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Computational Physics and Engineering Division Nuclear Engineering Applications Section Oak Ridge National Laboratory
Number 17, January 1998
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In This Issue ...
Coming Soon: SCALE-4.4
Version 4.4 of the SCALE code system is nearing completion. This new version should be available from the Radiation Safety Information and Computational Center (RSICC) in March or April. Watch our Web site for up-to-date information on its release.What's New in SCALE-4.4?
Many enhancements and corrections have been made to SCALE in the two years since the release of SCALE-4.3. SCALE-4.4 is compatible with the year 2000 (see "SCALE-4.4 is Year 2000 Compatible"). User-specified surface detectors have been added to SAS4/MORSE to improve its computational flexibility and efficiency (see "Improvements to SAS4 and MORSE"). Some significant improvements to the speed and stability of KENO-VI have been made recently (see "Recent KENO-VI Stability and Speed Improvements"). A large number of changes have been made to the SAS2 depletion module (see "SAS2 Corrections and Enhancements").Several enhancements have been made to the PC version of SCALE-4.4. A significant effort has been made to minimize the programming differences between the PC and Unix workstation versions. Both versions will contain the same modules. The heat transfer modules HTAS1, HEATING, and the HEATING auxiliary codes are now available in the PC version for the first time. The PC version can recognize DOS, Windows 95, and Windows NT operating systems and run under any of these three systems from a single user command. CSAS can now be run directly from the CSASIN input processor.
ORIGEN-ARP, which was first released in the PC version of SCALE-4.3, has been enhanced and now runs under the SCALE driver, so it can run easily on workstations as well as PCs. ORIGEN-ARP has been improved significantly. ARP now interpolates on moderator density as well as burnup and enrichment for BWR fuel types. Several auxiliary codes have been added that enable users to generate their own ORIGEN-ARP cross-section libraries via SAS2.
The default number of histories in KENO V.a and KENO-VI have been increased to 200,000 to produce more statistically accurate results. Color plots are now the defaults in both these codes.
PICTURE has been upgraded to generate two- dimensional (2-D) color plots of MORSE/MARS and QADS/QAD-CGGP geometry models like the color plots generated by KENO V.a and KENO-VI in SCALE-4.3. A new utility, LEGEND, has been created that adds a color/material legend and title to the color plots generated by KENO and PICTURE.
KMART is a new module to allow post-processing of a KENO V.a restart file, along with a working format cross-section library, to generate activities and/or broad-group fluxes and to compute the fission production activity if the components are available in the working cross-section library for the requested nuclide.
Other additions to SCALE-4.4 that have been discussed in previous issues include the new KENO biasing weights library for 16-, 27-, 44-, 218-, and 238-group problems; the C5TOC6 and K5TOK6 conversion utilities for KENO-VI; and the Q0RDPN binary to ASCII conversion utility for functional module FIDO input files.
The SCALE manual will be distributed in electronic format on CD with the software. The manual will be formatted in PDF files that can be read, searched, and printed using Adobe Acrobat Reader. Refer to the July 1997 issue of the SCALE Newsletter for more information. Users who desire a hard copy of the manual may obtain one from RSICC for an additional charge to cover reproduction costs.
Many other minor changes to SCALE are listed under "SCALE-4.3 Minor Modifications" in this and previous issues.
Improvements to SAS4 and MORSE
SAS4 and MORSE have been enhanced to allow users to specify multiple non-overlapping surface detectors on each surface (previously defaulted to 4 locations). These surface detectors can be divided into "sub- detectors" that enable the user to obtain detailed dose rate profiles. The flexibility in the use of these surface detectors makes them suitable for the substitution of point detectors, which are much less computationally efficient. Another enhancement to SAS4 was the addition of an option to generate geometry data only for the purpose of running PICTURE to view 2-D slices of the geometry.Improvements to MORSE include orderly termination of a problem when errors in tracking to detector exceed a limit, an option to print/not print flux output after each batch, user capability to specify the number of direct-access blocks allocated on scratch units, compatibility with the year 2000, and reduction of the amount of error output in some cases.
