JP3468903B2 - Thermocouple type water level monitor - Google Patents
Thermocouple type water level monitorInfo
- Publication number
- JP3468903B2 JP3468903B2 JP02171095A JP2171095A JP3468903B2 JP 3468903 B2 JP3468903 B2 JP 3468903B2 JP 02171095 A JP02171095 A JP 02171095A JP 2171095 A JP2171095 A JP 2171095A JP 3468903 B2 JP3468903 B2 JP 3468903B2
- Authority
- JP
- Japan
- Prior art keywords
- water level
- level detector
- hot junction
- water
- thermocouple
- 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
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、一般に、液体容器内の
液位の監視装置に関し、特に、加圧水型原子炉容器の炉
心上方にある上部プレナム内の水位（通常運転時は満
水）の監視に適する熱電対式水位監視装置に関するもの
である。
【０００２】
【従来の技術】図４は、従来の加圧水型原子炉の代表的
な一例を総括的に符号１０で示すもので、同原子炉１０
は、原子炉容器１１、その内部にある炉心１２、該炉心
１２を構成する多数の燃料集合体１３等を有する。同燃
料集合体１３における核分裂により発生した熱を取り出
すため、給水は、入口ノズル１４から原子炉容器１１内
に入って底部で反転し、燃料集合体１３の周囲及び内部
を上方に流れて、出口ノズル１５から出て図示しない蒸
気発生器に向かう。
【０００３】この給水は、原子炉容器１１内では、通
常、自由液面を形成することなく、炉心上方の原子炉容
器蓋１２ａ直下部を含む上部プレナム１６全体に充満さ
れて、前述のように循環して流れている。給水を循環さ
せるため上記入口ノズル１４、出口ノズル１５等に流体
連絡した循環水系即ち一次冷却系に配管破断等が発生し
たと仮定すると、水は、同破断箇所を経て原子炉１０か
ら放出される。この放出による水位１７の形成及びその
低下は、原子炉容器蓋１２ａを貫いて上部プレナム１６
内に垂下する水位計１８により監視されている。
【０００４】同水位計１８は、加熱型熱電対式と一般に
呼ばれているもので、図５に詳細に示すように、下端を
閉塞した検出器被覆管１８ａ内に絶縁材１８ｊと共にク
ロメル線１８ｃ及びアルメル線１８ｅがそれぞれ温接点
１８ｆ、冷接点１８ｇをつくるように配線されている。
また、温接点１８ｆを囲繞するように円筒体１８ｍが被
覆管１８ａ内に設けられており、その周面に、リード線
１８ｉに接続された発熱線１８ｈがコイル状に巻回され
ている。温接点１８ｆの周辺の被覆管１８ａの部分の外
側には、水の出入り口１８ｂを上下端近くに有する保護
筒１８ｋが設けられている。上述した保護筒１８ｋに類
似するものを有する水位監視装置は、例えば実公平０３
ー００１７６８号公報に開示されている。
【０００５】この水位計１８は、温接点１８ｆより上方
に水位が達している場合には、温接点１８ｆの周囲と冷
接点１８ｇの周囲との間の温度差が実質的になく、原子
炉容器１１内に水が存在すると判定するが、温接点１８
ｆより下方に水位が存在する場合には、温接点１８ｆ領
域での被覆管１８ａの外側雰囲気が気体になることか
ら、温接点１８ｆの周囲に配設された発熱線１８ｈによ
る加熱熱量の被覆管１８ａを介する除熱が低下して、冷
接点１８ｇとの間に温度差を発生し、この温度差が設定
値に達したとき、水が存在しないと判定するものであ
る。
【０００６】このような加熱型熱電対式水位計では、温
接点１８ｆの周辺の被覆管１８ａの表面が水没している
か否かによって、温度差出力が異なるものであるが、上
述の保護筒１８ｋが設けられていないと、被覆管表面が
気体に露出している場合でも、同表面に何等かの原因に
より水滴が付着すると、一時的に温度差出力が小さくな
り、その結果、水が存在すると誤認する可能性がある。
また、水位が徐々に低下していく過程でも、上述の保護
筒１８ｋが設けられていないと、水位計の上方に付着し
残留する水が検出部領域に垂れ落ちてきたり、水中の気
泡が弾けて水滴が検出部領域に飛散することにより、上
述したような誤認を起こす可能性があり、かかる可能性
のない信号が認識されるまでには、長時間が必要であり
応答性が悪くなる。このような事態は、複数の水位計を
束にして多点の水位検出を行う場合に多く経験されるこ
とであり、保護筒１８ｋを設けることによって、上述の
事態を回避することができる。
【０００７】
【発明が解決しようとする課題】上の説明から了解され
るように、保護筒１８ｋは、水位が低下する場合に、そ
れよりも遅れて落下してくる付着残留水の影響を無くし
たり、水滴の飛散を防止したりするために設けられてい
