RSIC CODE PACKAGE CCC- 657
1. NAME AND TITLE
BETA-S 6: A Code System to Calculate Multigroup Beta-Ray Spectra.
ENSDF-95: Beta-decay transition data based on the Evaluated Nuclear Structure Data Files maintained by NNDC at Brookhaven National Laboratory.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
CANDU Owner Group, Toronto, Ontario, Canada.
Atomic Energy of Canada Limited, Whiteshell Laboratories, Manitoba, Canada.
3. CODING LANGUAGE AND COMPUTER
FORTRAN 90; Pentium running Linux or Windows (C00657/MNYCP/01).
4. NATURE OF PROBLEM SOLVED
BETA-S calculates beta-decay source terms and energy spectra in multigroup format for time-dependent radionuclide inventories of actinides, fission products, and activation products. Multigroup spectra may be calculated in any arbitrary energy-group structure. The code also calculates the total beta energy release rate from the sum of the average beta-ray energies as determined from the spectral distributions. BETA-S also provides users with an option to determine principal beta-decaying radionuclides contributing to each energy group. The SCALE code system must be installed on the computer before installing BETA-S, which requires the SCALE subroutine library and nuclide-inventory generation from the ORIGEN-S code. This release is compatible with SCALE Versions 5.0, 5.1 and 6. The following enhancements were completed in this version:
· the BETA-S source code was converted to modern Fortran 90 standard
· dynamic memory allocation implemented
· the free-format input reading routines were replaced with reading modules in SCALE 5
· added the capability to obtain beta decay branching data from either a binary or card-image format ORIGEN data library (required for compatibility with ORIGEN-ARP)
· corrected an error associated with spectral calculation in highest energy group
· improved spectrum calculation by normalizing spectral energy to evaluated beta energy
· added capability to generate plot files compatible with PlotOPUS program.
Note that default input values were eliminated in this release, so all input variables are now needed. Some libraries now have different numbers of nuclides which can cause problems. To address this, the code now also works with either the card-image nuclear data library or a binary library (e.g., origen-arp). If the ORIGEN inventory file was generated using a binary library, BETA-S should be required to use the same library when doing the spectrum calculation to make sure the library is consistent with the nuclide set.
5. METHOD OF SOLUTION
Well-established models for the beta-energy distributions are used to explicitly represent allowed, and 1st -, 2nd - and 3rd -forbidden unique transition types. Forbidden non-unique transitions are assumed to have a spectral shape of allowed transitions. Multigroup energy spectra are calculated by numerically integrating energy distribution functions using an adaptive Simpson’s Rule algorithm.
Nuclide inventories are obtained from a binary interface produced by the ORIGEN-S code. BETA-S calculates the spectra for all isotopes on the binary interface that have associated beta-decay transition data in the ENSDF-95 library, developed for the BETA-S code. This library was generated from ENSDF data and contains 715 materials, representing approximately 8500 individual beta transition branches.
6. RESTRICTIONS OR LIMITATIONS
The algorithms do not treat positron (β+) decay transitions or internal conversion electrons. The neglect of β+ transitions is inconsequential for most applications involving aggregate fission products, since most of the decay modes are via β-. The neglect of internal conversion electrons may impact on the accuracy of the spectrum in the low-energy region (<1MeV). Approximations in the representation of the spectral shape factors for the forbidden transitions may lead to poor spectral representation for some nuclides.
7. TYPICAL RUNNING TIME
Typical problems require a few seconds to complete on a Pentium IV 2.66GHz.
8. COMPUTER HARDWARE REQUIREMENTS
BETA-S has been installed and verified on Personal Computers running Windows and Linux. Porting to any platform for which the SCALE system is available should require minimal effort. Source code is included and can be recompiled if the distributed executables do not work.
9. COMPUTER SOFTWARE REQUIREMENTS
BETA-S has been installed on Linux and Windows XP and Windows Vista operating systems. The code is written in Fortran 90. Several C language utility routines, primarily for system quality assurance functions, are obtained from the SCALE subroutine library. Included executables are compatible with SCALE Versions 5 and 6. They were created by linking with the SCALE 6 subroutine library on these systems:
· Fedora 8 Linux with the 32-bit Intel Fortran 11.0.069 compiler
· Red Hat Enterprise Linux 4 with the 64-bit Intel 10.1.015 compiler
· Windows XP Service Pack 2 with the Intel Fortran 10.1.021 compiler
I. C. Gauld, “Upgrade of the Multigroup Beta Calculation Code BETA-S,” ORNL paper (December 2008).
I. C. Gauld and S. G. King, “BETA-S: A Code to Calculate Multigroup Beta Spectra,” RC-1564 (COG-93-33-I) (April 1996).
11. CONTENTS OF CODE PACKAGE
Included are the referenced documents and one CD with a GNU compressed Unix tar file which includes BETA-S source files, ENSDF-95 library, test cases, executables and documentation..
12. DATE OF ABSTRACT
November 1997, revised December 2008.
KEYWORDS: BETA-RAY; MICROCOMPUTER; WORKSTATION