JPH0429092A - Annearling device for reactor pressure vessel - Google Patents

Abstract

PURPOSE:To efficiently work annearling without increasing the spatial radiation doze of radiat ray by providing a head enabled to keep the state of pressure reduction, movement device for head, freely movable heating arrangement, and moving device for heating arrangement. CONSTITUTION:In a head 1, a half dounut-shaped vacuum device 2, electromagnet 3, and gasket 4 are provided to be stuck to the innerwall surface of the reactor pressure vessel. In the head 1, a heating arrangement 7 is supported by a movement device 8 for heating arrangement. A signal from a remote control device is inputted to a cable supply part 6, and a voltage is impressed to the electromagnet 3 to stick the head 1 to the innerwall face of the reactor pressure vessel. By a command from a centralized management device 9, the inside of the device 2 is turned to the state of pressure reduction, and airtight, between the head 1 and the innerwall surface of the reactor pressure vessel, is kept. By operating the driving devices, etc., inside the reactor pressure vessel from the remote control device, the head 1 is moved to the part performing the annearling of inside the reactor pressure vessel, and the part is heated to be the temperature of the annearling by the heating arrangement 7.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a nuclear reactor for restoring the toughness of the inner wall surface of a reactor pressure vessel in a core region whose toughness has decreased due to neutron irradiation. This invention relates to an annealing device for pressure vessels.

(Prior Art) It is well known that the core region of a nuclear reactor pressure vessel is exposed to neutron irradiation during its service life, so that its strength increases and its ductility and toughness decrease with long-term service.

For this reason, the reactor pressure vessel is operated while monitoring the material of the inner wall surface of the core region to check for a decrease in toughness.

In the reactor pressure vessel, the operating conditions are set so as to show that there is sufficient margin for continued operation based on the predicted value of related temperature (RTNDT) adjustment that takes into account the fracture toughness of the material in the core region, and by examining the fracture force, etc. There is.

This will confirm the minimum operating temperature of nuclear power plant equipment.

In addition, if the reactor core is critical, the temperature of the reactor pressure vessel is required to be at least 22°C higher than the minimum operating temperature during startup and shutdown, and at least 33°C higher than the related temperature of the flange (RTNDT). .

If the above requirements are no longer met, or the possibility arises, the core region may be required to be annealed to restore its material toughness.

(Problem to be solved by the invention) However, in order to prevent the inner wall surface of the reactor pressure vessel from being annealed, it is sufficient to heat the inner wall surface to maintain it at a predetermined temperature, but since reactor water is present, There are technical challenges involved. In other words, the reactor water inside the reactor pressure vessel cannot be removed for radiation shielding purposes.

Therefore, annealing work on the inner wall surface of the reactor pressure vessel where reactor water exists can be performed without increasing the radiation dose.
There is a need for an annealing device that can perform annealing efficiently.

The present invention has been made to solve the above problems, and is capable of heating the inner wall surface of a reactor pressure vessel where reactor water exists in a dry state, and efficiently without increasing the air dose of radiation. An object of the present invention is to provide an annealing device for a nuclear reactor pressure vessel that can perform annealing.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a head that is airtightly and movably adhered to the inner wall surface of a reactor pressure vessel and that can maintain a reduced pressure state, and a head that is connected to the reactor pressure vessel. a head moving device that moves the head so as to stir it along the inner wall surface of the reactor; a movable heating device that is installed in the head and heats the inner wall surface of the reactor pressure vessel; It is characterized by being equipped with a heating device that can be moved almost vertically and horizontally within the heating device.

(Operation) The head is airtightly bonded to the inner wall of the reactor pressure vessel using a vacuum device, electromagnet, and gasket fixed to the head. Depressurization of the head and vacuum device is performed by a remote device connected externally. The head is slidably moved around the entire inner wall surface of the reactor pressure vessel by a remote device. The head is moved to the inner wall surface of the reactor pressure vessel to be annealed, the heating device is brought close to it, the heating device is activated, and the inner wall surface of the reactor pressure vessel is heated and annealed. This annealing restores the toughness of the inner wall surface of the reactor pressure vessel. Further, while moving the heating device in the head, the inner wall surface of the reactor pressure vessel to be annealed can be locally heated to perform annealing and restore toughness.

(Embodiment) An embodiment of the reactor pressure vessel annealing apparatus according to the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, a head 1 constitutes a container that isolates the inner wall surface of a reactor vessel 19, which will be described later, from reactor water, and is formed into a half-cylindrical semicylindrical shape. This head 1
Inside is a divided doughnut-shaped vacuum device2. An electromagnet 3 and a gasket 4 are provided so as to be adhered to the inner wall surface of the reactor pressure vessel 19. A gasket 4 and a casket holding plate 5 are installed around the vacuum device 2 to maintain sufficient vacuum.
Supported by This gasket presser plate 5 is fixed with a presser bar 5a. The vacuum device 2 is connected to a central control device 9 via a short pipe 2a. The central control device 9 is supplied with power from the cable supply section 6, and the inside of the vacuum device 2 is evacuated via the central control device 9 to maintain a reduced pressure state. A signal from a remote control device 19, which will be described later, is input to the cable supply section 6, and a support signal is output to the central pipe embedding @9. The interior of the head 1 is connected to an external vacuum pump or the like through a cable supply section 6, and the interior thereof is maintained at a low humidity atmosphere or at reduced pressure. Further, inside the head 1, a heating device a7 is installed, and a heating device moving device 8 is provided.
Supported by The heating device 7 directly heats the inner wall surface of the reactor pressure vessel 19, and can be moved vertically and horizontally within the head by a heating device moving device 8. The heating device moving device 8 has both ends moved along a horizontal axis 8a in the left-right direction, and moved in the vertical direction along a vertical axis 8b.

