JP2602302B2 - A method for removing the effects of photoneutrons on a boric acid concentration meter in heavy water reactors - Google Patents
A method for removing the effects of photoneutrons on a boric acid concentration meter in heavy water reactorsInfo
- Publication number
- JP2602302B2 JP2602302B2 JP63249936A JP24993688A JP2602302B2 JP 2602302 B2 JP2602302 B2 JP 2602302B2 JP 63249936 A JP63249936 A JP 63249936A JP 24993688 A JP24993688 A JP 24993688A JP 2602302 B2 JP2602302 B2 JP 2602302B2
- Authority
- JP
- Japan
- Prior art keywords
- neutron
- heavy water
- boric acid
- acid concentration
- container
- 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
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)
- Measurement Of Radiation (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 重水炉において減速材として使用される重水には中性
子吸収のため、ほう酸（10B）が含まれている。そして
重水中のほう酸濃度を変えることによって、重水炉にお
ける反応度が制御されている。従って、重水中のほう酸
の濃度測定は極めて重要である。The heavy water is used as moderator in BACKGROUND OF THE INVENTION (FIELD OF THE INVENTION) heavy-water reactors for neutron absorption contains boric acid (10 B) is. The reactivity in the heavy water reactor is controlled by changing the concentration of boric acid in the heavy water. Therefore, measuring the concentration of boric acid in heavy water is extremely important.
本発明はこのような重水中のほう酸濃度測定器におけ
る光中性子の影響除去方法に関するものである。The present invention relates to a method for removing the influence of photoneutrons in such a boric acid concentration meter in heavy water.
（従来技術） 第２図を参照してほう酸濃度測定器について概略説明
する。第２図に於て１は測定容器、２は測定容器１の外
部を囲む反射兼遮蔽体である。３は重水入口、４は中性
子計測器、５は中性子線源である。この線源５からの中
性子は前記反射兼遮蔽体によって反射され、中性子を容
器内に封じ込めて外部漏洩を防止すると同時に中性子を
外部に逃さないで効率的に利用するようになっている。(Prior Art) A boric acid concentration measuring device will be schematically described with reference to FIG. In FIG. 2, reference numeral 1 denotes a measuring container, and 2 denotes a reflection / shielding body surrounding the outside of the measuring container 1. 3 is a heavy water inlet, 4 is a neutron detector, and 5 is a neutron source. The neutrons from the radiation source 5 are reflected by the reflection / shielding body, and the neutrons are sealed in a container to prevent external leakage and at the same time to efficiently utilize the neutrons without escaping to the outside.
そして、重水入口３からほう酸を含んで重水を測定容
器１内に送り込み、容器頂部から中性子を照射し、重水
によって減速され、10Bに吸収されない中性子を中性子
計測器４で検出するようになっている。Then, heavy water containing boric acid is sent from the heavy water inlet 3 into the measuring container 1 and neutrons are irradiated from the top of the container, and neutrons 4 which are decelerated by the heavy water and not absorbed by 10 B are detected by the neutron measuring device 4. I have.
（発明が解決しようとする課題） 重水中の10B濃度のオンライン測定のため、中性子源
から出た中性子が重水で減速され、減速された中性子が
10Bに吸収されることを利用した測定器を開発するに当
り、重水中には放射性不純物があるが、この内24Na,56M
nからのγ線の一部は重水と反応して光中性子を生成す
る。この光中性子は10B濃度測定器に於て誤差要因とな
るので、この光中性子の影響を除去する方法を提供しよ
うとするものである。(Problems to be solved by the invention) For online measurement of 10 B concentration in heavy water, neutrons emitted from a neutron source are slowed down by heavy water, and the slowed-down neutrons
In developing a measuring device that utilizes absorption by 10 B, heavy water contains radioactive impurities, of which 24 Na, 56 M
Some of the gamma rays from n react with heavy water to produce photoneutrons. Since this photoneutron causes an error in a 10 B concentration measuring instrument, an attempt is made to provide a method for removing the influence of this photoneutron.
