Effects of the used calculation method and cross-section set upon safety physics parameters of a gas-cooled fast breeder reactor

Effects of the used calculation method and cross section set upon safety physics parameters of a gas-cooled fast breeder reactor have been studied with the GCFR pin reference core ''GBR-4''. The methods used to examine nuclear characteristics of the reference core design are ordinary diffusion theory, collision probability, and Monte Carlo, and the cross section sets are JAERI-FAST set-version II and RCBN set-version III, the latest libraries in JAERI. In conclusion, the ordinary diffusion treatment is applicable to a pin-type gas-cooled fast reactor, but cannot predict well the axial streaming of neutrons. There is significant difference in the neutron streaming between the collision probability and the Monte Carlo treatments. Effects of the cross section set used on the reactivity calculated is relatively small, which, however, increases with fuel burnup. (auth.)