The Critical Safety Of The Spent Fuel And The Dose Distribution Calculation

Because the spent fuel is a high-level waste, its disposition in security is related to theenvironment of homeland, public safety and the development of nuclear industry. And it is aessential part for the nuclear industry activities. Thus the disposal of high-level waste has tobe studied and solved safely.The KBS-3system is a technology for the processing of spent fuel, which is made ofductile cast iron lining and copper shielding developed by the Swedish nuclear fuel andnuclear waste management company. It is applied for the geological disposal of spent fuel inSweden, The cast iron liner support the mechanical strength, and the copper shield is used toprevent the containers from corrosion. In order to ensure that the critical safety andradioactive leakage are under the calibration standard, containers should be tried by means offall test, impact test, fire test, flooding test and so on before they are fixed.This thesis simulated the keffof the containers of spent fuel using MCNP to verify thecritical safety by considering the keffchange in extreme condition (flooding). The liningmaterials in the containers are I26and I24which are demonstrated well. The dose distributionof canister surface with different kinds of canister inserts (I24,I25and I26) is calculated byMCNP. Analysing the calculation results, I offered a referrence for selecting canister insertsmaterial from the radiation protection. This thesis simulate the changes of dose distribution ofthe containers in some typical accident. The shielding effectiveness of copper cladding andthe flooding test were simulated as well.