JPS62294997A - Method of measuring non-criticality - Google Patents
Method of measuring non-criticalityInfo
- Publication number
- JPS62294997A JPS62294997A JP61137904A JP13790486A JPS62294997A JP S62294997 A JPS62294997 A JP S62294997A JP 61137904 A JP61137904 A JP 61137904A JP 13790486 A JP13790486 A JP 13790486A JP S62294997 A JPS62294997 A JP S62294997A
- Authority
- JP
- Japan
- Prior art keywords
- multiplication system
- measured
- subcriticality
- neutron
- multiplication
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 18
- 230000009257 reactivity Effects 0.000 claims description 6
- 239000002915 spent fuel radioactive waste Substances 0.000 description 13
- 239000000463 material Substances 0.000 description 11
- 238000012958 reprocessing Methods 0.000 description 6
- 239000003758 nuclear fuel Substances 0.000 description 5
- 238000011088 calibration curve Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- OYEHPCDNVJXUIW-FTXFMUIASA-N 239Pu Chemical compound [239Pu] OYEHPCDNVJXUIW-FTXFMUIASA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- OYEHPCDNVJXUIW-AHCXROLUSA-N Plutonium-240 Chemical compound [240Pu] OYEHPCDNVJXUIW-AHCXROLUSA-N 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- TVFDJXOCXUVLDH-OUBTZVSYSA-N cesium-134 Chemical compound [134Cs] TVFDJXOCXUVLDH-OUBTZVSYSA-N 0.000 description 1
- TVFDJXOCXUVLDH-RNFDNDRNSA-N cesium-137 Chemical compound [137Cs] TVFDJXOCXUVLDH-RNFDNDRNSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- NIWWFAAXEMMFMS-OIOBTWANSA-N curium-244 Chemical compound [244Cm] NIWWFAAXEMMFMS-OIOBTWANSA-N 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- OYEHPCDNVJXUIW-VENIDDJXSA-N plutonium-238 Chemical compound [238Pu] OYEHPCDNVJXUIW-VENIDDJXSA-N 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- JFALSRSLKYAFGM-OIOBTWANSA-N uranium-235 Chemical compound [235U] JFALSRSLKYAFGM-OIOBTWANSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Landscapes
- Analysing Materials By The Use Of Radiation (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Measurement Of Radiation (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
３、発明の詳細な説明
［発明の目的］
（産業上の利用分野）
本発明は、使用済核燃料等の未臨界度を測定する未臨界
度の測定方法に関する。Detailed Description of the Invention 3. Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a subcriticality measuring method for measuring the subcriticality of spent nuclear fuel, etc.
（従来の技術）
一般に原子力発電所等で使用された使用済核燃料物質は
、核燃料再処理ｔＭ股等において再処理される。(Prior Art) Spent nuclear fuel materials used in nuclear power plants and the like are generally reprocessed at nuclear fuel reprocessing facilities and the like.
このような核燃料再処理施設内では、溶解槽、各種貯槽
、配管類等の内部に多種多用な使用済核燃料物質が存在
する。In such a nuclear fuel reprocessing facility, a wide variety of spent nuclear fuel materials exist inside dissolution tanks, various storage tanks, piping, and the like.
たとえば溶解槽内ては、３〜５ｃｍ長に切断された使用
済核燃料物質が、加熱された硝酸によって溶解される。For example, in a melting tank, spent nuclear fuel material cut into pieces of 3 to 5 cm in length is melted with heated nitric acid.
このため、溶解（曹では、ウラン−２３５、プルトニウ
ム−２３９、プルトニウム−２旧等の核分裂性核種と、
直接的または間接的に生成するセシウム−１３４、セシ
ウム−１３７、ヨーロビウムー１５４等の核分裂生成物
と、キュリウム−２４４、プルトニウム−２４０、プル
トニウム−２３８等の自発中性子を放出する核種とが流
体状物質内に混在し、中性子増倍体系を構成している。For this reason, dissolution (in carbon dioxide, fissile nuclides such as uranium-235, plutonium-239, and plutonium-2 old)
Nuclear fission products such as cesium-134, cesium-137, and eurobium-154, which are generated directly or indirectly, and nuclides that emit spontaneous neutrons, such as curium-244, plutonium-240, and plutonium-238, are present in the fluid material. They are mixed together to form a neutron multiplication system.
そして、これらの濃度は時間的あるいは局所的に複雑に
変化しており、この濃度が高くなった場合は臨界状態と
なる危険性がある。These concentrations change temporally or locally in a complicated manner, and if these concentrations become high, there is a risk of a critical state.
