Patent Number: 045284547
Section: summary

CROSS REFERENCE TO RELATED APPLICATIONS The present application is related to commonly assigned copending application Ser. No. 120,108 filed Feb. 8, 1980 (now U.S. Pat. No. 4,274,007 of June 16, 1981 and Ser. No. 966,951 filed Dec. 6, 1978 (now U.S. Pat. No. 4,278,892 of July 14, 1981 and making reference to then-pending applications Ser. No. 940,856 of Sept. 8, 1978, (now U.S. Pat. No. 4,272,683 of June 9, 1981, Ser. No. 940,098 (now U.S. Pat. No. 4,234,798), and Ser. No. 107,276 of Sept. 26, 1979 (now U.S. Pat. No. 4,288,698 of Sept. 8, 1981. Reference may also be had to U.S. Pat. Nos. 4,229,316 and 4,235,739 issued on still earlier applications commonly owned herewith. For the construction of the vessel and as to radiation-shielding properties thereof and the use of such vessels, these prior art applications and patents are hereby incorporated by reference in their entirety and it is noted that the prior art known to applicants to be the most relevant is the art of record in said applications. FIELD OF THE INVENTION As is pointed out in the aforementioned copending applications, it is known to provide for the transport and storage of radioactive wastes, containers or vessels of a radiation-shielding material and which may be provided with channels or compartments to contain radiation-blocking or radiation-attenuating materials, and with ribs or the like to promote heat exchange with ambient air. Radioactive material can be placed in such containers and sealed by cover arrangements of which the most pertinent is that found in application Ser. No. 120,128, in which it is pointed out that an effective closure for the vessel can be provided by forming the mouth of the vessel with a seat receiving the plug-type inner cover having a frustoconical portion and a cylindrical portion fitting into correspondingly shaped parts of the seat and sealed relative to the latter with elastomeric seals, generally O-rings. Above this inner cover an outer cover was provided which extended beyond the outline of the inner cover and was secured to the vessel. The container vessel, which is formed at its upper and lower ends with thickened portions for reinforcement and stability, generally in the form of annular beads or enlargements, can be composed of cast iron and especially spherulitic (nodular) cast iron, can be used for the storage and disposal of radioactive materials of various types, especially irradiated nuclear fuel elements upon their removal from the core of a nuclear reactor. As can be seen from German patent document No. 28 37 631 (see also U.S. Pat. No. 4,278,892), it is frequently advantageous to provide at least one bore in the wall of the vessel, extending from the upper end thereof to open into the interior of the vessel close to the bottom, which serves to feed material into or draw material from the interior of the vessel and/or for control or monitoring purposes. In earlier arrangements utilizing such a bore, the latter terminated at the upper end of the vessel outwardly of the outline of the radiation-shielding or plug-type cover and required special closures. This, in turn, made sealing difficult and complicated the problem of controlling the storage of the radiation material by making access to the material through the bore considerably more difficult. OBJECTS OF THE INVENTION It is the principal object of the present invention to provide an improved storage and transport container for radioactive materials which is free from the disadvantages described. Another object of the invention is to provide an improved container which extends the principles of our U.S. Pat. Nos. 4,274,007 and 4,278,892 mentioned above. It is also an object of the invention to provide a radiation-shielding transport and/or storage container which facilitates control and monitoring of the state of the contents of the vessel. A further object of the invention is the provision of an improved cover structure for a vessel to be utilized for the aforedescribed purposes. SUMMARY OF THE INVENTION These objects and others are attained, in accordance with the present invention, in a transport and/or storage container adapted to receive radioactive materials and in which the wall bore of the vessel terminates at the upper end and within the outline of the shielding or plug-type cover and preferably within the outline of the plug portion thereof, while this cover is formed with a bore adapted to be aligned with the wall bore and in which an obturating element (e.g. a valve or plug) can be fitted to extend into the wall bore and seal the latter, the bore of the cover being covered in turn by an additional or safety cover. In other words, when a plurality of wall bores are provided in the vessel of cast iron, each of them open in the region of the seat into which the plug-forming radiation-shielding cover fits to be aligned with corresponding bores in this cover. In this manner, the shielding cover can be formed in the region of the seat or socket with control, monitoring and test bores in which control or monitoring devices, fittings, valves or the like can be inserted so that these devices, if left in place, or the control or test bores can be covered by the outer of second cover. The number and type of control and test bores will depend upon the test required during transport and storage of the container as well as upon special purposes to which the container may be put and may be determined by a control or monitoring program, by regulation or by statute. Preferably, the additional cover does not sit directly upon the edge of the vessel but rather is recessed therein, i.e. fits into a recess forming a seat for this cover and provided in the mouth-forming end of the vessel so that the outer cover does not project beyond the vessel wall but is either recessed inwardly from this end of the vessel or is flush therewith. Naturally the vessel can be formed with a shoulder or seat against which the additional cover is sealingly set. It is possible to provide still further covers as described, for example, in our concurrently filed copending application Ser. No. 243,562 (now U.S. Pat. No. 4,450,042), for greater security or to facilitate monitoring the seals of the covers by monitoring a control gas which can be introduced into the vessel with the radioactive material as described in the latter application. The reinforcing bead or thickened end of the mouth of the vessel permits the system of the invention to be accommodated economically and without loss of radiation-shielding effect.