Research On Transmutation Of MA In The Thermal Reactor

Nuclear energy has provided lots of energy to the human, but also brings many social and environmental problems. One of the most urgent problems to be solved is how to dispose the spent nuclear fuel which contains a large number of long-lived and high-level radioactive wastes. Long life and high level wastes are mainly minor actinides (neptunium, americium, curium and so on) and long-lived fission product (LLFP). They have to go through hundreds of thousands years to decay to natural uranium toxicity level. So to resolve the long-lived high radioactive waste disposal problems is very important to the development of nuclear energy industry.The P&T Technology is considered as the best method to deal with the nuclear waste, which can extract the high-level radioactive nuclides and Pu, U nuclides from the spent fuel. Pu and U nuclides can be recycled, and the high-level radioactive nuclides can be turned into short-lived or stable nuclides, so it can eliminate the harm of the long-lived radioactive nuclides. Thermal reactor is the main reactor type at commercial operation in china, and the thermal neutron has a larger capture and fission cross section, so the study the transmutation of MA nuclides in the thermal reactor in China has an important significance. To study the efficiency and feasibility of thermal neutron transmute MA nuclides is the main content of our article, at the same time we also propose using high-flux neutron to transmute MA nuclides.In this paper, we use the MCNP code to build pressurized water reactor model, fast reactor model and high flux thermal reactor model. We study the neutron physics characteristic of the nuclear reactor core and the Influence of MA to the reactor, including the reactivity of the reactors and the neutron flux. We also study the feasibility of transmutation of MA in thermal reactor, calculate the MA capture and fission rate, and study the capacity of different reactors to transmute MA nuclides.The results showed:MA nuclides have a great effect to thermal reactor (PWR, high-flux thermal reactor). It can cause the reactivity of the reactors decline, so in order to make the nuclear reactor critical, we must increase fuel enrichment degree; After added the MA nuclides into the reactor, the thermal neutron flux decline; Through calculation and analysis of MA evolution bar in PWR after300days' irradiation, MA nuclides disappeared in large quantities, but mainly by neutron capture and transform into other super radioactive nuclides, such as Pu-238. And also we find the transmutation rate of MA in high flux thermal reactor is very high. The directly fission rate of MA nuclides in high flux thermal reactor in is not very high, but the indirect fission rate is very high.