NRSC, Neutron Resonance Spectrum Calculation System

1 - Description of program or function: The NRSC system is a package of four programs for calculating detailed neutron spectra and related quantities, for homogeneous mixtures of isotopes and cylindrical reactor pin cells, in the energy resonance region, using ENDF/B evaluated nuclear data pre-processed with NJOY or Cullen's codes up to the Doppler Broadening and unresolved resonance level. 2 - Methods: NRSC consists of four programs: GEXSCO, RMET21, ALAMBDA and WLUTIL. GEXSCO prepares the nuclear data from ENDF/B evaluated nuclear data pre-processed with NJOY or Cullen's codes up to the Doppler Broadening or unresolved resonance level for RMET21 input. RMET21 calculates spectra and related quantities for homogeneous mixtures of isotopes and cylindrical reactor pin cells, in the energy resonance region, using slowing-down algorithms and, in the case of pin cells, the collision probability method. ALAMBDA obtains lambda factors (Goldstein-Cohen intermediate resonance factors in the formalism of WIMSD code) of different isotopes for including on WIMSD-type multigroup libraries for WIMSD or other cell-codes, from output of RMET21 program. WLUTIL is an auxiliary program for extracting tabulated parameters related with RMET21 program calculations from WIMSD libraries for comparisons, and for producing new WIMSD libraries with parameters calculated with RMET21 and ALAMBDA programs. 3 - Restrictions on the complexity of the problem: GEXSCO program has fixed array dimensions that are suitable for processing all reasonable outputs from nuclear data pre-processing programs. RMET21 program uses variable dimension method from a fixed general array. ALAMBDA and WLUTIL programs have fixed arrays that are adapted to standard WIMSD libraries. All programs can be easily modified to adapt to special requirements.