Studies on wind tunnel experiments for safety analysis of a nuclear power reactor

Studies were made on the general techniques employed in the wind tunnel investigation of nuclear power stations and examples are described of recently performed studies. The following results were obtained. 1. The influence of terrain and building configuration on gas diffusion. 1) The influence of a reactor building was investigated by using models of BWR and PWR with one or two units. 2) A multi-regression formula was developed to estimate the terrain effect on gas diffusion. 3) An empirical formula was developed to estimate the ''equivalent source height'' in a potential accident. 2. Fundamental examination of the wind tunnel simulation of diffusion phenomena found in the field. 1) A scale model stack with ''orifice'' was developed to simulate plume rise phenomena found in the field at small values of Reynolds number. 2) Two kinds of experimental methods were developed to simulate lateral plume spread in the field, such as σy of the Pasquill chart. 3) It was confirmed that the results of the wind tunnel experiment agreed well with that of a field experiment at the EOCR site in Idaho Falls, U.S.A. (author)