JPH11153672A - Radiation detector equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve complexity accompanied by supply of liquid nitrogen, by connecting a liquid nitrogen production device and a liquid nitrogen storage part of a radiation detector with a supply pipe, and providing a control means for maintaining the storage quantity of liquid nitrogen in the liquid nitrogen production device and the liquid nitrogen storage part of the radiation detector larger than a certain amount. SOLUTION: A storage Dewar 8 of a liquid nitrogen production device 3 and a Dewar 2 of Ge detector 1 are connected with a supply pipe 10, and liquid nitrogen is supplied through this supply pipe 10. In the case the storage quantity of liquid nitrogen lowers than a certain level, the first control means, receiving a detection signal from a level meter 15, controls the operation of a compressor 9 and operation of the liquid nitrogen production device 3 so as to maintain the storage quantity of liquid nitrogen in the Dewar 8 over the level. In the supply pipe 10 connecting the Dewars 2 and 8, an electromagnetic value 11 is installed, which is controlled to open and close by receiving signals from a timer 12. A second control means for controlling the supply of liquid nitrogen from the Dewar 8 to the Dewar 2 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detection equipment for use in a controlled area of a nuclear power plant, for example, provided with a radiation detector which requires cooling by liquid nitrogen.

[0002]

2. Description of the Related Art For example, as is well known, a high-purity Ge detector can be stored at room temperature when not in use, but needs to be cooled with liquid nitrogen during use. There is. Therefore, conventionally, the same Ge detector used in a control area of a nuclear power plant has a 3
A vacuum thermos called a Dewar having a capacity of about 0 liters is used, and cooling is performed with liquid nitrogen stored in the vacuum thermos.

[0003] However, the capacity of the dewar of the detector that stores liquid nitrogen is as small as about 30 liters as described above due to space limitations. Therefore, liquid nitrogen is manually replenished once every one to two weeks. Must be
This replenishment work, carrying in and out of the dewar for transportation, and purchasing liquid nitrogen were very troublesome. In addition, incidental work such as contamination inspection accompanying the removal of the dewar was also required for each replenishment. In addition, there was no danger of inadvertently forgetting to replenish.

Therefore, recently, without using liquid nitrogen,
Although an electric cooling type is also provided, there is a risk that the performance of the detector may be deteriorated due to microphonic noise or the like.

The present invention has been made in view of the above-mentioned conventional problems, and has been made to solve the problem associated with replenishment of liquid nitrogen to a liquid nitrogen storage unit of a radiation detector by using a liquid nitrogen cooling method. It is an object of the present invention to provide a radiation detection facility capable of performing the above.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a liquid nitrogen production apparatus for extracting nitrogen gas from air and cooling the nitrogen gas to produce liquid nitrogen, and a liquid nitrogen storage unit of the production apparatus. The liquid nitrogen storage unit of the radiation detector is connected to the liquid nitrogen storage unit via a supply pipe, and the operation of the liquid nitrogen production unit is performed so as to maintain the storage amount of liquid nitrogen in the liquid nitrogen storage unit of the liquid nitrogen production unit at a certain level or more. A first control means for controlling the liquid nitrogen storage unit of the radiation detector from the liquid nitrogen storage unit of the radiation detector to the liquid nitrogen storage unit of the radiation detector so as to maintain the storage amount of liquid nitrogen in the liquid nitrogen storage unit of the radiation detector at a certain level or more. A second control means for controlling the supply of liquid nitrogen is provided.

That is, in the present equipment, a liquid nitrogen production apparatus attached thereto automatically extracts liquid nitrogen by extracting nitrogen gas from the air, and the liquid nitrogen produced in this manner is used as a radiation detector. Is automatically replenished to the storage unit. The air is
Since it is inexhaustible, it automatically manufactures liquid nitrogen from this air and automatically supplies it to the storage unit of the radiation detector. It is free from incidental work such as carrying in and out of the dewar for transportation and the accompanying contamination inspection.

