Study of spent fuel management by transmutation in an accelerator driven subcritical system

Monte Carlo CASCADE version 2004 code is used to simulate the neutron flux inside IAEA benchmark ADS design of a 1500 MW_th reactor. The reactor is found to have the capability of production of the said amount of thermal energy and has high left over neutron fluence. This n - fluence is equivalent to that of a critical reactor for a given input fuel. Incineration reactions of long lived fission products and long lived trans-uranic actinides are discussed and it is inferred that element like plutonium (239) may be degraded directly in the spallation neutrons close to the spallation target and Low Life Fission Product (LLFP) may better be degraded at later positions where highly thermalized neutrons are available. This stresses upon necessity of producing of an ADS design that accommodates these observations. In any condition, to obtain both energy and possibility of transmutation of the waste, ADS need to operate at criticality (k_eff <; 0.98).