るが、保護筒１８ｋと被覆管１８ａとの間の環状の隙間
は、水の表面張力によって水滴が同隙間に保持されない
ような半径方向の寸法が必要なため、また、発熱線１８
ｈは、温接点１８ｆを取り囲む円筒体１８ｍの周面にコ
イル状に巻回されているため、水位計全体（１８ｋ部）
の直径は約１０ｍｍ以上とならざるを得なかった。
【０００８】更に、現在稼働中の加圧水型原子炉プラン
トに上述したような水位計を設置すれば、事故時の確実
な運転操作の一助となり、安全性の向上に寄与しうる
が、既設プラントの原子炉容器蓋では、前述したように
直径が約１０ｍｍ以上になる水位計を挿入できる貫通穴
の直径が約３５ｍｍと小さいため、高々３本という僅か
な本数しか挿入することができず、多点検出の利点が損
なわれる。また、各水位計は個別に取り替えできないた
め取り替え時には放射性廃棄物の量が多くなる。
【０００９】従って、本発明の目的は、応答性の悪化
や、水滴の飛散による水位の誤認等が生ずることなく、
既設プラントの貫通穴に多数本容易に設置可能で、各水
位計を個別に保守、取り替えが可能な熱電対式水位監視
装置を提供することである。
【００１０】
【課題を解決するための手段】上述の目的を達成するた
め、本発明によると、熱電対式水位監視装置は、内外間
に流体連通する収納管と、該収納管内に収納される複数
の水位検出器案内管と、該水位検出器案内管の各々の内
部に挿通される水位検出器とを備えている。該水位検出
器は、長手方向に離間した冷接点及び温接点を形成する
よう接続された異種金属材料からなる熱電対と、該熱電
対の前記温接点に隣接して設けられた発熱線とを含む。
この水位監視装置において、水位検出器案内管の各々
は、各水位検出器の温接点より上方の部位で、同水位検
出器案内管の周壁に液密に嵌合する滴下防止板により収
納管に支持され、各発熱線は、各水位検出器案内管内の
熱電対の温接点の近傍で同水位検出器案内管の軸線方向
に少なくとも１回往復して延びており、また、前記収納
管はその下端部に気泡分離部を介して端栓を有し、前記
気泡分離部は筒状の横流れ防止部と当該流れ防止部材の
内部に設けられた気泡混入防止部からなり、前記筒状の
流れ防止部にはその上方部位に複数の連通穴が下方部位
に複数の排水穴が、また前記気泡混入防止部には、その
上方部位に複数の気泡混入防止小径穴が、下方部位に複
数の排水穴がそれぞれ設けられている。
【００１１】
【作用】水位が温接点以上まであれば、温接点が発熱線
により加熱されていても、熱電対の水中又は気中にある
冷接点と水中にある温接点との間には実質的に温度差が
生じないため、水位検出器は水が存在すると判定する。
水位が徐々に低下して温接点領域よりも下がると、冷接
点及び温接点間に温度差が生じて、熱電対は水位低下を
知らせる出力を出す。発熱線はコイル状ではなく軸線方
向に往復延在しているため、水位検出器は小径（実施例
では２〜３ｍｍ）である。
【００１２】このような水位低下の過程で、水面が収納
管の周面に沿って低下していくため、水面より上の周面
部分には水滴が付着するが、収納管には、水位検出器案
内管に対して液密に、少なくとも温接点を含む検出部領
域の上方位置に、滴下防止板が設けられているため、水
滴は検出部領域までは滴下しない。各滴下防止板の下方
で水位検出器案内管の周面に水滴が付着しても、滴下防
止板と検出部領域との間の距離は僅か（実施例では数１
０ｍｍ）であるから、数秒後には落下し、応答遅れは実
質的にない。
【００１３】また、収納管の下端部には流体連通する気
泡混入防止小径穴を備えた気泡分離部があるため、水中
に気泡があっても、この気泡は収納管内までは入らず、
水位低下の過程で水中の気泡が弾けて水滴が飛散して
も、検出部領域には達しない。
【００１４】
【実施例】次に、本発明による水位監視装置の好適な実
施例について添付図面を参照して詳細に説明するが、図
中、同一符号は同一又は対応部分を示すものとする。
【００１５】図１は、本発明の水位監視装置を総括的に
符号１で示すもので、同水位監視装置１は、細長い筒状
の収納管２を備え、その下端には気泡分離部３を介して
端栓４が溶接により取り付けられている。気泡分離部３
は、収納管外部の水中に多数の気泡が存在する状態でも
その侵入を防止するように、横流れ防止部３ａと気泡混
入防止部３ｂとからなり、横流れ防止部３ａには、その
上方部位に複数の連通穴３ａａが、下方部位に複数の排
水穴３ａｂが、気泡混入防止部３ｂには、その上方部位
に複数の気泡混入防止小径穴３ｂａが、下方部位に複数
の排水穴３ｂｂがそれぞれ穿設されている。
【００１６】上述した各種の穴の数は、収納管２の外部
の水位が変化したときに収納管内部の水位が所要の速さ
で応答するように決めればよく、また、気泡混入防止部
３ｂにある気泡混入防止小径穴３ｂａの直径は１〜２ｍ
ｍ程度であることが好ましい。この気泡混入防止小径穴
３ｂａによって、水中の気泡の体積率即ちボイド率が５
０％以下の状態なら、気泡が収納管内に混入しないこと
が実験で確認された。さらに、収納管２の外側にその軸
心に垂直な方向の流れ（横流れ）が存在するときに、こ
の流れにより気泡が横流れ防止部３ａ及び気泡混入防止
部３ｂを経て収納管内に押し込まれないように、横流れ
