JPH0341396A - Method and device for estimating burnup degree of failed nuclear fuel element - Google Patents
Method and device for estimating burnup degree of failed nuclear fuel elementInfo
- Publication number
- JPH0341396A JPH0341396A JP1175458A JP17545889A JPH0341396A JP H0341396 A JPH0341396 A JP H0341396A JP 1175458 A JP1175458 A JP 1175458A JP 17545889 A JP17545889 A JP 17545889A JP H0341396 A JPH0341396 A JP H0341396A
- Authority
- JP
- Japan
- Prior art keywords
- nuclear fuel
- fuel element
- inert gas
- amount
- released
- 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
- 239000003758 nuclear fuel Substances 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims description 21
- 239000011261 inert gas Substances 0.000 claims abstract description 35
- 239000000446 fuel Substances 0.000 claims abstract description 31
- 239000007789 gas Substances 0.000 claims abstract description 21
- 229910052743 krypton Inorganic materials 0.000 claims abstract description 9
- 230000004992 fission Effects 0.000 claims abstract description 8
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 claims abstract description 4
- DNNSSWSSYDEUBZ-AHCXROLUSA-N krypton-80 Chemical compound [80Kr] DNNSSWSSYDEUBZ-AHCXROLUSA-N 0.000 claims abstract description 3
- 230000005855 radiation Effects 0.000 claims description 18
- 238000005259 measurement Methods 0.000 claims description 13
- 238000001514 detection method Methods 0.000 claims description 7
- 238000005253 cladding Methods 0.000 claims description 5
- 230000002285 radioactive effect Effects 0.000 claims description 4
- 238000004949 mass spectrometry Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- CPELXLSAUQHCOX-OUBTZVSYSA-N bromine-81 Chemical compound [81BrH] CPELXLSAUQHCOX-OUBTZVSYSA-N 0.000 claims 1
- 238000007689 inspection Methods 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 description 13
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 230000000712 assembly Effects 0.000 description 6
- 238000000429 assembly Methods 0.000 description 6
- 230000000155 isotopic effect Effects 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000002826 coolant Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- 150000004678 hydrides Chemical class 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910001338 liquidmetal Inorganic materials 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052724 xenon Inorganic materials 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- -1 KrH are produced Chemical class 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005255 beta decay Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005264 electron capture Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004452 microanalysis Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000005025 nuclear technology Methods 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004441 surface measurement Methods 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-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)
Abstract
Description
【発明の詳細な説明】
〔発明の目的〕
（産業上の利用分野）
本発明は原子炉内における破損した核燃料要素の燃焼度
を推定する方法および装置に関する。DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION Field of Industrial Application The present invention relates to a method and apparatus for estimating the burn-up of a damaged nuclear fuel element in a nuclear reactor.
（従来の技ｗＩ）
原子炉内に多数本の燃料集合体が配列された炉心におい
て燃料集合体を構成する核燃料要素が破損した場合、そ
の破損した核燃料要素の属する燃料集合体が炉心内のど
の位置に配置されているものであるかを早期に特定し、
その燃料集合体の交換を早期に行うことは核分裂生成物
による冷却材および各機器の汚染を防止する上で重要な
ことである。また破損した燃料集合体の交換作業に伴う
作業員の放射線被曝の低減、さらに破損の伝播を防止す
る上でも極めて重要なことである。(Conventional technique wI) When a nuclear fuel element constituting a fuel assembly is damaged in a reactor core in which a large number of fuel assemblies are arranged, the fuel assembly to which the damaged nuclear fuel element belongs is located in which part of the reactor core. early identification of the location of the
It is important to replace the fuel assembly early in order to prevent contamination of the coolant and various equipment by fission products. It is also extremely important to reduce the radiation exposure of workers involved in replacing damaged fuel assemblies and to prevent the spread of damage.
従来、破損した核燃料要素の位置決めを行う手段として
はまず原子炉運転中または原子炉停止後に各々の燃料集
合体毎に近傍の冷却材をサンプリングし、そのサンプリ
ングした冷却材中の核分裂生成物の量を計測する方法が
知られている。また、それ以外の方法としては燃料集合
体を一体毎に炉心から取り出し、破損の有無を判定する
方法が知られている。Conventionally, the method for locating a damaged nuclear fuel element is to first sample the coolant in the vicinity of each fuel assembly during reactor operation or after reactor shutdown, and then determine the amount of fission products in the sampled coolant. There are known methods to measure In addition, as another method, a method is known in which each fuel assembly is taken out from the core and the presence or absence of damage is determined.
