SCALE Newsletter

MonacoAn issue with generating secondary gamma production wasresolved in continuous-energy calculations. Fission gammasor gammas from other particle productions (e.g., proton,alpha, and tritium) might have been disabled, depending onthe problem. Results for the Monaco regression problemsused for SCALE testing show an insignificant change in themagnitudes of flux and response values.NEWTIn addition to input keywords fluxplane, fluxplan, and flux,which are supported in SCALE 6.2, fluxplanes is alsosupported in SCALE 6.2.1.ORIGAMIOne of the first setup operations ORIGAMI performs is tointerpolate an ORIGEN library (with ARP) to the desiredenrichment, moderator density, and burnups. For decaycalculations, ORIGAMI uses the most recently loaded dataset with flux 0. For a restart decay calculation, values forthe interpolation parameters do not need to be defined.The previous logic was to assume the default enrichment of3.2% and moderator density and zero burnup. However,this caused an error when a reactor library could not beinterpolated to 3.2%. The updated logic for restart decaycalculations considers the data set with the lowestenrichment and moderator density.The “total” row in the neutron and gamma emissionsummary table of an ORIGAMI output is now suppressedsince it is a misnomer.ORIGENAdditional backwards compatibility was added for readingSCALE 6.1 and earlier FIDO style input.The default cutoff criteria for (alpha,n) sources has beenchanged from 1e-5 to 0 (no cutoff) based on therecommendation of Rick Migliore of AREVA, who noticedthat there can be 15% error in some cases in the (alpha,n)component of the total neutron source with the previousdefault cutoff of 1e-5. With the current implementation,the runtime increase incurred by using a zero cutoff insteadof 1e-5 is negligible.Issues resolved in SCALE 6.2.1: Crashes have sometimes occurred due to formattingof the beta principal emitter summary in the output,when trying to access an out-of-bounds array element.An issue was resolved in calculating the time stepwhen (1) isotopics where loaded from an f71 file and(2) the user specified a start time of zero in the timeblock. The output file shows the actual time steps usedin the calculation. The bug was fixed, and additionalinputs were added to control the material timeline andtime specification.PolarisThe use of size 2 for large water holes could sometimescause the calculation to terminate. The issue has beenresolved in this update.The Polaris MOC transport solver has been enhanced. PNcalculations are supported, with P2 designated as the newdefault scattering treatment. The accuracy of light waterreactor (LWR) reflector calculations has been significantlyimproved with the addition of anisotropic scattering.Transport cross section edits have been improved, withhydrogen transport cross sections being computed usingthe neutron-leakage-correction method. The MOCcalculation was modified to use less memory and provideimproved runtime performance through updates to theCoarse Mesh Finite Difference (CMFD) accelerationcalculation.PUFF (AMPX)The AMPX code PUFF for generating multigroup crosssection covariance data has been modernized andenhanced. PUFF has been rewritten in C to takeadvantage of the new C reading routines for (1) ENDF(which will also support the new GND format), (2) thenew in-memory input/output resource for the COVERXfile format, and (3) the new resonance processingapplication program interface (API). In addition, the newPUFF version adds covariance matrices for redundantreaction if not given by the evaluator (e.g., absorptionreaction when fission and capture are provided). Processingfor fission spectrum (chi) covariance matrices previouslyavailable in a different module has been incorporated intoPUFF.Errors found in the old version of PUFF that affected sometest libraries not distributed with SCALE have beencorrected. Results from previous and updated codes havebeen compared and found to be in good agreement, exceptfor cases in which erroneous covariance matrices werepreviously computed.A new keyword-based input with more options has beenadded, but the old FIDO-style input is still supported.SamplerSampler was updated to enable multi-dimensionalparametric analyses for studying the effects of combinationsof varying parameters on various calculated responses.Using the READ PARAMETRIC block, a user may enterone or more variables that have been defined with uniformdistributions, along with the number of