Method of retrofitting a spent nuclear fuel storage system

A method of retrofitting a spent nuclear fuel storage system, the method comprising:

• inserting a neutron absorbing apparatus into a first cell of an array of cells each configured to hold a spent nuclear fuel assembly, wherein each cell is separated from each adjacent cell by a cell wall, the neutron absorbing apparatus comprising:
• a corner spine;
• and
• a first wall and a second wall, each affixed to the corner spine to form a chevron shape, wherein each wall comprises:
• an absorption sheet affixed to the corner spine, the absorption sheet comprising a metal matrix composite having neutron absorbing particulate reinforcement;
• and
• a guide sheet affixed to the absorption sheet, the guide sheet extending over a top edge of the absorption sheet, and
• wherein at least one of the first wall and the second wall further comprises a first locking protuberance coupled to the respective guide sheet and protruding through an opening formed in the respective absorption sheet;
• and
• creating a second locking protuberance in a first cell wall of the first cell adjacent to the neutron absorbing apparatus, wherein the first locking protuberance and the second locking protuberance are positioned to interlock to retain the neutron absorbing apparatus in the one cell during removal of the fuel assembly from the first cell.

A system for storing nuclear fuel in a storage pool, the system comprising:

• a storage rack including an array of cells and a base plate supporting the array of cells, the base plate defining a horizontal plane;
• each cell configured to receive and store nuclear fuel rods;
• and
• a bearing pad configured for placement on a bottom surface of the storage pool, the bearing pad comprising a plurality of upward-extending support columns each engaging a corresponding one of a plurality of downwardly open receptacles on the base plate;
• wherein the support columns elevate the base plate of the storage rack above the bearing pad to allow cooling fluid to circulate under and upwards through apertures in the base plate.

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.