ANALISIS PERUBAHAN MASSA BAHAN FISIL DAN NON FISIL DALAM TERAS PWR 1000 MWe DENGAN ORIGEN-ARP 5.1

Abstract

Controlled fission reaction occurs in the reator core. Reactor components such as fuel, cladding and cooling water have an important role in the sustainability of the fission reaction. Fission reaction causes the formation of a number of fission product nuclides and activation products. Fission product nuclides are produced from thermal neutron capture reaction of fissile material while the activation products are originated from interaction of non-fissile materials such as cladding material and coolant by neutron and gamma. At each of reactor operation, the information of fuel material changes in the form of non-fissile or fissile material, is very usefull for the management of core fuel, such as for reactivity control, optimization and loading of fuel. Hence, it needs to perform a research in the fissile and non-fissile material changes in the reactor core. This can be done by observing the change of material mass in the reactor core. The objective of this research is to determine the change in mass of material in the core, such as the mass of the nuclear fuel elements, cladding and cooling water after use in the core. From mass changes can be delivered to burn up calculation or fuel consumption level. The calculation were performed on the basis of the United States PWR 1000 MWe by using a fission inventory computer code of ORIGEN-ARP 5.1, a new version of ORIGEN with specific library for nuclear power plant. The analysis results show that the U-235 fissile material having a mass reduction up to 58% or more than half from the initial U-235 mass for each operation cycle period. Fertile material U-238 was reduced by about 2% only from the initial mass for each operating cycle period. For other cases, the non-fissile material case, mass changes reduced in various for each operation cycle, depend on activation cross-sections and decay and formation rate of parent nuclides.