JPH01274094A - Method for measuring quantity of radioactivity in underwater structure - Google Patents
Method for measuring quantity of radioactivity in underwater structureInfo
- Publication number
- JPH01274094A JPH01274094A JP10324288A JP10324288A JPH01274094A JP H01274094 A JPH01274094 A JP H01274094A JP 10324288 A JP10324288 A JP 10324288A JP 10324288 A JP10324288 A JP 10324288A JP H01274094 A JPH01274094 A JP H01274094A
- Authority
- JP
- Japan
- Prior art keywords
- gamma
- gamma rays
- straight pipe
- hollow straight
- radioactivity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 10
- 238000000084 gamma-ray spectrum Methods 0.000 claims abstract description 22
- 230000005251 gamma ray Effects 0.000 claims abstract description 16
- 230000005855 radiation Effects 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 230000002285 radioactive effect Effects 0.000 claims abstract description 6
- 238000005259 measurement Methods 0.000 claims description 24
- 238000000691 measurement method Methods 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 2
- 238000005452 bending Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
Landscapes
- Measurement Of Radiation (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、水中にある構造物の放射能濃度を中空の直管
を用いて遠方より非破壊的に定量測定する方法の改良に
関するものである。当該測定法は、目的とする構造物の
測定箇所に先端を板で封じた中空の管を近接し水を遮蔽
体としてガンマ線コリメータを形成し、測定箇所から放
出されるガンマ線を直管中を通過させ、反対側に置かれ
たガンマ線スペクトル検出器に導き計測し、このスペク
トル解析結果をもとに当該構造物の放射能濃度を求める
ものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in a method for non-destructively quantitatively measuring the radioactivity concentration of structures in water from a distance using a hollow straight pipe. be. In this measurement method, a hollow tube whose tip is sealed with a plate is placed close to the measurement point of the target structure, forming a gamma ray collimator using water as a shield, and the gamma rays emitted from the measurement point are passed through the straight tube. The radioactivity concentration of the structure is determined based on the spectrum analysis results.
［従来の技術］
従来、当該測定法は第１図に示すように、目的とする構
造物の測定箇所１に先端を板２で封じた中空の直管３を
近接し、水４を遮蔽体としてガンマ線コリメータ５を構
成し、測定箇所から放出されるガンマ線６を直管中を通
過させ、反対側に置かれたガンマ線スペクトル検出器７
に導き計測し、このガンマ線スペクトルを解析して得ら
れるガンマ線計数結果をもとに構造物の放射能濃度を求
めてきた。[Prior Art] Conventionally, as shown in Fig. 1, the measurement method involves placing a hollow straight pipe 3 whose tip is sealed with a plate 2 in close proximity to a measurement point 1 of a target structure, and blocking water 4 with a shield. A gamma ray collimator 5 is configured as a gamma ray collimator 5, which passes gamma rays 6 emitted from a measurement point through a straight tube, and a gamma ray spectrum detector 7 placed on the opposite side.
The radioactivity concentration of the structure has been determined based on the gamma ray counting results obtained by analyzing the gamma ray spectrum.
［発明が解決しようとする課題］
従来の定量測定法により中空の直管を使用して水中の構
造物の放射能を測定する場合第２図に示すように、水中
８において中空の直管９の長さが長くまた挿入角度１０
が大きくなると浮力により中空の直管が曲りその直進性
を確保することは非常に難かしくなるため、中空の直管
が望む構造物の測定箇所１１から放出されるガンマ線１
２を他端に置かれたガンマ線スペクトル検出器１３によ
り完全に測定することは困難となり定量測定ができなく
なる問題点があった。[Problems to be Solved by the Invention] When measuring the radioactivity of underwater structures using a hollow straight pipe according to the conventional quantitative measurement method, as shown in FIG. The length is long and the insertion angle is 10
As the buoyancy increases, the hollow straight pipe bends and it becomes very difficult to ensure its straightness.
There was a problem in that it was difficult to completely measure 2 with the gamma ray spectrum detector 13 placed at the other end, making quantitative measurement impossible.