（発明が解決しようとする課題）
しかしながら、かかる方法では炉心内に数百本も装荷さ
れている燃料集合体を一体毎検査することになり、その
中から破損した核燃料要素を有する燃料集合体を特定す
ることは容易なことではなく、しかも特定するまでに多
大な労力と長時間を要するなどの課題があり、その課題
を解決することが要求されていた。(Problem to be Solved by the Invention) However, in this method, hundreds of fuel assemblies loaded in the reactor core must be inspected one by one, and fuel assemblies containing damaged nuclear fuel elements must be inspected. It is not easy to identify, and furthermore, there are problems such as requiring a great deal of effort and a long time to identify, and there has been a demand for a solution to this problem.
本発明は上記課題を解決するためになされたもので、破
損した核燃料要素を有する燃料集合体を特定するための
検査に要する時間および労力を大幅に低減させることが
可能な破損した核燃料要素の燃焼度を推定する方法およ
び装置、を提供することにある。The present invention has been made in order to solve the above-mentioned problems, and it is possible to burn a damaged nuclear fuel element by significantly reducing the time and labor required for inspection to identify a fuel assembly having a damaged nuclear fuel element. An object of the present invention is to provide a method and a device for estimating degree.
（課題を解決するための手段）
本発明は、核燃料物質を装填した長尺被覆管内に不活性
ガスを封入してなる核燃料要素に、前記不活性ガスの一
部としてＫｒ（クリプトン）の安定同位体である”Ｋｒ
（クリプトン８０）を封入して、前記核燃料要素の被覆
管の破損時にその破損した核燃料要素から放出されるｌ
１０Ｋｒの量と、原子炉内で前記核燃料要素を使用した
ことにより１１０Ｋｒが中性子とを吸収して生じた８１
Ｋｒの放出量とを測定し、それら”Ｋｒおよびｌ１０Ｋ
ｒの放出量の比から破損した核燃料要素の燃焼度を推定
する方法において、８ｆｉＫｒの放出量と原子炉内で前
記核燃料要素を使用したことにより燃料の核分裂生成物
として生じた１１５Ｋｒの放出量の比を質量分析法で測
定し、８″Ｋｒの放出量と、！１Ｋｒの放出量の比を各
々の放射線強度の測定により算出し、それらの結果から
”Ｋｒとｌ１０Ｋｒの放出量の比を算出することを特徴
とし、またこの方法を実現するため、破損した核燃料要
素から放出される不活性ガスを捕集するための不活性ガ
ス捕集装置と、捕集した不活性ガスに含まれる放射性ガ
スが崩壊するときに放出される放射線を検出するための
放射線検出装置と、捕集した不活性ガスをイオン化して
その質量対電荷比（ｍ／ｅ）を測定する質量分析型の不
活性ガス分析装置とから構成されることを特徴とする。(Means for Solving the Problems) The present invention provides a nuclear fuel element comprising an inert gas sealed in a long cladding tube loaded with nuclear fuel material, and a stable isotope of Kr (krypton) as part of the inert gas. "Kr" which is the body
(Krypton 80) is sealed and released from the broken nuclear fuel element when the cladding tube of the nuclear fuel element breaks.
10Kr and 110Kr absorbed neutrons due to the use of the nuclear fuel element in a nuclear reactor.81
The amount of Kr released was measured, and these "Kr and l10K"
In the method of estimating the burnup of a damaged nuclear fuel element from the ratio of the release amount of The ratio was measured by mass spectrometry, and the ratio between the amount of 8"Kr released and the amount of !1Kr released was calculated by measuring the radiation intensity of each. From these results, the ratio of the amount of release of ``Kr and 110Kr" was calculated. In order to realize this method, an inert gas collection device for collecting inert gas released from a damaged nuclear fuel element, and a radioactive gas contained in the collected inert gas are provided. A radiation detection device for detecting the radiation emitted when a substance decays, and a mass spectrometry-type inert gas analysis that ionizes the collected inert gas and measures its mass-to-charge ratio (m/e). It is characterized by being comprised of a device.
（作 用）
本発明では全ての核燃料要素に”Ｋｒを一定量以上封入
している。原子炉内では”Ｋｒ（ｎ。(Function) In the present invention, all nuclear fuel elements are encapsulated with a certain amount or more of Kr.
γ）ｌｌｌＫｒ反応で、 半減期２Ｉ万年の”Ｋｒが生
じる。γ) In the lllKr reaction, “Kr” with a half-life of 21 million years is produced.
核燃料要素に破損が発生した場合には封入したＫｒの安
定同位体がその破損箇所から核燃料要素の外に放出され
ることになる。この放出現象は極めて複雑であり、封入
量のうちどれだけの量が放出されるかを算出することは
困難である。しかしながら、 Ｋｒの同位体は化学的に
は同一の性質を示すために放出の割合は全ての同位体で
一定となり、よって２種の同位体の放出量の比はその時
点における核燃料要素内の同位体量の比と一致する。If a nuclear fuel element is damaged, the encapsulated stable isotope of Kr will be released from the damaged part to the outside of the nuclear fuel element. This release phenomenon is extremely complex, and it is difficult to calculate how much of the encapsulated amount is released. However, since the Kr isotopes exhibit chemically the same properties, the release rate is constant for all isotopes, and therefore the ratio of the release amounts of the two isotopes is determined by the isotopes in the nuclear fuel element at that time. Consistent with the ratio of body mass.