samples for eachvariable. Each variable is sampled uniformly over thedomain defined by its minimum and maximum values.Sampler generates a summary table of the parametricstudy, including values for which the minimum andmaximum of each response occurs. PTP plot files showingthe dependency of each response on each variable aregenerated.SCALE Runtime EnvironmentAn issue was resolved where the HTML icon graphics werenot properly copied to the htmd directory.Standard Composition ProcessingImproved warning messages are provided for nuclides notpresent on the user-specified cross section data library.Several warnings can be observed for models with multipleSCALE Newsletter (Fall 2016)3

compositions containing oxygen. Oxygen contains 0.2atoms % of O-18, for which cross section data are notavailable in ENDF/B-VII.0 or ENDF/B-VII.1. The user cannowexporttheenvironmentvariableMISSING NUCLIDE MSG LEVEL QUIET to reduce theamount of information printed for nuclides missing fromthe cross section library. The calculation is performed withthe nuclide removed from the model, using a zero crosssection for each of the missing nuclide(s); the impact onradiation transport results and activation/depletion resultshas been assessed as negligible for most tested cases.TSUNAMIThe job information data imbedded in sensitivity data files(.sdf) from TSUNAMI-3D continuous-energy calculationshas been updated to provide the expected data.The material processor now supports the legacy SOLNformatted solution composition input that was supportedin SCALE 6.1.XSProcIssues occurring in cross-section processing affect allSCALE modules or sequences where XSproc is used.TRITONAn error that impacts depletion analyses using the ASSIGNfunction was present in SCALE 6.2. The error led toincorrect calculation of mass and volume for some of thedepleted materials, and consequently, incorrect calculationof the specific power for these materials. This issue wascorrected in SCALE 6.2.1. All SCALE 6.2 T-DEPLcalculations using ASSIGN should be reanalyzed withSCALE 6.2.1.For multigroup data, temperature interpolation forthreshold reactions could sometimes generate a negativecross section, such as for 232Th. This issue was resolved.The T-DEPL sequence in SCALE 6.2 contains a newcapability to swap materials in the timetable block. Thiscapability is designed to allow users to swap in and outcontrol rods and burnable absorber materials duringdepletion simulations. A bug was discovered in the swapimplementation that caused an incorrect powernormalization. Power is incorrectly applied to materialsthat are swapped out, resulting in an incorrect powernormalization for all materials. This bug may not beapparent to users because the materials associated with theswap function are correctly placed in the geometry and thecalculated keff behavior may appear to be correct; however,the power assigned to those materials is incorrectlycalculated. The magnitude of the impact increases withincreasing fuel burnup. The error can be seen by inspectingthe power summary table in the TRITON output file(search for “Material powers” or “Transport k”). In the“Total Power” column of this table, users will notice thatmaterials swapped out at a certain time still have powerapplied to them. This issue was resolved in the SCALE 6.2.1update. All SCALE 6.2 T-DEPL calculations using SWAPshould be reanalyzed with SCALE 6.2.1.Calculations using DOUBLEHET failed when CELLMIX wasused. This issue was resolved.Output edits in multigroup depletion calculations hadADDNUX nuclides with missing titles. The results ofcalculations were not affected. The issue was resolved inSCALE 6.2.1.In KENO-based TRITON calculations, the geometryvolume was being recalculated for each depletion step. Theresults were not affected. The issue was resolved in SCALE6.2.1, and the calculation efficiency was improved.ALIAS expansion is now available in KENO-based TRITONcalculations.SAMS mixture numbers longer than 4 digits are nowprinted in various sensitivity edits. This issue was aholdover from previous SCALE releases where mixturenumbers could not exceed 2147.Total sensitivity coefficients by nuclide and total sensitivitycoefficients by mixture are now displayed for all mixtures.In the cell data block, changing the origin of the zonedefinition in a multiregion model caused the calculation tofail. This issue was resolved.Using upper-case continuous-energy library names causedthe problem to stop. This issue was resolved.Calculations when CENTRM