Thermal hydraulic analysis of the formation of 'cold plumes' during a primary-to-secondary leak in the event of rupture of 3 steam generator tubes with operator intervention (SGTR1, SGTR2, SGTR3 and SGTR4 processes)

Chapter 2 describes the codes used, i.e. REMIX and NEWMIX. Chapters 3-6 are devoted to the accidents analyzed. Each chapter describes the development of the accident as calculated by RELAP5 together with the boundary and initial conditions and results of the calculation. Chapter 7 contains concluding remarks. The analyses provide input data (coolant temperature at the internal wall of the reactor vessel, viz. both on the cold plume axis and beyond the cold plume) for subsequent mechanical analysis, enabling us to assess the effect of the accident on a potential initiation of a sudden break from cracks that might be present in the reactor pressure vessel wall. (P.A.)