このため従来は、使用済核燃料物質の濃度の最高値を非
常に低い値に制限したり、溶解、漕等の形状を内部の使
用済核燃料物質か決して臨界状態になることのない形状
とする等の方法で、使用済核燃料物質が臨界状態となる
ことを防止し、臨界安仝性の確保を行なっている。For this reason, conventional methods have been used, such as limiting the maximum concentration of spent nuclear fuel material to a very low value, and shaping the melting tank, etc., so that the spent nuclear fuel material inside never reaches a critical state. This method prevents spent nuclear fuel material from reaching a critical state and ensures criticality safety.
（発明が解決しようとする問題点）
しかしながら従来では、たとえば核燃料再処理施設の溶
解槽内等の使用済核燃料物質等の中性子増倍体系未臨界
度を測定する有効な方法がなく、このため核燃料再処理
施設等においては、使用済核燃料物質を確実に未臨界に
保ち、臨界安全性を確保するために必要以上に使用済核
燃料物質の最高濃度を低く抑制したり、使用済核燃料物
質の密度を低くするため溶解槽等の形状を細くあるいは
薄くする等、その設置に広い空間を必要とする形状とす
るため、処理効率の悪化や、建設コス１〜の増大を招く
等の問題があった。(Problem to be solved by the invention) However, in the past, there was no effective method for measuring the subcriticality of a neutron multiplier system such as spent nuclear fuel material in a melting tank of a nuclear fuel reprocessing facility. In reprocessing facilities, etc., it is necessary to keep the spent nuclear fuel material subcritical and to suppress the maximum concentration of the spent nuclear fuel material lower than necessary to ensure criticality safety, or to reduce the density of the spent nuclear fuel material. In order to lower the temperature, the shape of the dissolution tank or the like is made narrower or thinner, and the shape requires a wider space for installation, which causes problems such as deterioration of processing efficiency and increase in construction cost.
本発明はかかる従来の事情に対処してなされたもので、
簡単な装置で未臨界度を測定することができ、核燃料再
処理施設等にあける臨界安全性の確保と、処理効率の向
上および建設コストの低減を図ることのできる未臨界度
の測定方法を提供しようとするものである。The present invention has been made in response to such conventional circumstances,
We provide a method for measuring subcriticality that can measure subcriticality with a simple device, ensuring criticality safety in nuclear fuel reprocessing facilities, improving processing efficiency, and reducing construction costs. This is what I am trying to do.
［発明の構成］
（問題点を解決するための手段）
すなわち本発明の未臨界度の測定方法は、中性子源と中
性子検出器とを備えた標準増倍体系を、被測定増倍体系
に近づけ、前記標準増倍体系と前記被測定増倍体系との
反応度の干渉を前記中性子検出器により検出し、前記被
測定増倍体系の未臨界度を測定する。[Structure of the Invention] (Means for Solving the Problems) In other words, the method for measuring subcriticality of the present invention is to bring a standard multiplication system equipped with a neutron source and a neutron detector closer to the multiplication system to be measured. , detecting interference in reactivity between the standard multiplication system and the multiplication system to be measured by the neutron detector, and measuring the degree of subcriticality of the multiplication system to be measured.
（作用）
本発明方法では、反応度既知の中性子源と、中性子検出
器とを備えた標準増倍体系を、被測定増倍体系に近づけ
る。このとき、標準増倍体系と被測定増倍体系との間で
反応度の干渉が生じるので、この反応度の干渉を中性子
検出器の中性子計数率の変化により検出し、被測定増倍
体系の未臨界度を測定する。(Operation) In the method of the present invention, a standard multiplication system including a neutron source with known reactivity and a neutron detector is brought close to the multiplication system to be measured. At this time, interference in reactivity occurs between the standard multiplication system and the multiplication system to be measured, so this interference in reactivity is detected by changes in the neutron count rate of the neutron detector, and Measure subcriticality.
（実施例）
以下本発明方法の詳細を図面を参照して実施例について
説明する。(Example) The details of the method of the present invention will be described below with reference to the drawings.
第１図は本発明の一実施例方法を示すもので、この実施
例では、側方に中性子検出器１を配置され、内部に局所
的あるいは分散されて中性子源（図示せず）を配置され
た容器からなる標準増倍体系２を、例えば使用済核燃料
等の未臨界度が未知の被測定増倍体系３へ近づける。FIG. 1 shows a method according to an embodiment of the present invention, in which a neutron detector 1 is placed on the side and a neutron source (not shown) is placed locally or distributed inside. A standard multiplication system 2 consisting of a container made of a metal is brought close to a multiplication system 3 to be measured whose degree of subcriticality is unknown, such as spent nuclear fuel, for example.
