TIMS-1: A Processing Code for Production of Group Constants of Heavy Resonant Nuclei.

摘要

The TIMS-1 code calculates the infinitely dilute group cross sections and the temperature dependent self-shielding factors for arbitrary values of sigma sub 0 and R, where sigma sub 0 is the effective background cross section of potential scattering and R the ratio of the atomic number densities for two resonant nuclei if any. This code is specifically programmed to use the evaluated nuclear data file of ENDF/B or JENDL as input data. In the unresolved resonance region, the resonance parameters and the level spacings are generated by using Monte Carlo method from the Porter-Thomas and Wigner distributions, respectively. The Doppler broadened cross sections are calculated on the ultra-fine lethargy meshes of about 10 exp -3 to 10 exp -5 using the generated and resolved resonance parameters. The effective group constants are calculated by solving the neutron slowing down equation with the use of the recurrence formula for the neutron slowing down source. The output of the calculated results is given in a format being consistent with the JAERI-Fast set (JFS) or the Standard Reactor Analysis Code (SRAC) library. Both FACOM 230/75 and M200 versions of TIMS-1 are available. (Atomindex citation 12:630157)