RODLET ABSORBING MEMBERS FOR USE WITH SPENT FUEL

摘要

To attenuate heat generation due to the release of neutrons from remnant fissile fuel which remains in spent fuel rods, rod-like reaction attenuating members (RAM) are interspersed among the spent rods. When the rods contain boron such as B-10, most neutron capture occurs near the surface of the RAM. Accordingly, the formation of RAM cross sections having increasing surface area enables a reduction in the weight of the rod/unit length while maintaining the "blackness" or neutron opacity of the member. RAM can be deployed in both the spaces provided in the fuel rod assemblies for control rods during combustion, as well as about their periphery when they are removed from the reactor pressure vessel and are immersed in "on-site" storage pools. The rods provide flexibility in disposition and numbers and can thus be applied to a wide variety of different control rod assembly units and evaluated against a plurality of criteria. As the activity of the fuel decreases, rods can be removed, allowed to cool off for a few days and subsequently used in "hotter" incoming assemblies if so desired.