SCALE-4.4 is Year 2000 Compatible
SCALE-4.4 is year 2000 compliant. Current and earlier versions of SCALE should calculate results correctly beyond the year 2000. However, when the year 2000 occurs, the output from some codes in these earlier versions will incorrectly display the year as 1900 instead of 2000. All known instances of this problem have been corrected in SCALE-4.4.Recent KENO-VI Stability and Speed Improvements
Improvements have been made to KENO-VI since the last Web update to increase the stability and the speed of KENO-VI. To improve the code's stability, logic has been added to KENO-VI to check if a particle is still in the boundary region of a unit when it is no longer in any region. If this occurs, an error message is printed and the program terminates. This situation is often caused by an undefined volume in a unit and could previously lead to the program entering an infinite loop.To improve the execution speed of KENO-VI, the following modification has been made: When a particle is in an array, the particle is tracked both in the unit where it is currently within the array and in the unit containing the array. It needs to be tracked in the unit containing the array so it knows when it crosses out of the array. Previously, the crossing distance to every surface in that unit was calculated. The code has been changed to calculate only the crossing distance to the surfaces related to the array boundary. This change will significantly reduce the running time of problems where particles spend most of the time in an array or where the array is in a complex unit containing many additional regions unrelated to the array boundary. Running times have been reduced by as much as 15% for arrays contained in complex units.
SAS2 Corrections and Enhancements
A large number of corrections and enhancements have been completed in SAS2 for the release of SCALE-4.4. They are listed below.New Download Updates Available on SCALE Web Site
Two downloads have been updated on the "Download" page on the SCALE Web site.Words to the Wise...
SAS2 (alpha,n) spectra in fuel with Al
SAS2 users with interests in quantifying spent fuel source terms for non-LWR (light-water-reactor) applications should be aware of several issues. The SAS2 methodology was originally envisioned for PWR (pressurized-water reactor) and BWR (boiling- water reactor) applications only. Recent updates, such as the addition of the SYMMSLABCELL option in SAS2, have made it possible for plate-type fuel to be treated in a more rigorous manner. However, the user should be aware of several underlying assumptions in the SAS2/ORIGEN-S codes. The default means of accounting for neutron production from (alpha,n) reactions in ORIGEN-S and SAS2 is via a uranium dioxide (UO2) matrix. Although this default is appropriate for LWR-type fuel, care should be used in generating the neutron source from SAS2 for other type fuels (e.g., metal, carbide, ceramic metal). ORIGEN-S includes a borosilicate glass option for (alpha,n) production, but currently there is no option in SAS2 to exercise this feature. A stand-alone ORIGEN-S case, following a SAS2 case, is recommended to account for this effect.Under certain conditions, the stand-alone ORIGEN-S case will also have to modify the quantities of nuclides that are automatically passed from SAS2 to ORIGEN-S, typically via unit 71 (ft71f001). The reason for this correction is that the fuel and clad materials are passed to ORIGEN-S and included in the (alpha,n) source estimation. However, only the fuel isotopes should be included in the (alpha,n) source computation. The most direct way to selectively remove elements from ORIGEN-S processing is the use of the 79** array. The weight fraction of elements in the fuel for the fuel source term should be entered in this array. The input for this type of case can be prepared easily using either the ORIGNATE or the ORIGEN-ARP input processor.
Another important consideration is that of the resulting spectrum. The spectrum corresponding to the built-in UO2 (alpha,n) source is appropriate for the UO2 case. The borosilicate glass option, which must be used for all other fuel types, assumes a spectrum corresponding to boron. The boron spectrum is the hardest and, therefore, the most conservative. In some cases this spectrum could be considered overly conservative, and steps to correct this conservatism would be appropriate.
Materials that have a significantly larger (alpha,n) neutron production than that of oxygen should be treated via the borosilicate glass option. These include, but are not limited to, lithium, beryllium, boron, fluorine, magnesium, aluminum, silicon and sodium. For these materials, the (alpha,n) production may be large enough to compete with the spontaneous fission source term. For oxygen, the (alpha,n) source generation is typically an order of magnitude below the spontaneous fission contribution and thus of little importance overall.
Adjust End Fittings Source in SAS4
A recent question from a user highlighted the potential misinterpretation of an input quantity for the SAS4 code. The calculation of dose contributions from the hardware, or end fittings, region can be accomplished via the ISO parameter. When this option is used, the value of SFA, the total source normalization, must be specified carefully. This case is noted in the last paragraph of Sect. S4.2.4 of the SCALE manual.In SAS4, the cask model is assumed to be symmetric about the axial midplane. Thus, for either an axial or a radial calculation, with the source originating from the hardware region, the particles are started from BOTH the top and bottom hardware regions. The total source strength, SFA, is therefore twice the source intensity of one hardware region. If the SFA value corresponds to the total source strength from one end of the fuel hardware, the answers from the hardware need to be doubled. This adjustment is necessary whether the case is an axial or radial case.