（発明による課題の解決手段） 中性子源と中性子計測器を備えた容器を有するほう酸
濃度測定器と、中性子源を有しないで中性子計測器のみ
を備えた容器を共通の重水源と結び、ほう酸濃度測定器
側の中性子計数と、中性子源を有しない側の容器での中
性子計数の差を求めて光中性子の補正をし、重水炉にお
けるほう酸濃度測定器の光中性子の影響を除去するよう
にした。(Means for Solving the Problems According to the Invention) A boric acid concentration measuring device having a container provided with a neutron source and a neutron measuring device, and a container having only a neutron measuring device without a neutron source are connected to a common heavy water source to form a boric acid concentration. The difference between the neutron counting on the measuring instrument side and the neutron counting on the vessel without the neutron source was corrected for photoneutrons, and the effect of photoneutrons on the boric acid concentration measuring instrument in heavy water reactors was removed. .
又、中性子源を有しない側の容器を設置する代りにほ
う酸濃度測定器側容器の中性子源を定期的に除いた状態
で中性子計測計数を求めるようにした。In addition, instead of installing the vessel having no neutron source, the neutron measurement count was obtained with the neutron source periodically removed from the vessel on the boric acid concentration measurement instrument side.
（実施例１） 第２図を参照してほう酸濃度測定器における測定容器
１内における中性子の態様について説明する。(Example 1) The mode of neutrons in the measurement container 1 in the boric acid concentration measuring device will be described with reference to FIG.
中性子線源５の252Cfから中性子が放射される。これ
ら中性子は、測定容器１内の重水Ｄによって減速された
中性子と減速されない中性子とが混在している。又重水
Ｄで減速された中性子のうちには、さらに重水中のほう
酸10Bに吸収される中性子nBがある。従って、中性子線
源５から放射される中性子の総量のうち、計測器４にて
計測される量は重水Ｄであまり減速されないで計測器４
に達する中性子ｎと重水Ｄで減速されて計測器４に達す
る中性子nDの和（ｎ＋nD）となる。Neutrons are emitted from 252 Cf of the neutron source 5. These neutrons include neutrons slowed down by the heavy water D in the measurement container 1 and neutrons not slowed down. Also while the neutrons is reduced at heavy water D may neutrons n B which is further absorbed in the heavy water of boric acid 10 B. Therefore, of the total amount of neutrons emitted from the neutron source 5, the amount measured by the measuring device 4 is not decelerated by the heavy water D so much that the measuring device 4
It is reduced at the neutron n and heavy water D reaching to reach the measuring instrument 4 the sum of neutrons n D (n + n D).
一方、重水中には不純物である24Na、56Mnが存在する
が、これら24Naや56Mnから発生する高エネルギーγ線の
一部は重水Ｄと反応して光中性子nPを発生する。On the other hand, the heavy water is present 24 Na, 56 Mn is an impurity, part of a high-energy γ-rays generated from these 24 Na and 56 Mn generates light neutrons n P reacts with heavy water D.
したがって、計測器４では重水Ｄに減速された中性子
のうち10Bに吸収されなかった中性子nDと、あまり減速
されない中性子ｎ及び光中性子nPの３種の中性子ｎ＋nD
＋nPが計測されることになる。Therefore, the neutron n D which was not absorbed by 10 B among the neutrons decelerated by the heavy water D and the neutron n + n D which was not decelerated by the neutron n and the photoneutron n P were measured by the measuring device 4.
+ N P will be measured.
計測器４で計測される光中性子nPは252Cfからの中性
子でなく、発生源を異にしているので、計測器４での測
定値の誤差となる中性子である。The optical neutron n P measured by the measuring device 4 is not a neutron from 252 Cf but a neutron that causes an error in the measurement value of the measuring device 4 because the source is different.
