Initial core design of CANDLE burning fast reactor using plutonium from LWR spent fuel

Analyses were performed to determine the initial core design of a CANDLE burning fast reactor with 3000 MWt such that the reactor could maintain both criticality and maximum excess reactivity of less than 1% during its total operation period with a minimum amount of plutonium from LWR spent fuel. The initial core was designed with a starter fuel to initiate the reactor, and a booster fuel to increase the effective multiplication factor to more than unity. This reactor was able to maintain criticality with an excess reactivity of less than 1% throughout the operating period. The temperature coefficient was calculated, while it could be negative at the beginning of the operation, it was positive thereafter. Thermal hydraulic analyses were also performed. A fuel could be cooled to less than a criteria temperature at the equilibrium state, but during the transition period, the fuel could not be cooled even with the maximum coolant inlet velocity of 2.0 m/s. In order to make it possible to cool fuel to less than the criteria, reactor power was decreased so that the maximum temperature was lower than the limitation temperature.