Closure for casks containing radioactive materials

Abstract

An improved closure for covering and sealing a radioactive waste cask of the type having an opening circumscribed by a ledge is disclosed herein. The closure generally comprises an inner lid having an outer edge circumscribed by a gasket which is seatable over the ledge which circumscribes the opening, and an outer lid which is securable around the cask opening by either a screw-type or a breech-lock mechanism. In either case, the outer lid may be rotated into locking engagement with the container without imparting rotational forces to the gasket of the inner lid, thereby protecting the gasket from unnecessary rubbing forces. If the breech-lock mechanism is used, inner and outer lids may be rotatably connected to one another by a minimum of three suspension pin assemblies equidistantly spaced around the edges of both. The rotatable connection afforded by these suspension pin assemblies unitizes the closure while advantageously allowing the gasket of the inner lid to remain stationary while the outer lid is secured to the cask opening. To secure the gasket of the inner lid against the ledge of the cask opening, the outer lid is provided with a plurality of jack bolts engaged in threaded bores which extend completely through the outer lid. After the closure is secured over the cask opening, these jack bolts may be screwed through the outer lid into engagement against the inner lid, thereby forcing the inner lid gasket into sealing engagement with the ledge of the cask opening.