Patent Number: 044477333
Section: claims

1. A radiation-shielding transport and storage container for radioactive material, said container comprising: a radiation shielding vessel composed of cast iron or cast steel and defining a storage chamber for said radioactive material and a mouth opening into said chamber and formed with a plurality of seats;  a plug-type radiation-shielding cover received in one of said seats and sealed with respect to said vessel by an inner seal;  a safety cover speced outwardly from said shielding cover, received in another of said seats and sealed with respect to said vessel by an outer seal whereby said covers define a control space between said inner and outer seal containing gas at a pressure significantly higher than that in said chamber and than atmospheric pressure; and  pressure-monitoring means communicating with said space and responsive to a drop in the pressure therein below a predetermined threshold value for signaling a failure of one of said seals.  (a) introducing radioactive material into the chamber of the cast iron or cast steel vessel having a wall thickness sufficient to prevent escape of radiation through the walls of said vessel;  (b) sealing a radiation-absorbing cover in said vessel;  (c) sealing a safety cover to said vessel above said radiation-absorbing cover establishing a control space between said covers which is sealed by said covers from the interior of said vessel and the atmosphere respectively;  (d) pressurizing said space with gas at a pressure established above the pressure in the interior of said vessel and above atmospheric pressure; and  (e) monitoring the pressure in said space and signaling the failure of a seal of one of said covers upon the monitor pressure dropping below a predetermined threshold value.  inserting a plug into said vessel of a thickness sufficient to prevent radiation from escaping through said plug while sealing said chamber with at least one inner seal formed between said plug and said vessel;  disposing on said vessel above said plug a safety cover and sealing said safety cover to said vessel with at least one outer seal;  establishing a pressure within said chamber of substantially 0.8 to 1.5 bar;  establishing with the compartment defined between said cover and said plug and between said inner and outer seals a pressure of substantially 6 bar; and  monitoring the pressure in said compartment to detect a change in pressure representing a breach of one of said seals, thereby enabling corrective action. 2. The container defined in claim 1 wherein the pressure in said space is about 6 bar and the pressure in said chamber is between 0.8 and 1.5 bar. 3. The container defined in claim 1 or claim 2 wherein a further cover is mounted on said vessel and sealed relative thereto above said safety cover. 4. The container defined in claim 3 wherein said shielding cover has a frustoconical inner portion and cylindrical outer portion overhanging said inner portion, said outer portion forming a shoulder, said inner seal including sealing rings between each of said portions and said vessel. 5. The container defined in claim 4 wherein said shielding cover and said vessel are composed of spherolytic cast iron. 6. A method of packaging radioactive material which comprises the steps of: 7. A method of operating a transport and storage vessel for radioactive waste which comprises introducing radioactive material into a chamber of a cast iron or steel vessel having a wall thickness sufficient to prevent escape of radiation therefrom;