そこで、核燃料要素の破損時に放出される” Ｋｒと”
Ｋｒの量を測定し、その比から燃焼度を推定する。すな
わち、たとえば液体金属冷却の高速増殖炉の典型的な条
件下では、 ５サイクル（７４０Ｅ Ｆ Ｐ Ｄ） （
Ｅ Ｆ Ｐ Ｄ＝ Ｅｆｆｅｃｔｉｖｅ Ｆｕｌ、ｌ
ＰｏｗｅｒＤａｙ ＝ １００％換算運転日数）運転し
たときの”Ｋｒの生成量は核燃料要素当り約６ Ｘ １
０”−５Ｎ ａｎ３（ＯＲＩＧＥＮ −ｎによる計算結
果）である。”Ｋｒの生成量はさらに少ない。また、ガ
スプレナム部の中性子スペクトルでの”Ｋｒの（ｎ＋
γ）断面積は約３．４ｂａｒｎであり、５サイクル運転
で２〜３％の”Ｋｒが中性子を吸収し、１Ｋｒを生成す
る。Therefore, "Kr" is released when a nuclear fuel element breaks down.
The amount of Kr is measured and the burnup is estimated from the ratio. That is, for example, under typical conditions of a liquid metal cooled fast breeder reactor, 5 cycles (740E F P D) (
E F P D = Effective Ful, l
PowerDay = 100% conversion operation days) The amount of Kr produced during operation is approximately 6 x 1 per nuclear fuel element.
0"-5N an3 (calculation result by ORIGEN-n)."The amount of Kr produced is even smaller. In addition, the neutron spectrum of “Kr (n+
γ) The cross-sectional area is about 3.4 barn, and 2-3% of Kr absorbs neutrons and produces 1 Kr in 5-cycle operation.
従って、十分な量の”Ｋｒを封入しておけば、良い精度
で
（０） −ａ８ｏφｔ （０）
（０）Ｎｌｌｏ＝ＮＢｏｅミＮｌ１ｏ（ニーσＩ
１．φｔ） ＝ Ｎｓ。Therefore, if a sufficient amount of "Kr" is sealed, (0) -a8oφt (0)
(0) Nllo = NBoe mi Nl1o (knee σI
1. φt) = Ns.
（０） −σ８ｏφｔ −σ、１１φｔＮ８１ ＝
（ｆｆｓｏ／（（７ｓｔ ｆｆ５ｏ）） Ｎ５ｏ（
ｅ ｅ ）（０）
ミＮ８ｏσ８０φｔ
Ｎｇ１／ Ｎ！ｌ［ｌ ミσＢｏφｔ
ただし、 Ｎ８ｏは”Ｋｒの量、 Ｎ３□は１１１Ｋｒ
の量、σは中性子吸収断面積、 φは中性子束、ｔは時
刻である。(0) −σ8oφt −σ, 11φtN81 =
(ffso/((7st ff5o)) N5o(
e e ) (0) Mi N8oσ80φt Ng1/ N! l[l MiσBoφt However, N8o is the amount of Kr, N3□ is 111Kr
, σ is the neutron absorption cross section, φ is the neutron flux, and t is the time.
”Ｋｒの初期封入量に依らず、８１Ｋｒと”Ｋｒの放出
量の比はσ８ｏφｔ、すなわち運転時間のみで決定され
る。従って、８１Ｋｒと８０Ｋｒの放出量の比を測定す
ることにより、破損した核燃料要素の原子炉内での使用
時間が計算可能であり、その燃焼度を推定することが可
能である。Regardless of the initial amount of Kr enclosed, the ratio between the amount of 81Kr and the amount of Kr released is determined only by σ8oφt, that is, the operating time. Therefore, by measuring the ratio of the released amounts of 81 Kr and 80 Kr, it is possible to calculate the usage time of a damaged nuclear fuel element in the reactor, and it is possible to estimate its burnup.
このため、破損した核燃料要素から放出される８１Ｋｒ
、 ！。Ｋｒ等を含むガスを捕集し、ガス中のクリプト
ンの同位体組成を測定することにより、”’Ｋｒと”Ｋ
ｒの放出量の比を算出する。For this reason, the 81Kr released from the damaged nuclear fuel element
, ! . By collecting gas containing Kr etc. and measuring the isotopic composition of krypton in the gas, we can
Calculate the ratio of the released amounts of r.