本発明はこの測定値の誤差をなくす方法を提供するも
のである。即ち第１図に示すようにほう酸濃度測定器1a
とは別に同形，同寸法の中性子源をもたない容器1bを用
意し、この容器には重水のみを供給し、ほう酸濃度測定
器の容器1aと同様に中性子を測定する。この測定器で容
器1b側の中性子測定器4bで測定される中性子I2は光中性
子のみであるので、ほう酸濃度測定器4aでの中性子計数
I1から測定器4bでの中性子計数I2を差し引くことで光中
性子の補正ができる。The present invention provides a method for eliminating this measurement error. That is, as shown in FIG.
Separately, a container 1b having no neutron source of the same shape and dimensions is prepared, and only heavy water is supplied to this container, and neutrons are measured in the same manner as the container 1a of the boric acid concentration measuring device. Since neutrons I 2 measured by the neutron measuring instrument 4b of the container 1b side in the instrument is only photoneutrons, a neutron count at a boric acid concentration measuring instrument 4a
It is light neutrons corrected by subtracting the neutron count I 2 of the measuring instrument 4b from I 1.
（実施例２） この実施例２の場合、第２の容器1bを設けることをし
ないで、即ち第２図と同様容器1aのみとし、ほう酸濃度
測定器の容器1aから定期的に中性子源５を抜き、そのと
きはほう酸濃度測定器自体を中性子源５がない容器と考
え、そのときの計数率I2を中性子源がある場合の係数率
I1から差し引くことで光中性子の補正ができる（第３
図）。つまり、時間差で第１図の２つの容器1aと1bがあ
るかのようにして利用する方法でもよい。(Example 2) In the case of Example 2, the neutron source 5 was periodically provided from the container 1a of the boric acid concentration meter without providing the second container 1b, that is, only the container 1a as in FIG. vent, then the considered vessel no neutron source 5 boric acid concentration measuring instrument itself coefficient ratio when a certain count rate I 2 at that time neutron source
It is light neutrons correction by subtracting from I 1 (3
Figure). In other words, a method may be used in which two containers 1a and 1b in FIG. 1 are used as if there were a time difference.
（実施例３） 中性子源を持たない容器1bがほう酸濃度測定器側の容
器1aより小さい場合には、重水量（試料厚み）によって
光中性子の発生量がほう酸濃度測定器と異ってくる。即
ち光中性子の発生は重水量によるので、中性子源を持た
ない容器で測定される光中性子I2とほう酸濃度測定器で
測定される光中性子Iphは比例関係にあると考えられ、I
ph＝NI2で得られる。発生した光中性子も重水による減
速、10Bによる吸収が考えられるので形状が異なる場
合、Ｎは10B濃度の関数となることが考えられ、Iph＝Ｎ
（χ）I2となる。Ｎ（χ）を求めれば、小型の容器を使
っても光中性子の補正が可能である。この場合、Ｎ
（χ）はほう酸濃度測定器から中性子源を除き、ほう酸
濃度測定器の計数率I1との比から求めることができる。(Example 3) When the container 1b having no neutron source is smaller than the container 1a on the boric acid concentration measuring device side, the amount of generated photoneutrons differs from that of the boric acid concentration measuring device depending on the amount of heavy water (sample thickness). That is, generation of light neutrons by heavy water, photoneutron Iph measured in the photoneutron I 2 and boric acid concentration measuring instrument is measured in a container without a neutron source is considered to be proportional, I
obtained by ph = NI 2. The generated photoneutrons can also be decelerated by heavy water and absorbed by 10 B. If the shape is different, N is considered to be a function of 10 B concentration, and Iph = N
(Χ) the I 2. If N (χ) is obtained, it is possible to correct photoneutrons even with a small container. In this case, N
(Chi), except for the neutron source from boric acid concentration measuring instrument, it can be determined from the ratio of the count rate I 1 of the boric acid concentration measuring instrument.
