The Evaluation of ROP Trip Set Point for the Different CANDU-6 Fuel Type

This system has the 58 detectors divided into three safety channels and actuates according to the two out of two, trip logic. The each safety channel must provide the trip signal with 98% trip probability. The ROP trip set point is decreasing due to core aging effect and bad thermal condition. Therefore, the operating power is decreased to maintain the trip probability. Recently the new designed fuel is being developed to enhance the trip set point. The fuel bundle used in domestic CANDU reactor has the 37 elements to be the same diameter. The diameter of central element in the new designed fuel is reduced to increase the coolant flow area. In this paper the ROP trip set point is evaluated to estimate the effect of fuel design change. At 8000EFPD with the assumption of no pressure tube creep, the trip set point of new fuel design is respectively increased above 10%. This study has shown that the trip set point is enhanced by means of the fuel design change. Because the thermal hydraulic model in this paper is assumed without the pressure creep, the trip set point to be applied to the plant operating must be reevaluated with the proper plant's data