Apparatus for storing and/or transporting high level radioactive waste, and method for manufacturing the same

Abstract

A system for storing and/or transporting high level radioactive waste, and a method of manufacturing the same. In one aspect, the invention is a ventilated vertical overpack (“VVO”) having specially designed inlet ducts that refract radiation back into the storage cavity. A clear line-of-sight does not exist through the inlet ducts and, thus, the canister can be supported on the floor of the VVO. Also disclosed is a method of manufacturing a variable height VVO that falls within a regulatory license previously obtained for a shorter and taller version of the VVO.

What is claimed is: 
     
         1 . An apparatus for transporting and/or storing high level radioactive waste comprising:
 a cylindrical radiation shielding body comprising an inner surface defining an internal cavity and having a vertical axis;   a base enclosing a bottom end of the cavity;   a plurality of air inlet ducts formed in a bottom of the radiation shielding body, each of the air inlet ducts configured to form a non-linear air flow channel extending horizontally through the radiation shielding body from an external atmosphere to a bottom portion of the cavity which blocks a straight line of sight through the air flow channel from the cavity to the external atmosphere; and   a radiation shielding lid enclosing a top end of the cavity.   
     
     
         2 . The apparatus according to  claim 1 , wherein each air inlet duct comprises a pair of non-linear airflow channels from the external atmosphere to the bottom portion of the cavity. 
     
     
         3 . The apparatus according to  claim 2 , wherein the non-linear air flow channels each have a semi-circular arcuate shape which blocks the straight line of sight through the non-linear air flow channel. 
     
     
         4 . The apparatus according to  claim 2 , wherein each of the non-linear air flow channels converge into a common outer opening at an outer surface of the radiation shielding body and converge into a common inner opening at the inner surface of the radiation shielding body adjacent to the cavity. 
     
     
         5 . The apparatus according to  claim 4 , wherein the non-linear air flow channels diverge from each other between the common outer and inner openings within the radiation shielding body. 
     
     
         6 . The apparatus according to  claim 4 , wherein the common inner and outer openings each have a vertically elongated rectangular shape. 
     
     
         7 . The apparatus according to  claim 1 , wherein the non-linear air flow channel has a semi-circular arcuate shape which blocks the straight line of sight through the air flow channel. 
     
     
         8 . The apparatus according to  claim 2 , further comprising a circumferentially oriented flat metallic plate disposed in each air inlet duct which extends between the pair of non-linear airflow channels. 
     
     
         9 . The apparatus according to  claim 8 , wherein the flat metallic plate is embedded in a concrete column extending vertically through each air inlet duct which defines a radiation shielding structure that bifurcates the inlet duct into the pair of non-linear airflow channels. 
     
     
         10 . The apparatus according to  claim 9 , wherein each of the non-linear airflow channels have an arcuate semi-circular shape. 
     
     
         11 . The apparatus according to  claim 9 , wherein the concrete column rests on the base at the bottom end of the cavity. 
     
     
         12 . The apparatus according to  claim 11 , wherein the radiation shielding body has a dual wall composite structure comprising an inner metal shell, an outer metal shell, and an annular concrete mass disposed between the shells. 
     
     
         13 . The apparatus according to  claim 12 , wherein the concrete column structurally supports portions of the concrete mass above the plurality of air inlet ducts. 
     
     
         14 . The apparatus according to  claim 9 , wherein the concrete column is cylindrical. 
     
     
         15 . The apparatus according to  claim 14 , wherein the concrete column is encased in a cylindrical metallic plate. 
     
     
         16 . The apparatus according to  claim 8 , wherein the flat metallic plate is centrally positioned within each air inlet duct. 
     
     
         17 . The apparatus according to  claim 2 , wherein the pair of non-linear airflow channels form an uninterrupted continuous circular airflow loop between the external atmosphere and the cavity of the radiation shielding structure. 
     
     
         18 . The apparatus according to  claim 2 , wherein each non-linear airflow channel is defined by a first arcuate metallic plate on one side and an opposing second arcuate metallic plate on another side, the first and second arcuate metallic plates arranged transversely between inner and outer surfaces of the radiation shielding structure. 
     
     
         19 . The apparatus according to  claim 16 , wherein the first and second arcuate metallic plates are spaced uniformly apart. 
     
     
         20 . The apparatus according to  claim 1 , further comprising a cylindrical radiation shielding structure arranged within each of the air inlet ducts that divides the air inlet duct into a pair of arcuately shaped non-linear airflow channels which blocks the straight line of sight from the cavity to the external atmosphere through the air inlet duct.