防止部３ａにある連通穴３ａａ及び排水穴３ａｂは、気
泡混入防止部３ｂにある気泡混入防止小径穴３ｂａ及び
排水穴３ｂｂと半径方向に整列しない位置に設けられて
いる。
【００１７】収納管２内には、ポジショナ（滴下防止
板）５により水位検出器案内管６が垂直に支持されてい
る。図示の実施例では、図２から了解されるように、６
本の案内管６が互いに離間してポジショナ５に液密に嵌
合して設けられており、これ等の案内管６内に、高さ方
向における位置をそれぞれ異にして、６本の水位検出器
７が挿通されている。円板状の仕切板であるポジショナ
５は、ピン８を介して収納管２により支持されており、
中心部から下方に傾斜したその周縁には、円周方向に等
間隔で離間して三日月状の排水口５ａが形成されてい
る。従って、図示の実施例では、６本の水位検出器７が
収納管２に収容されていて、高さ方向に検出点を分散し
て、原子炉内の水位を多点で監視する。実施例では６本
の水位検出器案内管６が１つの収納管２に収納されてい
るが、水位検出器全体の直径が小さいために、例えば８
本というような更に多くの水位検出器案内管を収納可能
である。
【００１８】また、図１に示すように、収納管２にはガ
ス抜き穴２ａが複数穿設され、水位検出器案内管６の下
方部位には排水口６ａが、上方部位には別の排水口６ｂ
が穿設されている。
【００１９】図３は、水位検出器７の拡大断面図で、下
端を端栓７ｂで封止された被覆管７ａ内には、絶縁材７
ｊで覆われて、リード線７ｉ、７ｉにＵ字状に接続され
た発熱線７ｈ、７ｈと、アルメル線７ｅを介してＵ字状
に接続されたクロメル線７ｃ、７ｄとが設けられてお
り、クロメル線７ｄの下端とアルメル線７ｅの上端との
接続点は冷接点７ｇとなり、アルメル線７ｅの下端とク
ロメル線７ｃとの接続点は温接点７ｆとなっている。
【００２０】発熱線７ｈ、７ｈは、温接点７ｆの近傍に
おいて、コイル状に巻回されるのではなく、被覆管７ａ
の軸線方向に少なくとも１回往復して延びており、これ
により被覆管７ａひいては水位検出器７はその直径が約
２〜３ｍｍと小形化することができる。その結果、水位
検出器案内管６も数ｍｍとなり、原子炉容器蓋１２ａ
（図４参照）の約３５ｍｍの貫通穴に挿通される収納管
２内に最大８本（実施例では６本を挿入）の水位検出器
の設置が可能となる。
【００２１】以上のような水位監視装置１において、各
水位検出器７は、案内管６内に挿入されて、水の有無を
検出するその温接点７ｆに対応する被覆管部分もしくは
検出部領域が案内管６の下端から下方に突出する位置で
固定される。しかる後、水位検出器７の先端から数１０
ｍｍ上方にポジショナ５がピン８により収納管２に固定
される。案内管６とポジショナ５とは、ポジショナ５に
設けた穴に案内管６を挿通し、溶接により隙間を埋める
ことにより液密に取り付けられる。
【００２２】
【発明の効果】本発明によれば、発熱線を軸線方向に往
復して延在する形状としたため、水位検出器が小径とな
って、１つの収納管内により多くの水位検出器を収納す
ることができ、より多くの高さでの監視が可能となっ
た。しかも、水位検出器は、水位検出器案内管に挿通さ
れていて炉外に引き出し可能であり、定期検査時等に点
検のため外部へ取り出すことができるので、信頼性の向
上に大きく寄与する。
【００２３】また、水位検出器の検出部領域の上方には
水位検出器案内管の周面に対して液密にポジショナ即ち
滴下防止板が装着されているため、水位検出器を小形に
維持したまま、検出器領域に水滴が付着する可能性が低
減し、水位の誤認や応答遅れを可及的に防止できる。
【００２４】更に、収納管の下端部には気泡混入防止小
径穴を備えた気泡分離部が設けられているため、収納管
の内部に気泡が混入することがなく、気泡の潰れによる
水滴飛散に伴う問題が生じないので、水位監視に対する
高い信頼性を確保することができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an apparatus for monitoring a liquid level in a liquid container, and more particularly to a device for monitoring a liquid level in a liquid container, in an upper plenum above the core of a pressurized water reactor vessel. The present invention relates to a thermocouple type water level monitoring device suitable for monitoring a water level (full water during normal operation). 2. Description of the Related Art FIG. 4 shows a typical example of a conventional pressurized water reactor generally designated by the reference numeral 10.
