Patent Number: 043366147
Section: claims

1. A tube-in-shell heat exchanger comprising a tubular shell having inlet ports for conducting a first heat exchange fluid through the shell,  a plurality of spaced heat exchange tubes extending longitudinally within the shell, the tubes penetrating at least one end closure of the shell for conducting a second heat exchange fluid,  a series of longitudinally spaced transverse grids for bracing the heat exchange tubes apart,  a spine disposed on the longitudinal axis of the shell for supporting said transverse grids, and  resiliently yieldable means for mounting said grids on the spine, each resiliently yieldable means comprising  an annular series of brackets rigidly secured to the spine, the brackets each having a pair of radially outwardly extending forked arms,  a complementary annular series of forked brackets having radially inwardly extending arms rigidly secured to a grid, each bracket of one series being interposed between two neighbouring brackets of the complementary series and  a resiliently flexible annular member disposed transversely to the spine in engagement with the forked arms of both complementary series of brackets.  a tube-in-shell intermediate heat exchanger immersed in the pool of primary coolant and comprising  a tubular shell having inlet and outlet ports for conducting primary coolant through the shell,  a plurality of spaced heat exchange tubes extending longitudinally within the shell, the tubes penetrating at least one end closure of the shell for conducting a secondary coolant,  a series of longitudinally spaced transverse grids for bracing the heat exchange tubes apart,  a spine disposed on the longitudinal axis of the shell for supporting said transverse grids and  resiliently yieldable means for mounting said grids on the spine, each resiliently yieldable means comprising  an annular series of brackets ridigly secured to the spine, the brackets each having a pair of radially outwardly extending forked arms,  a complementary annular series of forked brackets having radially inwardly extending arms rigidly secured to a grid, each bracket of one series being interposed between two neighbouring brackets of the complementary series, and  a resiliently flexible annular member disposed transversely to the spine in engagement with the forked arms of both complementary series of brackets. 2. A tube-in-shell heat exchanger according to claim 1 wherein the resilient annular member comprises a stack of relatively slidable annular laminations. 3. A tube-in-shell heat exchanger according to claim 2 wherein successive grids of the series brace the tubes from their nominal in-line positions in opposed directions. 4. In a liquid metal cooled fast breed nuclear reactor construction of the kind comprising a primary vessel, a pool of primary coolant contained in the primary vessel and a nuclear fuel assembly submerged in the pool of primary coolant,