ここで、 Ｋｒの同位体組成の測定は質量分析計で行う
のが通例であり、文献（Ｃ，Ａ、 ５ｔｒａｎｄ ａｎ
ｄ−
Ｒ，Ｅ、５ｃｈｅｎｔｅｒ、Ｎｕｃｌｅａｒ Ｔｅｃｈ
ｎｏｌｏｇｙ、 Ｖｏｌ、２６（１９７５）、 ｐｐ
４７２〜４７９参照）に示すとおり、 ラギング法に
おけるＫｒおよびＸｅ（キセノン）の同位体組成の測定
も質量分析計で行われている。このラギング法では、Ｋ
ｒの同位体組成の測定は７１′Ｋｒ。Here, the isotopic composition of Kr is usually measured using a mass spectrometer, and is described in the literature (C, A, 5 tran and
d- R, E, 5center, Nuclear Tech
Nology, Vol. 26 (1975), pp.
472-479), the isotopic compositions of Kr and Xe (xenon) in the lagging method are also measured using a mass spectrometer. In this lagging method, K
The isotopic composition of r was determined to be 71'Kr.
”Ｋｒ、”Ｋｒの３種種について行われるが、本発明で
は”Ｋｒと１１１Ｋｒについて行う必要がある。The test is carried out for three types: "Kr" and "Kr", but in the present invention, it is necessary to carry out the test for "Kr" and 111Kr.
８１Ｋｒの測定では、前記のとおりその相対組成が”Ｋ
ｒの最大数％（前記では、 ５サイクル運転で２〜３％
）であり、給体量が少ないため測定が難しい。また、ラ
ギング法では測定核種の質量数が７８、８０．８２であ
り、質量数に２ずつの隔たりがあるので測定ピークの分
離が完全に行われるとともに、不純物水素によって生成
される水素化物（７１１ＫｒＨ２！。ＫｒＨ，”ＫｒＨ
）の影響を受けないが、１Ｋｒの測定では、多量に存在
する″。Ｋｒの水素化物（”ＫｒＨ，質量数が８１であ
り”Ｋｒの質量数に等しい）の影響を受けやすい。In the measurement of 81Kr, as mentioned above, its relative composition is "Kr".
Maximum several % of r (in the above, 2 to 3% for 5 cycle operation)
), which is difficult to measure due to the small amount of food being fed. In addition, in the lagging method, the mass numbers of the measured nuclides are 78 and 80.82, and since there is a gap of 2 in the mass numbers, the measurement peaks can be completely separated, and the hydride (711KrH2 !.KrH,”KrH
), but in the measurement of 1Kr, it is easily affected by Kr hydride (KrH, whose mass number is 81 and is equal to the mass number of Kr), which is present in large quantities.
以上の理由により、多量の”Ｋｒと少量の”Ｋｒを質量
分析計により測定することは適切とは言えず、他の方法
より測定する必要があった。For the above reasons, it is not appropriate to measure "a large amount of Kr and a small amount" of Kr using a mass spectrometer, and it has been necessary to use other methods for measurement.
他の微量分析の方法として、１Ｋｒが放射性核種である
ことに着目し、その放射線強度を測定することによって
定量を行う方法がある。しかしながら、”Ｋｒは非放射
性であり、質量分析計で定量せざるを得す、面測定値を
較正する必要が生じた。Another method for microanalysis is a method that focuses on the fact that 1Kr is a radionuclide and performs quantification by measuring its radiation intensity. However, since Kr is non-radioactive, it had to be quantified using a mass spectrometer, making it necessary to calibrate surface measurements.
（実施例）
本発明の第工番目の発明は、上記の問題点を解決すべく
、放射性核種として燃料の核分裂により核分裂生成物と
して多量に生じる６″’Ｋｒ（半減期１０．７年）を使
用するものである。すなわち、ｌ１ＳＫｒは核分裂によ
り多量に生成されるため、質量分析計を使用して精度良
く′″５Ｋｒと！″′Ｋｒの被分析ガス中の相対組成を
求めることができる。また、”Ｋｒは放射性であるため
、その放射線強度を測定することにより、精度良＜ ８
１Ｋｒと”Ｋｒの被分析ガス中の相対組成を求めること
ができる。(Example) In order to solve the above-mentioned problems, the first invention of the present invention uses 6″Kr (half-life: 10.7 years), which is produced in large quantities as a fission product during nuclear fission of fuel, as a radionuclide. In other words, since 11SKr is produced in large quantities through nuclear fission, a mass spectrometer is used to accurately determine ``5Kr!'' It is possible to determine the relative composition of Kr in the gas to be analyzed.Also, since Kr is radioactive, by measuring its radiation intensity, it is possible to obtain accurate < 8.
The relative composition of 1Kr and ``Kr'' in the gas to be analyzed can be determined.
従って、両者の結果から、”Ｋｒと”Ｋｒの被分析ガス
中の相対組成を精度良く算出することが可能である。Therefore, from both results, it is possible to accurately calculate the relative composition of "Kr" and "Kr" in the gas to be analyzed.
