When a nuclear power plant is in shutdown conditions for refuelling, the reactor coolant system water level is reduced. This situation is known as mid-loop operation, and the residual heat removal (RHR) system is used to remove the decay power heat generated in the reactor core. In mid-loop conditions, some accidental situations may occur with not a negligible contribution to the plant risk, an...

The heat transfer model of the RELAP5/MOD3.1 (R5M3) code was extensively reviewed and assessed. The most important deficiency of the current version of the code was attributed to its treatment of the transition boiling heat transfer regime. The current transition boiling model significantly underpredicts the heat transfer rate to the liquid phase. Since at low quality conditions the liquid boil...

The paper presents the simple and efficient analysis method of frequency-domain to control core power coolant temperature Nuclear Power Plants (NPPs). In order properly describe neutron kinetic thermal transmission NPPs, a one-dimensional dynamic model has been accomplished by using linearizing in time domain discretizing spatial domain, then transfer function matrix can be obtained through Lap...