Nuclear Analysis for the Boraflex Used in a Typical Spent-Fuel Storage Assembly

The safety and credibility of boraflex, a neutron absorbing material widely used in the spent-fuel storage assembly, has been analyzed from a nuclear point of view. The nuclear heating (absorbed dose) rate and the neutron-induced radioactivity for the boraflex under a typical nuclear environment were calculated. The result showed that in a normal condition, the total absorbed dose for the boraflex was mainly due to the decay photons originating from the spent fuel and compatible with the dose limit prescribed in the literature. Furthermore, the induced radioactivity level for the boraflex after 30 yr (the expected lifetime of the storage rack) of spent-fuel neutron irradiation was well below the limit stated in 10CFR61.55, so it can be classified as Class A waste.