The effectiveness of sheltering against internal exposure in nuclear reactor accidents, 3

Sheltering is a simple and safe protection action for the general public living around nuclear facilities in an emergency such as a nuclear reactor accident. The reduction of internal exposure by sheltering directly depends on natural ventilation rates of houses. The coefficients and indexes of air flow resistance in small openings in the house and the wind pressure coefficients on outer periphery of the house are neccessary for calculation of the natural ventilation rate. This paper describes the method of measurement of these coefficients and indexes and the results. The coefficients and indexes of air flow resistance were measured for nine test pieces, for instance doors and windows, which were existing in a real reinforced concrete house chosen for the measurement and calculation of the natural ventilation rates, and 20 small opening models, which were expected to exisit in Japanese houses. The window pressure coefficients of the following three houses for various wind directions were measured using models of the houses: a real reinforced concrete house and Japanese one-story and two-story houses. The useful data for calculation of the natural ventilation rates of houses were obtained. (author)