X - 5) 7 . , .>ti• .• :

New Features

• Mesh Tally Enhancements- A geometry-independent user defined grid on

which volume averaged fluxes are calculated.

- Original release in MCNP5 .

- Could be used in conjunction with FM card tocalculate reaction rates for a single material .

- Now whatever material the particle is in can b eused, important when mesh tally coversmultiple materials .

D iagn ostics ~Applications ~

AlamosGroup (X-5) 1 . .

Bug Fixes

• 13 Bugs fixed

• Only 4 bugs caused incorrect answers- DXTRAN spheres in lattice s

- Incorrect DE DX interpolation for mesh tallies

- Incorrect material usage for FM & mesh tallies

- Incorrect atten/mult sets for FM & mesh tallies

• Others: crash w/ transform macro, problemwith reading runtpe files .

DiagnosticsAppl i cations , aAlamosGroup (X-5) >, ' ., 1,nC .. . .11 .

New Data Library

• t 16 2003- pre ENDF/B-VII evaluations from Los Alamos Group T-

16 for 15 isotopes :

- H-3

- U-232, U-233, U-234, U-235, U-236, U-237, U-238,

- U-239, U-240, U-24 1

- Np-237

- Pu-239

- Am-241, Am-243

• http ://laurel . lanl .gov/PROJECTS /DATA/nuclear/nuclear . html

DiagnosticsApplications j LosAlamos. , , _ , . .Group (X-5)

Crit Validation Suite w/ new data

Range

j k l < 6

6 < I k l < 26

j k l > 26

P re-ENDF/B-VI I

19

7

5

E N D F/B-VI

13

9

9

Substantial improvements for bare metal spheres (Jezebel-233, Godiva,and Jezebel), BIG TEN, HEU and Pu metal spheres in water (Godiver and Pu-MF-011, respectively), and LEU lattice (B&W XI (2) )

ORNL resonance parameters improve results for Godiver, ORNL-10, IEU-CT-03, STACY (36), B&W XI (2), and LEU-ST-02 (2 )

R . D . Mosteller, "Comparison of Results from the MCNP Validation Suite Using ENDF/B-VI and PreliminaryENDF/B-VII Nuclear Data," presented at the International Conference on Nuclear Data for Science andTechnology, Santa Fe, NM, Sept 27 - Oct 1, 2004 (LA-UR-04-6489) . Diagnost i cs / -~

Applicat i ons , Los Aldm05G ro up ( X -5)

RSICC Distribution

• 3 CDROMs- Unix

• data_new, data_webpages, source & executables

• patch & patch description, readme file s

- Windows Data Installer• InstallShield0 installer for new dat a

Windows Executables Installer• InstallShield0 installer for source, executable s

• data_webpages, patch & patch description,readme s

D i agnostics i`Applications ,Group (X-5) ' Los Alamos

Updated MCNP Homepage

• http : //laws .lanl .gov/x5/MCNP/index .html

- MCNPS_RSICC_ 1 .3 0 patch & description

- 2005 MCNP Workshops

MCNP5 discussion and description

Volume I (Overview and Theory) of MCNP SManual

- Publications - 40 recent LAUR reports

DiagnosticsApp licationsGroup ( X • 5) Los Alamos

Future Work

• Mesh Tally plotting (done )

• Distribution of n emitted from fission [V] (done )

• Plot tallies as a function of lethargy (done )

• Log interpolation [ilog] in input deck (done )

• Expanded Large Lattice Capability

• Stochastic Geometry

D iagno stics i`App licat i ons ~G roup (X - 5) -

LosAlamos

Fission Neutron Distributio n• Currently, one of two integer values are selected for

neutrons emitted from fission

• Ex. U-235, v-2 .43, 2 neutrons are selected withp=0.47 and 3 neutrons are selected with p=0 .43

• Now, an isotope specific, E-dependant (-Gaussian)distribution of neutrons can be selected on phys card .

# n's emittednu = 0nu = 1

nu = 2

nu = 3

nu = 4

nu = 5

nu = 6

nu = 7

# fraction0 .038940 .159300 .327110 .311590 .134790 .025880 .002300 .00009

error0 .038940 .198230 .525340 .836930.971720.997600.999900.99999

Print Table 11 5

James Terrell, "Distribution of FissionNeutron Numbers," Phys. Rev . 108, 783(1957).

John Lestone, X-5 research note .

D i agnos tics ^App l i cat i ons ~Group ( X - 5) ~ ~Alamos

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Diagnostics /`App l ications ~Group ( X - 5) , Los Alam05

Expanded Lattice Capabilitie s

100 Million voxel model of VIP-Man, geometry (left) meshtally plot (right)

Collaboration with Prof. George Xu (xug2@rpi .edu), and Brian Wang (RPI )

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Diagnostic sApplication sGroup (X-5) WsAlamos

Stochastic Geometry

* Fixed lattice with random kernelsstochastic geometry ]- 5x5x5 cubical lattice

[MCNP

- Lattice edge chosen to preserve the specified packing fraction .

- Fuel kernels randomly placed on-the-fly within the cubical cells

- Reflecting boundaries on the outer surface s

- Uses new MCNP5 stochastic geometry

o

Fuel kernel displaced randomlyOOQ a ~OQ ~~ ~ ~ ~

.~ '` ~ 0~ 0, 01,010a ~

within lattice element each tim eth a t neutron enters

Stochastic Geometry for MCNP5, F.B .Brown,W.R. Martin (U. Mich) ANS Winter 2004 (Wed -

AM)

DiagnosticsApplicationsGroup (X-5) WsAla fI'105