JPH0458915B2 - - Google Patents
Info
- Publication number
- JPH0458915B2 JPH0458915B2 JP60104597A JP10459785A JPH0458915B2 JP H0458915 B2 JPH0458915 B2 JP H0458915B2 JP 60104597 A JP60104597 A JP 60104597A JP 10459785 A JP10459785 A JP 10459785A JP H0458915 B2 JPH0458915 B2 JP H0458915B2
- Authority
- JP
- Japan
- Prior art keywords
- neutron
- keff
- multiplication factor
- subcritical
- value
- 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.)
- Expired - Lifetime
Links
- 238000005259 measurement Methods 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 14
- 238000012937 correction Methods 0.000 claims description 5
- 230000004907 flux Effects 0.000 claims description 5
- 239000003758 nuclear fuel Substances 0.000 claims description 4
- 239000006096 absorbing agent Substances 0.000 claims 1
- 238000001514 detection method Methods 0.000 claims 1
- 230000005855 radiation Effects 0.000 claims 1
- 238000011088 calibration curve Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 239000002915 spent fuel radioactive waste Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-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
Landscapes
- Monitoring And Testing Of Nuclear Reactors (AREA)
Description
【発明の詳細な説明】
［発明の技術分野］
本発明は、水中に配設された燃料集合体等の未
臨界体系の側面に、中性子源と中性子検出器を配
置し、中性子源から放出された中性子を未臨界体
系に入射させ、形成された増倍中性子束（以下φ
と記す）を測定して未臨界体系の実効中性子増倍
率（以下Keffと記す）を求める方法に関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention disposes a neutron source and a neutron detector on the side of a subcritical system such as a fuel assembly disposed underwater, and detects the neutrons emitted from the neutron source. The multiplied neutron flux (hereinafter referred to as φ
This paper relates to a method for determining the effective neutron multiplication factor (hereinafter referred to as Keff) of a subcritical system by measuring the
［発明の技術的背景とその問題点］
原子炉の燃料集合体等の未臨界体系のKeffを
測定することができれば、得られた測定値と設計
計算値との比較によつて設計手法の妥当性を検討
でき、さらにはまた、運転監視に使用される半実
験的計算値（プロセス計算値）との比較によつて
運転監視手法の妥当性も検討することができるた
め、原子炉の適切かつ効率的な設計に役立つとと
もに、使用済燃料の輸送、貯蔵、再処理時にも安
全性及び経済性の面で重要なデータを提供するこ
とになる。[Technical background of the invention and its problems] If it is possible to measure Keff of a subcritical system such as a nuclear reactor fuel assembly, the validity of the design method can be determined by comparing the obtained measured value with the design calculation value. Furthermore, it is possible to examine the validity of the operation monitoring method by comparing it with the semi-experimental calculation values (process calculation values) used for operation monitoring. It will not only help with efficient design, but also provide important data on the safety and economic aspects of spent fuel transportation, storage, and reprocessing.
本発明者等は長い間、未臨界体系特に使用済燃
料集合体の増倍率測定方法及びその装置に関し研
究を重ね、多くの提案を行なつてきた。それらの
過程でφは次式で表わされることを見出した。 For a long time, the present inventors have conducted research on methods and devices for measuring the multiplication factor of subcritical systems, particularly spent fuel assemblies, and have made many proposals. Through these processes, it was discovered that φ can be expressed by the following formula.
φ＝（Ａ／（１−Keff））・Ｆ（Keff） ……(1)
ここで、Ａは定数、Ｆ（Keff）は局所的に外部
から中性子源を導入するための補正因子である。
外部に中性子源を配置しないで集合体内に一様に
中性子源が分布している時は、Ｆ（Keff）＝１と
なるが、局所的に外部から中性子源を導入する
と、一般にはＦ（Keff）＝１とならない。Ｆ
（Keff）はKeffの一次近似として次式で表わされ
る。 φ=(A/(1−Keff))·F(Keff) (1) Here, A is a constant, and F(Keff) is a correction factor for locally introducing a neutron source from the outside.
When neutron sources are uniformly distributed within the aggregate without placing any external neutron sources, F(Keff) = 1, but if a neutron source is locally introduced from the outside, generally F(Keff) )=1. F
(Keff) is expressed by the following equation as a linear approximation of Keff.
Ｆ（Keff）＝１＋Ｂ（１−Keff） ……(2) 但し、Ｂは定数である。 F(Keff)=1+B(1-Keff)...(2) However, B is a constant.