なお、被測定増倍体系３は内部の組成によって１票準増
倍体系２が離れている場合でも中性子放出率が変化する
場合があるので、被測定増倍体系３の側方には、この変
化をモニタするための中性子検出器４か配置されている
。Note that the neutron emission rate of the multiplication system 3 to be measured may change depending on the internal composition even if the 1-vote semi-multiplying system 2 is far away, so this A neutron detector 4 is also arranged to monitor changes.
このようにして標準増倍体系２を被測定増倍体系３へ近
づけると、標準増倍体系２と被測定増倍体系３との間に
反応度の干渉が生じる。When the standard multiplication system 2 is brought closer to the multiplication system 3 to be measured in this manner, interference in reactivity occurs between the standard multiplication system 2 and the multiplication system 3 to be measured.
第２図のグラフは縦軸を中性子検出器１の中性子計数率
φの逆数、横軸を標準増倍体系２と被測定増倍体系３と
の距離℃として、曲線ａ、ｂ、ｃはそれぞれでの変化に
よる１／φの変化を示すもので、βが充分に大きな時は
、標準増倍体系２は被測定増倍体系３とは独立で、１／
φは被測定増倍体系３の未臨界度とは無関係に一定とな
るが、λが小さくなると、実効増倍率に干渉効果が生じ
、被測定増倍体系３の未臨界度に応じて、１／φには曲
線ａ、ｂ、ｃに示すような異なった変化が生じる。In the graph of Figure 2, the vertical axis is the reciprocal of the neutron count rate φ of the neutron detector 1, the horizontal axis is the distance °C between the standard multiplication system 2 and the multiplication system to be measured 3, and the curves a, b, and c are respectively This shows the change in 1/φ due to a change in .When β is sufficiently large, standard multiplication system 2 is independent of measured multiplication system 3, and 1/φ
φ remains constant regardless of the subcriticality of the multiplication system 3 to be measured, but as λ becomes smaller, an interference effect occurs on the effective multiplication factor, and depending on the subcriticality of the multiplication system 3 to be measured, φ becomes constant. /φ undergoes different changes as shown in curves a, b, and c.
従って、予め想定される幾つかの被測定増倍体系３の未
臨界度に対して、標準増倍体系２内の中性子源の条件か
ら計算により第２図のグラフに示す曲線ａ、ｂ、ｃのよ
うな校正曲線を求めてあき、中性子検出器１で測定され
る中性子計数率の変化がどの校正曲線に従って変化する
かによって、被測定増倍体系３の未臨界度を測定するこ
とができる。Therefore, curves a, b, and c shown in the graph of FIG. The degree of subcriticality of the multiplication system 3 to be measured can be determined by finding a calibration curve such as the following and determining which calibration curve the change in the neutron count rate measured by the neutron detector 1 follows.
第３図は、他の実施例方法を示すもので、この実施例方
法では、側方に２個の中性子検出器１ａ、１ｂを配置さ
れ、内部の中央部に中性子源を内臓する中性子検出器１
Ｃが配置された容器からなる標準増倍体系２ａを、例え
ば使用済核燃料等の未臨界度未知の被測定増倍体系３ａ
に近づける。なおこの実施例でも、被測定増倍体系３ａ
の側方には、被測定増倍体系３ａの中性子放出率の変化
をモニタするための中性子検出器４ａが配置されている
。FIG. 3 shows another embodiment method. In this embodiment method, two neutron detectors 1a and 1b are arranged on the sides, and a neutron source is built in the center of the neutron detector. 1
A standard multiplication system 2a consisting of a container in which C is placed is used as a multiplication system 3a to be measured with unknown subcriticality, such as spent nuclear fuel.
get closer to Note that in this embodiment as well, the multiplication system to be measured 3a
A neutron detector 4a for monitoring changes in the neutron emission rate of the multiplication system 3a to be measured is arranged on the side of the neutron detector 4a.
