Volume 3, Issue 10 (November 2006)
Influence of the Multigroup Approximation on VVER-1000 RPV Neutron/Gamma Flux Calculation
One-dimensional calculations of neutron and gamma group fluxes and radiation damage in terms of DPA have been carried out for VVER-1000 mock-up realized at LR-0 critical assembly, Rez, Czech Republic in order to evaluate the influence of energy dependence multigroup approximation on VVER-1000 RPV Neutron/Gamma flux calculation. Two calculational methods have been applied: Monte Carlo method (MC) with continuous energy dependence description and discrete ordinates (DO) method with multigroup energy dependence approximation. Two different multigroup neutron/gamma cross section libraries have been used: BGL1000—created especially for VVER-1000 application and BUGLE96—created for PWR application. A good consistency between the results for both methods and different cross section libraries is obtained for neutrons with energy above 0.1 MeV. The worst consistency is obtained for the thermal neutrons. For gammas a better consistency between DO and MC results is obtained when BGL1000 library is applied.