(1)式と(2)式より、φを表わす式の未知数は
Keffの他にＡとＢの２つとなる。この２つの未
知数を決定するためには、Keffの値が大きく異
なる２つのKeffが既知の未臨界体系が必要とな
るが、使用済燃料受入れプールのような施設では
そのような要求を実現するのは容易ではない。 From equations (1) and (2), the unknown quantity of the equation representing φ is
In addition to Keff, there will be two, A and B. In order to determine these two unknowns, a subcritical system with two known Keff values that are significantly different is required, but it is difficult to realize such a requirement in facilities such as spent fuel receiving pools. is not easy.
［発明の目的］
本発明はかかる点に対処してなされたもので、
上述のＦ（Keff）の値がKeffに無関係にほぼ1.0と
なる条件を求め、未知数の数を１つに減じて、φ
とKeffとの相関関係を単純化し、較正曲線の作
成作業を簡略化することができるような未臨界体
系の増倍率測定方法を提供しようとするものであ
る。[Object of the Invention] The present invention has been made to address the above problems, and
Find the conditions under which the value of F (Keff) mentioned above is approximately 1.0 regardless of Keff, reduce the number of unknowns to one, and obtain φ
The purpose of this invention is to provide a method for measuring the multiplication factor of a subcritical system that can simplify the correlation between Keff and Keff and simplify the work of creating a calibration curve.
［発明の概要］
すなわち本発明は、水中に配設された核燃料の
未臨界体系をはさんで一側に中性子源を他側に中
性子検出器を配置した測定体系により増倍率を測
定する方法において、実効中性子増倍率Keffを
前記中性子検出器により測定された中性子束の値
φを用いて次式
Keff＝（１−Ａ／φ）・Ｆ（Keff）
（但しＡは定数、Ｆ（Keff）は中性子源を局所
的に配置するために必要な補正因子を表わす）で
表わすとともに、予め補正因子Ｆ（Keff）の値が
実効中性子増倍率Keffの値に独立にほぼ1.0の値
となる測定体系を模擬実験又は解析により求め、
この測定体系と同条件の下で測定した未臨界体系
の中性子束の値φから実効中性子増倍率Keffを
求めることを特徴とする未臨界体系の増倍率測定
方法である。[Summary of the Invention] That is, the present invention provides a method for measuring a multiplication factor using a measurement system in which a neutron source is placed on one side and a neutron detector is placed on the other side of a subcritical system of nuclear fuel disposed underwater. , the effective neutron multiplication factor Keff is calculated by the following formula using the neutron flux value φ measured by the neutron detector: Keff=(1-A/φ)・F(Keff) (where A is a constant and F(Keff) is (represents a correction factor necessary for locally locating a neutron source), and a measurement system in which the value of the correction factor F (Keff) is approximately 1.0 independently of the value of the effective neutron multiplication factor Keff is established in advance. Determined through simulation experiments or analysis,
This is a subcritical system multiplication factor measurement method characterized by determining the effective neutron multiplication factor Keff from the neutron flux value φ of the subcritical system measured under the same conditions as this measurement system.
［発明の実施例］
以下、図面に示す実施例について本発明を詳細
に説明する。[Embodiments of the Invention] The present invention will be described in detail below with reference to embodiments shown in the drawings.
第１図は本発明の実効増倍率測定方法の一実施
例を示すフローチヤートである。この実施例で
は、まず、(1)式におけるＦ（Keff）の値がKeffの
値にほとんど関係なくほぼ1.0となる測定体系を、
模擬実験又は解析により求める。ついで、組成既
知又はKeff既知の１つの標準未臨界体系を用い
て、上記のＦ（Keff）≒1.0の測定体系におけるφ
対Keffの較正曲線を作成するとともに、測定す
べき未臨界体系のφを前記測定体系と同じ条件の
下で測定し、前記φ対Keffの較正曲線からKeff
を求める。 FIG. 1 is a flowchart showing an embodiment of the effective multiplication factor measuring method of the present invention. In this example, first, we will establish a measurement system in which the value of F (Keff) in equation (1) is approximately 1.0, almost regardless of the value of Keff.
Obtained through simulation experiments or analysis. Next, using one standard subcritical system with known composition or known Keff, φ in the above measurement system with F(Keff)≒1.0
In addition to creating a calibration curve for Keff vs. φ, measure φ of the subcritical system to be measured under the same conditions as the measurement system, and use the calibration curve for φ vs. Keff to
seek.
第２図ないし第４図はＦ（Keff）≒1.0となる測
定体系の実施例を示すもので、図中NSは中性子
源、ｄは中性子検出器を表わす。 Figures 2 to 4 show examples of measurement systems in which F (Keff)≈1.0, where NS represents a neutron source and d represents a neutron detector.
