چكيده به لاتين
Abstract:
Uranium and thorium are the most important nuclear fuels; thorium has many resources, which can be found as 232Th fertile isotope in the nature and has no fissionable isotope therfore it needs an auxiliary fissionable isotope (like 235U, 239Pu). By absorbing low level energy neutrons, 232Th produces the 233U fissionable isotope and with respect to the fact that natural fissionable material resources are not enough for human needs in long term, it is required to use new fuel cycles in nuclear reactors. Thorium fuel cycle is preferred to the others considering the high breeding in thermal and epithermal neutron spectra. In recent years, with respect to providing of safety requirements, waste management and abundant resources, many interests in thorium fuel cycle are reformed. Whereas thorium utilization in the light water reactors was not investigated yet in details, therefore, in this research we intend to investigate neutronic consideration and possibility of U3O8-ThO2-Al fuel replacement in Tehran Research Reactor using MCNPX nuclear code. MCNPX is a nuclear code, which is used to transport neutrons by Monte Carlo method. First, we simulated Tehran research reactor using the code and replaced U3O8-Tho2-Al fuel with the routine fuel U_3 O_8-Al and then via calculation of the neutronic parameters we compared these two fuels. The results of the calculations showed that applying (U35%3O8-Al)(70%)-Tho2(30%) don’t disturb safety and neutronic parameters of the core and causes plutonium, which is considered as one of the most important biological hazardous wastes (HLW), to decrease about 1.56 times than when we use U20%3O8-Al fuel.
Keywords: Tehran research reactor, Thorium, neutronic parameters, MCNPX code, fuel consumption.
