Pressure transients in NET building compartments under LOCA conditions

Abstract

The NET cooling systems for in-vessel components and vessel are generally based on low pressure and low temperature water. However, the cooling loops for the breeder blanket are intended to operate at a water temperature of about 250°C. A pipe break in a loop with such data would pressurize the compartment where the break takes place. Therefore, as a basis for proper compartment design, it is important to analyze possible pressure increases following pipe breaks. It may also be necessary to introduce equipment for pressure relief or pressure suppression. The objective of the parameter study presented is to determine the relationship between allowed maximum containment pressure following postulated large pipe break in breeding blanket loop and required containment volume. Parameters varied are: blanket loop temperature and pressure (within the range of burn and baking), and pressure suppression system inclusion/exclusion. The analysis has been performed by means of the Swedish containment code COPTA. The results of the analysis are summarized in a plot showing the influence of the varied parameters on required containment volume. In addition, the results presented include required vent areas, heat sink capacities, etc.