Loss of flow accident analysis in Atucha II nuclear power plant using RELAP5 model

CORZO SANTIAGO; UGARTE RICARDO; GODINO DARÍO; DAMIAN RAMAJO

NUCLEAR ENGINEERING AND DESIGN

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2023 vol. 402 p. 1 - 24

0029-5493

The loss of flow accident (LOFA) in nuclear power plants (NPP) isconsidered a design base initiating event (DBIE) and it is broadlyanalyzed in safety and licensing evaluation. Therefore, this iscommonly chosen to assess computational models. The current paperaddresses the simulation of LOFA under single and total main coolantpump (PMP) trips during full power in Atucha-II Pressurized HeavyWater Reactor (PHWR). RELAP5-mod3.3 NPP was used for solvingthe thermal-hydraulics, neutron kinetics, and control and safety logic insteady-state and LOFA events. Simulations were assessed against realplant data recorded during a single-PMP trip obtaining very goodagreement. After that, the total-PMP trip was simulated, showing thatthe plant also reached a safe steady condition, guaranteeing the removalof decay heat by natural flow circulation. The very good agreement interms of the main thermal-hydraulics parameters demonstrated thecapability of the computational model to reproduce the overall NPPbehavior.