Rack for underwater storage of spent nuclear fuel

A nuclear fuel storage apparatus comprising:

• a fuel assembly having a top section, a middle section, and a bottom section, nuclear fuel being stored within the middle section;
• and
• a fuel rack comprising:
• a top;
• a plurality of vertically-extending corners;
• a base plate;
• and
• an array of cells, the fuel assembly located in a first cell of the array of cells, the array of cells comprising:
• a plurality of horizontal first slotted plates slidably interlocked with one another to form a top portion of the array of cells, the plurality of first slotted plates being formed of a first material, outermost perimetrically arranged ones of the plurality of first slotted plates forming exposed external surfaces of the middle portion of the array of cells;
• a plurality of horizontal second slotted plates slidably interlocked with one another to form a middle portion of the array of cells, outermost perimetrically arranged ones of the plurality of second slotted plates forming exposed external surfaces of the middle portion of the array of cells, each of the plurality of second slotted plates being formed of a second material and welded together, wherein the second material is a neutron absorbing material and the first and second materials are metallurgically incompatible, the middle section of the fuel assembly being located entirely within the middle portion of the first cell of the array of cells;
• and
• a plurality of horizontal third slotted plates slidably interlocked with one another to form a bottom portion of the array of cells, the plurality of third slotted plates formed of the first material and connected to a top surface of the base plate, outermost ones of the plurality of second slotted plates being perimetrically arranged forming exposed external surfaces of the middle portion of the array of cells;
• wherein the exposed external surfaces of the top, middle, and bottom portions collectively form planar sidewalls of the fuel rack which extend from corner to corner and from the top to the base plate of the fuel rack.

A fuel rack for nuclear fuel assemblies, the fuel rack comprising:

• a top;
• a plurality of vertically-extending corners;
• a base plate;
• an array of cells for holding fuel assemblies, the array of cells comprising:
• a plurality of horizontal first slotted plates slidably interlocked with one another to form a top portion of the array of cells, the plurality of first slotted plates being welded together and formed of a first material;
• a plurality of horizontal second slotted plates slidably interlocked with one another to form a middle portion of the array of cells, the plurality of second slotted plates being formed of a second material, wherein the second material is a neutron absorbing material and the first and second materials are metallurgically incompatible;
• and
• a plurality of horizontal third slotted plates slidably interlocked with one another to form a bottom portion of the array of cells, the plurality of third slotted plates formed of the first material and welded to a top surface of the base plate;
• wherein outermost ones of the plurality of first, second, and third slotted plates extend perimetrically around the fuel rack, the outermost ones each comprise outward facing plates having first major surfaces that collectively form exposed external planar sidewalls of the array of cells, each sidewall extending from corner to corner and from the top to the base plate of the fuel rack;
• and
• a plurality of tie members, each tie member welded to the exposed external surface of the array of cells along each of the top and bottom portions of the array of cells.