［課題を解決するための手段］
本発明の測定方法の一つは、中空の直管の直進性が得ら
れなくなった場合でも、基準となる円板状のガンマ線線
源を用いることによって測定したガンマ線計測結果を較
正し、目標としている構造物の放射能濃度を求めること
を特徴とするものである。[Means for Solving the Problems] One of the measurement methods of the present invention is that even when straightness of a hollow straight pipe cannot be obtained, measurement can be performed by using a disc-shaped gamma ray source as a reference. This method is characterized by calibrating the gamma ray measurement results and determining the radioactivity concentration of the target structure.
本発明の測定方法の他の一つは、中空の直管の先端に置
いた円板状の光源をガンマ線スペクトル検出器の直前で
モニタしその投影面積をもとにガンマ線スペクトル検出
器によって計測されたガンマ線計数を補正し、水中にお
いて中空の直管が曲がった場合にも構造物の放射能濃度
を定量できることを特徴としている。Another measurement method of the present invention is to monitor a disc-shaped light source placed at the tip of a hollow straight tube in front of a gamma-ray spectrum detector, and to measure the area using the gamma-ray spectrum detector based on its projected area. This method corrects the gamma ray counts obtained by using this method, and is capable of quantifying the radioactivity concentration of a structure even when a hollow straight pipe is bent underwater.
［実 施 例コ 本発明の前者の測定方法を図によって説明する。[Implementation example] The former measuring method of the present invention will be explained with reference to the drawings.
本発明の原理図（実施例）を第３図に示す。水中１４に
挿入された先端を板１５で封じた中空の直管１６の先端
部１７に直管内径と同じ直径１８の円板状で一様な放射
能分布を持ちかつ測定する放射能と異なるエネルギーの
ガンマ線を放出する標準線源１９を装着する。使用する
放射能核種は測定する核種以外のものから１種類以上を
選択する。この線源を第３図に示すように封じ切り板に
固定する。この場合、中空の直管が望む構造物の測定箇
所２０から放出されるガンマ線がガンマ線スペクトル検
出器に入射する時の幾何学条件と当該円板状線源から放
出されるガンマ線がガンマ線スペクトル検出器２１に入
射する時の幾何学条件２２が同等になる。A principle diagram (embodiment) of the present invention is shown in FIG. The tip 17 of a hollow straight tube 16 whose tip is inserted into water 14 and sealed with a plate 15 has a disk shape with a diameter 18 that is the same as the inner diameter of the straight tube, has a uniform radioactivity distribution, and is different from the radioactivity to be measured. A standard radiation source 19 that emits energetic gamma rays is attached. As the radioactive nuclide to be used, one or more types are selected from those other than the nuclide to be measured. This radiation source is fixed to a sealing plate as shown in FIG. In this case, the geometric conditions when the gamma rays emitted from the measurement point 20 of the structure where the hollow straight pipe is desired are incident on the gamma ray spectrum detector, and the gamma rays emitted from the disc-shaped source are the gamma ray spectrum detector. The geometrical conditions 22 when incident on 21 become equivalent.
従って、中空の配管の直進性が得られなくなり、一部の
ガンマ線が中空の配管及び周囲を取り巻く水によって吸
収されても、中空の直管が望む構造物の測定箇所から放
出されるガンマ線及び円板状の標準線源から放出される
ガンマ線ともガンマ線スペクトル検出器まで到達するま
でに同じ比率で減少する。Therefore, even if the straightness of the hollow pipe is no longer obtained and some gamma rays are absorbed by the hollow pipe and the surrounding water, the gamma rays emitted from the measurement point of the structure where the hollow straight pipe is desired and the circular Both gamma rays emitted from the plate-shaped standard radiation source are reduced at the same rate before reaching the gamma ray spectrum detector.