第２図ａは燃料集合体１の軸２に対して中性子
源の中心と中性子検出器の中心とを結ぶ直線３が
斜交するように、中性子源及び中性子検出器を配
置した測定体系を側面から見た図で、第２図ｂは
第２図ａを上からみた図である。第２図ｃは、沸
騰水型原子炉の燃料集合体と同程度の大きさで、
濃縮度を１％、２％、３％と変化させた未臨界体
系について、Keffの計算値とφの計数値との関
係を(1)式で表わしたときのＦ（Keff）の値を、中
性子源の中心を通り軸２と直交する直線４からの
中性子源の位置のずれの大きさ（以下Ｈと記す）
に関してプロツトしたものである。図中、曲線
Ｋ、Ｌ、ＭはそれぞれKeffの値が0.4、0.5、0.6の
ときのグラフである。この例では、Ｈの値がほぼ
10cmのときにＦ（Keff）の値がほぼ1.0となり、
Keff依存性がなくなることを示している。Ｆ
（Keff）の値がほぼ1.0となるＨの値は、未臨界体
系の大きさや形状によつても変化する。 Figure 2a shows a measurement system in which a neutron source and a neutron detector are arranged so that a straight line 3 connecting the center of the neutron source and the center of the neutron detector is obliquely intersected with the axis 2 of the fuel assembly 1. FIG. 2b is a view of FIG. 2a viewed from above. Figure 2c is about the same size as a boiling water reactor fuel assembly.
For a subcritical system in which the enrichment is changed to 1%, 2%, and 3%, the value of F (Keff) when the relationship between the calculated value of Keff and the counted value of φ is expressed by equation (1) is: The amount of deviation in the position of the neutron source from the straight line 4 passing through the center of the neutron source and perpendicular to axis 2 (hereinafter referred to as H)
It is plotted with respect to In the figure, curves K, L, and M are graphs when the Keff values are 0.4, 0.5, and 0.6, respectively. In this example, the value of H is approximately
At 10cm, the value of F (Keff) is approximately 1.0,
This shows that Keff dependence disappears. F
The value of H at which the value of (Keff) is approximately 1.0 also changes depending on the size and shape of the subcritical system.
第３図では、第２図におけるＨの値が０となる
ように中性子源と中性子検出器が配置されている
が、図に示すように燃料集合体１と中性子源の間
及び／又は燃料集合体１と中性子検出器の間に中
性子吸収材、例えばCd板を配置することによつ
てＦ（Keff）の値がほぼ1.0となつた。これは、拡
散距離の長い高速中性子が未臨界体系に供給され
るためと考えられる。 In FIG. 3, the neutron source and neutron detector are arranged so that the value of H in FIG. By placing a neutron absorbing material, such as a Cd plate, between the body 1 and the neutron detector, the value of F (Keff) became approximately 1.0. This is thought to be because fast neutrons with long diffusion distances are supplied to the subcritical system.
第４図ａ，ｂ，ｃ，ｄに示す測定体系は原理的
には第２図に示した測定体系と同じで、同様な効
果を得ることができる。すなわち、第４図ａは中
性子検出器の中心を通り燃料集合体１の軸２に直
交する直線４をはさんで上下にずらして中性子源
を２個配置したものであり、ｂはａと逆に１個の
中性子源に対して２個の中性子検出器を上下にず
らして配置したものである。ｃは中性子源に対し
て上下に長い中性子検出器を配置した測定体系を
示し、ｄはｃと逆に中性子検出器に対して上下に
長い中性子源を配置した測定体系を示す。 The measurement systems shown in FIGS. 4a, b, c, and d are the same in principle as the measurement system shown in FIG. 2, and similar effects can be obtained. That is, Fig. 4 a shows two neutron sources arranged vertically shifted across a straight line 4 passing through the center of the neutron detector and orthogonal to the axis 2 of the fuel assembly 1, and b is the opposite of a. In this system, two neutron detectors are arranged vertically shifted for one neutron source. c shows a measurement system in which long neutron detectors are arranged above and below the neutron source, and d shows a measurement system in which long neutron sources are arranged above and below the neutron detector, contrary to c.
［発明の効果］
以上の記載からも明らかなように、本発明によ
れば、(1)式におけるＦ（Keff）の値がKeffの値に
関係なくほぼ1.0となる測定条件で実施されるた
め、従来ではKeffの大きく異なる２つの標準未
臨界体系が必要であつたのに対し、Keff既知の
１つの標準未臨界体系のみで較正曲線を作成する
ことができ、より容易にKeffを求めることがで
きる。[Effects of the Invention] As is clear from the above description, according to the present invention, measurement is performed under measurement conditions in which the value of F (Keff) in equation (1) is approximately 1.0 regardless of the value of Keff. , whereas conventionally two standard subcritical systems with significantly different Keff were required, a calibration curve can be created using only one standard subcritical system with known Keff, making it easier to obtain Keff. can.
