Transmutation Of Neptunium-237 In AP1000

Nuclear power plant produces almost twenty metric tons of spent nuclear fuel(SNF)per year.This SNF contains minor actinides which live for millions of years.Their long-term radioactivity,cause storage problem and most feasible solution until now is deep geological repository.Transmutation is considered as an alternative method to solve this problem.MA:Np-237,Am-241 and Am-243 have very large thermal neutron capture cross sections in the thermal energy region,so in this thesis I introduced Np-237 because it has the longest half-life of 2.14 million years for transmutation in AP1000 reactor core to examine the potential of AP1000 for Np-237 transmutation as a near-term solution.The loading of NpO2 to the AP1000 reactor core disturb the criticality;for study this criticality analysis is done using MCNP code.NpO2 is loaded into AP1000 core using three different methods and the transmutation characteristics in all these methods has been studied.The First method is to coat a thin layer of Np-237 around burnable poison rod when the thickness of the layer is 0.11 cm the keff is 0.99736 which is dropped down a little bit but can be controlled the total loaded mass is 1897.21 kg.In second is the coating a thin layer with different thickness in the water gap of the burnable poison rods at the thickness of the layer 0.07 cm the keff is 0.98088 and the mass ofNpO2 is 1685.26 kg.In the third method is the homogeneous mixing of NpO2 in the burnable poison rod when the burnable poison is totally replaced by which the percentage is 100%NpO2 the keff is 0.98349 and the total loaded mass of NpO2 is 1414.79 kg.NpO2 loading to AP1000 does not consume extra neutron but consumes the neutrons which absorbed by the removed burnable poisons.There is no need to modify the configuration of the PWR core and composition of nuclear fuel.