Research On Hydrogen Removal Mitigation Measures During Severe Accident Of Qinshan Phase Two Extensional Project

The global nuclear industry group has already make the same consciousness on the research of the severe accident and the management of the severe accident, the main nuclear power states in the world has already or now implementing the management of the severe accident; NNSA takes a new requirement to the management of the severe accident in the nuclear power plant of our country, so the domestic nuclear power plant begins to propose the governing plan of the severe accident.Confirmation by various risk studies, hydrogen combustion is one of the main reasons to cause invalidation of the containment under the severe accident. When the hydrogen concentrations reached certain proportion in the containment, and under the suitable external condition (such as temperature, pressure, oxygen concentrations,etc.), the hydrogen may burn or deflagrate rapidly. Therefore, the phenomenon can damage some parts the equipment and system which related to the security, and even can damage the structure of the containment, so cause a large number of radioactive materials to enter the environment.By using MELCOR code, Calculations of hydrogen propagation in the containment have been performed for large LOCA and small LOCA with failure of the ECCS active part ,station blackout. Indicated by the analysis, the different severe accident has the different quantities and distribution of the hydrogen. So the large LOCA severe accident can produce the high speed hydrogen, and the small LOCA can produce the more total amount of hydrogen; The hydrogen is mainly gathered in the break area at the time of the serious accident of the large break, and under the station blackout serious accident, the hydrogen mainly through the primary circuit depressurization discharge to the other space of the containment.In case of severe accident, by suitable locating the passive autocatalytic recombiners (PAR)in the containment can reduce the concentrations of the hydrogen effectively in the containment, and prevent the phenomenon that the hydrogen burn or deflagrated rapidly. And the PAR can achieve the relevant confirmation criterion requirement that the hydrogen concentrations smaller than 10% in the containment.By the research of this subject, valid approved the application of the PAR in the Qinshan Phase Two Extensional Project, and make the foundational technical support for the Qinshan Phase Two extensional project make the governing plan of the severe accident, management guider of the severe accident, and establish the link procedure of the emergency of procedure & severe accident management.