ここで、放射線強度の測定は、”Ｋｒについてはその崩
壊時に放出される５１４ ＫｅＶのガンマ−線を、”Ｋ
ｒについては２７６ＫｅＶのガンマ−線または軌道電子
捕獲によって生じる１１１Ｂｒのにエックス線（１２Ｋ
ｅ Ｖ ）をエネルギー分解計数することにより、被
分析ガス中に含まれる他の放射性核種等によるバックグ
ラウンドの影響を軽減でき、精度の高い測定が可能とな
る。Here, the measurement of radiation intensity is based on the measurement of 514 KeV gamma rays emitted during the decay of Kr.
For r, 276KeV gamma rays or 111Br X-rays (12K
By energy-resolved counting of e V ), it is possible to reduce the background influence caused by other radionuclides contained in the gas to be analyzed, and it is possible to perform highly accurate measurements.
次に、８１Ｋｒと”Ｋｒの放出量の比から運転時間すな
わち燃焼度を推定する方法について第１図を参照して説
明する。第１図は横軸に運転時間をとり、縦軸に”Ｋｒ
と”Ｋｒの封入量の比をとり、封入量の比の時間変化を
示した図である。封入量の比の時間変化は前記のとおり
Ｎ！１１（ｔ） ／ Ｎｅｏ（ｔ） ａσｌｌｏ・φ・
ｔとなり、炉内での使用時間（１）に比例する値となる
。したがって、まず放出量の比を測定し、この放出量の
比がその時点における封入量の比に等しいことを使用す
ると、その放出量の比から運転時間を推定することがで
きる。Next, a method for estimating the operating time, that is, burnup, from the ratio of the amount of 81Kr released and the amount of "Kr" released will be explained with reference to FIG. 1. In FIG.
This is a diagram showing the time change in the ratio of the enclosed amounts of Kr and Kr.The time change in the ratio of the enclosed amounts is as described above N!11(t) / Neo(t) aσllo・φ・
t, which is a value proportional to the usage time (1) in the furnace. Therefore, by first measuring the ratio of released amounts and using the fact that this ratio of released amounts is equal to the ratio of enclosed amounts at that time, it is possible to estimate the operating time from the ratio of released amounts.
高速増殖炉の燃料は例えば３年間炉内で使用され、工年
毎に全燃料集合体の１７３ずつが交換される。したがっ
て、全燃料はその交換時期により３つのグループに分け
られる。よって、本実施例のように核燃料要素内に予め
”Ｋｒを封入しておき、核燃料要素が破損したときに”
Ｋｒと”Ｋｒの放出量の比を測定することにより、該測
定結果から被覆管の破損した核燃料要素の運転時間を推
定し、この推定した運転時間からその核燃料要素を含む
グループを特定することができる。これによって全燃料
の中から１／３を特定することができ、以後はこの１／
３の中から破損燃料の特定を行えばよく、従来に比べて
簡単に前記核燃料要素を有する燃料集合体を特定するこ
とが可能となる。The fuel of a fast breeder reactor is used in the reactor for, for example, three years, and 173 of the total fuel assemblies are replaced every year. Therefore, all fuels are divided into three groups depending on their replacement period. Therefore, as in this example, Kr is sealed in the nuclear fuel element in advance, and when the nuclear fuel element is damaged,
By measuring the ratio of Kr and Kr emissions, the operating time of a nuclear fuel element with a damaged cladding can be estimated from the measurement results, and the group containing the nuclear fuel element can be identified from this estimated operating time. This allows us to identify 1/3 of the total fuel, and from now on we will focus on this 1/3.
It is only necessary to specify the damaged fuel from among the three, and it becomes possible to specify the fuel assembly having the nuclear fuel element more easily than in the past.
本発明の第２番目の発明は、前記方法を実施するために
使用する装置であり、その実施例を第２図および第３図
を参照して説明する。The second aspect of the present invention is an apparatus used to carry out the method, and an embodiment thereof will be described with reference to FIGS. 2 and 3.
第２図において、１は液体金属冷却形高速増殖１１
炉の原子炉容器、２は炉心、３は液体ナトリウム等の冷
却材、４はアルゴンガス等のカバーガス、５はしやへい
プラグを示す。また、上記炉心２には図示していない燃
料集合体および炉心構造物が設置されており、各燃料集
合体を構成する核燃料要素には”Ｋｒを含む不活性ガス
が封入されている。また、６は上記カバーガス４を炉外
に導くガス配管、７はポンプ、８は仕切弁であり、これ
らは−次アルゴンガス循環系９を構成している。In Fig. 2, 1 is the reactor vessel of the liquid metal cooled fast breeder 11 reactor, 2 is the reactor core, 3 is a coolant such as liquid sodium, 4 is a cover gas such as argon gas, and 5 is a cold plug. . Further, fuel assemblies and core structures (not shown) are installed in the reactor core 2, and the nuclear fuel elements constituting each fuel assembly are filled with an inert gas containing Kr. Reference numeral 6 designates a gas pipe that guides the cover gas 4 to the outside of the furnace, 7 a pump, and 8 a gate valve, which constitute a secondary argon gas circulation system 9.