このため、標準線源の放射能核種として、放射能濃度が
既知の種々のエネルギーのガンマ線を放出する核種を使
用し、ガンマ線スペクトル検出器のガンマ線エネルギー
に対する検出効率を求め、この検出効率をもとに中空の
直管が望む構造物の測定箇所から放出されるガンマ線を
較正すれば、中空の直管の直進性が完全に得られなくて
も構造物の放射能濃度を定量測定することが可能となる
。For this reason, we use nuclides that emit gamma rays of various energies with known radioactive concentrations as the radioactive nuclides in the standard radiation source, calculate the detection efficiency of the gamma ray spectrum detector for gamma ray energy, and based on this detection efficiency. By calibrating the gamma rays emitted from the measurement point of the structure where the hollow straight pipe is desired, it is possible to quantitatively measure the radioactivity concentration of the structure even if the straightness of the hollow straight pipe cannot be obtained completely. becomes.
また、本発明の定量測定法を使用すれば、長さを変える
ことのできる中空の管を使用した場合でも自動的に上記
円板状標準線源によって検出効率が求まるためどの位置
でも定量測定ができる。Furthermore, if the quantitative measurement method of the present invention is used, even if a hollow tube whose length can be changed is used, the detection efficiency is automatically determined using the disc-shaped standard radiation source, so quantitative measurement can be performed at any position. can.
本発明の後者の測定方法を図によって説明する。The latter measuring method of the present invention will be explained with reference to the drawings.
本発明の原理図（実施例）を第４図に示す。中空の直管
２３、封じ切り板２４、円板状の光源２５、反射板２６
、投影板２７、ガンマ線スペクトル検出器２８から構成
される。円板状の光源は、中空の管の内径と同じ直径の
光源とする。この光源を第４図に示すように中空の直管
の先端内部に固定する。この場合、中空の直管が十分長
い場合には、中空の直管が望んだ構造物の測定箇所２９
から放出されたガンマ線がガンマ線スペクトル検出器に
入射する時の幾何学条件と円状の光源から放出される光
が反射板で反射され投影板に映される時の幾何学条件が
同等になる。従って、中空の直管が浮力等により曲り直
進性が得られなくなり、一部のガンマ線が中空の直管に
よって吸収されても、中空の直管が望んだ構造物の測定
箇所から放出されたガンマ線及び円状の光源から放出さ
れる光線とも、他端にあるガンマ線スペクトル検出器及
び投影板まで到達するまでに同じ比率で減少するので、
この比率をもとにガンマ線計数結果を補正すれば、中空
の直管の直進性が完全に得られなくなっても、構造物の
放射能を精度良く測定できる。また、反射板については
、薄いものを使用しかつ材質及びその厚さが分かってい
ればガンマ線の吸収補正を行うことができるため、測定
中も外す必要はない。A principle diagram (embodiment) of the present invention is shown in FIG. Hollow straight pipe 23, sealing plate 24, disc-shaped light source 25, reflection plate 26
, a projection plate 27, and a gamma ray spectrum detector 28. The disc-shaped light source has the same diameter as the inner diameter of the hollow tube. This light source is fixed inside the tip of a hollow straight tube as shown in FIG. In this case, if the hollow straight pipe is long enough, the hollow straight pipe can be used at the desired measurement point 29 of the structure.
The geometric conditions when the gamma rays emitted from the circular light source enter the gamma ray spectrum detector are the same as the geometric conditions when the light emitted from the circular light source is reflected by the reflector and projected onto the projection plate. Therefore, even if the hollow straight pipe bends due to buoyancy and cannot achieve straightness, and some gamma rays are absorbed by the hollow straight pipe, the gamma rays emitted from the measurement point of the structure desired by the hollow straight pipe Since both the light rays emitted from the circular light source and the light rays emitted from the circular light source decrease at the same rate before reaching the gamma ray spectrum detector and projection plate at the other end,
By correcting the gamma ray counting results based on this ratio, the radioactivity of the structure can be measured with high accuracy even if the straightness of the hollow straight pipe cannot be achieved completely. Furthermore, as long as a thin reflector is used and the material and thickness are known, gamma ray absorption correction can be performed, so there is no need to remove it during measurement.