Has a reactor vessel 11, a core 12 inside the reactor vessel, a number of fuel assemblies 13 constituting the core 12, and the like. In order to extract the heat generated by the fission in the fuel assembly 13, the feedwater enters the reactor vessel 11 from the inlet nozzle 14, reverses at the bottom, flows upward and around the fuel assembly 13, and exits. It exits from the nozzle 15 and goes to a steam generator (not shown). [0003] In the reactor vessel 11, this water supply usually fills the entire upper plenum 16 including the portion immediately below the reactor vessel lid 12a above the core without forming a free liquid level, and as described above. It is circulating and flowing. Assuming that a pipe break has occurred in the circulating water system, that is, the primary cooling system, which is in fluid communication with the inlet nozzle 14, the outlet nozzle 15, and the like in order to circulate the water supply, water is discharged from the reactor 10 through the break point. . The formation and lowering of the water level 17 due to this discharge is caused through the upper plenum 16 through the reactor vessel lid 12a.
The water level is monitored by a water level gauge 18 hanging down. The water level gauge 18 is generally called a heating type thermocouple type. As shown in detail in FIG. 5, a chromel wire 18c together with an insulating material 18j is provided in a detector cladding tube 18a having a closed lower end. And an alumel wire 18e are wired so as to form a hot junction 18f and a cold junction 18g, respectively.
Further, a cylindrical body 18m is provided in the cladding tube 18a so as to surround the hot junction 18f, and a heating wire 18h connected to the lead wire 18i is wound around the peripheral surface thereof in a coil shape. Outside the portion of the cladding tube 18a around the hot junction 18f, a protection tube 18k having a water inlet / outlet 18b near the upper and lower ends is provided. A water level monitoring device having a structure similar to the above-described protection cylinder 18k is described in, for example,
-001768. [0005] When the water level reaches above the hot junction 18f, there is substantially no temperature difference between the periphery of the hot junction 18f and the periphery of the cold junction 18g. It is determined that water is present in
When the water level exists below f, since the atmosphere outside the cladding tube 18a in the region of the hot junction 18f becomes gas, the cladding tube of the heating heat by the heating wire 18h disposed around the hot junction 18f. The heat removal via 18a is reduced to generate a temperature difference with the cold junction 18g, and when this temperature difference reaches a set value, it is determined that water does not exist. In such a heating type thermocouple type water level meter, the temperature difference output differs depending on whether or not the surface of the cladding tube 18a around the hot junction 18f is submerged. If the surface of the cladding tube is not exposed to gas, the temperature difference output will temporarily decrease if water droplets adhere to the surface for some reason, even if the surface of the cladding tube is exposed to gas. May be mistaken.
Also, even in the process of gradually lowering the water level, if the above-described protective cylinder 18k is not provided, the water adhering above the water level gauge and remaining water drools down to the detection area or bubbles in the water pop. Water droplets scattered in the detection area may cause the above-described misidentification, and it takes a long time until a signal that does not have such a possibility is recognized, resulting in poor responsiveness. Such a situation is often experienced when a plurality of water level gauges are bundled to perform multi-point water level detection. By providing the protection cylinder 18k, the above-described situation can be avoided. As will be understood from the above description, the protection cylinder 18k eliminates the influence of the residual water that falls after the water level falls and that falls later. Although it is provided in order to prevent water droplets from scattering, the annular gap between the protective tube 18k and the cladding tube 18a is formed in a radial direction such that water droplets are not held in the gap by the surface tension of water. Is required.
