Patent ID: 7995701

Claim:
A nuclear core component hold-down assembly that accommodates top mounted instrumentation systems comprising: a base plate sized to seat within a top nozzle of a nuclear reactor fuel assembly above and spaced from an adapter plate of the top nozzle, the base plate having a number of openings that align with an equal number of holes in the adapter plate through each of which a corresponding control rod guide thimble in the fuel assembly is accessed; a vertical, hollow sleeve elongated along a dimension of elongation, having an axis along said dimension of elongation, the sleeve extending through and below a central opening in the base plate to mate with an upper opening in an instrument thimble in the fuel assembly, the sleeve extending vertically above the base plate and sized to extend through an upper core plate in the reactor when installed in a core of the reactor; a hold-down bar slidably mounted on the sleeve and having an axial travel length that is restrained a given distance below the top of the sleeve so that the sleeve extends above the hold-down bar when the hold-down bar is fully extended in a direction away from the base plate; and a spring concentrically positioned around the sleeve and extending substantially between the hold-down bar and the base plate.