［発明の効果コ
本発明により、直管の直進性が損なわれても水中の構造
物の放射能濃度を定ｍ測定することが可能となったため
、直管の厚さ等を厚くすることなく水中の深い場所に置
かれた構造物の放射能濃度を求めることが可能となった
。また、検出効率も測定ごとに同時に測定されるため、
測定精度を上げることができる。[Effects of the invention] The present invention makes it possible to measure the radioactivity concentration of underwater structures at a constant meter even if the straightness of the straight pipe is impaired, without increasing the thickness of the straight pipe. It has become possible to determine the radioactivity concentration of structures placed deep underwater. In addition, detection efficiency is also measured at the same time for each measurement.
Measurement accuracy can be increased.
第１図は従来の放射能定量測定法の原理図である。
第２図は従来の放射能定量測定法により水中の深い場所
にある構造物の放射能濃度を測定した例である。
第３図は本発明の原理図（実施例）である。
第４図は本発明の原理図（実施例）である。
１４・・・水 １５・・・封じ切り板１
６・・・中空の直管 １７・・・先端部１８・
・・直管内径と同じ直径
１９・・・円板状で一様な放射能分布を持ちかつ測定す
る放射能と異なるエネルギーの
ガンマ線を放出する標準線源
２０・・・中空の直管が望む構造物の測定箇所２１・・
・ガンマ線スペクトル検出器
２２・・・円板状線源から放出されるガンマ線がガンマ
線検出器に入射する時の幾何学
条件
２３・・・中空の直管 ２４・・・封じ切り仮
２５・・・円板状の光源 ２６・・・反射板２７
・・・投影板
２８・・・ガンマ線スペクトル検出器
２９・・・中空の直管が望む構造物の測定箇所” −、
ｌ” ！FIG. 1 is a diagram showing the principle of a conventional quantitative radioactivity measurement method. Figure 2 is an example of measuring the radioactivity concentration of a structure located deep underwater using the conventional quantitative radioactivity measurement method. FIG. 3 is a diagram (embodiment) of the principle of the present invention. FIG. 4 is a principle diagram (embodiment) of the present invention. 14...Water 15...Sealing board 1
6...Hollow straight pipe 17...Tip 18.
・Same diameter as the inner diameter of the straight pipe 19 ・Standard radiation source 20 that is disc-shaped and has a uniform radioactivity distribution and emits gamma rays with energy different from the radioactivity to be measured 20 ・A hollow straight pipe is desired Measurement point 21 of structure...
- Gamma ray spectrum detector 22...Geometric conditions when gamma rays emitted from a disc-shaped source enter the gamma ray detector 23...Hollow straight tube 24...Temporarily sealed 25... Disc-shaped light source 26...Reflector plate 27
...Projection plate 28...Gamma ray spectrum detector 29...Measurement point of structure where hollow straight pipe is desired" -,
l”!
Claims (2)
の直管を近接し、水を遮蔽体としてガンマ線コリメータ
を構成し、当該構造物から放出されるガンマ線を直管内
部を通過させ他端に置かれたガンマ線スペクトル検出器
によって計測し当該構造物の放射能濃度を定量測定する
方法において、先端を板で封じた中空の直管の先端部に
直管内径と同じ直径の円板状で一様な放射能分布を持ち
かつ測定する放射能と異なるエネルギーのガンマ線を放
出する標準線源を装着し当該標準線源から放出されるガ
ンマ線と中空の直管が望む構造物の測定箇所から放出さ
れるガンマ線とを同時に中空の直管の他端においたガン
マ線スペクトル検出器によって計測し、当該円板状標準
線源から放出されるガンマ線の計測結果から得られる検
出効率曲線をもとに中空の直管が望む構造物の測定箇所
から放出されるガンマ線の計測結果を較正することによ
って測定箇所の放射能濃度を求める水中構造物放射能定
量測定法。(1) A gamma ray collimator is constructed by placing a hollow straight pipe whose tip is sealed with a plate close to the surface of an underwater structure, using water as a shield, and passing the gamma rays emitted from the structure through the inside of the straight pipe. In this method, the radioactive concentration of the structure is quantitatively measured by measuring with a gamma ray spectrum detector placed at the other end of the structure. Measurement of a structure in which gamma rays emitted from the standard source and a hollow straight pipe are desired by attaching a standard radiation source that is plate-shaped and has a uniform radioactivity distribution and emits gamma rays with energy different from the radioactivity to be measured. The gamma rays emitted from the spot are simultaneously measured by a gamma ray spectrum detector placed at the other end of the hollow straight tube, and the detection efficiency curve obtained from the measurement results of the gamma rays emitted from the disc-shaped standard radiation source is based on the detection efficiency curve. An underwater structure radioactivity quantitative measurement method that determines the radioactivity concentration at the measurement point by calibrating the measurement results of gamma rays emitted from the measurement point of the structure using a hollow straight pipe.