SCALE-4.3 Minor Modifications
The following minor corrections and updates will be included in the RSICC release of SCALE-4.4. Unless otherwise noted, these modifications resulted in insignificant changes in overall results or allowed cases to run that previously failed. Other minor modifications from version 4.3 to 4.4 have been listed in previous issues of the SCALE Newsletter.KENO V.a: (a) Corrected variable type in format statements for debug prints. This discrepancy causes problems on some systems, including PCs when debug print is turned on (DBG=YES). (b) Changed default plot type to color. (MRRs 97-015 and 98-007)
KENO-VI: (a) Corrected an error in placement of starting points for start type 6. (b) Corrected an error in the flux calculation for regions containing holes or arrays. (c) Corrected a roundoff problem with arrays offset a long distance from the origin. This problem could sometimes cause an infinite loop. (d) Corrected a variable that was misnamed and, as a result, was used without being initialized. (e) Set a lower limit for the calculated crossing tolerance to prevent the code from entering an infinite loop. Also made minor changes to the particle-tracking output when parameter TRK=YES. (f) Updated to allow starting points in a volume larger than the global unit. (g) Updated to terminate a problem if a particle in subroutine TRACK gets lost. Also, updated to allow problems that contain array data but do not reference the arrays in the GEOMETRY data block to run. (h) Updated to change the logic in calculating the array boundary crossing distance (decreases running time for some problems) and to change the default plot type to color. (MRRs 97-022, 97-029, 97-030, 97- 035, 98-001, 98-006)
AWL: Added AWL to SCALE to convert AMPX working format libraries between ASCII and binary formats. It is required for the SCALE Criticality V&V package. (MRR 97-023)
BONAMI: Updated to improve error handling procedure and messages. (MRR 97-033)
MORSE: Updated to include changes to surface detectors for SAS4 cases, to correct a problem in DIREC for NDSG=17 case, to allow orderly termination of a problem when errors in tracking to detector exceed a limit, to add an option to print/not print flux output after each batch, to input the number of direct-access blocks allocated on scratch units, to change the way date is output (to handle the year 2000 and beyond) and to reduce the amount of error output in some cases. (MRR 97-025)
COUPLE: Updated for year 2000 compatibility, PC version compatibility, uppercase or lowercase input files, and for printing the banner page only when COUPLE is first called. (MRR97-036)
ORIGEN: Updated for year 2000 compatibility and to correct calculation of He-3 and H-3 for long time steps and high flux. (MRR 97-037)
SAS3: Updated to be compatible with the new MORSE input options and to implement the PARM=SIZE parameter which was not being passed to MORSE. (MRR 97-040)
XSDRNPM: Updated to correct the accumulation of zone fluxes when inner-cell weighting is selected. (MRR 98-002)
Standard Composition Library: Updated the standard composition ZIRC2 for consistency with current technical standard and updated densities for SS304 and SS316. (DRR 97-010)
CSAS / KENO V.a / KENO-VI/SAS2 sample problems: Updated to use the 44-group library. (DRRs 97-011, 97-012, and 97-013)
238- and 44-group cross-section libraries: Corrected negative scattering and total cross sections for minor actinides, fission products, and beryllium metal. Also corrected thermal Bondarenko factors for potassium. Only significant impact should be on cases where potassium is important in the thermal range. (DRRs 97-014 and 97-015)
27-group Burnup cross-section library: Updated data on rhodium-103 so that Bondarenko factors are generated in the unresolved resonance range. A test case based on 4.5 wt % UO2 burned to 54,585 MWD/MTU, cooled for 5 years, was run. The calculated keff increased by 0.06% with the new Rh-103 cross sections. (DRR98-002)
The MRR (or DRR) number refers to the Module (or Dataset) Revision Report that documents the change(s) made under the SCALE Configuration Management Plan. It is provided to assist readers who contact the SCALE staff concerning any of these changes
SCALE Training Course Schedule for 1998
The SCALE staff at ORNL will be offering several training courses in 1998. The courses emphasize hands-on experience solving practical problems on PCs in workgroups of three persons each. No prior experience in the use of SCALE is required to attend these courses. All courses are conducted at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The registration fee for each course is $1,200. A combined registration fee of $2,000 is available for the two fall courses, which are offered on consecutive weeks. A copy of the SCALE software and manual on CD is included in the registration fee. Registrations will be accepted on a first-come basis. Registration forms may be submitted via FAX or e-mail to reserve your place.The agenda and registration form for the SCALE KENO-VI Training Course are included in this Newsletter.
