Siemens Aktiengesellschaft

Kraftwerk Union Aktiengesellschaft

Framatome Anp Gmbh

Reaktor-brennelement Union Gmbh

Gerhard Gradel

Martin Peehs

Wolfgang Dorr

Harald Cura

Wolfgang D&ouml;rr

Thorsten Gerdes

Monika A Willert-Porada

Wolfgang Doerr

Bruno Schmitt

Thomas Sondermann

Erhard Ortlieb

Alfons Roppelt

Richard A Perkins

Reinhard Schafer

Peter Wahode

A nuclear fuel sintered body is produced from a powder which contains at least one fissile heavy metal oxide. During the further treatment of the powder over the course of the process preceding the sintering operation, a dopant that contains at least 100 ppm of an iron oxide compound is added to the powder. The powder is a UO -containing powder obtained from a dry-chemical conversion process, and if appropriate, a powder which contains further fissile heavy metal oxide (U O , PuO , inter alia). As a result, the sintered body is provided with high plasticity combined, at the same time, with a large grain size. This advantageously reduces an interaction between the nuclear fuel sintered body and a fuel rod cladding tube during an operation of the reactor.

Method of producing a nuclear fuel sintered body

A furnace is provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.

Furnace for microwave sintering of nuclear fuel

A method and a furnace are provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.

Method and furnace for microwave sintering of nuclear fuel

A sintered nuclear fuel body includes (U, Pu)O,mixed crystals having a mean particle size in a range from 7.5 &mgr;m to 50 &mgr;m. This sintered nuclear fuel body has a high retention capacity for fission gas in a power reactor. In order to produce the sintered nuclear fuel body by sintering a body in a hydrogen-containing sintering atmosphere, a powered substance selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, chromium oxide, aluminum stearate, aluminum distearate and aluminum tristearate is added to the starting powder for the body. As an alternative or in addition, the body made from the starting powder is sintered during a holding period of 10 minutes to 8 hours at a sintering temperature of 1400&deg; C. to 1800&deg; C. in a hydrogen-containing sintering atmosphere, initially with an oxygen partial pressure of 10,to 10,bar and then from 10,to 10,and then cooled in a hydrogen-containing atmosphere having an oxygen partial pressure of 10,to 10,bar.

Method for producing a sintered nuclear fuel body

A sintered nuclear fuel body includes (U, Pu)O.sub.2 mixed crystals having a mean particle size in a range from 7.5 .mu.m to 50 .mu.m. This sintered nuclear fuel body has a high retention capacity for fission gas in a power reactor. In order to produce the sintered nuclear fuel body by sintering a body in a hydrogen-containing sintering atmosphere, a powered substance selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, chromium oxide, aluminum stearate, aluminum distearate and aluminum tristearate is added to the starting powder for the body. As an alternative or in addition, the body made from the starting powder is sintered during a holding period of 10 minutes to 8 hours at a sintering temperature of 1400.degree. C. to 1800.degree. C. in a hydrogen-containing sintering atmosphere, initially with an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar and then from 10.sup.-8 to 10.sup.-10 and then cooled in a hydrogen-containing atmosphere having an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar.

Sintered nuclear fuel body and method for producing a sintered nuclear

A uranium-containing nuclear-fuel sintered pellet containing UO.sub.2, (U, Pu)O.sub.2, (U, Th)O.sub.2, (U, RE)O.sub.2, (U, Pu, Th)O.sub.2, (U, Pu, RE)O.sub.2, (U, Th, RE)O.sub.2 or (U, Pu, Th, RE)O.sub.2, wherein RE=rare earth, has a sintered-pellet surface layer being formed of at least 80% by volume of a chemical boron compound UB.sub.x or (U, . . . )B.sub.x, wherein x=2;4;6 or 12, and a remainder of the sintered pellet containing at most 5% by volume of the chemical boron compound. A nuclear-reactor fuel assembly has a fuel rod containing such a uranium-containing nuclear-fuel sintered pellet in a cladding tube with the boron as a burnable absorber for thermal neutrons. The surface layer having the chemical boron compound is obtained by treating the nuclear-fuel sintered pellet with boron or a boron-containing chemical compound at an appropriately high treatment temperature.

Uranium-containing nuclear-fuel sintered pellet

UO.sub.2 base powder exhibiting any specific surface and crystallite diameter properties is mixed with rare earth (SE) oxide-containing powder, the particles of which exhibit at least in one surface layer, a crystal lattice of the fluorite type, with the stoichiometric composition (SE.sub.0.5, U.sub.0.5) 0.sub.2.00 and/or form it in sintering; and is compacted to form compacts which are sintered in a gas atmosphere with reducing action at 1500.degree. C. to 1750.degree. C. to form high-density sintered bodies.

Method for producing oxidic sintered nuclear fuel bodies

Method for determining the contents of a fuel rod within a testing range extending in the longitudinal direction of the fuel rod, characterized by the features that

Method for determining the contents of a fuel rod

Method for the manufacture of oxidic sintered nuclear fuel bodies by compacting UO.sub.2 -starting powder or a mixture of UO.sub.2 -and PuO.sub.2 starting powder which contains up to 10% by weight rare-earth oxide, especially Gd.sub.2 O.sub.3, as an additive into blanks and subsequent densification of these blanks by a heat treatment in a sintering atomsphere with reducing action. The UO.sub.2 -starting powder used for compacting has a specific surface in the range of 2 to 4.5 m.sup.2 /g and/or a mean crystallite diameter in the range of 80 nm to 250 nm, and the heat treatment in the sintering atmosphere with reducing action is carried out at a temperature in the range of 1,500.degree. C. to 1,750.degree. C.

Method for manufacturing oxidic sintered nuclear fuel bodies

Manufacture of very dense oxidic fuel bodies of UO.sub.2 with rare earth oxides in which pressed blanks are subjected to sintering in an oxidizing atmosphere at relatively low temperature and are sintered in a reducing atmosphere at a higher temperature. This avoids sintering-inhibiting phases and permits very dense bodies with greater content of rare earth oxides to be produced.

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Forchheim, Germany

Gerhard Gradel