Radioactive waste analysis of CNPP-1 (PWR) spent nuclear fuel

Nuclear power is safe, reliable, environment friendly and large scale energy generating technology. But it is also a fact that the public serious concern about the management of radioactive waste is associated with this technology. The spent nuclear fuel is being safely stored at nuclear power facilities for about 50 years. It has not yet decided whether the used fuel is treated as a resource or waste. About 96% of Uranium is still present in the fuel when it is removed from the reactor. The spent fuel composition depends on the initial amount of fuel, irradiation time and power of the reactor. This paper focuses to simulate the material composition, radioactivity and its corresponding decay heat profiles of the CNPP-I using depletion computer code ORIGEN-2. For this purpose irradiation model of the single PWR fuel assembly (with 3% U-235 fuel enrichment) is developed for the period of 365 days. The simulated values of radioactivity of actinides, fission products and activation products and their decay heat are compared with the analytical results obtained from the Malbrain et al. Model. This study shows that, nuclei heavier than uranium are obtained when uranium captures one or several neutrons without fission. Thus, one finds almost 1% of plutonium. Actinides other than plutonium (neptunium, americium, and curium) are less abundant. About 3% of the mass consists of fission products of 235 239 U and Pu. The spent nuclear fuel decay heat comes mainly from unstable fission products, unstable actinides, and activated structural and cladding materials. The main source of decay heat production in spent nuclear fuel is the beta decay of fission products.