Framatome Gmbh

Areva Np Gmbh

Compagnie Generale Des Matieres Nucleaires

Framatome Anp Gmbh

Cogema, Inc.

Nitruvid

Cogema Velizy

Dominique Hertz

Bernard Delmas

Jean-Paul Lebrun

Laurent Poirier

Bernard Lis

Alain Blocquel

Angelo Beati

Thierry Muller

Gilles Morel

Luc Pillet

Marcel Bouffier

Laurent Gauthier

Jean-Michel Couturier

Hassan Idrissi

Francoise Defoort

Sylvain Audisio

Henri Michel

Thierry Belmonte

Jerome Gavillet

Gérard Barbe

Yves Desprez

Noemie Gomez

Noémie Gomez

An absorber cluster for a nuclear reactor includes at least a first absorber assembly and a second absorber assembly. Each absorber assembly respectively comprises neutron absorbing elements. Absorber elements of each of the first absorber assembly and the second absorber assembly are made from the same material or the same combination of materials selected from the group of neutron absorbing materials consisting of a first europium hafnate, a second europium hafnate, a first samarium hafnate, a second samarium hafnate, hafnium carbide, and samarium hexaboride. The first europium hafnate and the second europium hafnate have different compositions. The first samarium hafnate and the second samarium hafnate have different compositions. The absorber elements of the first absorber assembly have a cross-sectional structure different to that of the absorber elements of the second absorber assembly.

Absorber rod assembly for nuclear reactor

A method for thermochemically treating a part while masking a portion and corresponding mask are provided. The method includes the steps of providing a mask comprising a body with a seat, at least a deformable sealing washer located in the seat, and a tightening bushing, the body having a cavity, placing a first portion of the part in the cavity, a second portion of the part being located in a passage in the sealing washer, and a third portion of the part being located outside the mask, moving the tightening bushing to its tightened position so that the sealing washer is deformed and applied against the second portion of the part, and applying a thermochemical treatment to the third portion of the part.

Method for thermochemically treating a part while masking a portion and corresponding mask

A method for producing a wear-resistant and corrosion-resistant stainless steel part for a nuclear reactor is provided. This method includes steps of providing a tubular blank in austenitic stainless steel whose carbon content is equal to or lower than 0.03% by weight; shaping the blank; finishing the blank to form the cladding; hardening the outer surface of the cladding by diffusing one or more atomic species; the blank, before the providing step or during the shaping or finishing step, being subjected to at least one hyper quenching with sub-steps of: heating the blank to a sufficient temperature and for a sufficient time to solubilize any precipitates present; quenching the blank at a rate allowing the austenitic structure to be maintained in a metastable state at ambient temperature and free of precipitates.

Method for producing, from a preform made of austenitic stainless steel with a low carbon content, a wear-resistant and corrosion-resistant cladding for a nuclear reactor, corresponding cladding and corresponding control cluster

A method for surface processing at least a portion of a component of zirconium or hafnium alloy, including at least one operation of nanostructuring a surface layer of the alloy so as to confer on the alloy over a thickness of at least 5 &#x3bc;m a grain size which is less than or equal to 100 nm, the nanostructuring being carried out at a temperature which is less than or equal to that of the last thermal processing operation to which the component was previously subjected during its production. Component of zirconium or hafnium alloy processed in this manner.

Method for surface processing a zirconium or hafnium alloy, and component processed in this manner

A grid including at least two meshed grid parts intended to be superposed in a longitudinal direction, each grid part extending in a transverse plane, and the grid parts being moveable one relative to the other in at least one transverse direction between an open configuration for the insertion of nuclear fuel rods in the longitudinal direction through the grid parts, and a closed configuration allowing each fuel rod inserted through the grid parts to be clamped transversely between the grid parts. According to one aspect of the invention, the grid includes elements for transversely immobilizing the grid parts in the closed configuration, the immobilizing elements being designed to engage as the superposed grid parts are moved closer together in the longitudinal direction.

Nuclear fuel rod spacer grid and framework and assembly comprising such a grid

A control cluster for a pressurized water nuclear reactor comprising a bundle of neutron-absorbing rods each of which comprises a metal tube called cladding which is sealed off by a top end plug at its top end and by a bottom end plug at its bottom end and has a support, or spider, of radiating shape to which the absorber rods are attached through their upper end plugs, characterized in that the cladding of at least some of the absorber rods is weld-free hafnium tubes, the top end plugs of the absorber rods having hafnium cladding being of titanium-based alloy and being welded to the top end part of the hafnium cladding of the absorber rod, the bottom end plugs being of massive hafnium and being welded to the bottom.

Cluster for adjusting a nuclear reactor core reactivity, absorber rod of the cluster and method for protecting the absorber rod against wear

After a nuclear reactor has been stopped and allowed to cool down following a period of operation, action is taken in a pool of the nuclear reactor on at least one guide tube of the activated upper internal equipment of the nuclear reactor to enlarge () guide channels () of the guide tube () in at least one continuous guidance zone. The enlargement is preferably performed by machining discontinuous cavities along the length of the guide channel (). Enlargement is preferably performed on the guide tube () in place within the upper internal equipment that has been placed on a storage stand in the reactor pool.

Method and device for restoring the fall-time of at least one control cluster for regulating reactivity in the core of a light-water-cooled nuclear reactor

Process for coating a passivatable metal or alloy substrate with an

A control cluster for a water cooled and moderated nuclear reactor, comprises a spider and rods suspended from the spider. Each rod contains neutron-absorbing material. In a lower portion of each rod, the material is a metal neutron absorber. In an upper portion, it is a stack of pellets of boron carbide B.sub.4 C. In a middle fraction occupying a height lying in the range 35% to 45% of the total height, it is zirconium diboride ZrB.sub.2 isotopically enriched in boron 10 or hafnium diboride HfB2.

Neutron-absorbent control cluster for a nuclear reactor

Oxidation treatments by ionic bombardment or post-discharge result in the formation on the surface of passivatable metals and alloys of a layer of oxide having a thickness of a few micrometers which protects the substrates from subsequent corrosion. The gas activated by the electric discharge is put in contact with the surface of the part (2) to be oxidized, which is brought to a temperature of 350.degree. to 650.degree. C. The treatment may be employed in particular for forming a protective covering on an element or a complete framework composed of a zirconium alloy of a fuel assembly of a water-cooled nuclear reactor.

Process for the surface oxidation of a part composed of passivatable

An organometallic chromium compound in the gaseous phase is brought into contact with a substrate consisting of the inner surface of the zirconium alloy tubular cladding (5) of the fuel element, or the outer surface of the pellets of fuel material, the substrate being kept at a temperature between 300.degree. and 600.degree. C. The organo metallic compound may consist of chromium acetylacetonate. The process enables a chromium oxide coating to be obtained inside the tubular cladding (5) and/or on the outer surface of the nuclear fuel pellets. Pellet/cladding interaction is thus prevented or limited when this fuel element is used in the reactor.

Process for forming a chromium oxide insulating layer between the

A sheath for a nuclear reactor control rod consists of chromium nickel stainless steel. It is protected against friction wear by nitridation over a depth of from 15 to 50 .mu.m obtained by an electric discharge in a nitrogen containing atmosphere.

Stainless steel tubular element with improved wear resistance

For improving the corrosion resistance of the sheaths of fuel rods used in water cooled and moderated reactors, part at least of the outer surface of the sheath is coated with a dense and adhering carbon layer having a thickness of from 0.1.mu. to 5.mu.. The layer may be deposited by radiofrequency reactive sputtering in a lower alkyl containing atmosphere.

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Sainte Foy Les Lyon, France

Dominique Hertz