Break Characteristic Modelling for Debris Generation Following a Design Basis Loss of Coolant Accident

An important safety concern regarding long-term recirculation cooling following a loss of coolant accident (LOCA) is the transport of debris materials to interceptors (i.e. trash racks, debris screens, suction strainers) inside containment and the potential for debris accumulation to result in adverse blockage effects. Debris resulting from a LOCA, together with pre-existing debris, could block the emergency core cooling system (ECCS) debris interceptors and result in degradation or loss of recirculation flow margin. Potential debris sources can be divided into three categories: (1) debris that is generated by the LOCA and is transported by blowdown forces (e.g. insulation, paint); (2) debris that is generated or transported by washdown; and (3) other debris that existed before a LOCA (dust, sand, etc.). Each debris source is separately evaluated to estimate the quantity and other ...