Other

Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Norio Kawashima

Yoshiharu Kikuchi

Akira Koizumi

Yasuyuki Gotoh

Yasuhiro Aizawa

Hidemi Haga

Kouichi Machida

Satoru Aoike

Hiromasa Hirakawa

Takashi Fukumoto

Michio Nakayama

Yoshitaka Nishino

Hideaki Ishizaki

Shinobu Okido

Hirofumi Oizumi

Takayuki Arakawa

Koichi Machida

Kazuki Kobayashi

Takayoshi Yasuda

A control rod for a boiling water reactor is provided with a structure element having mutually-perpendicular four blades. The four blades have a neutron absorber-filling region that neutron absorber is held, respectively. In the structure element, a plurality of regions formed in an axial direction of the control rod include a first region having a first cross-section that forms a first united cruciform cross-section of the four blades connected one another, a second region having a second cross-section that has each separated cross-section of the four blades, and a third region having a third cross-section that has a second united cross-section of continuous two blades of the four blades, disposed in a diametrically opposite direction and facing each other and each separated cross-section of remaining two blades of the four blades, disposed perpendicularly to the continuous two blades.

Control rod for boiling water reactor

A control rod includes a tie-rod, a handle mounted to an upper end portion of the tie-rod, either a connector plate or a fall velocity limiter mounted to a lower end portion of the tie-rod, sheaths having a U-shaped cross-section, welded intermittently to the tie-rod at a plurality of locations in the axial direction of the tie-rod, and having an upper end welded to the handle and a lower end welded to either the connector plate or the fall velocity limiter, and a neutron absorbing member disposed inside each of the sheaths. An upper end of a weld portion located at uppermost position in an axial direction of the tie-rod among a plurality of weld portions between the tie-rod and the sheath is disposed at a position within a range between 0.8 and 13% of total axial length Ls of the sheath below an upper end of the sheath.

Control rod

A control rod for a BWR according to the present invention comprises a first unit composed of a tie rod, a handle mounted on an axially upper portion of the tie rod and a lower support member or falling speed limiter mounted on a axially lower portion of the tie rod; and a second unit composed of a sheath containing therein reactivity control material, an upper end plate mounted on an axially upper portion of the sheath and a lower end plate mounted on an axially lower portion of the sheath, wherein an upper portion of the upper end plate is fixed to the handle, a lower portion of the lower end plate is fixed to the lower support member or falling speed limiter, whereby the control rod is constructed as a joined body of the first unit and the second unit.

Control rod for boiling water reactor, unit for control rod and production method of control rod

In order to provide a boiling water type nuclear reactor use control rod with a guide use roller which improves corrosive environment at a clearance in the guide use roller and suppresses a generation of stress corrosion cracking while maintaining sliding function of the control rod by the guide use roller, at least one of a handle a lower portion supporting plate and a dropping speed limiter is provided with the guide use roller, and a space which causes water flow in a clearance between a pin and a pin hole in the guide use roller is provided adjacent the clearance.

Boiling water type nuclear reactor use control rod

To reduce the manufacturing processes of a control rod and shorten the time required for manufacturing a control rod, for the lower part support member,, the thin parts,A and,B are formed in the neighborhood of each of the left and right sides of the window,. In the left and right sides of the pull-up handle,, the grooves,A and,B are formed respectively. The groove,B is deeper than the groove,A. The thin part,A is fitted into the groove,A and the thin part,B is fitted into the groove,B. The gap formed between the end of the thin part,B and the bottom of the groove,B is larger than the gap formed between the end of the thin part,A and the bottom of the groove,A. Therefore, the thin part,A can be simply fitted into the groove,A.

Control rod and manufacturing method for the control rod

The present invention relates to a control rod installed in a boiling water reactor (BWR), and particularly to a control rod using metal. An object of the present invention is to provide a manufacturing method of a control rod for a boiling water reactor, having excellent corrosion resistance in high temperature water and excellent wear resistance at the time of fabrication, and in which the influence of the manufacturing process is slight. In order to achieve the above described object, the present invention provides a manufacturing method of a control rod for a boiling water reactor constructed with sheaths having a U-shaped cross section attached to each end of a tie rod having a cruciform cross section, and rod, plate or oval tube cross section metal hafnium type neutron absorber material contained inside the sheaths, in which an anodized film is provided on a surface of the neutron absorber material as a pre-process of assembly of the neutron absorber material in the structure of the control rod.

Manufacturing method of control rod for boiling water reactor

A control rod assembly for a boiling water reactor comprises a tie-rod of a cross-shaped section, and four sheaths. Each of the sheaths is of a U-shaped section and mounted to the respective arms of the tie-rod. One or more neutron absorber materials are disposed within a space defined by the arm and the sheath. The neutron absorber material is axially separated into two portions. One of two portions is supported by a supporting member. The other portion is suspended by a handle.

Control rod assembly for a boiling water reactor

A paper feeder for a printer which is adapted for feeding both continuous printing paper and cut sheet printing paper. A second frame which may carry the platen supports the rear end of a first frame which in turn supports the tractor feeder in such a manner that the first frame can be rotated backward from a first position adapted for feeding continuous paper to a second position adapted for making a room for mounting a paper guide to the printer. If the tractor feeder is adapted for pushing continuous paper towards the platen, continuous paper can be kept on the tractor feeder even when the second frame is at its second position.

Paper feeder for a printer

A paper feeder for a printer having a platen and a tractor feeder which is provided with a pin belt having pins projecting from upper and lower surface of the tractor feeder, and the tractor feeder can be selectively placed either one of a first position in which the paper feeding plane of the paper feeding pins of the lower surface of the tractor feeder aligns with a tangential direction of a lower part of the platen and a second position in which the paper feeding plane of the paper feeding pins of the upper surface is aligned with a tangential direction of an upper part of the platen. Preferably, the tractor feeder can be held at a third position which is intermediate between the first and the second position and a middle plane between the upper and the lower paper feeding plane align with a radial line of the platen. Thus, depending on the position of the tractor feeder, the printing paper can be pulled from the platen, pushed toward the platen or pushed and pulled towards and away from the platen as desired.

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Mito, Japan

Norio Kawashima