As shown in FIG. 2, the head 1 can be moved over the entire inner peripheral surface of the reactor pressure vessel 19 by the head moving device IO as the reactor pressure vessel external drive device 13 moves on the platform 20. It has become.

The head moving device 10 is a reactor pressure vessel internal drive device 11
, the reactor pressure vessel internal drive device 11 is supported by a support moving device af1.
2, the supporting and moving devices 12 are sequentially connected to the reactor pressure vessel external drive devices 13 on the circular platform 20, respectively. A cable 15.1 is connected to the external drive device 13 of the reactor pressure vessel to the intermediate control device I4, and the intermediate control device 14 is connected to the remote control device 16 mounted on the reactor well 17.
8.

As shown in FIG. 3, the heating device 7 has a nichrome wire 21 coated with ceramics 22, and a terminal 23 of the nichrome wire 21 is connected to an external power source (not shown) through a cable supply section 5 and a remote control device 16. . This heating device 7 heats the inner wall surface of the reactor pressure vessel 19 .

Note that this heating device is not limited to the above-mentioned configuration, and a gas burner, a laser beam, or the like may be used.

Next, the operation of the reactor pressure vessel annealing device having the above configuration will be explained.

The support signal from the remote control device 16 is transmitted to the head moving device 1.
0 is input, a voltage is applied to the electromagnet 3 from the cable supply section 6, and the head 1 is temporarily bonded using the electromagnet 3 to the inner wall surface of the reactor pressure vessel I9 in which reactor water is contained. In addition, the vacuum device 2
The inside of the reactor pressure vessel 19 is evacuated to create a reduced pressure state, and airtightness between the head 1 and the inner wall surface of the reactor pressure vessel 19 is maintained. Furthermore, the reactor water in the head 1 is discharged from a vacuum pump (not shown) via the cable supply section 6 to maintain a reduced pressure state.

The head 1 is moved from the remote control device 16 to the intermediate control device 14 and the reactor pressure vessel external drive device 13 by operating the reactor pressure vessel internal drive device If and the head moving device IO to move the head 1 inside the reactor pressure vessel 19. The part is moved to the part to be tempered, and the heating device 7 heats that part to the annealing temperature.

For example, the heating temperature is 35°C on the inner wall surface of the reactor pressure vessel 19.
The capacity of the heating device 7 is set so that the temperature is 0° C. or higher.

When heating the inner wall surface of the reactor pressure vessel, if reactor water exists in the head 1, the heat will be absorbed by the reactor water and the efficiency will drop significantly. maintain it.

By heating the heating device 7 while isolating it from the reactor water in this manner, the reactor water outside the head absorbs significantly less heat, reduces the generation of bubbles, and improves work efficiency. Also,
It is possible to restore the toughness of the inner wall surface within the reactor pressure vessel in the reactor core region that has become brittle due to neutron irradiation.

[Effects of the Invention] According to the present invention, a head equipped with a heating device that can be operated by remote control is slidably adhered to the inner wall surface of a reactor pressure vessel while reactor water is present, and the inside of the head is It is possible to maintain a reduced pressure state and heat the inner wall surface of the reactor pressure vessel in a dry state.

Therefore, annealing work can be performed efficiently without increasing the air dose of radiation.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the reactor vessel annealing device according to the present invention, FIG. 2 is a schematic diagram schematically showing an example of how the device in FIG. 1 is used, and FIG. FIG. 2 is a perspective view showing the heating device in FIG. 1; 1...Head, 2...Vacuum device, 3...
electromagnet. 4... Gasket, 5... Gasket holding plate,
6... Cable supply unit, 7... Heating device,
8... Heating device moving device, 9... Central control device, 10... Head moving device, 11... Reactor pressure vessel internal drive device, 12... Support moving device, 13...
...Reactor pressure vessel external drive device, 14...Intermediate control device, +5, 18...Cable, 16...Remote control device, 17...Reactor well, 19...Reactor pressure vessel , 20... Platform, 21... Nichrome wire, 22... Ceramics. 23...Terminal. (g733) See Patent Attorney Inomata (and 1 other person)

Claims (1)

[Claims] A head that is airtightly and slidably adhered to the inner wall surface of a reactor pressure vessel and that can maintain a reduced pressure state, and a head that moves this head so as to slide along the inner wall surface of the reactor pressure vessel. A moving device, a movable heating device provided in the head to heat an inner wall surface of the reactor pressure vessel, and a heating device moving device to move the heating device substantially vertically and horizontally in the head. An annealing device for a nuclear reactor pressure vessel characterized by: