Hitachi, Ltd.

Hideo Maki

Masahisa Inagaki

Iwao Takase

Isao Masaoka

Masayoshi Kanno

Fuminobu Takahashi

Keiichi Kuniya

Tomiharu Yoshida

Junjiro Nakajima

Jiro Kuniya

Hajime Umehara

Kenji Tsuchita

Makoto Senoh

Tatsuyuki Omote

Tetsuo Yasuda

Toshimi Yoshida

Hiromasa Hirakawa

Katsutoshi Shinbo

Hideaki Ishizaki

Takanori Hosokawa

Ryutarou Jimbow

Nobukazu Yamamoto

Shozo Nakamura

Satoshi Kanno

Kimihiko Akahori

Kiyomi Nakamura

Akira Maru

Tsuneyuki Hashimoto

Toraki Sakuma

Kouichi Matsumoto

Ryutaro Jinbo

Tetsuro Yasuda

Nobuhiro Okazaki

Syouko Tanikoshi

A fuel assembly avoiding the generation of irradiation damage, a Zr alloy used for the same, and a manufacturing method thereof. According to one embodiment, a super-saturated solid-solution Zr alloy powder having a crystal grain size in the range of 1000 nm or less and containing Fe, Ni and Cr is prepared by mechanical alloying, and the alloy powder is subjected to HIP, hot-working, cold-working and final heat-treatment.

Fuel assembly for nuclear reactor and manufacturing method thereof

A nuclear fuel identification code reader has an optical sensor for detecting a nuclear fuel identification code marked on a fuel assembly and an ultrasonic wave sensor for detecting the nuclear fuel identification code. It further has first means for recognizing the nuclear fuel identification code based on information derived from the optical sensor and second means for recognizing the nuclear fuel identification code based on information derived from the ultrasonic wave sensor. When the nuclear fuel identification code cannot be recognized by the first means, the detection by the ultrasonic wave sensor and the recognition of the nuclear fuel identification code by the second means are effected. The nuclear fuel identification code can be recognized in a short time with a high accuracy.

Method for reading a nuclear fuel assembly identification code

In a method of fabricating a channel box for use in a nuclear reactor, Zr-alloy sheet material is formed into a tubular channel box. The method includes solution heat treatment of the Zr-alloy sheet material including quenching from a temperature at which .beta.-phase is present. After the solution heat treatment, portions of the Zr-alloy sheet are thinned relative to other portions by a non-stressing thinning process, such as chemical etching in a bath. The corrosion resistance imparted by heat treatment is retained, and the heat treatment itself is easily performed on material of uniform thickness.

Method of fabricating a channel box or other part for a nuclear reactor

A fuel assembly, where crystallographic orientations of a channel box are brought into a random distribution; and cladding tubes, spacers and a channel box are made from highly corrosion-resistant, Fe--Ni, zirconium-based alloy, hardened in the (.alpha.+.beta.) phase or .beta.-phase temperature region, has an average discharge burnup level of 50 to 550 GWd/t.

Fuel assembly, components thereof and method of manufacture

A fuel assembly for a nuclear reactor comprising a fuel cladding tube of three-layer structure having an outer surface in contact with reactor water of the nuclear reactor, an inner surface layer in contact with the nuclear fuel, and an intermediate layer interposed between the outer surface layer and the inner surface layer. the outer surface layer is made of a Zr-based alloy containing Nb, Sn and Mo. The inner surface layer is made of pure zirconium. The intermediate layer is made of a high ductility alloy which is higher in ductility than the outer surface layer and is higher in strength than the inner surface layer.

Fuel assembly for nuclear reactor, method for producing the same and

A nuclear fuel assembly having first and second nuclear fuel identification codes marked on the fuel assembly. The first nuclear fuel identification code is of a different expression than the second nuclear fuel identification code and is arranged adjacent thereto.

Nuclear fuel assembly having identification codes

A nuclear fuel identification code reader has an optical sensor for detecting a first nuclear fuel identification code marked on a fuel assembly and an ultrasonic wave sensor for detecting a second nuclear fuel identification code marked on the fuel assembly. It further has first means for recognizing the nuclear fuel identification code based on information derived from the optical sensor and second means for recognizing the nuclear fuel identification code based on information derived from the ultrasonic wave sensor. When the nuclear fuel identification code cannot be recognized by the first means, the detection by the ultrasonic wave sensor and the recognition of the nuclear fuel identification code by the second means are effected. The nuclear fuel identification code can be recognized in a short time with a high accuracy.

Nuclear fuel assembly identification code reader

A channel box and/or a spacer of a fuel assembly is a welded construction and made of a Zr-Nb-Sn alloy comprising 0.5-2.2 wt % Nb, 0.5-1.5 wt % Sn contained so as to satisfy the relation of Sn(wt %) 22.times.Nb(wt %)--3.0, and balance Zr or a Zr-Nb-Sn-Mo alloy comprising 0.5-2.2 wt % Nb, 0.5-1.5 wt % Sn contained so as to satisfy the relation of Sn(wt %).gtoreq.2.times.Nb(wt %)--0.3, 0.1-0.8 wt % Mo, and balance Zr. The welded portion, its heat affected zone and the unwelded portion of the channel box and/or the spacer have substantially the whole equilibrium phase structure.

Nuclear reactor fuel assembly

A zirconium-based alloy with a high corrosion resistance, consisting essentially of 1 to 2 wt % Sn, 0.20 to 0.35 wt % Fe, 0.03 to 0.16 wt % Ni and the balance substantially Zr. The Fe/Ni content ratio of the alloy ranges between 1.4 and 8. The structure of the alloy has fine intermetallic compound of Sn and Ni is precipitated within the zirconium crystal grain of .alpha.-phase. The alloy may further contain 0.05 to 0.15 wt % Cr. This alloy exhibits reduced hydrogen absorption rate and suffers from no nodular corrosion, so that it can suitably be used as a material of nuclear fuel cladding tubes. The nuclear fuel cladding tube made of this alloys exhibits extended service life when used in a nuclear reactor of high degree of burn-up.

Zirconium-based alloy with high corrosion resistance

In a process for producing a zirconium-based alloy in which after the zirconium-based alloy is subjected to hot plastic working, it is subjected to cold plastic working and then to annealing and these steps are repeated at least twice, the present invention provides a process for producing a zirconium-based alloy characterized in that after the alloy is subjected to solid solution treatment in which it is heated to a temperature within the range including the .alpha. phase and the .beta. phase of the alloy, or within the range of the .beta. phase and is then quenched, cold plastic working is effected at least twice.

Process for producing zirconium-based alloy

Process for producing zirconium-based alloy and the product thereof

A zirconium alloy having superior corrosion resistance, containing Sn of a small amount not less than the amount of Sn existing in the solid-solution of the zirconium alloy at a room temperature, and at least one kind of Fe and Cr each of a small amount not less than the amount of each of Fe and Cr existing in the solid-solution of the zirconium alloy at a room temperature,

Zirconium alloy having superior corrosion resistance

First nuclear fuel elements in which a fissionable material in which a burnable poison is incorporated is loaded and second nuclear fuel elements in which a fissionable material in which no burnable poison is incorporated is loaded are disposed in a nuclear fuel assembly. Content of the fissionable material in the first nuclear fuel element is less than about 72% of that of the fissionable material in the second nuclear fuel element adjacent to the first nuclear fuel element.

Nuclear fuel assembly

A method of starting operation of a nuclear reactor which contains fresh fuel rods comprising increasing a fuel power P(Kw/ft) produced by the fresh fuel rods to an amount determined by the following inequality;

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Katsuta, Japan

Hideo Maki