Abb Atom Ab

Santrade, Ltd

Ab Asea-Atom

Asea Brown Boveri Inc.

Compagnie Europeenne Du Zirconium Cezus

Gunnar Vesterlund

Mats Dahlback

Airy-Pierre Lamaze

Jean Boutin

Erik T Anderson

The invention relates to a fuel element for a pressurized-water reactor comprising a number of fuel rods arranged in a square lattice and wherein certain positions in the lattice contain guide tubes for receiving control rods, wherein the fuel element can be used for higher burnup by manufacturing the guide tubes of the element such that their irradiation-induced growth is reduced and their corrosion resistance is increased compared with conventionally manufactured guide tubes. This is achieved by finally heat-treating the guide tubes in two steps, the first step being a beta quenching and the second step a heat treatment in the alpha-phase region.

Fuel element for pressurized-water reactor with guide tubes finally

Fuel element for pressurized--water reactor with guide tubes finally

The invention relates to a process for the production of a neutron absorbing pellet for use in a nuclear reactor control device, comprising the following stages:

Process for the production of a neutron absorbing pellet, the pellet

A control rod for a nuclear reactor comprising a number of absorber plates (13-16) which are connected to each other along a center line on the control rod and which are each provided with a plurality of bored channels (18b), which extend at least substantially perpendicularly to the center line of the rod, contain boron carbide or other absorber material which swells upon irradiation and are sealed off from communication with the surroundings of the control rod. Within at least one region of an absorber plate, each channel is arranged at a smaller distance to an adjacent channel than to the surface of the absorber plate. Preferably, each channel within the stated region of the absorber plate is arranged at a smaller distance to the adjacent channel on one of its sides than to the adjacent channel on its other side.

Control rod for nuclear reactors

In the manufacture of cladding tubes of a zirconium-based alloy for fuel rods for nuclear reactors by extrusion of the zirconium-based alloy and cold rollings of the extruded product with annealings, intermediate annealings, between the cold rollings and a .beta.-quenching prior to the last cold rolling, a cladding tube is provided which has at the same time good corrosion properties and mechanical properties by performing the .beta.-quenching prior to a cold rolling, after which an intermediate annealing is performed at a temperature of 500.degree.-610.degree. C.

Method of manufacturing cladding tubes of a zirconium-based alloy for

In the manufacture of cladding tubes of a zirconium-based alloy for fuel rods for nuclear reactors by extrusion of the zirconium-based alloy and cold rollings of the extruded product with annealings, intermediate annealings, between the cold rollings and a .beta.-quenching of the extruded product prior to the last cold rolling, a cladding tube is provided which has at the same time good corrosion properties and mechanical properties by performing the .beta.-quenching prior to a cold rolling, after which an intermediate annealing is performed at a temperature of 500.degree.-675.degree. C., and preferably at a temperature of 500.degree.-610.degree. C. The zirconium-based alloy is a zirconium-tin alloy comprising 1.2-1.7% tin, 0.07-0.24% iron, 0.05-0.15% chromium and 0-0.08% nickel.

In the process of applying a layer of copper and a layer of zirconium dioxide to the internal surface of a tube of a zirconium-based alloy, with the layer of zirconium dioxide being located between the copper layer and the internal surface of the tube, the tube surface is first treated with an activating solution in the form of an aqueous solution containing from about 1 to about 3 grams/liter of hydrogen fluoride, from about 2 to about 8 grams/liter of ammonium fluoride and from about 0.1 to about 0.5 gram/liter of sulfuric acid, the amounts of hydrogen fluoride and ammonium fluoride being chosen so that the amount of ammonium fluoride, calculated in moles, exceeds the amount of hydrogen fluoride, calculated in moles, by at least 5 percent.

Method of treating zirconium-based alloy tubes

A method for providing a barrier against copper diffusion into a zirconium alloy tube which is lined with copper for the purpose of increasing the resistance of the tube to stress corrosion induced by fission products when the tube is used to fuel a nuclear reactor. The method involves the deposition of a copper lining on the zirconium alloy tube and the subsequent exposure of the lined tube to a substance such as steam, water, nickel oxide or carbon dioxide or another material which has the ability to oxidize the zirconium without oxidizing the copper. Thus, a zirconium oxide layer is developed between the zirconium alloy tube and the copper lining thereon.

Growing community of inventors

Vaster.ang.s, Sweden

Gunnar Vesterlund