Studies On Radiation Dose Prediction Model And Emergency Capability Assessment Approach In Case Of Nuclear Accident For The W Nuclear Power Plant

Actively developing nuclear power has become an important measure to change the energy structure,achieve the goal of carbon peak and carbon neutralization,and promote social and economic sustainable development.However,in case of severe nuclear accident in nuclear power plant(NPP),large amounts of radionuclides will be released into the atomosphere,causing the radiation hazards to staff and the public by means of atmospheric transportation,dispersion and deposition.Meanwhile,the strong nuclear accident emergency capacity should be built up so as to completely eradicate nuclear accident.Therefore,how to predict the radiation dose in case of nuclear accident to ascertain the radiation influence degree and range,and how to assess the emergency capability to avoid the nuclear accident have become the urgent and major research topics in the NPP region.In this paper,the hypothetical short-term station blackout(STSBO)nuclear accident in the W NPP(WNPP)was taken as the case for the research.The radiation dose prediction from the airborne radionuclides and the emergency capability assessment for the NPP nuclear accident were studied in depth,and the following important research findings were obtained.(1)The WRF model and HYSPLIT model were coupled to establish the WRF-HYSPLIT coupling model for the analysis of atmospheric dispersion of airborne radionuclides from the nuclear accident in NPP,the numerical simulation was carried out,and the atmospheric dispersion regularity of airborne radionuclides from the nuclear accident for NPP was revealed by using the coupling model.(2)The mathematical model for radiation dose prediction and RESRAD-OFFSITE model were used to establish the radiation dose prediction models for the early stage and the middle and late stages after the nuclear accident based on atmospheric dispersion theory,respectively.(3)Using the above(1)and(2)research findings,the radiation dose prediction approach for airborne radionuclides from the nuclear accident based on the atmospheric dispersion was proposed.The radiation doses due to the airborne radionuclides to staff and the public at different times after the nuclear accident were calculated,and the evolution regulatory of radiation dose due to the airborne radionuclides to staff and the public was revealed by using the proposed approach.(4)Based on the above(3)research finding,the index system for the assessment of NPP nuclear accident emergency capability was established using literature review,brainstorming and Delphi methods by consulting many experts and several modifications,the model for the assessment of NPP nuclear accident emergency capability was established through using analytic network process,cloud model,interval type 2 fuzzy set,and improved D-S evidence theory,and the approach for the assessment of NPP nuclear accident emergency capability was proposed,which can deal with fuzziness,randomness,uncertainty and conflict information in the assessment process.(5)The proposed approach for the assessment of NPP nuclear accident emergency capability was applied to assess the nuclear accident emergency capability for the WNPP.The results showed that the nuclear accident emergency capability of the WNPP was assessed as level I(excellent level),and the weak points of nuclear accident emergency capacity for the WNPP were also identified.(6)For the weak points,four countermeasures and suggestions,including dynamically implementing the quality assurance management,dynamically upgrading the nuclear accident emergency management system,identifying,assessing and controlling the risk,and enhancing the staff training,were proposed to further promote the nuclear accident emergency capability of the WNPP,and completely eradicate the nuclear accident.