Kinetic study of fission product activity released inside containment under loss of coolant transients in a typical MTR system.

Based on continuous release of fission product (FP) activity from fuel to the coolant and then to the containment, a kinetic model is developed for source term after a LOCA in a typical MTR type system. The time dependent source, re-suspension rate, decay of fission products, leakage, deposition on surfaces, and re-circulation of air through filters are employed with a partial prompt source plus a time varying source. Releases of different FP activities are simulated for various release rates.