の直管を近接し、水を遮蔽体としてガンマ線コリメータ
を構成し、当該構造物から放出されるガンマ線を直管内
部を通過させ他端に置かれたガンマ線スペクトル検出器
によって計測し当該構造物の放射能濃度を定量測定する
方法において、先端を板で封じた中空の直管の先端内部
に、直管の内径と同じ直径の円板状の光源を置き、他端
のガンマ線スペクトル検出器の直前に置かれた反射板及
び投影板を用いてこの円板状の光源の形状を映し、全て
の光源が見える時を基準に、中空の直管が曲がることに
よって減少する投影面積の割合を求め、この割合をもと
にガンマ線スペクトル検出器によって計測された中空の
直管が望んだ構造物の測定箇所から放出されたガンマ線
計数結果を補正し、中空の直管が水中で曲がり完全に構
造物から放出されたガンマ線を計測できない場合でも構
造物の放射能濃度を定量可能とする水中構造物放射能定
量法。(2) A gamma ray collimator is constructed by placing a hollow straight pipe whose tip is sealed with a plate close to the surface of a structure in water, using water as a shield, and allowing the gamma rays emitted from the structure to pass through the inside of the straight pipe. In this method, a gamma ray spectrum detector placed at the other end of the structure is used to quantitatively measure the radioactivity concentration of the structure. A disc-shaped light source is placed, and the shape of this disc-shaped light source is projected using a reflection plate and a projection plate placed just in front of the gamma ray spectrum detector at the other end, and the time when all the light sources are visible is used as a reference. , find the ratio of the projected area that decreases when the hollow straight pipe bends, and based on this ratio, calculate the gamma ray count emitted from the measurement point of the structure where the hollow straight pipe is desired, measured by a gamma ray spectrum detector. A method for quantifying radioactivity in underwater structures that corrects the results and makes it possible to quantify the radioactivity concentration in structures even when the gamma rays emitted from the structures cannot be measured completely due to bending of hollow straight pipes underwater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10324288A JPH01274094A (en) | 1988-04-26 | 1988-04-26 | Method for measuring quantity of radioactivity in underwater structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10324288A JPH01274094A (en) | 1988-04-26 | 1988-04-26 | Method for measuring quantity of radioactivity in underwater structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01274094A true JPH01274094A (en) | 1989-11-01 |
| JPH0520710B2 JPH0520710B2 (en) | 1993-03-22 |
Family
ID=14348971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10324288A Granted JPH01274094A (en) | 1988-04-26 | 1988-04-26 | Method for measuring quantity of radioactivity in underwater structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01274094A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015227868A (en) * | 2014-05-08 | 2015-12-17 | 有限会社 川原商会 | Radiation shield capability testing method, and container and plate body used for the same |
-
1988
- 1988-04-26 JP JP10324288A patent/JPH01274094A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015227868A (en) * | 2014-05-08 | 2015-12-17 | 有限会社 川原商会 | Radiation shield capability testing method, and container and plate body used for the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0520710B2 (en) | 1993-03-22 |
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