Date Title Description April 27 - 30 SCALE KENO-VI Course In-depth introduction to CSAS6/KENO-VI criticality safety code for complex geometries Oct. 27 - 30 SCALE KENO V.a Course In-depth introduction to CSAS/KENO V.a (May be combined with the SCALE Shielding & Source Terms Course) Nov. 2 - 5 SCALE Shielding & Source Terms Course In-depth introduction to SCALE shielding and depletion/decay sequences (including ORIGEN-ARP)
Classes are limited to 24 participants and are subject to cancellation if minimum enrollment is not obtained. Course fees are refundable up to one month before each class. Classes are cosponsored by RSICC.
For further information, contact Steve Bowman, scalehelp@ornl.gov , 423-574-5263.
SCALE KENO-VI Training Course Agenda (April 27 - 30)
Monday, April 27
Introduction to CSAS6
Resonance Self-Shielding
Standard Composition Library
Unit Cell Types
KENO-VI Parameters
KENO-VI Geometry
KENO-VI Plot Data
Problem Session 1
Tuesday, April 28
Review of Problem Session 1
Geometry Modification Data
(Chords/Rotate/Translate)
Media/Holes
Media/Arrays
Problem Session 2
Wednesday, April 29
Review of Problem Session 2
KENO-VI Output - How to Read It
Start Data
Bias Data
Boundary Data
Mixing Table
Problem Session 3
Thursday, April 30
Review of Problem Session 3
Monte Carlo Uncertainties
Code and Data Validation Issues
Problem Session 4 (Bring your own problems)
SCALE KENO-VI Training Course Registration Form
Oak Ridge National Laboratory, Oak Ridge, Tennessee
Conducted by the SCALE Project Staff
April 27-30, 1998
Cosponsored by the Radiation Safety Information and Computational Center (RSICC)I am registering for the KENO-VI Course. Fee: $1,200 Name ___________________________________________________________ Citizenship ___________________________________________________________ Organization ___________________________________________________________ Mailing address ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ Telephone: ________________________ Fax: ________________________ E-mail: ___________________________________________________________ Your experience using the following computer programs (circle one for each): Extensive None Criticality CSAS 5 4 3 2 1 0 KENO V.a 5 4 3 2 1 0 CSAS6 5 4 3 2 1 0 KENO-VI 5 4 3 2 1 0 What are your personal objectives in taking this course (e.g., what do you hope to do or learn at the course)? Please mail this form and payment of $1,200 registration fee to:SCALE KENO-VI Training Course
c/o Steve Bowman
Oak Ridge National Laboratory
P.O. Box 2008, MS 6370
Oak Ridge, Tennessee 37831-6370
NOTE: Classes are limited to 24 participants and may be canceled if minimum enrollment is not obtained. Course fees are refundable up to one month before each class.
A copy of the SCALE software and manual on CD is included in the registration fee.
Hotel Registration Form
Several restaurants and shopping locations and the American Museum of Science and Energy are within walking distance of the hotel.
Return to:
GARDEN PLAZA HOTEL
215 S. Illinois Avenue
Oak Ridge, Tennessee 37830
Tel.: 423/481-2468
Fax: 423/481-2474
Please reserve a room in my name in the block of rooms available for the SCALE KENO-VI Training Course.
Block room rate: $65 per night plus tax
Deadline for reserving a room at this special rate is April 5.Name _______________________________________________________________ Organization _______________________________________________________ Credit Card No. ____________________________________________________ Arrival Date & Time:_____________Departure Date & Time______________ Airline Discount for SCALE KENO-VI Training Course
Delta Air Lines is offering the following special discounted fares for the SCALE KENO-VI Course:
Additional discount may be available if tickets are purchased 60 days or more before travel. Some restrictions will apply and seats are limited. To obtain these special fares, call or have your travel agent call 1-800-241-6760. Refer to File No. 110424A. Reference to the meeting title is not necessary.
SCALE Newsletter is published twice a year by Oak Ridge National Laboratory and sponsored by the Spent Fuel Project Office of the U.S. Nuclear Regulatory Commission and by the Office of Transportation, Emergency Management, and Analytical Services of the U.S. Department of Energy.
Address all correspondence (including address additions or changes) to:
SCALE Newsletter Oak Ridge National Laboratory P.O. Box 2008, MS-6370 Oak Ridge, TN 37831-6370
FAX: (423) 576-3513
E-mail: scalehelp@ornl.gov
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Last Modified Feb. 20, 1998