Evaluation method for initiative emission decision of containment vessel in nuclear power plant

Abstract

The invention discloses an evaluation method for an initiative emission decision of a containment vessel in a nuclear power plant. The evaluation method comprises an overpressure threat relieving decision evaluation step and further comprises a hydrogen threat relieving decision evaluation step, an emission stopping decision evaluation step and a radioactive fission product release relieving evaluation step, wherein the overpressure threat relieving decision evaluation step comprises the steps of calculating an initiative emission radioactive dosage consequence desired value M1; firstly calculating the overpressure critical failure probability of the containment vessel when the M1 is equal to a no-emission radioactive dosage consequence desired value N1; then determining overpressure critical failure pressure F1 of the containment vessel; calculating a pressure recommended setting value F0 of the containment vessel after certain allowance is considered; requesting to execute initiative emission when the pressure of the containment vessel is up to the F0. The evaluation method disclosed by the invention is used for the initiative emission decision of the containment vessel under a serious accident, and provides decision basis for emergency command, containment vessel emission is initiatively carried out, overpressure or hydrogen threat of the containment vessel is relived, the releasing of fission products is relieved, and radioactive pollution after the serious accident can be reduced.

Description

technical field [0001] The invention relates to the technical field of nuclear power plant accident handling, in particular to a decision-making evaluation method for active discharge of containment shells in nuclear power plants. Background technique [0002] According to the nuclear power safety concept of defense in depth and multiple barriers, the containment is the last barrier to prevent the release of radioactive fission products. Many domestic pressurized water reactor nuclear power plants have set up containment filtration and exhaust system (Containment Filtration and Exhaust System, English abbreviation CFES) in order to alleviate the fission product release of large dry containment. CFES can effectively filter volatile fission products and aerosols, usually filter The efficiency reaches more than 99%. In order to alleviate the release of fission products caused by containment leakage, active filtering and emission can be considered. [0003] A serious accident o...

AI Technical Summary

Problems solved by technology

[0006] Problem 1. In the management of severe accidents in nuclear power plants, active containment venting is required to mitigate the threat of containment overpressure

Moreover, some power plants only give the opening pressure of the discharge in the severe accident management guidelines, without clearly specifying the conditions for terminating the discharge. Some power plants simply set the value of the containment pressure, such as half or 40% of the opening pressure as the closing setting value , the lack of rigorous evaluation methods

[0007] Question 2. Currently, in the management of severe accidents in power plants, the purpose of applying filter discharge system for active containment discharge is limited to alleviating the threat of overpressure and hydrogen to the integrity of containment

[0008] Question 3, the release of fission products caused by the "normal" leakage of the containment under severe accidents is attracting attention in the field of nuclear power safety. The allowable leakage rate under the design pressure is 0.1-0.3% / day, and it is assumed that ten times the normal leakage rate exceeds the design pressure. Leakage, high level of radioactivity in the leaking gas

Images