MEASUREMENT OF THE NATURAL NEUTION SOURCE IN TWO CORES

摘要

The natural sources for two types of cores have been measured. The first core, with the mainnsource contribution coming from the spontaneous fission of U235 and U 238 , gave measured resultsnin nominal agreement with the theoretical calculations of Harris (Ref 1). Because of the poor statis¬tics and relatively wide variation in results from day to day for this core, it is not possible to say whether adjoint ratio calculations using Tape 5 or using Tape 0 gave the best agreement with Harris' source calculations. The second core, with the main source contribution coming from the B(ff,n) reaction in the fuel meat, gave measured results which were about 15% lower than Harris' calcula¬tions when Tape 5 adjoint ratios were used, and about 36% lower when Tape 0 ratios were used. The statistics and consistency of the measurements from day to day were good for this core.