Analysis of In-vessel Hydrogen Source Term during Severe Accident Induced by SB-LOCA

With an integral severe accident analysis computer code,severe accident sequences induced by small-break loss-of-coolant accident（SB-LOCA） in Daya Bay Nuclear Power Plant（900 MWe PWR NPP） are calculated.The impacts of different sizes and locations on the progression of accident and the generation of the in-vessel hydrogen source term are analyzed in this paper.The results are summarized as follows: A mass of in-vessel hydrogen source generates at oncoming and initial stage of core melting;The amount of in-vessel hydrogen source term is with obscure relation to the break size,and with many different sizes of breaks,the amount of in-vessel hydrogen source term distributes in a small area,and the average amount of the hydrogen production is about 500 kg;The location of break has a small impact on the generation of the hydrogen source term.