Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.