Hitachi, Ltd.

Hitachi Kyowa Kogyo Co., Ltd.

Masato Koshiishi

Kunio Miyazaki

Isao Sumida

Shouichirou Kinoshita

Minoru Akita

Takahiko Kato

Hisanori Okamura

Takeshi Tsukamoto

Jiro Kuniya

Masayoshi Kanno

Takeshi Obana

Yositeru Chiba

Kikuo Takeshima

Shin Kumagai

Tomomi Shiraki

Provided are an underwater processing apparatus which can effectively prevent water from entering a shield for a workpiece having a surface ruggedness, and in which variation in a gas flow for a processing part is reduced, a processing method and an application thereof to a nuclear reactor, and the under water processing device is composed of a shield means which locally cover the processing part with the gas in order to prevent water from entering the shield member, the shield means having a solid wall formed of a member which is slidable in a part where it make contact with the workpiece, and adapted to make contact with the workpiece and to be moved up and down by a pressing force, and a water jetting means for forming a water curtain around the outer periphery of the solid wall.

Underwater processing device and underwater processing method

A wear resistant material containing no cobalt is used for a sliding portion of a control rod driving mechanism of a nuclear plant for reducing the exposure dose due to elution of cobalt and ensuring smooth driving of a control rod under a high load for a long time. A control rod driving mechanism employs a roller and a pin, each of which is made of a wear resisting alloy comprising coarse particles of a hard phase, having a particle size of from 20 to 100 .mu.m, and dispersed in a soft matrix made of an iron-based or nickel-based alloy containing chromium and having a hardness of 300 Hv or less. A nuclear reactor employs this control rod driving mechanism.

Wear resisting sintered alloy and its production, and control rod

Hard facing layers provided on engagement portions of a valve body and engagement portions of a valve box of a valve apparatus, consisting of cobalt-free Ni-base alloys. One of the Ni-base alloys for the hard facing layers comprises not more than 15% Fe and less than 2% W (tungsten), and the other comprises more than 15% Fe. More specifically, one of the cobalt-free Ni-base alloys essentially consists of, by weight, 15 to 20% Cr, 5 to 10% Si, 10 to 15% Fe, less than 2% W, and the balance of Ni and unavoidable impurities, and has a Vickers hardness (Hv) 510 to 630, and the other essentially consists of, by weight, 5 to 15% Cr, 5 to 10% Si, more than 15% and not more than 30% Fe, 1 to 4% W, and the balance of Ni and unavoidable impurities, and has a Vickers hardness (Hv) 400 to 470. The valve apparatus of the invention is suitably installed in a water pipe line which communicates with a nuclear reactor.

Valve having facing layers of co-free Ni-base Alloy

Disclosed is liquid filling apparatus for a high-temperature and high-pressure vessel. The apparatus comprises a high-temperature and high-pressure vessel, a closed liquid storage tank disposed at a level higher than that at which liquid is supplied to the high-temperature and high-pressure vessel, a liquid-filling flow passage for supplying liquid from the closed liquid storage tank into the high-temperature and high-pressure vessel, a pressure-feed flow passage for supplying a pressure from the high-temperature and high-pressure vessel to the closed liquid storage tank, valves equipped on the liquid-filling flow passage and the pressure-feed flow passage respectively, and a liquid-filling liquid source adapted to communicate with the interior of the closed liquid storage tank via a valve, whereby the environmental surroundings of the closed liquid storage tank are lower in temperature than the interior of the high-temperature and high-pressure vessel.

Liquid filling method for a high-temperature and high-pressure vessel

Disclosed is a liquid filling apparatus for high-temperature and high-pressure vessel. The apparatus comprises a high-temperature and high-pressure vessel, a closed liquid storage tank disposed at a level higher than that at which liquid is filled into the high-temperature and high-pressure vessel, a liquid-filling flow passage for supplying liquid from the closed liquid storage tank into the high-temperature and high-pressure vessel, a pressure-feed flow passage for supplying pressure from the high-temperature and high-pressure vessel to the closed liquid storage tank, valves equipped on the liquid-filling flow passage and the pressure-feed flow passage respectively, and a liquid-filling liquid source adapted to communicate with the interior of the closed liquid storage tank via a valve, whereby the environmental surroundings of the closed liquid storage tank are lower in temperature than the interior of the high-temperature and high-pressure vessel.

Growing community of inventors

Takahagi, Japan

Masato Koshiishi