used npxs 0 and nfst 6 failed.This issue was resolved.In some depletion calculations when CENTRM was usedwith a user-provided Dancoff factor, memory grew perdepletion step. This issue was resolved.An issue was resolved with the thermal calculation routineusing the CENTRM 2D MOC solver option (npxs 6). Theimpact on criticality calculations for SCALE sample inputproblems was very small. Calculations with other npxsvalues are not affected.The CENTRM "iterp" temperature interpolation message isnow correctly identified as a warning (not an error) and islimited to one occurrence per calculation.Multigroup calculations involving multiregion cells withinvalid zone radii (equal radii for more than one zone)produced a misleading lbar is zero error. This message hasbeen updated to indicate the line and column of bothoffending cell radii.The default settings for legacy standalone (FIDO input)CENTRM calculations have been updated for consistencywith XSProc-based CENTRM.The MOC solver was updated to use equal-volume radialmesh for discretizing each material zone. Previous versionsof the MOC solver used equal-radii radial mesh. Althoughthe equal-volume radial mesh is more appropriate, thiscode change has little impact on the accuracy of selfshielded calculations.SCALE Newsletter (Fall 2016)4

Y12 (AMPX)A memory defect was resolved in the AMPX Y12 module,which would sometimes cause calculations to fail.SCALE 6.2 Open IssuesThe issues described below have not been resolved in theSCALE 6.2.1 update and are planned to be addressed in alater patch to the current release or in the next release ofSCALE.Units printed in the TRITON system masssummary output tableThe TRITON depletion sequences produce a system masssummary output table (see SCALE 6.2 documentationSection 3.1.5.4.3). One column header of this table states“Fractional HM Mass (g).” The values of this columncorrespond to fractional heavy metal (HM) mass, which is aunitless quantity. Users should be aware that the units arenot grams as the column header suggests. Moreover, thesystem mass summary table provides units for the HMmass of each material, as well as the units of thenormalization factor required to normalize the mass to 1metric ton of HM in the system. For example, for the 2Ddepletion (t-depl) sequence, the units of the HM massshould be g/cm, and the unit of the normalization should becm, For the 3D KENO sequences (t5-depl and t6-depl), thedisplayed units should be g and no units. However, the unitsdisplayed in the table are always g/cm and cm, regardless ofthe geometry's dimension. Users should be aware that for3D depletion calculations (and 1D slab or spheredepletion), the output file displays incorrect units for themass summary table. However, the data in the tables arecorrect and correspond to units based on the actualgeometry’s mpositions in TRITON calculationsSCALE has historically treated unreferenced compositions(i.e., compositions not explicitly identified in theCELLDATA block) as infinite homogeneous media nreferenced compositions undergo BONAMI andCENTRM self-shielding calculations based on the infinitehomogeneous treatment (if parm bonami, only BONAMI iscalled). To reduce runtime for depletion calculations,TRITON has historically performed only BONAMI infinitehomogeneous media self-shielding calculations for theunreferenced compositions, regardless of the parmspecification.TRITON in SCALE 6.2 further reduces runtime by treatingthe compositions as infinitely dilute instead of as an infinitehomogeneous media, meaning that resonance self-shieldingcalculations are not performed unless the composition isexplicitly identified in the CELLDATA block. In most cases,this update has a minor effect on results, as mostcompositions require self-shielding definitions. However,several compositions (e.g., structural materials) may beunreferenced, and the infinitely dilute treatment can lead tosome noticeable effects. To test for consistency, infinitehomogeneous media self-shielding can be explicitly addedto the cell block for any unreferenced composition (e.g., inf10 end to specify infinite homogeneous medium treatmentfor mixture 10 or inf 10 20 30 end to treat mixtures 10, 20,and 30 using only one line of input). Users can test forconsistency by comparing eigenvalue differences betweenTRITON and CSAS calculations, as CSAS continues toprovide the traditional approach of treating unreferencedcompositions as infinite homogeneous media.SCALE Quality Assurance ProgramThe SCALE quality