SPACE code ECCX Component Model and Comparisons with RELAP5/Mod 3.3 Code Predictions

During the loss of coolant accident, especially when the break is considered a large break, in the nuclear power plant system, an emergency core cooling (ECC) injection is activated once the pressure has decreased sufficiently. The ECCS provides the process of the reestablishment of liquid/fuel contact by refilling, reflooding and quenching of the heated fuel rod cladding. The performance of the ECC injection at its initial stage is affected by the process of mixing of a jet of a cold water injected into a two-phase and the resulting steam condensation that follows. SPACE code incorporates a special component ECCX to account for the mixing and condensation phenomena near the ECC injection. This paper outlines the implemented models and assessment results of the ECCX component