Kabushiki Kaisha Toshiba

Hitachi, Ltd.

Masanobu Watanabe

Kunihiko Kinugasa

Tsuyoshi Hagiwara

Hiroyuki Adachi

Jun Suzuki

Hajime Mori

Ken Okuda

Masahiko Warashina

Ken Uchida

Noboru Saito

Michio Sato

Shigeru Kasai

Tadahiro Mitsuhashi

Yuki Minato

Satoshi Yamamoto

Takeshi Maehara

Satoru Abe

Tsutomu Ooishi

Tsutomu Shioyama

Yoshinori Katayama

Yuusuke Watanabe

Hisaki Sato

Chikako Iwaki

Tomoo Oofuji

Tetsuzo Yamamoto

Kozue Matsukawa

Kiyofumi Saiki

Yasumi Kitajima

Satoshi Miyamura

Yusuke Ozawa

Tatsumi Ikeda

Kiichi Ito

Hideshi Iwasa

Daiki Takeyama

Shioyama Tsutomu

A jet pump measuring pipe repair method that repairs a ruptured part of a measuring pipe horizontally installed to a lower portion of a jet pump provided in reactor water inside a reactor pressure vessel. The repair method includes: fixing a support member to the jet pump near the measuring pipe left remained; mounting, after the support member fixing, a measuring pipe connector provided with a pipe-repairing pipe having both ends over which connecting pipes are fitted, respectively, to the support member; connecting, after the connector mounting, the remaining measuring pipe and connecting pipe using the measuring pipe connector.

Method of repairing jet pump measuring pipe and repair device therefor

A reactor measurement-pipe maintenance clamp apparatus includes a first clamp mechanism and a second clamp mechanism. The first clamp mechanism includes clamps to fix the measurement pipe between the clamps, first clamp operation bolts that are allowed to be turned by remote control from above a reactor core, and wedge mechanisms to convert the turning of the clamp operation bolts to displacement of the clamps in a radial direction of the diffuser to generate clamping forces for securing the measurement pipe. The second clamp mechanism includes a support clamp to hold the support, a second clamp operation bolt that is allowed to be turned by remote control from above the reactor core, and a wedge mechanism to convert the turning of the second clamp operation bolt to displacement of the support clamp in a tangential direction of the diffuser to generate clamping force for fixing the support.

Reactor measurement-pipe maintenance clamp apparatus

The pressurized water reactor according an embodiment comprises: a cylindrical reactor pressure vessel () to which inlet nozzles are connected; fuel assemblies which are contained within the reactor pressure vessel (); a cylindrical reactor core barrel () which surrounds the fuel assemblies and forms an annular downcomer () between the reactor core barrel () and the inner surface of the reactor pressure vessel (); and radial supports. The radial supports are supports which are arranged below the downcomer () at intervals in the circumferential direction, each has vertical flow path formed therein, and position the reactor core barrel () and the reactor pressure vessel (). The radial supports each has, for example, a flow path-equipped radial keys () and a key groove member ().

Pressurized water reactor

A jet pump which can restrain self-excited vibration in a connection portion between an inlet mixer pipe and a diffuser pipe without inhibiting a structural deformation due to thermal expansion and the like includes a slip joint structure connecting the inlet mixer pipe and the diffuser pipe to each other by inserting the inlet mixer pipe into an upper end opening of the diffuser pipe with a clearance left therebetween; and a self vibration damping structure configured such that when the clearance defined by an outer pipe wall of the inlet mixer pipe and an inner pipe wall of the diffuser pipe is widening or narrowing due to vibration of the inlet mixer pipe or the diffuser pipe, a flow path resistance inside a clearance flow path for pumped coolant water defined by the clearance is not smaller than a fluid inertia force all over the clearance flow path.

Jet pump and method for restraining vibration of the same

The present invention provides a vibration monitoring apparatus that monitors vibration of a jet pump disposed in a reactor pressure vessel using ultrasonic wave, including: an ultrasonic sensor that is attached to an outside the reactor pressure vessel, and transmits and receives ultrasonic wave; a reflector that is mounted on a surface of a riser pipe of the jet pump, and includes a planar reflecting surface that can reflect ultrasonic wave; and a signal processing unit that performs signal processing of the ultrasonic wave transmitted by the ultrasonic sensor, reflected by the reflecting surface of the reflector, and received by the ultrasonic sensor, and measures a vibration amplitude of the riser pipe and calculates a vibration waveform.

Vibration monitoring apparatus and vibration monitoring method

A reactor metering pipe fixing device fixes a reactor metering pipe disposed in a reactor to a cylindrical outer surface of a jet pump diffuser and reduces stress that may be induced in a weld zone in the reactor metering pipe. An outer holding memberis held on the cylindrical outer surfaceof a jet pump diffuserby a C-shaped holding member. The reactor metering pipeis clamped from radial directions by the outer holding memberand inner holding membersand. Wedgesandare wedged into a gap between the cylindrical outer surfaceand the inner holding memberand a gap between the cylindrical outer surfaceand the inner holding memberto fix the reactor metering pipefirmly to the cylindrical outer surface

Device and method for fixing a reactor metering pipe

A horizontal fly-back transformer having a high voltage winding for generating high voltage pulses fed to the anode of a cathode ray tube is provided with a tertiary winding which in turn is connected to a rectifying-smoothing circuit, and a DC voltage in proportion to the anode high voltage is obtained from the rectifying-smoothing circuit. The DC voltage is divided by a resistor divider circuit and a division of the DC voltage is fed to the gate of a thyristor via a Zener diode which is turned on when the anode high voltage exceeds a critical voltage. A thryistor gate current which flow concurrent with the conduction of the Zener diode causes the thyristor to turn on so that the operating voltage o a horizontal oscillator circuit may be reduced until the horizontal oscillator circuit stops oscillating, thereby preventing generation of the anode high voltage. In addition to the aforementioned high voltage prevention circuit, a beam current detector circuit is connected in series with the high voltage winding and when the amount of beam current is below a predetermined value, detecting current dependent on the beam current is passed through a part of a resistor circuit. DC voltage for turning on the Zener diode and accordingly, the anode high voltage in proportion thereto depends on th beam current below the predetermined value so that an anode high voltage level at which the high voltage prevention circuit is operated is varied with the amount of the beam current.

High voltage protection circuit

Growing community of inventors

Yokohama, Japan

Masanobu Watanabe