assurance (QA) program was updatedin 2013 to provide improved high-quality software and datato the user community. The new QA program is compliantwith international standards in ISO 9001-2008, USDepartment of Energy Order 414.1D, and the ORNLStandards-Based Management System, and it is consistentwith US NRC guidelines in NUREG/BR-0167, as well asASME NQA-1. The SCALE QA program implements astreamlined Kanban process with continuous integration ofnew features and an automated test system that performsapproximately 100,000 tests per day on Linux, Macintosh,and Windows operating systems. This QA programprovides for rapid introduction of new features fordeployment to end users. However, the SCALE teammakes no guarantees regarding the performance of SCALEfor any specific purpose, and users should independentlysubmit the software to their own site- or program-specifictesting and validation prior to use.See http://scale.ornl.gov/moreinfo.shtml to download acopy of the SCALE QA plan.SCALE PublicationsThe SCALE team produces numerous publications ondevelopment and application activities, including peerreviewed journals, technical reports, and conferencepublications. Publications are often jointly created withusers and developers throughout the community. Asummary of publications released to date in 2016 isprovided here.Peer-Reviewed Journal ArticlesI. C. Gauld, J. M. Giaquinto, J. S. Delashmitt, J. Hu, G. Ilas,T. J. Keever, and C. Romano, “Re-evaluation of SpentNuclear Fuel Assay Data for the Three Mile Island Unit 1Reactor and Application to Code Validation,” Annals ofNuclear Energy 87, 267–281 .026A. E. Isotalo, G. G. Davidson, T. M. Pandya, W. A.Wieselquist, and S. R. Johnson, “Flux Renormalization inConstant Power Burnup Calculations,” Annals of NuclearEnergy 96, 148–157 .031S. W. D. Hart, C. Celik, G. I. Maldonado, and L. Leal,“Creation of Problem-dependent Doppler-broadenedCross Sections in the KENO Monte Carlo Code,” Annalsof Nuclear Energy 88, 49–56 .011SCALE Newsletter (Fall 2016)5

U. Mertyurek and I. C. Gauld, “ORIGEN Libraries forMOX Fuel Assembly Designs,” Nuclear Engineering andDesign 297, 220–230 11.027T. M. Pandya, S. R. Johnson, T. M. Evans, G. G. Davidson, S.P. Hamilton, and A. T. Godfrey, “Implementation,Capabilities, and Benchmarking of Shift, a Massively ParallelMonte Carlo Radiation Transport Code,” Journal ofComputational Physics 308, 239–272 V. Sobes, L. Leal, G. Arbanas, and B. Forget, “ResonanceParameter Adjustment Based on Integral Experiments,”Nuclear Science and Engineering 183(3), 347–355 (2016).http://dx.doi.org/10.13182/NSE15-50C. M. Perfetti, B. T. Rearden, and W. R. Martin, “SCALEContinuous-Energy Eigenvalue Sensitivity CoefficientCalculations,” Nuclear Science and Engineering 182(3), 332–353 (2016). http://dx.doi.org/10.13182/NSE15-12B. Ade, A. Worrall, J. Powers, and S. Bowman, “Analysis ofKey Safety Metrics of Thorium Utilization in LWRs,”Nuclear Technology 194, 162–177 (2016).http://dx.doi.org/10.13182%2fNT15-100M. T. Pigni, S. Croft and I. C. Gauld, “UncertaintyQuantification in (α,n) Neutron Source Calculations for anOxide Matrix,” Progress in Nuclear Energy 9, 147–152(2016). hnical ReportsJ. Hu, I. C. Gauld, J. L. Peterson, and S. M. Bowman, “U.S.Commercial Spent Nuclear Assembly Characteristics:1968–2013,” NUREG/CR-7227 s/nuregs/contract/cr7227/W. J. Marshall, B. J. Ade, S. M. Bowman, and J. S. MartinezGonzalez, “Axial Moderator Density Distributions, ControlBlade Usage, and Axial Burnup Distributions for ExtendedBWR Burnup Credit,” NUREG/CR-7224 s/nuregs/contract/cr7224/Conference ProceedingsT. A. Eckleberry, W. J. Marshall, E. L. Jones, and G. I.Maldonado, “Validation of KENO Thermal ModeratorDoppler Broadening Method in SCALE 6.2 Beta5 UsingContinuous-Energy B-VII.1 Library,” ANS Transactions 114,484–487 (2016).S. P. Hamilton, G. G. Davidson, T. M. Evans, and K.Banerjee, “Accelerated Monte Carlo Fission SourceConvergence with Fission Matrix and Kernel DensityEstimators,” ANS Transactions 114, 385–387 (2016).W. J. Marshall, B. J. Ade, and S. M. Bowman, “ApparentMonte Carlo Source Convergence Problem with BWR FuelDepleted with Partial Control Blade Insertion,” ANSTransactions 114, 475–478 (2016).C. M. Perfetti and B. T. Rearden, “CE TSUNAMI-3DAlgorithm Improvements in SCALE 6.2.,” ANS Transactions114, 385–387 (2016).C. M. Perfetti and B. T. Rearden, “A New TSUNAMI-3DCapability for Calculating Undersampling Metrics andBiases,” ANS Transactions 114, 385–387 (2016).G. Ilas, B. Betzler, B. Ade, “Impact