上記説明のこの実施例方法では、中性子源を内臓する中
性子検出器１Ｃと、２個の中性子検出器１ａ、１ｂによ
り、ミハルツのＰＳＤ法といわれる方法で、標準増倍体
系２ａ内の実効増倍率ｋを直接求める。ここで測定され
る実効増倍率には、標準増倍体系２ａと被測定増倍体系
３ａとの距離βを小さくした場合、干渉効果を含む標準
増倍体系２ａと被測定増倍体系３ａとの総合的な実効増
倍率となり、縦軸を実効増倍率ｋ、横軸を標準増倍体系
２ａと被測定増倍体系３ａとの距離ｌとした第４図のグ
ラフに曲線ｄ、ｅ、ｆ、ｇで示すように、前述の実施例
と同様にλを小さくした場合被測定増倍体系３ａの未臨
界度により異なった変化を示すので、このような校正曲
線を予め計算または実測により求めておき、前述の実施
例と同様に被測定増倍体系３ａの未臨界度を測定するこ
とができる。In this embodiment method described above, a neutron detector 1C containing a neutron source and two neutron detectors 1a and 1b are used to calculate the effective multiplication rate within the standard multiplication system 2a using a method called the Michaltz PSD method. Find k directly. The effective multiplication factor measured here includes the difference between the standard multiplication system 2a and the multiplication system 3a, including interference effects, when the distance β between the standard multiplication system 2a and the multiplication system 3a to be measured is made small. This is the overall effective multiplication factor, and the curves d, e, f, As shown in g, when λ is made smaller as in the previous embodiment, different changes occur depending on the degree of subcriticality of the multiplication system 3a to be measured, so such a calibration curve should be obtained by calculation or actual measurement in advance. , the subcriticality of the multiplication system 3a to be measured can be measured in the same manner as in the above embodiment.
［発明の効果］
上述のように本発明の未臨界度の測定方法では、簡単な
装置で未臨界度を測定することができ、核燃料再処理施
設等における臨界安全性の確保と、処理効率の向上およ
び建設コストの低減を図ることができる。[Effects of the Invention] As described above, the method for measuring subcriticality of the present invention enables the measurement of subcriticality with a simple device, ensuring criticality safety in nuclear fuel reprocessing facilities, etc., and improving processing efficiency. It is possible to improve the performance and reduce construction costs.
第１図は本発明の一実施例方法を示す説明図、第２図は
標準増倍体系と被測定増倍体系との距離と中性子計数率
の逆数との関係を示すグラフ、第３図は他の実施例の方
法を示す説明図、第４図は標準増倍体系と被測定増倍体
系との距離と標準増倍体系および被測定増倍体系の実効
増倍率との関係を示すグラフである。
１・・・・・・・・・中性子検出器
訃・・・・・・・・標準増倍体系
３・・・・・・・・・被測定増倍体系
出願人 日本原子力事業株式会社同
株式会社 東芝
代理人 弁理士 須 山 佐 −
ｏ”
第１図
λ
第２図
σ℃４ｄ
第３図
」
第４図FIG. 1 is an explanatory diagram showing one embodiment of the method of the present invention, FIG. 2 is a graph showing the relationship between the distance between the standard multiplication system and the multiplication system to be measured and the reciprocal of the neutron count rate, and FIG. An explanatory diagram showing the method of another embodiment, FIG. 4 is a graph showing the relationship between the distance between the standard multiplication system and the multiplication system to be measured and the effective multiplication factor of the standard multiplication system and the multiplication system to be measured. be. 1...Neutron detector death...Standard multiplication system 3...Measurement multiplication system Applicant: Japan Atomic Energy Corporation
Toshiba Corporation Agent Patent Attorney Suyama Sa-o” Figure 1 λ Figure 2 σ℃4d Figure 3 Figure 4
Claims (1)
を、被測定増倍体系に近づけ、前記標準増倍体系と前記
被測定増倍体系との反応度の干渉を前記中性子検出器に
より検出し、前記被測定増倍体系の未臨界度を測定する
ことを特徴とする未臨界度の測定方法。(1) A standard multiplication system equipped with a neutron source and a neutron detector is brought close to the multiplication system to be measured, and the interference in the reactivity between the standard multiplication system and the multiplication system to be measured is eliminated by the neutron detector. A method for measuring a degree of subcriticality, characterized in that the degree of subcriticality of the multiplication system to be measured is measured by detecting the degree of subcriticality.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61137904A JPS62294997A (en) | 1986-06-13 | 1986-06-13 | Method of measuring non-criticality |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61137904A JPS62294997A (en) | 1986-06-13 | 1986-06-13 | Method of measuring non-criticality |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62294997A true JPS62294997A (en) | 1987-12-22 |
Family
ID=15209397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61137904A Pending JPS62294997A (en) | 1986-06-13 | 1986-06-13 | Method of measuring non-criticality |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62294997A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009133701A (en) * | 2007-11-30 | 2009-06-18 | Toshiba Corp | Criticality safety control method for continuous dissolver in reprocessing facility |
-
1986
- 1986-06-13 JP JP61137904A patent/JPS62294997A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009133701A (en) * | 2007-11-30 | 2009-06-18 | Toshiba Corp | Criticality safety control method for continuous dissolver in reprocessing facility |
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