Further, a cooling device for cooling the compressor of the liquid nitrogen production device is provided, and the cooling device is constituted by a circulating water cooling device, so that it is not necessary to discharge cooling water. The use of liquid nitrogen production equipment in the radiation control area of the country becomes easy.

[0009]

Next, an embodiment of the present invention will be described with reference to FIG.

The radiation detection equipment shown in FIG. 1 is used, for example, in a controlled area of a nuclear power plant.
Is a high-purity Ge detector as a radiation detector, and reference numeral 2 is a dewar as a liquid nitrogen storage unit. The capacity of the dewar 2 is, for example, 35 liters. Reference numeral 3 denotes a liquid nitrogen production device, and reference numeral 4 denotes a circulating water cooling device.

The liquid nitrogen production apparatus 3 includes a dehumidifying / dust removing filter 5, a nitrogen gas filter 6, a refrigerator 7, and a storage dewar 8 as a liquid nitrogen storage unit.
The introduced air A (for example, 7 kg / cm ² G) is dehumidified / dedusted by the dehumidification / dedusting filter 5, nitrogen gas is extracted by the nitrogen gas filter 6, and the nitrogen gas is cooled by the refrigerator 7. The obtained liquid nitrogen is stored in the storage dewar 8. The refrigerator 7 uses He gas as a refrigerant, and the reference numeral 9 denotes a compressor. Reference numeral 16 is a drain.

The storage dewar 8 of the liquid nitrogen production apparatus 3 and the dewar 2 of the Ge detector 1 are connected to each other through a supply pipe 10 so as to communicate with each other.
, The supply of liquid nitrogen is performed.

The radiation detection equipment includes first control means for controlling the operation of the liquid nitrogen production device 3 so as to maintain the storage amount of liquid nitrogen in the storage dewar 8 of the liquid nitrogen production device 3 at a certain level or more. Provided. That is, a level meter 15 is provided in the storage dewar 8 of the liquid nitrogen production apparatus 3 and, when the storage amount decreases to a certain level or more, the level meter 15 is used.
The compressor 9 is automatically operated in response to the detection signal from the CPU.

Further, in the present detection equipment, from the dewar 8 of the liquid nitrogen production device 3 to the dewar 2 of the Ge detector 1 in order to maintain the storage amount of liquid nitrogen in the dewar 2 of the Ge detector 1 at a certain level or more. Second control means for controlling the supply of liquid nitrogen is provided. That is, a solenoid valve 11 is interposed in the supply pipe 10 connecting the two dewars 2 and 8, and the solenoid valve 11 is controlled to open and close at a predetermined timing in response to a signal from the timer 12, whereby the dewar 8 is controlled. The supply of liquid nitrogen to the dewar 2 from is automatically controlled. Further, in this facility, a tube 13 is led out of the dewar 2 of the Ge detector 1, and a temperature sensor 14 is provided at the tip thereof. In the case of overflowing from 13,
This is detected by the temperature sensor 14, and based on the detection signal, the electromagnetic valve 11 is automatically closed, and the supply of liquid nitrogen is automatically stopped.

The circulating water cooling device 4 is a radiator for cooling the compressor 9 and eliminates the need for discharging cooling water by circulating the radiator, thereby enabling the liquid nitrogen production device 3 in the radiation control area to be cooled. It is easy to use in terms of safety and the like. Needless to say, the drive unit such as the compressor 9 should be installed sufficiently away from the Ge detector 1 so as not to give vibrations that cause noise to the Ge detector 1.

In the above facility, the production capacity of liquid nitrogen is, for example, about 6 liters / day, the transfer capacity of liquid nitrogen is, for example, about 1-2 liters / minute, and the overall size is designed to be a size that can be installed indoors. ing. Maintenance only needs to be performed once a year for replacement of consumables such as filters.

