Hitachi, Ltd.

Babcock-hitachi Kabushiki Kaisha

Tokyo Gas Company Limited

Hitachi Nuclear Engineering Co., Ltd.

Fuminobu Takahashi

Masahiro Koike

Kenji Tsuchita

Izumi Yamada

Shunsuke Uchida

Tomiharu Yoshida

Hideo Maki

Makoto Senoh

Haruo Fujimori

Takaharu Fukuzaki

Satoshi Ogura

Yoshihiro Michiguchi

Tatsuyuki Omote

Kazunori Koga

Kazuo Hiramoto

Hideki Inoue

Masatsugu Nishi

Masakazu Hisatsune

Shinji Sonoda

Yosinori Musha

Shuuji Kamimoto

Shinji Naito

Tsukasa Sasaki

Yuuji Ichinose

Makiko Miyauchi

Yuuichirou Mizumachi

Toshikazu Nishino

Makoto Nagase

Shigeru Izumi

Yoshiaki Ichikawa

Atsushi Takagi

Eriko Takeda

Ren Morinaka

Masahiro Otaka

Hajime Umehara

Kazumichi Suzuki

Yoshiaki Nagashima

Chikara Sato

Takahiro Kanamori

Kenichi Fujiwara

Norio Awamura

Takehiro Ooura

Masao Sato

Kozo Domon

Shinji Naitoh

Nuclear fuels are taken from a nuclear reactor pressure vessel, a rail for running is mounted under the reactor pressure vessel drain piping in parallel with a horizontal portion of the reactor pressure vessel drain piping inside a pedestal positioned on the lower side of the reactor pressure vessel, an inspection apparatus is mounted on the-rail, and the inspection apparatus is moved along the rail to inspect the reactor pressure vessel drain piping, whereby the reactor pressure vessel drain piping can be surely inspected while reducing radiation exposure to an inspector.

Inspection method and apparatus for piping

Nuclear fuels are taken from a nuclear reactor pressure vessel, a rail for running is mounted under the reactor pressure vessel drain piping in parallel with a horizontal portion of the reactor pressure vessel drain piping inside a pedestal positioned on the lower side of the reactor pressure vessel, an inspection apparatus is mounted on the rail, and the inspection apparatus is moved along the rail to inspect the reactor pressure vessel drain piping, whereby the reactor pressure vessel drain piping can be surely inspected while reducing radiation exposure to an inspector.

A stress evaluation method for evaluating stress acting on a test piece includes the steps of transmitting acoustic waves including a surface wave, a longitudinal wave, and a shear wave through the test piece; receiving the acoustic waves after they have propagated through the test piece; obtaining acoustic velocities of the surface wave at a non-loaded portion and a loaded portion of the test piece based on the received acoustic waves; evaluating a stress in a surface layer of the test piece based on a difference between the surface wave acoustic velocities at the non-loaded portion and the loaded portion and a predetermined relationship between surface wave acoustic velocities and stresses; obtaining an acoustic velocity of the longitudinal wave at the non-loaded portion based on the received acoustic waves; calculating an acoustic velocity of the shear wave at the loaded portion based on the received acoustic waves and the longitudinal wave acoustic velocity at the non-loaded portion; evaluating an internal average stress in the test piece based on the shear wave acoustic velocity at the loaded portion; evaluating an internal stress distribution in the test piece by correcting a hypothetical internal stress distribution in the test piece based on the stress in the surface layer and the internal average stress; and conducting a diagnosis of the test piece based on the internal stress distribution.

Stress evaluation method and apparatus therefor

Plant operating conditions 1, apparatus operating conditions 2 and environment conditions 3 are accumulated, combined and put together as a set of plant status variables 8 through a monitor 6, while water chemistry information 4 is accumulated as another set of plant status variables 9. The set of status variables 8 is updated and the past data are accumulated in the set of status variables 9. Periodical inspection data 5 are also accumulated in the set of status variables 9 along with the water chemistry information 4. The set 9 is compressed and stored as a plant chart 11 such as a personal clinical chart. A status variable prediction 12 is performed in consideration of the personality of a plant. Both data of the sets 8 and 10 are compared with each other by comparison means 13. If both the data nearly coincide with each other, the plant is diagnosed to the normal and, if not, it is diagnosed to be abnormal. When the plant is diagnosed to abnormal, an abnormal apparatus and an abnormal factor are identified.

Plant monitoring and diagnosing method and system, as well as plant

A measurement system for measuring material deterioration in accordance with a magnetic field of the material in the presence of radiation. The measurement system includes a detection circuit which detects a magnetic field of the material and generates a signal indicative thereof which signal includes noise due to the radiation, a signal processing circuit including semiconductor devices to process the signal generated from the detection circuit and a noise reducing circuit for at least reducing noise in the generated signal which is due to the radiation. The signal processing circuit is installed at a place where a dose equivalent of radiation is equal to or smaller than that of a place where the detection circuit is installed.