h is wound in a coil around the peripheral surface of the cylindrical body 18m surrounding the hot junction 18f, so that the entire water level gauge (18k portion)
Had to be about 10 mm or more in diameter. Further, if the above-described water level gauge is installed in a currently operating pressurized water reactor plant, it can assist in reliable operation in the event of an accident and contribute to improvement of safety. In the reactor vessel lid, as mentioned above, the diameter of the through-hole into which a water gauge with a diameter of about 10 mm or more can be inserted is as small as about 35 mm, so that only a small number of at most three can be inserted. The advantage of outgoing is lost. In addition, since each water level gauge cannot be replaced individually, the amount of radioactive waste increases at the time of replacement. [0009] Therefore, an object of the present invention is to prevent the response from being deteriorated and the water level from being erroneously recognized due to the scattering of water droplets.
Thermocouple type water level monitoring that can be easily installed in a large number of through-holes in an existing plant and each water level gauge can be individually maintained and replaced
It is to provide a device . According to the present invention, there is provided a thermocouple type water level monitoring apparatus, comprising: a storage pipe in fluid communication between an inside and an outside; and a storage pipe in the storage pipe. A plurality of water level detector guide tubes are provided, and a water level detector inserted into each of the water level detector guide tubes. The water level detector includes a thermocouple made of a dissimilar metal material connected to form a cold junction and a hot junction spaced apart in a longitudinal direction, and a heating wire provided adjacent to the hot junction of the thermocouple. Including.
In this water level monitoring device, each of the water level detector guide tubes is located above the hot junction of each of the water level detectors. Supported, each heating wire extends back and forth at least once in the axial direction of the water level detector guide tube near the hot junction of the thermocouple in each water level detector guide tube, and the storage tube is has an end plug at the lower end portion through the bubble separation, the bubble separation is made bubbly prevention unit that is provided inside the cylindrical crossflow preventing portion and the flow prevention member, the tubular flow the prevention portions plurality of drainage holes plurality of communication holes in lower portion to its upper part is also in the bubbly prevention unit includes a plurality of bubble mixing prevention small-diameter hole in its upper part is, the more the lower portion drainage holes are provided, respectively. [0011] If the water level is equal to or higher than the hot junction, even if the hot junction is heated by the heating wire, there is substantially no water between the cold junction in the water or the air of the thermocouple and the hot junction in the water. Since there is no temperature difference, the water level detector determines that water is present.
When the water level gradually drops below the hot junction area, a temperature difference occurs between the cold junction and the hot junction, and the thermocouple outputs an output indicating the low water level. Since the heating wire does not have a coil shape but reciprocates in the axial direction, the water level detector has a small diameter (2 to 3 mm in the embodiment). In the process of lowering the water level, the water surface drops along the peripheral surface of the storage pipe, so that water droplets adhere to the peripheral surface portion above the water surface. Since the drip prevention plate is provided at a position above the detecting section including at least the hot junction in a liquid-tight manner with respect to the container guide tube, water droplets do not drop to the detecting section. Even if water droplets adhere to the peripheral surface of the water level detector guide tube below each drip prevention plate, the distance between the drip prevention plate and the detection unit area is small (in the embodiment, the number 1).
0 mm), it falls after a few seconds, and there is substantially no response delay. Since the lower end of the storage tube has a bubble separating portion having a small hole for preventing air bubbles from communicating with the fluid, even if bubbles exist in the water, the bubbles do not enter the storage tube.
Even if bubbles in the water burst during the process of lowering the water level and the water droplets scatter, they do not reach the detection area. Next, a preferred embodiment of a water level monitoring apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. FIG. 1 shows a water level monitoring apparatus of the present invention generally designated by the reference numeral 1. The water level monitoring apparatus 1 has an elongated tubular storage tube 2 and a bubble separating section 3 at the lower end thereof. The end plug 4 is attached by welding. Bubble separation unit 3
Is composed of a lateral flow prevention part 3a and a bubble mixing prevention part 3b so as to prevent intrusion of a large number of air bubbles in the water outside the storage tube. , A plurality of drain holes 3ab are formed in the lower part, a plurality of small diameter holes 3ba are formed in the upper part, and a plurality of drain holes 3bb are formed in the lower part. Have been. The number of the above-mentioned various holes may be determined so that the water level inside the storage tube responds at a required speed when the water level outside the storage tube 2 changes. The diameter of the small hole 3ba for preventing air bubbles from entering is 1-2m
m is preferable. By the small hole 3ba for preventing air bubbles from entering, the volume ratio of bubbles in water, that is, the void ratio is 5%.
