Study on Calculation Method of Accidental Source Term for Pool-type Sodium-cooled Fast Reactor and Its Application

To deal with the problem that the traditional light water reactor accidental source term calculation method is not suitable for sodium-cooled fast reactor, calculation methods for accidental source term of pool-type sodium-cooled fast reactor, including core damage type, leak type and sodium fire type, were studied and derived on basis of the analysis of release path of potential design basis accidents and beyond design basis accidents. The methods were applied to six typical accidents of the demonstration fast reactor, including the total instantaneous blockage of one fuel assembly, the leakage of cover gas region of reactor main vessel, the damage of primary argon decay tank, the leakage of main vessel, the leakage of sodium purification pipeline without protective sleeve outside the primary circuit, and the leakage of external auxiliary pipeline without protective sleeve outside the primary circuit or the isolation valve tube not be closed. The calculation of accidental source terms and their radiological consequences were carried out. The results show that the radioactive dose consequences of the six accidents are lower than the requirements of GB 6249-2011. The methods proposed can provide reference to the calculations of accidental source term of loop-type sodium-cooled fast reactor, lead-cooled fast reactor and gas-cooled fast reactor.