CALCULATIONS FOR ZPR-VII FLUX-TRAP REACTORS WITH HEAVY WATER-MODERATED CORES

摘要

Calculations have been made relating to flux-trap re¬actors constructed in the ZPR-VII critical assembly having heavy water-moderated cores of THUD or Babcock and Wilcox fuel. The flux-trap regions consisted of heavy water, except for a few light water flux traps with THUD-fueled cores. Various flux ratios and quantities, such as ratios of maximum thermal flux to maximum power density or total core power, are com¬pared for THUD-fueled lattices. In connection with the B-and-W-fueled lattices, which have thin cores with high resonance absorption, a study is made of reactors having cores with k∞ < 1. It is shown that it is possible for a reflected reactor having a core with k∞ < 1 to be critical if k∞/p > 1, where p is the reso¬nance escape probability, and if the dimensions and material constants involved are of suitable magnitudes.