Experiments have confirmed that, when the state is 0% or less, no air bubbles enter the storage tube. Furthermore, when a flow (lateral flow) in a direction perpendicular to the axis of the storage tube 2 exists outside the storage tube 2, the flow prevents bubbles from being pushed into the storage tube via the horizontal flow prevention unit 3 a and the bubble mixing prevention unit 3 b. In addition, the communication hole 3aa and the drain hole 3ab in the lateral flow prevention part 3a are provided at positions that are not radially aligned with the bubble mixing prevention small-diameter hole 3ba and the drain hole 3bb in the bubble mixing prevention part 3b. A water level detector guide tube 6 is vertically supported by a positioner (drip prevention plate) 5 in the storage tube 2. In the illustrated embodiment, as can be seen from FIG.
The two guide tubes 6 are provided separately from each other in a liquid-tight manner with respect to the positioner 5, and six water levels are detected in the guide tubes 6 at different positions in the height direction. The container 7 is inserted. The positioner 5, which is a disk-shaped partition plate, is supported by the storage tube 2 via a pin 8,
A crescent-shaped drain port 5a is formed at a peripheral edge inclined downward from the center at equal intervals in the circumferential direction. Therefore, in the illustrated embodiment, six water level detectors 7 are housed in the storage pipe 2, and the detection points are dispersed in the height direction to monitor the water level in the reactor at multiple points. In the embodiment, six water level detector guide pipes 6 are housed in one storage pipe 2. However, since the diameter of the whole water level detector is small, for example, 8
More water level detector guide tubes such as books can be stored. As shown in FIG. 1, the storage pipe 2 is provided with a plurality of gas vent holes 2a, a drain port 6a is provided below the water level detector guide pipe 6, and another drain port is provided above the water level detector guide pipe 6. Mouth 6b
Are drilled. FIG. 3 is an enlarged sectional view of the water level detector 7, in which an insulating material 7 is provided in a cladding tube 7a having a lower end sealed with an end plug 7b.
j, and heating wires 7h, 7h connected in a U-shape to the lead wires 7i, 7i, and chromel wires 7c, 7d connected in a U-shape via an alumel wire 7e are provided. The connection point between the lower end of the chromel wire 7d and the upper end of the alumel wire 7e is a cold junction 7g, and the connection point between the lower end of the alumel wire 7e and the chromel wire 7c is a hot junction 7f. The heating wires 7h, 7h are not wound in a coil shape in the vicinity of the hot junction 7f, but are covered with a coating tube 7a.
Extends at least once in the axial direction, whereby the cladding tube 7a and, consequently, the water level detector 7 can be reduced in size to about 2-3 mm in diameter. As a result, the water level detector guide tube 6 also becomes several mm, and the reactor vessel lid 12a
A maximum of eight (six in this embodiment) water level detectors can be installed in the storage pipe 2 inserted into the through hole of about 35 mm (see FIG. 4). In the water level monitoring apparatus 1 as described above, each water level detector 7 is inserted into the guide pipe 6, and a cladding tube portion or a detection area corresponding to the hot junction 7f for detecting the presence or absence of water is provided. It is fixed at a position protruding downward from the lower end of the guide tube 6. Then, several tens of meters from the tip of the water level detector 7
The positioner 5 is fixed to the storage tube 2 by pins 8 mm above. The guide tube 6 and the positioner 5 are mounted in a liquid-tight manner by inserting the guide tube 6 into a hole provided in the positioner 5 and filling the gap by welding. According to the present invention, since the heating wire is formed to extend back and forth in the axial direction, the water level detector has a small diameter, and more water level detectors can be provided in one storage pipe. It can be stowed, allowing monitoring at more heights. Moreover, the water level detector is inserted into the water level detector guide tube and can be pulled out of the furnace, and can be taken out for inspection at the time of periodic inspection or the like, which greatly contributes to improvement in reliability. Further, since the positioner, that is, the drip prevention plate is mounted above the detecting portion area of the water level detector in a liquid-tight manner with respect to the peripheral surface of the water level detector guide tube, the water level detector is kept small. As a result, the possibility that water droplets adhere to the detector area is reduced, and erroneous recognition of the water level and response delay can be prevented as much as possible. Further, since a bubble separating portion having a small-diameter hole for preventing air bubbles from entering is provided at the lower end of the housing tube, air bubbles do not enter the inside of the housing tube, and water droplets are scattered due to collapse of the air bubbles. Since no accompanying problems occur, high reliability for water level monitoring can be ensured.
