Analysis of the Steam Generator Tube Rupture Source Term for a PHWR

The reactor building bypass sequences are distinctly different from the non-bypass sequences in that there exists a direct flow path from the primary system to outside the reactor building boundary which bypasses the main reactor building gas volume. Hence the gravity fallout and engineered mitigation features inside the reactor building become ineffective for reducing a fission product release into the environment. Consequently, bypass sequences can result in relatively large source term releases soon after the onset of a core damage. The reactor building bypass sequences can be further subdivided into a steam generator tube rupture (SGTR) group and an interfacing system LOCA (ISLOCA or Event V) group, because their radionuclide release pathways are different. Both of these have been defined by a plant damage state attribute as a 'Reactor building Bypass'. The purpose of this paper is to analyze the steam generator tube rupture source term for the Wolsong plants