of Reactor OperatingParameters on Cask Reactivity in BWR Burnup Credit,”CD Proceedings, PATRAM 2016, Kobe, Japan (2016).W. J. Marshall, B. J. Ade, and S. M. Bowman, “Study of AxialBurnup Profile Effects on BWR Burnup Credit,” CDProceedings, PATRAM 2016, Kobe, Japan (2016).D. Chandler and R.J. Ellis, “Development of an EfficientApproach to Perform Neutronics Simulations forPlutonium-238 Production,” CD Proceedings, PHYSOR2016, Sun Valley, ID, USA (2016).G. G. Davidson, T. M. Pandya, A. E. Isotalo, S.R. Johnson, T.M. Evans, W. A. Wieselquist, “Nuclide DepletionCapabilities in the Shift Monte Carlo Code,” CDProceedings, PHYSOR 2016, Sun Valley, ID, USA (2016).G. Radulescu and K. J. Connolly, “A Parametric Analysis ofFactors Affecting Calculations of Estimated Dose Ratesfrom Spent Nuclear Fuel Shipments,” CD Proceedings,WM2016 Symposium, Phoenix, AZ, USA (2016).Do you have a publication documenting the applicationof SCALE to a challenging analysis scenario? Submit yourpublication to scalehelp@ornl.gov and it may appear in afuture edition of the SCALE Newsletter!SCALE Newsletter (Fall 2016)6

SCALE TeamThe SCALE team consists of 40 talented and diverse staff members from ORNL’s Reactor and Nuclear Systems Division. Mostof our team members hold advanced degrees in nuclear engineering, physics, and/or computer science. SCALE development,testing, deployment, and training are organized into task-oriented teams as shown below in Fig. 2 Many other internal andexternal collaborators and students also contribute to SCALE on an ongoing basis.A photo of the team members present for the release of SCALE 6.2 is shown in Fig. 3 below.SCALE Leadership TeamBrad ReardenManager, SCALE Code SystemMatt JesseeDeputy Manager, SCALE Code SystemSteve BowmanGroup Leader, Reactor PhysicsMike DunnGroup Leader, Nuclear Data and Criticality SafetyBob GroveGroup Leader, Radiation TransportRob LefebvreSoftware Development CoordinatorMark WilliamsStrategic VisionDistinguished R&D StaffQuality Assurance PlanBudgets and StaffingChange Control BoardInfrastructureDevelopment andand SoftwareSupportTony WalshSeth JohnsonBrandon LangleyJordan LefebvreRob LefebvreAdam ThompsonSheila WalkerQuality AssuranceSystemBuild and TestFrameworkDeploymentMonte CarloMethodsBrad ReardenBrian AdeKaushik BanerjeeKursat BekarCihangir CelikGreg DavidsonTom EvansCole GentryShane HartGermina IlasSeth JohnsonTara PandyaChris PerfettiKatherine RoystonDoro WiardaSteve n, Decay,and ActivationMethodsReactor PhysicsMethodsMatt JesseeBrian AdeKursat BekarBen BetzlerGreg DavidsonTom EvansCole GentrySteven HamiltonRob LefebvreUgur MertyurekDoro WiardaWill WieselquistMark WilliamsWill WieselquistIan GauldShane HartGermina IlasThomas MillerSteve Skutnik (UT)Doro WiardaMark WilliamsORIGENORIGAMIDepletion, Decay,and ActivationDataTRITONPolarisAdvancedReactor R&DNuclear Data andMethodsCihangir CelikCharles DailyShane HartAndrew HolcombMatt JesseeSeth JohnsonKang Seog KimRob LefebvreB.J. MarshallMarco PigniDoro WiardaMark WilliamsXSProcNeutron and GammaCross Section Data(MG&CE)Covariance DataUser InterfaceDevelopmentRob LefebvreMatt JesseeBrandon LangleyBJ MarshallJosh PetersonAdam ThompsonWill WieselquistFulcrumSNAPGeometry andData VisualizationSensitivity andUncertaintyAnalysisChris PerfettiGoran ArbanasAaron BevilleKeith BledsoeMatt JesseeElizabeth JonesJordan LefebvreB.J. MarshallUgur MertyurekThomas MillerVladimir SobesWill WieselquistMark WilliamsTSUNAMITSURFERSAMPLEROptimization andInverse AnalysisUser Interactionand TrainingGermina IlasBrian AdeBen BetzlerJustin ClarityIan GauldShane HartMatthew JesseeHenrik LiljenfeldtB.J. MarshallThomas MillerDon MuellerChris PerfettiDouglas PeplowJoel RisnerSheila WalkerWill WieselquistCourses at ORNL, NEAData Bank, NRC, and UserFacilitiesConference WorkshopsHelpline, documentation,beta distributions30 SCALEFig. 2. SCALE Team StructureFig. 3. SCALE 6.2 Team Photo - April 2016 (Left to right. First Row: Jianwei Hu, Germina Ilas, Tara Pandya, Shane Hart, Lester Petrie,Brad Rearden, Bob Grove, Mike Dunn, Mark Williams, Georgeta Radulescu, Elizabeth Jones, Ian Gauld; Second Row: Matt Jessee, SteveSkutnik, Kevin Clarno, Tony Walsh, Cihangir Celik, R

CCC-466/SCALE 3 in 1985 CCC-725/SCALE 5 in 2004 CCC-545/SCALE 4.0 in 1990 CCC-732/SCALE 5.1 in 2006 SCALE 4.1 in 1992 CCC-750/SCALE 6.0 in 2009 SCALE 4.2 in 1994 CCC-785/SCALE 6.1 in 2011 SCALE 4.3 in 1995 CCC-834/SCALE 6.2 in 2016 The SCALE team is thankful for 40 years of sustaining support from NRC