Method for assessing the consequences of radiation accidents in the rooms of a power-generating unit of a nuclear power plant with a VVÉR-1000 reactor

Monte-Carlo estimation of the dose rate of external radiation from volume and surface sources of a gas-aerosol radioactive impurity, arising in the rooms of a power-generating unit during a radiation accident at a nuclear power plant, is examined. The volume and surface sources are distributed uniformly. The radial distribution of the dose buildup factor and the dose rate are obtained as functions of the γ-ray energy at different heights. The calculations are performed for distances no more than four γ-ray mean-free path lengths (µd ≤ 4) by the local flux estimation method. Comparisons with similar calculations performed with computer programs employing the discrete-ordinate method show satisfactory agreement.