抄録
A variety of 20% enriched uranium loaded and graphite-moderated cores consisting of the different lattice cells in wide range of carbon to uranium atomic ratio have been built at SemiHomogeneous Experimental Critical Assembly (SHE) to perform the critical experiments systematically.
The results of the critical experiments on the cores are presented and compared with calculation using the nuclear data of ENDF/B-3, ENDF/B-4 and GGC-4 for the purpose being utilized for evaluating the accuracy of core design calculation for the experimental reactor for multi-purpose high temperature reactor. Experimental data compose of critical masses of uranium, kinetic parameters and reactivity worths of the experimental control rods and also the power distribution in the cores inserted with those rods.
Calculations are made by the homogeneous and the heterogeneous models; the structures of the lattice cells of the cores are completely disregarded in the former, but are reasonably considered in the latter. As for the critical masses of uranium, it is made clear that the both models are valid for the homogeneously fuel loaded cores, but for the heterogeneously fuel loaded cores only the heterogeneous models proved to be successful.
As for the other experimental data, analyses are applied with use of the homogeneous model in which some group constants are adjusted so as to explain the critical masses, and then agreement between measurement and calculation is satisfactory for the requirements from the design of the experimental reactor.
