Abstract: A control rod having a spring device on its lower end for eliminating oscillatory contact of the rod against its adjacent guide tube wall. The base of the device is connected to the lower tip of the rod. A plurality of elongated extensions are cantilevered downward from the base. Each extension has a shoulder for contacting the guide tube, and the plurality of shoulders as a group has a transverse dimension that is preset to be larger than the inner diameter of the guide tube such that an interference fit is obtained when the control rod is inserted in the tube. The elongated extensions form an open-ended, substantially hollow member through which most of the liquid coolant flows, and the spaces between adjacent extensions allow the flow to bypass the shoulders without experiencing a significant pressure drop.

Abstract: The present invention relates to an improved attachment assembly for clamping a nuclear reactor foot ring into engagement with a surrounding support wall while allowing for thermal expansion of the foot ring.

Abstract: A bimetallic spacer means designed to be cooperatively associated with a nuclear fuel assembly and operative to resist the occurrence of in-reactor bowing of the nuclear fuel assembly. The subject bimetallic spacer means in accord with one embodiment of the invention includes a member formed, at least principally, of zircaloy to which are attached a plurality of stainless steel strips. The latter stainless steel strips are located on the external surface of the zircaloy member and with the major axis of each of the plurality of stainless steel strips extending substantially perpendicular to the major axis of the zircaloy member.

Abstract: A liquid metal cooled nuclear reactor comprising a core, a main vessel comprising a first supporting means, a primary vessel mounted inside said main vessel and coaxial therewith, at least one exchanger outside said vessels. Said primary vessel comprises a core-diagrid and a second supporting means integral with the main vessel lateral wall and with the primary vessel lateral wall. These lateral walls define an annular space in which is formed a horizontal partition.