Authors & Affiliations
Ivanov A.S., Karpov A.S.
Alexandrov Research Institute of Technoloqy, Sosnovy Bor, Russia
Ivanov A.S. – Cand. Sci. (Tech.), Alexandrov Research Institute of Technoloqy.
The SAPFIR_95 program based on the many-group neutron data libraries calculates neutronic characteristics of reactor cells during the fuel burnup. ABBN 78/S 95 many-group library is used together with the certified version of the program.
Today the new many-group neutron data library is received and the new fuel burnup scheme is developed on the basis of the modern evaluated nuclear data files of ROSFOND. Cross sections libraries and burnup schemes are formed automatically using NJOY-B30 system. Neutron cross section libraries in epithermal region use 23-groups of the ABBN system and 40-group representation for thermal region. The fuel burnup scheme plainly considers around four hundred of fission fragments and actinides. Fission yield in the scheme is specified with regard to the energy of the neutrons that cause the fission of fuel nuclides. It helps to create the uniform scheme of fuel burnup for both thermal and fast reactors.
The SAPFIR_95 program is considerably upgraded as well. First, the segment of fuel burnup calculation has been completely revised. The new algorithm does not use the approach of effective fission fragment anymore and considers all significant fission fragments. Neutron cross-sections of fission fragments are presented in the many-group form considering the factors of resonant self-screening in the region below the 15th group. New version of the program does not use the simulated fission spectrum and considers the actual spectrums of fission neutrons of the main fissile materials. Matrixes of inelastic processes and ranges of fission neutrons are increased by one group. The resonance correlation algorithm when using the generalized subgroup approach is developed for region of the resolved resonances.
This paper describes the structure of neutron data libraries and upgraded algorithms. The results of test calculations using the new libraries and fuel burnup schemes are given.
cells of reactor calculation, SAPFIR_95 program, evaluated ROSFOND and ENDF/B-VII data, group constant, fuel burnup
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