Loss-of-Coolant Accidents in Small Compact Nuclear Reactors

The maximum credible accident for which a nuclear reactor must be analyzed is a loss-of-coolant accident (LOCA) due to a major rupture in the primary system. Such an accident has been analyzed for a conceptual design of a consolidated nuclear steam system (CNSS) using the thermal-hydraulic computer code RELAP4/MOD5. The results of the analysis show that the maximum fuel cladding temperature during the accident is ∼344°C (652°F), which is sufficiently low to preclude any damage to the reactor core. Based on the results of this analysis, it appears that a LOCA in a CNSS may be less severe than in typical loop-type pressurized water and boiling water reactors. This result is expected because of the smaller piping connected to the CNSS reactor vessel