Status of updating the cross section library of the Juelich reactor dynamic codes TINTE/MGT to ENDF-B-7 - 018

The nuclear cross section library SPECLIB used in the Juelich reactor-dynamic codes TINTE and MGT are based on the 43 groups MUPO library. This paper reports on updating the cross section library to ENDF-B-VII data. The generation of transport, absorption, and fission cross section as well as the preparation of resonance tables will be described. Absorption cross sections of 232Th, 238U, 240Pu, and 242Pu in the resonance range as function of temperature and nuclide concentration were calculated with MCNP4C. First MGT simulations performed with the new ENDF-B-VII based SPECLIBN2009 library and 43 energy groups will be presented and compared to the results obtained with the old MUPO based SPECLIBN-r04 library. First results obtained with the new library for a steady state as well as for selected transients will be presented. Deviations compared to results calculated with the old library will be discussed. It will be shown, that the new ENDF-B-VII based library influences strongly keff , but shows only negligible deviations in case of temperatures, power profiles, and neutron fluxes. With the new updated TISPEC library SPECLIBN2009 the Juelich core design program system VSOP and the Juelich reactor-dynamic codes TINTE/MGT are now based on the same evaluated nuclear data library ENDF-B-VII. (authors)