Study On The Critical Security Uncertainty Of The Spent Fuel Pool

Be ensure the healthy sustainable development of nuclear power industry in China. We put forward to further development the spent fuel storage technology.To satisfied the requirements the premise of nuclear criticality safety guideline,increasing the safety and storage capacity of the spent fuel storage.In this paper,in the case of spent fuel assumption into new fuel,carried on studied to critical security of spent fuel storage:Study the spent fuel storage framework material and size effects on the critical safety,Optimization layout scheme of AP1000 spent fuel storage pool.Secondly,according to perturbation theory, carried out perturbation uncertainty calculation and analysis to AP1000 spent fuel storage grid.At last,calculation subcriticality of AP1000 pools,and use uncertainty analysis methods,evaluating AP1000 spent fuel pool criticality safety performance,verify the calculated results and given reasonable safety allowance.The studies have shown that:(1) Select Al- B4 C composite material as the spent fuel storage framework neutron absorption material is reasonable.Based on the system process and critical safety requirements,following the HAD102/15 and ANS57.2 rules and confirm the layout of spent fuel pool.At the same time, initial fuel enrichment degree was5%,the Keff value of Pools is less than 0.95.Satisfy the requirement of the spent fuel pool criticality safety.(2) Due to the perturbation calculation problem is complexity.According to perturbation calculation and analysis,it is difficult to give the accuracy conclusion,if the disturbance won't make the characteristic function hasobvious change,using the PERT perturbation calculation module of MCNP5 can save computation time and can get more accurate results effective.But the material change(cross section) is very large, its value and use MCNP5 direct method of numerical have larger deviation.(3) The AP1000 spent fuel storage pool in the area I is research object,we conservative select fuel assembly maximum enrichment degree is5%.Fully considering the spent fuel storage pool water density and grid storage uncertainty of technology influence on the critical safety,critical analysis of the calculated maximum effective multiplication factor Keff value is0.94175.The critical analysis of the below standards require that Keff value suggest no more than 0.95.Therefore, the spent fuel pool criticality safety is guaranteed.The above conclusions will provide spent fuel storage long-term security and improve the ability is of great importance.