次アルゴンガス循環系９と並列に燃料破損検知器ｌＯが
設けられている。この検知器１０は、破損した燃料集合
体からカバーガス４中に放出される気体状核分裂生成物
を検出することにより、燃料集合体が破損したか否かを
判別するものである。また、１１は破損した核燃料要素
の燃焼度を推定する装置であり、 Ｋｒガス等の不活性
ガスを捕集する不活性ガス捕集装置１２と不活性ガス分
析装置１３および図示されていない放射線検出装置とか
ら構成されている。１４は仕切弁である。第３図は破損
した核燃料要素の燃焼度を推定する装置１１を拡大して
示ｚ
したものであり、本図には放射線検出装置■５が示され
ている。A fuel failure detector lO is provided in parallel with the secondary argon gas circulation system 9. This detector 10 determines whether or not a fuel assembly is damaged by detecting gaseous fission products released into the cover gas 4 from the damaged fuel assembly. Further, 11 is a device for estimating the burnup of a damaged nuclear fuel element, an inert gas collection device 12 for collecting inert gas such as Kr gas, an inert gas analyzer 13, and a radiation detection device (not shown). It consists of a device. 14 is a gate valve. FIG. 3 shows an enlarged view of the device 11 for estimating the burnup of a damaged nuclear fuel element, and the radiation detection device 5 is shown in this figure.
以上のように構成された破損集合体の燃焼度を推定する
装置］１は、燃料破損検知器１０による破損の検知後に
起動される。本破損の検知は、ポンプ７により連続的に
サンプリングされるカバーガス４中の放射能濃度を監視
することにより、通常行われる。破損が検知されると仕
切弁１４を開とし、不活性ガス捕集装置１２により破損
した核燃料要素から放出された”Ｋｒ、 ！１Ｋｒ、
ＳＫｒ等を含む不活性ガスを数時間にわたり捕集す
る。不活性ガス捕集装置Ｉ２は、一般には活性炭深冷装
置が使用され、低温に保持された活性炭により多量の不
活性ガスを吸着する。不活性ガスの捕集が終了すると、
仕切弁１４を閉とし、不活性ガス捕集袋［１１２を昇温
することにより、捕集された不活性ガスの再放出を行う
。不活性ガス分析装置１３は再放出された不活性ガスを
取り込み、その同位体組成を測定する。The apparatus for estimating the burnup of a damaged assembly configured as described above] 1 is activated after the fuel damage detector 10 detects damage. Detection of this damage is normally performed by monitoring the radioactivity concentration in the cover gas 4 that is continuously sampled by the pump 7. When damage is detected, the gate valve 14 is opened, and the inert gas collection device 12 detects "Kr, !1Kr," released from the damaged nuclear fuel element.
Inert gas containing SKr etc. is collected for several hours. The inert gas collection device I2 generally uses an activated carbon deep cooling device, and adsorbs a large amount of inert gas by the activated carbon kept at a low temperature. Once the collection of inert gas is completed,
By closing the gate valve 14 and raising the temperature of the inert gas collection bag [112], the collected inert gas is released again. The inert gas analyzer 13 takes in the re-released inert gas and measures its isotopic composition.
従来は、不活性ガス分析装置１３として質量分析計を使
用し、被測定ガスの同位体組成を測定していた。ところ
が、前記のように、本発明が解決しようとする測定の条
件では、”Ｋｒが多量に存在し、被測定ガス中の水素を
含んだ不純物により！。ＫｒＨ等の水素化物が生成され
、少量の”Ｋｒの測定を著しく困難としていた。また、
さらに多量に存在するｌＩ２Ｋｒの測定の影響を受ける
可能性があった。Conventionally, a mass spectrometer has been used as the inert gas analyzer 13 to measure the isotopic composition of the gas to be measured. However, as mentioned above, under the measurement conditions to be solved by the present invention, ``a large amount of Kr exists, and due to impurities containing hydrogen in the gas to be measured!'', hydrides such as KrH are produced, and a small amount of Kr is present. This made it extremely difficult to measure Kr. Also,
Furthermore, there was a possibility that the measurement would be affected by the measurement of lI2Kr, which is present in large amounts.