【図面の簡単な説明】
【図１】 本発明による熱電対式水位監視装置の一実施
例の簡略化された縦断面図である。
【図２】 図１のII−II線における拡大断面図である。
【図３】 図１の水位監視装置における水位検出器の拡
大断面図である。
【図４】 従来の水位監視装置を備えた加圧水型原子炉
の代表的な例を示す断面図である。
【図５】 図４の水位監視装置における水位検出器の拡
大断面図である。
【符号の説明】
１…熱電対式水位監視装置
２…収納管
３…気泡分離部
５…ポジショナ（滴下防止板）
６…水位検出器案内管
７…水位検出器
７ｃ…熱電対を構成するクロメル線
７ｄ…熱電対を構成するクロメル線
７ｅ…熱電対を構成するアルメル線
７ｆ…温接点
７ｇ…冷接点
７ｈ…発熱線BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified longitudinal sectional view of one embodiment of a thermocouple type water level monitoring device according to the present invention. FIG. 2 is an enlarged sectional view taken along line II-II of FIG. FIG. 3 is an enlarged sectional view of a water level detector in the water level monitoring device of FIG. FIG. 4 is a cross-sectional view showing a typical example of a pressurized water reactor equipped with a conventional water level monitoring device. FIG. 5 is an enlarged sectional view of a water level detector in the water level monitoring device of FIG. [Description of Signs] 1 ... Thermocouple type water level monitoring device 2 ... Storage tube 3 ... Bubble separation unit 5 ... Positioner (drip prevention plate) 6 ... Water level detector guide tube 7 ... Water level detector 7c ... Chromel constituting thermocouple Wire 7d: Chromel wire 7e forming a thermocouple ... Alumel wire 7f forming a thermocouple ... Hot junction 7g ... Cold junction 7h ... Heating wire
───────────────────────────────────────────────────── フロントページの続き (73)特許権者 000230940 日本原子力発電株式会社 東京都千代田区神田美土代町１番地１ (73)特許権者 000006208 三菱重工業株式会社 東京都港区港南二丁目16番５号 (72)発明者 高岡 幸久 大阪府大阪市北区中之島三丁目３番22号 関西電力株式会社内 (72)発明者 畑中 信三 大阪府大阪市北区中之島三丁目３番22号 関西電力株式会社内 (72)発明者 勝山 佳明 大阪府大阪市北区中之島三丁目３番22号 関西電力株式会社内 (72)発明者 前田 宗昭 大阪府大阪市北区中之島三丁目３番22号 関西電力株式会社内 (72)発明者 加藤 善史 香川県高松市丸の内２番５号 四国電力 株式会社内 (72)発明者 本房 克紀 福岡県福岡市中央区渡辺通二丁目１番82 号 九州電力株式会社内 (72)発明者 青木 孝行 東京都千代田区大手町一丁目６番１号 日本原子力発電株式会社内 (72)発明者 上田 三男 兵庫県高砂市荒井町新浜二丁目１番１号 三菱重工業株式会社高砂研究所内 (72)発明者 藤本 哲郎 兵庫県高砂市荒井町新浜二丁目１番１号 三菱重工業株式会社高砂研究所内 (72)発明者 川崎 茂樹 兵庫県高砂市荒井町新浜二丁目１番１号 三菱重工業株式会社高砂研究所内 (72)発明者 中森 信夫 兵庫県高砂市荒井町新浜二丁目１番１号 三菱重工業株式会社高砂研究所内 (72)発明者 近藤 雄一 兵庫県神戸市兵庫区和田崎町一丁目１番 １号 三菱重工業株式会社神戸造船所内 (72)発明者 吉田 成臣 兵庫県神戸市兵庫区和田崎町一丁目１番 １号 三菱重工業株式会社神戸造船所内 (72)発明者 梅田 賢治 兵庫県神戸市兵庫区和田崎町一丁目１番 １号 三菱重工業株式会社神戸造船所内 (72)発明者 堀川 好一 兵庫県神戸市兵庫区和田崎町一丁目１番 １号 三菱重工業株式会社神戸造船所内 (56)参考文献 特開 平６−167374（ＪＰ，Ａ) 特開 昭57−158522（ＪＰ，Ａ) 特開 昭58−47217（ＪＰ，Ａ) 実開 昭60−118725（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) G21C 17/035 G01F 23/00 ──────────────────────────────────────────────────続 き Continuing on the front page (73) Patent holder 000230940 Japan Atomic Power Co., Ltd. 1-1, Kanda-Midshiro-cho, Chiyoda-ku, Tokyo (73) Patent holder 000006208 Mitsubishi Heavy Industries, Ltd. 2-16 Konan, Minato-ku, Tokyo No. 5 (72) Inventor Yukihisa Takaoka 3-2-2 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Inside Kansai Electric Power Co., Inc. (72) Inventor Shinzo Hatanaka 3-2-2, Nakanoshima, Kita-ku, Osaka City, Kansai, Kansai Yoshiaki Katsuyama, the inventor of Electric Power Co. (72) 3-2-2, Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (72) Muneaki Maeda 3-2-2, Nakanoshima, Kita-ku, Osaka, Kansai Electric Power Co., Inc. (72) Inventor Yoshifumi Kato 2-5 Marunouchi, Takamatsu City, Kagawa Prefecture Shikoku Electric Power Co., Inc. (72) Inventor Katsunori Mototsuji Watanabe, Chuo-ku, Fukuoka City, Fukuoka Prefecture 1-82 Kyushu Electric Power Co., Inc. (72) Inventor Takayuki Aoki 1-6-1, Otemachi, Chiyoda-ku, Tokyo