Precision evaluation method for gas-carrying radioactive source item in serious accident of underground nuclear power station

Abstract

The invention discloses a precision evaluation method for a gas-carrying radioactive source item in a serious accident of an underground nuclear power station. The precision evaluation method comprises the steps of 1) performing reactor core burn-up calculation specific to a specific underground nuclear power station rector; 2) determining a burn-up point with the maximum radioactive activity according to an underground nuclear power station burn-up database; 3) calculating catalogues and activity of the radioactive material which is released from fuel to a pressure container; 4) calculating activity of the radioactive material which is released from the pressure container to a rector building; 5) calculating changes of the activity of the radioactive material which is released from the rector building to an underground cavity along with time; 6) performing evaluation on engineering measures and natural cover for defense of the underground nuclear power station cavity, and calculating the activity of the radioactive material which enters atmosphere; and 7) calculating the activity of the radioactive material which enters environment finally. By combination with the characteristics of the underground nuclear power station, and through efficient and fine burn-up calculation theory and a natural surrounding rock shielding calculation model, quantitative evaluation on the diffusion behavior of the gas-carrying radioactive source item in the serious accident of the underground nuclear power station is realized.

Description

technical field [0001] The invention relates to nuclear power technology, in particular to a method for accurately evaluating airborne radioactive source items in severe accidents of underground nuclear power plants. Background technique [0002] The accident source term refers to the form, quantity, composition and time-varying release characteristics of radioactive substances released into the environment by a nuclear power plant when an accident occurs. Accident source items are the basis of accident management and emergency planning of nuclear power plants, and are divided into design basis accident source items and severe accidents. Severe accident source term is an important input of accident consequence evaluation. After the Fukushima nuclear accident, severe accident source term evaluation has been widely concerned and valued. Estimating airborne radioactive source items in severe accidents and calculating the radiation consequences inside and outside the accident s...

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Problems solved by technology

However, these accident source items are all calculated on the basis of a specific reactor, which are general source items and cannot be accurately calculated for specific reactors.

After the Fukushima nuclear accident in Japan, a large number of studies on the source term of severe accidents have been carried out at home and abroad, but none of them have clearly proposed t

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