Simulation of IRIS pressurizer out-surge transient using two and three volumes simulation models

Numeric models of the IRIS reactor pressurizer having either two or three volumes were employed to simulate a typical out-surge transient. The vapor volume may contain liquid drops. Vapor bubbles can be generated in the liquid volume. The mass, the energy, the constitutive, and the state equations, represent all relevant phenomena. A pressure equation is derived by the substitution of the mass and energy equations onto the presurizer volume constraint, assuming that the instantaneous pressure is the same in all volumes. The pressurizer experimental data of a loss of load transient in the Shippingport reactor is used to validate these pressurizer models. These models are also employed to verify the capacity of the thermal power controller to restore the pressure in the IRIS out-surge transient. The preliminary validation, using the Shippingport experimental data, and the close agreement reached by all the developed software, for the IRIS out-surge transient, recommends further validation of these models for the test evaluation and the design of scaled experiments for the IRIS pressurizer