An embodiment of the present invention has been described above.
The present invention is not limited to this, and various design changes can be made without departing from the spirit of the invention. For example, a level meter is provided in the dewar 2 of the Ge detector 1 as the above-mentioned second control means, and when the stored amount decreases to a certain level or more, a detection signal from the level meter is received and the electromagnetic wave is automatically set. A control method in which the valve 11 is opened may be adopted. That is, the first and second control means described in the above embodiment are merely examples, and in the present invention, various other types of control means configurations may be used as the first and second control means. . Further, the detector is not limited to the high-purity Ge detector 1, but may be a Si (Li) detector or a Ge (L) detector.
i) Various radiation detectors requiring cooling, such as a detector, may be used.

[0018]

As described above, the radiation detection equipment of the present invention is provided with a liquid nitrogen production apparatus for producing liquid nitrogen by extracting nitrogen gas from air and cooling the nitrogen gas. The liquid nitrogen storage unit of the radiation detector is connected to the liquid nitrogen storage unit of the radiation detector by a supply pipe, and the liquid nitrogen production device automatically manufactures liquid nitrogen, and the liquid nitrogen storage unit of the radiation detector Liquid nitrogen is supplied automatically, so you can purchase liquid nitrogen,
Eliminate the manual work of regular replenishment, transporting and unloading of dewars for transport, and accompanying incidental work such as contamination inspections, and eliminate the complexity associated with replenishing liquid nitrogen storage in the radiation detector with liquid nitrogen. Can be. There is no need to forget to supply. In addition, since the cooling is performed by liquid nitrogen, there is no fear that the performance of the detector deteriorates due to microphonic noise or the like.

Moreover, since a circulating water cooling device is employed as a cooling device for the compressor of the liquid nitrogen production apparatus, there is no need to discharge cooling water, and for example, liquid nitrogen production in a radiation control area such as a nuclear power plant. Use of the device can be facilitated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an overall configuration of a detection facility according to an embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Ge detector 2 Dewar (reservoir) 3 Liquid nitrogen production device 4 Circulating water cooling device 8 Dewar (reservoir) 9 Compressor 10 Refill pipe

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 000230940 Japan Atomic Power Co., Inc. 1-6-1, Otemachi, Chiyoda-ku, Tokyo (71) Applicant 591212349 Nuclear Engineering Co., Ltd. 1-3-3 Tosabori, Nishi-ku, Osaka-shi, Osaka No. 7 (72) Inventor Toshitaka Nakamura 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Inside Kansai Electric Power Company (72) Inventor Muneo Tanaka 61-2, Minatomachi, Matsuyama-shi, Ehime Prefecture Shikoku Electric Power Company Inside the company (72) Koichi Tazaki 2-82, Watanabe-dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture Inside Kyushu Electric Power Company (72) Inventor Taku Ohira 1-6-1, Otemachi, Chiyoda-ku, Tokyo Nippon Atomic Energy (72) Inventor Masataka Yamada 1-3-7 Tosabori, Nishi-ku, Osaka-shi, Osaka Within Nuclear Engineering Co., Ltd.

Claims (2)

[Claims] 1. A liquid nitrogen production device for extracting nitrogen gas from air and cooling the nitrogen gas to produce liquid nitrogen, and a liquid nitrogen storage unit of the production device and a liquid nitrogen storage unit of a radiation detector. And a first control means for controlling the operation of the liquid nitrogen production device so as to maintain the storage amount of liquid nitrogen in the liquid nitrogen storage unit of the liquid nitrogen production device at a certain amount or more, and Controlling the replenishment of liquid nitrogen from the liquid nitrogen storage unit of the liquid nitrogen production device to the liquid nitrogen storage unit of the radiation detector in order to maintain the storage amount of liquid nitrogen in the liquid nitrogen storage unit of the radiation detector at a certain level or more. Radiation detection equipment comprising two control means. 2. The radiation detection equipment according to claim 1, further comprising a cooling device for cooling a compressor of the liquid nitrogen production device, wherein the cooling device comprises a circulating water cooling device.