Apparatus for supporting spent nuclear fuel

Abstract

A fuel rack apparatus includes: a base plate having an upper surface and a lower surface; and a plurality of storage tubes coupled to and extending upward from the upper surface of the base plate, the storage tubes arranged in a side-by-side arrangement to form an array of the storage tubes. Each of the storage tubes extend along a longitudinal axis and include: an outer tube having an inner surface defining an inner cavity; and an inner plate-assemblage positioned within the outer tube that divides the inner cavity into a plurality of interior flux trap chambers and a fuel storage cell.

What is claimed is: 
     
         1 . A fuel rack apparatus for storing spent nuclear fuel, the fuel rack apparatus comprising:
 a base plate having an upper surface and a lower surface;   a plurality of storage tubes coupled to and extending upward from the upper surface of the base plate, the storage tubes arranged in a side-by-side arrangement to form an array of the storage tubes, each of the storage tubes extending along a longitudinal axis and comprising:
 an outer tube having an inner surface defining an inner cavity; and 
 an inner plate assemblage positioned within the outer tube that divides the inner cavity into a plurality of interior flux trap chambers and a fuel storage cell; 
   wherein for each of the storage tubes, the interior flux trap chambers have a different transverse cross-sectional shape than a transverse cross-sectional shape of the fuel storage cell.   
     
     
         2 . The fuel rack apparatus according to  claim 1 , wherein the array of the storage tubes is a rectilinear array comprising a plurality of rows of the storage tubes and a plurality of columns of the storage tubes; wherein for each of the rows of the storage tubes, the longitudinal axes of adjacent ones of the storage tubes in the row are separated from one another by a first distance; and wherein for each of the columns of the storage tubes, the longitudinal axes of adjacent ones of the storage tubes in the column are separated from one another by a second distance, the second distance being greater than the first distance. 
     
     
         3 . The fuel rack apparatus according to  claim 2 , wherein for each of the rows of the storage tubes, adjacent ones of the storage tubes in the row are spaced apart from one another by an exterior flux trap formed between the outer tubes of the adjacent ones of the storage tubes in the row. 
     
     
         4 . The fuel rack apparatus according to  claim 3 , wherein for each of the columns, the outer tubes of adjacent ones of the storage tubes in the column are in surface contact with one another. 
     
     
         5 . The fuel rack apparatus according to  claim 1 , wherein for each of the storage tubes, the outer tubes have a rectangular transverse cross-section having a width in a row direction and a length in a column direction, the length being greater than the width. 
     
     
         6 . The fuel rack apparatus according to  claim 2 , wherein for each of the columns, the fuel storage cells of adjacent ones of the storage tubes in the column are separated from one another by a first subset of the interior flux trap chambers of a first one of the adjacent ones of the storage tubes in the column and a second subset of the interior flux trap chambers of a second one of the adjacent ones of the storage tubes in the column. 
     
     
         7 . The fuel rack apparatus according to  claim 1 , wherein for each of the storage tubes, the interior flux trap chambers have a triangular transverse cross-section and the fuel storage cell has a hexagonal transverse cross-section. 
     
     
         8 . The fuel rack apparatus according to  claim 1 , wherein for each of the storage tubes, the inner plate assemblage comprises a pair of angled wall plates and the outer tube comprises a plurality of straight wall plates arranged to form a rectangular tube structure in transverse cross section, each of the angled wall plates being arranged obliquely to the wall plates of the outer tube. 
     
     
         9 . The fuel rack apparatus according to  claim 8 , wherein the angled wall plates each comprise a first wall plate and a second wall plate oriented at an oblique angle to the first wall plate. 
     
     
         10 . The fuel rack apparatus according to  claim 9 , wherein each angled wall plate includes a pair of opposing edges welded to the inner surface of two different wall plates of the outer tube. 
     
     
         11 . The fuel rack apparatus according to  claim 10 , wherein the different wall plates of the outer tube are opposite and parallel to each other. 
     
     
         12 . The fuel rack apparatus according to  claim 9 , wherein the angled wall plates have a chevron shape in transverse cross section. 
     
     
         13 . The fuel rack apparatus according to  claim 1 , wherein each flux trap chamber is isolated from an adjoining flux trap chambers by the inner plate assemblage. 
     
     
         14 . The fuel rack apparatus according to  claim 1 , wherein the cross-sectional shape of the interior flux chambers is triangular. 
     
     
         15 . A fuel rack apparatus comprising:
 a base plate having an upper surface and a lower surface;   a plurality of storage tubes coupled to the upper surface of the base plate in a side-by-side arrangement to form a rectilinear array of the storage tubes, each of the storage tubes extending along a longitudinal axis and comprising:
 a rectangular outer tube comprising a plurality of outer wall plates each with an inner surface collectively defining an inner cavity, the outer wall plates forming corner sections; 
 an inner plate assemblage disposed in the inner cavity and comprising a plurality of inner wall plates, the inner wall plates arranged to form a fuel storage cell for holding spent nuclear fuel; 
 one of the inner wall plates of the inner plate assemblage spanning diagonally across each corner section of the outer tube to form a plurality of interior flux chambers each isolated from the fuel storage cell; and 
 a neutron absorbing plate disposed in each interior flux chamber. 
   
     
     
         16 . The fuel rack apparatus according to  claim 15 , wherein each interior flux chamber is isolated from every other interior flux chamber. 
     
     
         17 . The fuel rack apparatus according to  claim 15 , wherein the inner wall plates are arranged in conjoined pairs each comprising a first wall plate and a second wall plate joined along an apex edge, the first wall plates of each pair being oriented at an obtuse angle to the second wall plate. 
     
     
         18 . The fuel rack apparatus according to  claim 17 , wherein each conjoined pair of inner wall angled wall plates includes a pair of opposing edges welded to the inner surfaces of two different outer wall plates of the outer tube, the two different first and second outer wall plates of the outer tube being opposite and parallel to each other. 
     
     
         19 . The fuel rack apparatus according to  claim 18 , wherein the first and second outer wall plates include a neutron absorbing plate. 
     
     
         20 . The fuel rack apparatus according to  claim 19 , wherein the apex edges of each conjoined pair of inner wall plates engage the inner surfaces of third and fourth outer wall plates of the outer tube, the apex edges being located in a reference plane that includes the longitudinal axis of the storage tube. 
     
     
         21 . The fuel rack apparatus according to  claim 15 , wherein a cross-sectional shape of the interior flux chambers is triangular. 
     
     
         22 . The fuel rack apparatus according to  claim 15 , wherein fuel storage cell is defined by a first pair of the inner wall plates, an opposing second pair of the inner wall plates, and an opposing pair of outer wall plates.