Nuclear data for nuclear reactor analyses—An overview

Abstract

The development of large scale computers made possible detailed neutronics calculations and helped to free the reactor designer from his dependence on experimental mock-ups and crude calculational models. With the ability to represent realistic reactor geometries, nuclear reactions, and the transport of particles, increased emphasis was placed on nuclear data. Extensive data libraries were needed in computerized form to match the sophisticated deterministic and stochastic calculational systems developed to perform reactor calculations. Because experimental data were often contradictory or sparse, large scale data evaluation efforts were launched to fill information gaps and provide the necessary computerized data base. The United States mustered the required manpower for its evaluated data effort by forming the Cross Section Evaluation Working Group (CSEWG), a cooperative effort of representatives from over 20 laboratories, see Pearlstein (1970). The work of CSEWG, begun in 1966, continues to produce successive versions and modifications to the Evaluated Nuclear Data File (ENDF/B). The last major revision, ENDF/B-V, was issued in 1979, see Kinsey (1979). Extensive experience has been gained using ENDF/B and other evaluated data bases in a comparison between reactor calculations and reactor experi-