第１図は本発明の一実施例を説明するフローチ
ヤート、第２図ａ及びｂはそれぞれ本発明の測定
体系の一実施例を示す側面図及び平面図、第２図
ｃは第２図ａにおけるＨの値によるＦ（Keff）の
値の変化を示すグラフ、第３図は本発明の測定体
系の他の実施例を示す平面図、第４図ａ，ｂ，
ｃ，ｄはそれぞれ本発明の測定体系のさらに他の
実施例を示す側面図である。
１……燃料集合体、NS……中性子源、ｄ……
中性子検出器。
FIG. 1 is a flowchart illustrating an embodiment of the present invention, FIGS. 2 a and b are a side view and a plan view, respectively, showing an embodiment of the measurement system of the present invention, and FIG. FIG. 3 is a plan view showing another embodiment of the measurement system of the present invention, and FIG. 4 a, b,
c and d are side views respectively showing still other embodiments of the measurement system of the present invention. 1... Fuel assembly, NS... Neutron source, d...
Neutron detector.
Claims (1)
んで一側に中性子源を他側に中性子検出器を配置
した測定体系により増倍率を測定する方法におい
て、実効中性子増倍率Keffを前記中性子検出器
により測定された中性子束の値φを用いて次式 Keff＝（１−Ａ／φ）・Ｆ（Keff） （但しＡは定数、Ｆ（Keff）は中性子源を局所
的に配置するために必要な補正因子を表わす）で
表わすとともに、予め補正因子Ｆ（Keff）の値が
実効中性子増倍率Keffの値に独立にほぼ1.0の値
となる測定体系を模擬実験又は解析により求め、
この測定体系と同条件の下で測定した未臨界体系
の中性子束の値φから実効中性子増倍率Keffを
求めることを特徴とする未臨界体系の増倍率測定
方法。 ２ 測定体系は、中性子源の中心と中性子検出器
の中心を結ぶ直線が未臨界体系の軸と斜交するよ
うに、前記中性子源及び中性子検出器を配置して
なる特許請求の範囲第１項記載の未臨界体系の増
倍率測定方法。 ３ 測定体系は、未臨界体系と、中性子源及び／
又は中性子検出器との間に熱中性子吸収材が配置
されてなる特許請求の範囲第１項記載の未臨界体
系の増倍率測定方法。 ４ 測定体系は、中性子源の線源及び中性子検出
器の検出端の長さ及び個数の少なくともいづれか
を制御することにより得られる特許請求の範囲第
１項記載の未臨界体系の増倍率測定方法。[Claims] 1. A method for measuring a multiplication factor using a measurement system in which a neutron source is placed on one side and a neutron detector is placed on the other side of a subcritical system of nuclear fuel disposed underwater. The multiplication factor Keff is calculated by the following formula using the neutron flux value φ measured by the neutron detector: Keff=(1-A/φ)・F(Keff) (where A is a constant and F(Keff) is the neutron source. (represents the correction factor necessary for local placement), and simulated or simulated a measurement system in which the value of the correction factor F (Keff) is approximately 1.0 independently of the value of the effective neutron multiplication factor Keff. Obtained by analysis,
A method for measuring the multiplication factor of a subcritical system, characterized in that the effective neutron multiplication factor Keff is determined from the value φ of the neutron flux of the subcritical system measured under the same conditions as this measurement system. 2. Claim 1, wherein the measurement system is such that the neutron source and neutron detector are arranged such that a straight line connecting the center of the neutron source and the center of the neutron detector intersects obliquely with the axis of the subcritical system. A method for measuring the multiplication factor of the described subcritical system. 3 The measurement system consists of a subcritical system, a neutron source and/or
The subcritical system multiplication factor measuring method according to claim 1, wherein a thermal neutron absorber is disposed between the neutron detector and the neutron detector. 4. The method for measuring the multiplication factor of a subcritical system according to claim 1, wherein the measurement system is obtained by controlling at least one of the length and number of the radiation source of the neutron source and the detection end of the neutron detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60104597A JPS61262691A (en) | 1985-05-16 | 1985-05-16 | Method of measuring multiplication factor of non-critical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60104597A JPS61262691A (en) | 1985-05-16 | 1985-05-16 | Method of measuring multiplication factor of non-critical system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61262691A JPS61262691A (en) | 1986-11-20 |
| JPH0458915B2 true JPH0458915B2 (en) | 1992-09-18 |
Family
ID=14384835
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60104597A Granted JPS61262691A (en) | 1985-05-16 | 1985-05-16 | Method of measuring multiplication factor of non-critical system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61262691A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5085029B2 (en) * | 2005-10-28 | 2012-11-28 | 株式会社東芝 | Subcriticality monitoring device |
-
1985
- 1985-05-16 JP JP60104597A patent/JPS61262691A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61262691A (en) | 1986-11-20 |
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