本発明では、ゲルマニウム検出器等の高分解能の半導体
検出器を放射線検出装置１５として使用し、捕集された
不活性ガスの放射線をエネルギー分解して測定し、１Ｋ
ｒとｌｌ５Ｋｒの組成比を求め、次に質量分析計を使用
した不活性ガス分析装置１３によるｌｌ５Ｋｒと”Ｋｒ
の組成比を求め、その両組酸比から１１１Ｋｒと”Ｋｒ
の組成比すなわち放出量の比を求めることにより、破損
した核燃料要素の燃焼度を推定する装置を提供する。In the present invention, a high-resolution semiconductor detector such as a germanium detector is used as the radiation detection device 15, and the radiation of the collected inert gas is energy-resolved and measured.
The composition ratio of r and ll5Kr is determined, and then ll5Kr and "Kr" are determined by the inert gas analyzer 13 using a mass spectrometer.
111Kr and "Kr
Provided is an apparatus for estimating the burnup of a damaged nuclear fuel element by determining the composition ratio, that is, the ratio of the emitted amount.
＋１５Ｋｒは半減期１０．７年でβ崩壊し、 その崩壊
に伴ない５１４ ＫｅＶのエネルギーのガンマ−線を１
００崩壊あたり０．４１箇放出する（分岐比０．４１％
）。+15Kr undergoes β-decay with a half-life of 10.7 years, and as a result of this decay, a gamma ray with an energy of 514 KeV is emitted by 1
0.41 units are released per 00 decay (branching ratio 0.41%
).
また、”Ｋｒは軌道電子捕獲により半減期２１万年で崩
壊し、２７６ＫｅＶのガンマ−線を１００崩壊あたり３
．６箇放出する（分岐比３．６％）。従って、半導体検
出器等を使用して両ガンマー線を計数し、検出器の効率
、不活性ガス捕集装置１２内での減衰等を補正すること
により、！１Ｋｒと”Ｋｒの捕集ガス中の組成比を求め
ることができる。また、Ｂ１Ｋｒは軌道電子捕獲に伴い
、１２ Ｋ ｅ Ｖのエックス線（８１Ｂｒのにエック
ス線）を放出するので、”Ｋｒの放射線強度の測定とし
て、 このＸ線を計数することも可能である。In addition, ``Kr decays with a half-life of 210,000 years due to orbital electron capture, and emits 276 KeV gamma rays at 3 times per 100 decays.
．． 6 parts are released (branching ratio 3.6%). Therefore, by counting both gamma rays using a semiconductor detector or the like and correcting the efficiency of the detector, attenuation within the inert gas collection device 12, etc.,! The composition ratio of 1Kr and ``Kr'' in the collected gas can be determined. Also, since B1Kr emits 12 K e V X-rays (X-rays of 81Br) as it captures orbital electrons, the radiation intensity of ``Kr'' can be determined. It is also possible to count these X-rays to measure .
以上本実施例によると、破損した核燃料要素を有する燃
料集合体を特定するに要する時間を大幅に短縮させるこ
とができるとともに、それに要する労力を軽減させるこ
とができ、また作業員の被曝低減をも図ることが可能と
なる。As described above, according to this embodiment, the time required to identify a fuel assembly having a damaged nuclear fuel element can be significantly shortened, the labor required for this can be reduced, and the radiation exposure of workers can also be reduced. It becomes possible to achieve this goal.
本発明によれば核燃料要素の破損時にその核燃料要素を
有する燃料集合体を速やかに特定することが可能となり
、破損燃料の早期発見それによ１５
る二次災害の防止を効果的に図ることができ安全性を大
幅に向上させることが可能となる。また、検査作業に要
する時間の短縮および労力の軽減により作業員の被曝低
減を図ることができる。According to the present invention, when a nuclear fuel element is damaged, it is possible to quickly identify the fuel assembly containing the nuclear fuel element, and the damaged fuel can be detected early, thereby effectively preventing secondary disasters. It becomes possible to significantly improve safety. Furthermore, it is possible to reduce the exposure of workers to radiation by shortening the time and labor required for inspection work.
Claims (5)
を封入してなる核燃料要素に、前記不活性ガスの一部と
してＫｒ（クリプトン）の安定同位体である＾８＾０Ｋ
ｒ（クリプトン８０）を封入し、前記核燃料要素の被覆
管の破損時にその破損した核燃料要素から放出される＾
８＾０Ｋｒの量と、原子炉内で前記核燃料要素を使用し
たことにより＾８＾０Ｋｒが中性子を吸収して生じた＾
８＾１Ｋｒの放出量とを測定し、それら＾８＾１Ｋｒお
よび＾８＾０Ｋｒの放出量の比から破損した核燃料要素
の燃焼度を推定する方法において、＾８＾０Ｋｒの放出
量と原子炉内で前記核燃料要素を使用したことにより燃
料の核分裂生成物として生じた＾８＾５Ｋｒの放出量の
比を質量分析法で測定し、＾８＾５Ｋｒの放出量と＾８
＾１Ｋｒの放出量の比を各々の放射線強度により測定し
、それらの結果から＾８＾１Ｋｒと＾８＾０Ｋｒの放出
量の比を算出することを特徴とした破損した核燃料要素
の燃焼度を推定する方法。(1) A nuclear fuel element consisting of a long cladding tube filled with nuclear fuel material and sealed with an inert gas contains a stable isotope of Kr (krypton) as part of the inert gas.
r (krypton 80) is enclosed and released from the damaged nuclear fuel element when the cladding tube of the nuclear fuel element breaks.
