1. NAME AND TITLE
STAYSL PNNL: STAYSL PNNL Suite of Software Tools.
BCF – calculates flux history correction factors
SigPhi Calculator – calculates corrected SigPhi estimates
SHIELD – perform self-shielding calculations
NJOY99 – Processes data to obtain cross sections and covariances (not included in package)
NJpp – Extracts cross section and covariance data to a useful format
Northwest National Laboratory, Richland, Washington.
3. CODING LANGUAGE AND COMPUTER
Fortran, Excel; PC – Windows, XP (P00589PCX8600).
4. NATURE OF PROBLEM SOLVED
The STAYSL PNNL software suite provides a set of tools for working with neutron activation rates measured in a nuclear fission reactor, an accelerator-based neutron source, or any neutron field to determine the neutron flux spectrum through a generalized least-squares approach. This process is referred to as neutron spectral adjustment since the preferred approach is to use measured data to adjust neutron spectra provided by neutron physics calculations. The input data consist of the reaction rates based on measured activities, an initial estimate of the neutron flux spectrum, neutron activation cross sections and their associated uncertainties (covariances), and relevant correction factors. The output consists of the adjusted neutron flux spectrum and associated covariance matrix, which is useful for neutron dosimetry and radiation damage calculations.
5. METHOD OF SOLUTION
The software suite consists of the STAYSL PNNL, SHIELD, BCF, and NJpp Fortran codes and the SigPhi Calculator spreadsheet tool. In addition, the development of this software suite and associated data libraries used the third-party NJOY99 Fortran code. The NJOY99 and NJpp codes are used to assemble cross section and covariance input data libraries (for both SHIELD and STAYSL PNNL) from the International Reactor Dosimetry File of 2002 (IRDF-2002) developed by the Nuclear Data Section of the International Atomic Energy Agency (Vienna, Austria). The BCF, SigPhi Calculator, and SHIELD software tools are used to calculate corrected activation rates and neutron self-shielding correction factors, which are inputs to the STAYSL PNNL code.
6. RESTRICTIONS OR LIMITATIONS
STAYSL PNNL is best used for spectral adjustment to refine a reasonable estimate of the neutron spectrum, not as a tool to determine a completely unknown neutron spectrum. The STAYSL PNNL suite using the IRDF-2002 data is limited to evaluations for neutrons below 20 MeV. For problems with neutrons above 20MeV, different cross section and covariance libraries are required. STAYSL PNNL is limited to using four cover materials (boron, cadmium, gadolinium, and gold). The mini-spectrum output is a collapsed representation provided for user convenience in diagnostic assessment of the output or as an aid to more compact reporting of results.
7. TYPICAL RUNNING TIME
8. COMPUTER HARDWARE REQUIREMENTS
IBM compatible personal computer of recent manufacture.
9. COMPUTER SOFTWARE REQUIREMENTS
Windows Xp or Windows 7. Microsoftt Excel 2003 or Excel 2007.
a) Included Documentation:
Readme_STAYSL_PNNL_Suite_2013-04-12 (April 12, 2013).
11. CONTENTS OF CODE PACKAGE
The package is distributed on a CD with a compressed zip file including an installation file, documentation, and test cases.
12. DATE OF ABSTRACT
KEYWORDS: COVARIANCE DATA PROCESSING; DATA PROCESSING, SPECTRA; ENDF FORMAT; UNFOLDING