The Effect Of Transmutation Minor Actinide On PWR Temperature Coefficient

With the development of nuclear energy,nuclear spent fuel reprocessing is the key technology for the sustainable development of nuclear power.Minor actinides are the primary contributors to long term radiotoxicity in spent fuel.The disposal of minor actinide is the research subject of many countries.We can transmute the MA into short-lived nuclide and valueable nuclide by the neutron transmutation technology.This is one of the most efficient ways for the MA disposal.We decide to transmute MA in pressurized water reactor(PWR),because the majority of commercial reactors in operation in the world are PWRs,so to study the minor actinide transmutation charateristics in the PWRS and ultimately realize the successful minor actinide tranmutation in PWRs are crucial problem in the area of the nuclear waste disposal.Based on the previous research result of our research group.We decide to study the MA transmute in burnable poison rods,we design three loading patterns.The first pattern is that minor actinides substitute for burnable poison directly.The second pattern is that we coat a thin layer of minor actinides in the water gap between the zircaloy cladding and the stainless steel which is filled with water.The third pattern is that we uniform mix the burnable poison with MA.We study the impact of MA on fuel temperature coefficient and moderator coefficient under three loding patterns.Besides,we claculate the reactivity changed with temperature under different loading amount.According to calculation result,we analyze the impact of MA on the temperature coefficient,the result shows that the loading of MA will improve the the reactor temperature coefficient.In order to study the impact of temperature,we need to make a nuclear data base in different temperature by NJOY 99 code.Then,we can calculate the keff under different temperature by MCNP code.Next,we study the burnup by SCALE code,calculate the lifetime of reactor core under different loading patterns and amount.Accroding to the calculation result,the loading of MA will reduce the lifetime of reactor core.At last,we study the transmutation production and the transmutation rate.The result shows that PWR have high transmutation rate,the most of transmutation production is short-lived nuclide and Pu-240.We summarize several conclusions:Firstly,loading of MA will improve the fuel temperature coefficient and moderator temperature coefficient.Secondly,the loading of MA will reduce the lifetime of reactor core.Thirdly,the PWR can well transmute the MA and the production have low radioactivity.Finally,we believe that there are good prospects in PWR transmutation.The innovation of this paper mainly include the following points:firstly,research come up with a new method to transmute MA.Secondly,we study the lifetime of reactor core and temperature coefficient under different loading patterns and amount.Finally,we calculate the MA transmutation rate and production in different loading patterns and amount.