A Preliminary Research Of Emergency Preparedness And Response For Molten Salt Research Reactor With Liquid Fuel

The molten salt reactor(MSR)is among the six advanced reactor types proposed in the Generation IV International Forum.The Chinese Academy of Sciences launched a 2 MWt thorium molten salt reactor–liquid fuel(TMSR-LF1),a type of MSR,to develop the fourth generation advanced nuclear energy technology.From a safety perspective,the TMSR-LF1 has several characteristics: temperature negative feedback,no risk of fuel melt,low pressure operation,cooling without water,an online cover-gas purge system,and a redundant passive air-cooled system.The accident occurrence possibility and their consequences are much lower for the TMSR-LF1 than that of traditional reactors.However,for increased safety,a preliminary research of emergency preparedness and response for the TMSR-LF1 is required.The main chapters of this study are as follow:Chapter 1: Introduction.An introduction of the history of emergency preparedness and response for MSRs was present.The methods of developing emergency preparedness and response for research reactor by the United States and IAEA were present and compared.Chapter 2: Accident analysis and emergency reference accident selection.Accident analysis is the basis and premise for the development of emergency preparedness for reactor.Accident analysis results directly affect emergency classification levels,emergency action level development and emergency planning zone.According to primary design of the TMSR-LF1,classify and analyze all possible accidents by deterministic analysis method.Based on the demonstration of radioactive release possibility of every accident,the accidents that would lead to radioactive release were single out.The fuel salt leak,the cover gas leak,the off gas system failure and the cooling salt leak were single out.The cover gas leak accident was selected as the emergency reference accident of TMSR-LF1 by comparing the severity of the environmental impact consequence of accidents.Chapter 3: Radiation consequence assessment of emergency reference accident.Based on the method of source term estimation recommended by IAEA,the release source terms of the emergency reference accident were analyzed and calculated.The ARCON96 program with revised Gaussian plume model is used to estimate the distribution of radionuclide activity concentration in site.After the calculation of accident radiation dose,the influence of the cover gas flow rate,scram process,tritium,exposure ways and time on the emergency reference accident dose were discussed.According to the accident radiation consequence,the emergency classification levels of TMSR-LF1 would not require the General Emergency.Chapter 4: Preliminary development of emergency preparedness and response for the TMSR-LF1.The preliminary framework of emergency action levels of the Category A for the TMSR-LF1 was developed according to the previous emergency classification levels and the development methodologies recommended by IAEA.Based on the calculation analysis,the traditional concept of emergency planning zone is not suitable to TMSR-LF1.At last,preliminary suggestions were put forward for the emergency organization design and emergency response measures for TMSR-LF1.Chapter 5: Summary and prospect.The achievements and the insufficient of the present work were summarized,and the possible improvements were prospected.