Mandrel-wound, splined monolithic fuel assembly core, fuel assembly and reactor incorporating same, and methods of manufacture

A method of manufacturing an insulated fuel assembly core, the method comprising:

• forming a tensioned fuel monolith stack mandrel assembly;
• and
• forming an insulation layer on an outer surface of the tensioned fuel monolith stack mandrel assembly by mandrel winding,
• wherein forming the tensioned fuel monolith stack mandrel assembly includes:
• assembling a plurality of fuel monoliths into a stack along a longitudinal axis, wherein each of the plurality of fuel monoliths has a shape of a right circular cylinder and includes a first end surface, a second end surface, a side surface connecting the first end surface to the second end surface, a plurality of first channels extending axially from the first end surface to the second end surface, and a first keyway in the side surface;
• inserting a first alignment rod into the first keyway of each of the plurality of fuel monoliths to align the plurality of fuel monoliths;
• inserting an alignment drill rod through one of the plurality of first channels in a direction of the longitudinal axis;
• attaching an exhaust support plate to a first end of the assembled stack to form a core stack, wherein the exhaust support plate includes a first end face, a second end face, a circumferential surface connecting the first end face to the second end face, a first exhaust support plate keyway in the circumferential surface, and a plurality of second channels extending from the first end face to the second end face, and wherein attaching the exhaust support plate includes inserting the alignment drill rod through one of the plurality of second channels and inserting an end of the first alignment rod into the first exhaust support plate keyway;
• inserting a first set of tensioning cables through a first portion of the plurality of first channels in the plurality of fuel monoliths and through a first portion of the plurality of second channels in the exhaust support plate;
• attaching a plurality of second mandrel spacers to a second end of the core stack;
• inserting the first set of tensioning cables through the plurality of second mandrel spacers;
• attaching a plurality of first mandrel spacers to a first end of the core stack, wherein the first end of the core stack includes the exhaust support plate attached to the first end of the assembled stack;
• inserting a second set of tensioning cables through:
• (i) the plurality of first mandrel spacers, (ii) a second portion of the plurality of second channels in the exhaust support plate, (iii) a second portion of the plurality of first channels in the plurality of fuel monoliths, and (iv) the plurality of first mandrel spacers;
• tensioning the first set of tensioning cables and the second set of tensioning cables;
• and
• attaching a first threaded mandrel cap to a distal end of the plurality of first mandrel spacers and a second threaded mandrel cap to a distal end of the plurality of second mandrel spacers.