（効果） 中性子源をもつ容器の計数率と、中性子源を持たない
容器の計数率の割合で求めるだけで誤差の原因となる光
中性子の補正ができ、簡単に光中性子の補正をすること
ができる。(Effect) Photoneutrons that cause errors can be corrected simply by calculating the ratio between the count rate of containers with a neutron source and the count rate of containers without a neutron source, making it easy to correct optical neutrons. it can.
第１図は本発明に係る方法を実施するほう酸濃度測定器
を示す。 第２図はほう酸濃度測定器内の中性子の態様を示す。 第３図は本発明の第２実施例の説明図。 図において； １……測定容器 1a……（ほう酸濃度測定器の）容器 1b……（中性子源のない）容器、２……反射兼遮蔽体 ３……重水入口、４……中性子計測器 4a……ほう酸濃度測定器、4b……中性子測定器 ５……中性子源FIG. 1 shows a boric acid concentration meter for carrying out the method according to the invention. FIG. 2 shows an embodiment of neutrons in a boric acid concentration measuring instrument. FIG. 3 is an explanatory view of a second embodiment of the present invention. In the figure: 1... Measurement container 1a... (Borate concentration measurement device) container 1b... (Without neutron source) 2... Reflection and shield 3... Heavy water inlet 4... Neutron measurement device 4a …… Boric acid concentration measuring instrument, 4b …… Neutron measuring instrument 5 …… Neutron source
Claims (2)
するほう酸濃度測定器と、中性子源を有しないで中性子
計測器のみを備えた容器を共通の重水源と結び、ほう酸
濃度測定器側の中性子計数I1と、中性子源を有しない側
の容器での中性子計数I2とを求め、その差（I1−I2）を
求めることによって光中性子の補正をするようにしたこ
とを特徴とする重水炉におけるほう酸濃度測定器の光中
性子の影響除去方法。1. A boric acid concentration measuring device having a container provided with a neutron source and a neutron measuring device, and a container having only a neutron measuring device without a neutron source connected to a common heavy water source, wherein the neutron count I 1, obtains a neutron count I 2 in no side of the container a neutron source, that it has to be a correction of the optical neutrons by determining the difference (I 1 -I 2) Method for removing the influence of photoneutrons in a boric acid concentration meter in a heavy water reactor.
りにう酸濃度測定器測容器の中性子源を定期的に除いた
状態で中性子計測計数I2を求めるようにしたことを特徴
とする請求項１）記載の重水炉におけるほう酸濃度測定
器の光中性子の影響除去方法。And characterized in that so as to obtain the neutron measurement count I 2 in a state wherein the cormorants acid concentration measuring instrument measuring vessel neutron source instead of installing the container having no side neutron source was removed periodically The method for removing the influence of photoneutrons in a boric acid concentration measuring instrument in a heavy water reactor according to claim 1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63249936A JP2602302B2 (en) | 1988-10-05 | 1988-10-05 | A method for removing the effects of photoneutrons on a boric acid concentration meter in heavy water reactors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63249936A JP2602302B2 (en) | 1988-10-05 | 1988-10-05 | A method for removing the effects of photoneutrons on a boric acid concentration meter in heavy water reactors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0298694A JPH0298694A (en) | 1990-04-11 |
| JP2602302B2 true JP2602302B2 (en) | 1997-04-23 |
Family
ID=17200375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63249936A Expired - Lifetime JP2602302B2 (en) | 1988-10-05 | 1988-10-05 | A method for removing the effects of photoneutrons on a boric acid concentration meter in heavy water reactors |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2602302B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101903276B1 (en) * | 2017-03-09 | 2018-11-13 | 가천대학교 산학협력단 | Boron concentrations measuring system for correcting error and method using the same |
-
1988
- 1988-10-05 JP JP63249936A patent/JP2602302B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101903276B1 (en) * | 2017-03-09 | 2018-11-13 | 가천대학교 산학협력단 | Boron concentrations measuring system for correcting error and method using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0298694A (en) | 1990-04-11 |
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