Due to the amount of 8^0 Kr and the use of the nuclear fuel element in the reactor, 8^0 Kr was produced by absorbing neutrons.
In the method of estimating the burnup of a damaged nuclear fuel element from the ratio of the released amounts of ^8^1 Kr and ^8^0 Kr, the release amount of ^8^1 Kr and the reactor The ratio of the amount of ^8^5Kr released as a fission product of the fuel by using the above nuclear fuel element was measured by mass spectrometry, and the ratio of the amount of released ^8^5Kr to the amount of ^8
The burnup of a damaged nuclear fuel element is measured by measuring the ratio of the emitted amount of ^1Kr by each radiation intensity, and calculating the ratio of the emitted amount of ^8^1Kr and ^8^0Kr from the results. How to estimate.
きに放出される５１４ＫｅＶのガンマー線および＾８＾
１Ｋｒが崩壊するときに放出される２７６ＫｅＶのガン
マー線を計数することにより行う請求項１記載の破損し
た核燃料要素の燃焼度を推定する方法。(2) Measurement of radiation intensity uses 514 KeV gamma rays and ^8^ emitted when ^8^5Kr decays.
2. The method for estimating burnup of a damaged nuclear fuel element according to claim 1, which is carried out by counting 276 KeV gamma rays emitted when 1Kr decays.
きに放出される５１４ＫｅＶのガンマー線および＾８＾
１Ｋｒが崩壊するときに放出される＾８＾１Ｂｒ（臭素
８１）のＫエックス線（１２ＫｅＶ）を計数することに
より行う請求項１記載の破損した核燃料要素の燃焼度を
推定する方法。(3) Measurement of radiation intensity uses 514 KeV gamma rays and ^8^ emitted when ^8^5Kr decays.
2. The method for estimating burnup of a damaged nuclear fuel element according to claim 1, which is carried out by counting K-X-rays (12 KeV) of ^8^1Br (bromine 81) released when 1Kr decays.
捕集するための不活性ガス捕集装置と、捕集した不活性
ガスに含まれる放射性ガスが崩壊するときに放出される
放射線を検出するための放射線検出装置と、捕集した不
活性ガスをイオン化してその質量対電荷比（ｍ／ｅ）を
測定する質量分析型の不活性ガス分析装置とから構成さ
れることを特徴とする破損した核燃料要素の燃焼度を推
定する装置。(4) An inert gas collection device for collecting inert gas released from damaged nuclear fuel elements and detecting the radiation released when the radioactive gas contained in the collected inert gas decays. and a mass spectrometry-type inert gas analyzer that ionizes the collected inert gas and measures its mass-to-charge ratio (m/e). A device for estimating the burn-up of damaged nuclear fuel elements.
計数するエネルギー分解型の放射線検出装置である請求
項４記載の破損した核燃料要素の燃焼度を推定する装置
。(5) The device for estimating burnup of a damaged nuclear fuel element according to claim 4, wherein the radiation detection device is an energy-resolving type radiation detection device that counts gamma rays and X-rays.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1175458A JPH0341396A (en) | 1989-07-10 | 1989-07-10 | Method and device for estimating burnup degree of failed nuclear fuel element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1175458A JPH0341396A (en) | 1989-07-10 | 1989-07-10 | Method and device for estimating burnup degree of failed nuclear fuel element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0341396A true JPH0341396A (en) | 1991-02-21 |
Family
ID=15996422
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1175458A Pending JPH0341396A (en) | 1989-07-10 | 1989-07-10 | Method and device for estimating burnup degree of failed nuclear fuel element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0341396A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2858103A1 (en) * | 2003-07-25 | 2005-01-28 | Framatome Anp | Estimating number of fuel rods with seal failure in nuclear reactor comprises calculations based on release of fission products |
| JP2011021923A (en) * | 2009-07-14 | 2011-02-03 | Japan Atomic Energy Agency | Method for measuring neutron irradiation amount and method for detecting nuclear fuel failure |
-
1989
- 1989-07-10 JP JP1175458A patent/JPH0341396A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2858103A1 (en) * | 2003-07-25 | 2005-01-28 | Framatome Anp | Estimating number of fuel rods with seal failure in nuclear reactor comprises calculations based on release of fission products |
| JP2011021923A (en) * | 2009-07-14 | 2011-02-03 | Japan Atomic Energy Agency | Method for measuring neutron irradiation amount and method for detecting nuclear fuel failure |
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