JPS6058435B2 - Cooling method and device inside the reactor containment vessel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for cooling the inside of a nuclear reactor containment vessel.

In general, the reactor containment vessel (hereinafter referred to as PCV) is the core of nuclear power generation, which is the core of the nuclear reactor, main steam pipes, water supply pipes, recirculation water pipes, recirculation pumps, and other important components used to generate and transport heat sources. It is an important device for storing equipment and protecting the general public and employees from radiation hazards caused by leakage of coolant from these equipment.

When the nuclear reactor is operated, the temperature of the internal atmosphere inside the PCV rises due to the passage of heat from the heat insulating material of the reactor and piping. When this atmospheric temperature rises, it causes trouble to the electrical control equipment that controls important equipment such as the nuclear reactor, and has a negative impact on the reliability and safety of the nuclear reactor. For this reason, a cooling device is installed inside the PCV to cool the inside of the PCV so as to keep the atmospheric temperature inside the PCV below a specified value. Generally speaking, this cooling method is to install a gas-liquid heat exchanger inside the PCV and diffuse the gas cooled by this heat exchanger through a duct into the inside of the PC using a blower. It has been adopted. By the way, at nuclear power plants, periodic inspection work is carried out to maintain the reactor main body and control equipment in the PCV, but in order to prevent workers from being exposed to radiation, efforts are being made to expand the work space and simplify the work. ing.

However, conventional cooling equipment that combines a blower, a gas-to-liquid heat exchanger, a duct, etc. occupies approximately 6% of the internal capacity of a PC, and there is a demand for its miniaturization. The purpose of the present invention is to use a simple device to lower the ambient temperature inside a PC to a specified temperature or lower using a low-cost and small-occupancy device, as well as to expand the space available for periodic inspections and prevent workers from being exposed to radiation. The objective is to provide a method and device for cooling the inside of a nuclear reactor containment vessel.

The present invention sprays liquefied inert gas into the PCV,
The purpose is to achieve the above object by cooling the inside of the PCV using the heat of vaporization. Hereinafter, one embodiment of the present invention will be described in more detail with reference to the drawings.

A reactor containment vessel (PCV) 1 whose outer periphery is covered with concrete and is further installed in a reinforced concrete building houses a nuclear reactor 2 with a heat source inside, and a radiation shielding wall 3 is placed around this reactor 2. ．． It is provided.

A plurality of spray nozzles 4 are disposed outside the radiation shielding wall 3 inside the PCVl as a spraying means for spraying liquid nitrogen as a liquid inert gas into the PCVl.

These spray nozzles. The pipe 4 is connected via a pipe 6 having a flow control valve 5 in the middle to a liquid nitrogen storage device 7 provided at the bottom of the PCVl as a liquid nitrogen supply means. This liquid nitrogen storage device 7 has a pump for pumping liquid nitrogen and a storage tank, and is connected to a nitrogen liquefaction device 8 as a recovery and liquefaction means installed on the side of the storage device 7. Temperature detectors 9 are provided at predetermined positions within the PC 1, that is, at a plurality of locations convenient for measuring the rise in the temperature of the internal atmosphere of the PC 1 due to heat sources inside the PC 1.

A signal from the temperature detector 9 is connected to the flow control valve 5 and is configured to be transmitted to a temperature controller 10 that controls the flow rate of the control valve 5. In such a configuration, liquid nitrogen sent from the liquid nitrogen storage device 7 is sprayed into the PCVl through the pipe 6 from the spray nozzle 4 provided at an appropriate height and location inside the PC1.

This sprayed liquid nitrogen evaporates and becomes PC.
(2) Absorbs the latent heat of vaporization from the atmosphere inside PC (1) to lower the temperature of the internal atmosphere of PC (1). This vaporized nitrogen is liquefied by a nitrogen liquefaction device 8 consisting of an expander and the like, stored again in the liquid nitrogen storage device 7, and circulated again in the above-described route. The amount of liquid nitrogen to be sprayed is determined by operating the temperature controller 10 based on the temperature of the internal atmosphere of the PCV1 detected by temperature detectors 9 installed at various locations inside the PC1. is activated and controlled.

By controlling the amount of spraying, the temperature of the PCVl internal atmosphere is maintained at a specified temperature. In carrying out the process, the inert gas to be liquefied is not limited to nitrogen gas, but other inert gases such as argon gas may be used, but if nitrogen gas is used, it is usually necessary to avoid explosion of control equipment etc. inside the PCVl. is filled with nitrogen gas, which is economically advantageous because it can be used as is.

In addition, a liquid inert gas recovery and liquefaction means (nitrogen liquefaction device 6
) and the liquid inert gas supply means (liquid nitrogen storage 7) do not necessarily have to be installed inside the PCVl, but if they are installed inside, leakage of radioactive coolant can be avoided. This has the advantage that countermeasures can be easily taken at any time. Further, as the spraying means, it is preferable to use the spray nozzle 4, but the invention is not limited thereto, and it may be simply dripping, or it may be evaporated from a porous substance such as cloth or sintered metal. . As described above, according to the present invention, the volume occupied within the PCV is smaller than that of a conventional cooling system that combines a blower, a gas-liquid heat exchanger, a duct, etc., and the work space during periodic inspections is expanded, making it easier to carry out work. This has the effect of maintaining the safety of people.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view of a reactor containment vessel housing an embodiment of a cooling device according to the present invention. 1... Reactor containment vessel, 2... Nuclear reactor, 4... Spray nozzle as a spraying means, 5...
...Flow control valve, 6...Piping, 7...
...Liquid nitrogen storage as a supply means, 8...
・Nitrogen liquefaction device as recovery liquefaction means, 9...
Temperature detector, 10...Temperature controller.

Claims (1)

[Claims] 1. Spraying liquid inert gas into the reactor containment vessel while controlling based on the detected value of a temperature detector installed in the reactor containment vessel. A method for cooling the inside of a reactor containment vessel, characterized in that the temperature inside the reactor containment vessel is maintained at a temperature most suitable for protecting control equipment contained within the reactor containment vessel. 2. The method for cooling the inside of a nuclear reactor containment vessel according to claim 1, wherein the liquid inert gas is liquid nitrogen. 3. A liquid inert gas dispersion means provided at a predetermined position within the reactor containment vessel, a supply means for supplying liquid inert gas to the liquid inert gas dispersion means, and a liquid inert gas dispersion means disposed within the reactor containment vessel and vaporized. a recovery liquefaction means for recovering and liquefying the inert gas; and piping connecting the liquid inert gas distribution means and the supply means via a liquid inert gas flow rate control valve;
The reactor containment vessel includes a temperature detector installed at a predetermined location, and a temperature controller that controls the liquid inert gas control valve to open at high temperature based on the detected value from the temperature detector. A cooling device inside a nuclear reactor containment vessel, characterized by: 4. In the cooling device inside the reactor containment vessel according to claim 3, the liquid inert gas supply means and the liquid inert gas recovery and liquefaction means are provided within the reactor containment vessel. A cooling device inside a nuclear reactor containment vessel, characterized by: 5. The cooling device for the inside of the reactor containment vessel according to claim 3 or 4, wherein the liquid inert gas distribution means is a spray nozzle. Device. 6. The cooling device for the inside of the reactor containment vessel according to any one of claims 3 to 5, wherein the liquid inert gas is liquid nitrogen. Cooling system.