Framatome Gmbh

Framatome & Cie.

Claude Leroy

Jean-Paul Millot

Eric Gonse

Guy Desfontaines

Jean Paul Millot

During operation of a light water moderated and cooled nuclear reactor, rods varying the neutron energy spectrum are introduced into the core of the reactor in the course of a first phase of the cycle in order to reduce the ratio of the volume of moderator to the volume of fissile material in the core. In a second phase of the cycle the spectrum displacement rods are extracted. The rods are of a mixture of thorium energy neutrons. The rods may be of fertile material and--depleted uranium. The invention is of particular interest in PWRs.

Spectral shift nuclear reactor with improved efficiency

For operating a PWR with spectral shift during all combustion cycles and with undermoderation during some cycles only, the reactor structure is designed for receiving either one of two types of fuel assemblies, having the same geometry. All fuel assemblies have guide tubes for receiving spectral shift clusters containing fissile material but with different elements bundles so as to be able to choose the type of operation.

Spectral shift light water nuclear reactor

A control device for a PWR includes a plurality of clusters arranged for insertion into and removal from the core and each having a plurality of rods connected to a common carrier vertically slidable in a stationary guide structure and connectable to a drive shaft. First clusters contain neutron absorbing material and are each individually associated with electromagnetic actuation means for adjusting the amount of insertion of the associated one of the first clusters. Second clusters contain a different material and are each individually associated with hydraulic actuation means controllable to cause upward and downward movement. A set of one first cluster and one second cluster is associated with some of said fuel assemblies, with the drive shafts of the two clusters in each set being arranged symmetrically with respect to the axis of a single stationary structure located above the associated fuel assembly and arranged for authorizing mutually independent movement of the first and second clusters.

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Lardy, France

Claude Leroy