Measurement system with noise reduction circuit

A diagnosis system having sensors for supervising a plant, signal processors for processing signals of the sensors, and a state quantity arithmetic operation unit. The state quantity arithmetic operation unit calculates a quantity of state expressing the environment of the plant on the basis of supervisory information inputted through the signal processors. A state quantity prediction unit predictively calculates a quantity of state after a predetermined time on the basis of the quantity of state, supervisory information and a time change of the quantity of state inputted through the state quantity arithmetic operation unit. A future event prediction unit predicts a future event on the basis of predicted information of the quantity of state inputted through the state quantity prediction unit. An image information processor converts the quantity of state given by the state quantity arithmetic operation unit into image information and indicates the image information on a display unit. An image information processor converts the predicted quantity of state after the predetermined time, given by the state quantity prediction unit, into image information and indicates the image information on a display unit. An image information processor converts the future event predicted by the future event prediction unit into image information and indicates the image information on a display unit.

Diagnosis system

An ultrasonic flaw detecting apparatus for efficiently detecting a flaw existing in a deep portion of a multi-layer structure includes a first sensor arranged so as to transmit an ultrasonic wave into a different property layer surrounded by a medium having a different acoustic impedance in the multi-layer structure, a function generator for generating a pulse-shaped sine wave, a power amplifier for amplifying and supplying the pulse-shaped sine wave to the first sensor, a second sensor arranged so as to receive a boundary echo from the different property layer, a first amplifier for amplifying the boundary echo received by the second sensor, an intensity detector for judging the intensity of an amplified signal of the boundary echo, a third sensor arranged so as to receive an echo from a flaw inside a layer in a deep portion of the different property layer, a second amplifier for amplifying the flaw echo received by the third sensor, a recorder for recording the amplified flaw echo signal, and a control unit for reading data from the intensity detector and outputting commands to the function generator and the recorder.

Ultrasonic flaw detecting apparatus for inspecting multi-layer structure

Ultrasonic waves from a transmit device are transmitted to an object subject to measurement. A surface reflected wave propagated in a contact medium and reflected at the surface of a tube and bottom surface reflected waves passing through an oxidation layer on the tube and reflected at the inner surface of the tube are convened into electric signals. A feature extracting part 5, in consideration of a correlation relationship of energy with respect to the frequency of a received signal, based on the received signal of ultrasonic waves converted to electric signals, extracts a signal feature data determined beforehand which has a strong correlation relationship with the thickness of a measured part. Based on the extracted signal feature data, a thickness conversion part references a relationship storage part which has stored therein beforehand a function that shows a relationship between the signal feature data and the thickness of the oxidation layer, and obtains the thickness of the oxidation layer.

Method and apparatus for measuring thickness of layer using acoustic

Plant operating conditions 1, apparatus operating conditions 2 and environment conditions 3 are accumulated, combined and put together as a set of plant status variables 8 -through a monitor 6, while water chemistry information 4 is accumulated as another set of plant status variables 9. The set of status variables 8 is updated and the past data are accumulated in the set of status variables 9. Periodical inspection data 5 are also accumulated in the set of status variables 9 along with the water chemistry information 4. The set 9 is compressed and stored as a plant chart 11 such as a personal clinical chart. A status variable prediction 12 is performed in consideration of the personality of a plant. Both data of the sets 8 and 10 are compared with each other by comparison means 13. If both the data nearly coincide with each other, the plant is diagnosed to be normal and, if not, it is diagnosed to be abnormal. When the plant is diagnosed to be abnormal, an abnormal apparatus and an abnormal factor are identified.

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

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 scanning method used by a laser radar for scanning a predetermined scanning region with a laser beam so that the whole of the scanning region is illuminated with the laser beam, is disclosed in which a laser beam makes a first spiral scanning outwardly or inwardly and then makes a second spiral scanning inwardly or outwardly so that the rotational direction of the second spiral scanning is the same as that of the first spiral scanning, and the first spiral scanning and the second spiral scanning are repeated. According to this scanning method, the output of drive means for driving an optical system which causes a laser beam to perform a scanning, can be reduced, since a maximum power necessary for causing a body large in inertia to make a curvilinear or rotational motion is far smaller than a maximum power necessary for causing the body to make a linear motion.

Scanning method used by laser radar and laser radar for carrying out the

A method and an apparatus are disclosed in which paying attention to the fact that the rate of attenuation of laser lilght propagating in the atmosphere changes depending on meteorological conditions, the rate of attenuation is detected and the optimum laser beam emission or divergence angle is controlled in accordance with the detected rate of attenuation. There are also disclosed a method and an apparatus in which the optimum beam angle is controlled in accordance with a distance to a target existing in the atmosphere or the shape of the target. Further, there are disclosed a method and an apparatus in which the optimum beam angle is controlled taking either two or all of the rate of attenuation, the distance to the target and the shape of the target into consideration.

Method of detecting an object by use of laser light and laser radar

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Katsuta, Japan

Fuminobu Takahashi