Japan Atomic Power Co., Inc. (72) Inventor Mitsuo Ueda 2-chome, Araimachi, Takasago City, Hyogo Prefecture No. 1-1 Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Tetsuro Fujimoto 2-1-1, Araimachi, Araimachi, Takasago City, Hyogo Prefecture Inside the Takasago Research Institute, Mitsubishi Heavy Industries, Ltd. 2-1-1, Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (72) Inventor Nobuo Nakamori 2-1-1, Araimachi, Takasago-shi, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (72) Inventor Yuichi Kondo Kobe, Hyogo Prefecture 1-1-1, Wadasaki-cho, Hyogo-ku Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Shigeomi Yoshida 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe, Hyogo Prefecture Inventor Kenji Umeda Hyogo Ward, Kobe City, Hyogo Prefecture 1-1-1, Tazakicho, Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Yoshikazu Horikawa 1-1-1, Wadasakicho, Hyogo-ku, Kobe, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (56) References JP-A-6-167374 (JP, A) JP-A-57-158522 (JP, A) JP-A-58-47217 (JP, A) JP-A-60-118725 (JP, U) (58) Fields investigated (Int.Cl. 7 , DB name) G21C 17/035 G01F 23/00
Claims (1)
管内に収納される複数の水位検出器案内管と、該水位検
出器案内管の各々の内部に挿通される水位検出器とを備
え、該水位検出器は、長手方向に離間した冷接点及び温
接点を形成するよう接続された異種金属材料からなる熱
電対と、該熱電対の前記温接点に隣接して設けられた発
熱線とを含む熱電対式水位監視装置において、 前記水位検出器案内管の各々は、各水位検出器の前記温
接点より上方の部位で、同水位検出器案内管の周壁に液
密に嵌合する滴下防止板により前記収納管に支持され、
前記各発熱線は、各水位検出器案内管内の前記熱電対の
温接点の近傍で同水位検出器案内管の軸線方向に少なく
とも１回往復して延びており、 前記収納管はその下端部に気泡分離部を介して端栓を有
し、前記気泡分離部は筒状の横流れ防止部と当該流れ防
止部材の内部に設けられた気泡混入防止部からなり、前
記筒状の流れ防止部にはその上方部位に複数の連通穴が
下方部位に複数の排水穴が、また前記気泡混入防止部に
は、その上方部位に複数の気泡混入防止小径穴が、下方
部位に複数の排水穴がそれぞれ設けられたことを特徴と
する熱電対式水位監視装置。(57) [Claim 1] A storage pipe which is in fluid communication between the inside and the outside, a plurality of water level detector guide pipes stored in the storage pipe, and the inside of each of the water level detector guide pipes A thermocouple made of a dissimilar metal material connected to form a cold junction and a hot junction spaced apart in a longitudinal direction, and the hot junction of the thermocouple. And a heating wire provided adjacent to the water level detector guide tube, wherein each of the water level detector guide tubes is located at a position above the hot junction of each water level detector, and the same water level detector guide tube is provided. Supported by the storage tube by a drip prevention plate that fits liquid-tightly to the peripheral wall of
Each of the heating wires extends back and forth at least once in the axial direction of the water level detector guide tube in the vicinity of the hot junction of the thermocouple in each water level detector guide tube, and the storage tube is provided at the lower end thereof. has an end plug through the bubble separation, the bubble separation is made bubbly prevention unit that is provided inside the cylindrical crossflow preventing portion and the flow prevention member, to the tubular flow prevention section the plurality of communication holes in its upper part has a plurality of drainage holes in the lower portion, and the bubbly prevention unit includes a plurality of bubble mixing prevention small-diameter hole in its upper part has a plurality of drainage holes in the lower portion A thermocouple type water level monitoring device, each of which is provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02171095A JP3468903B2 (en) | 1995-02-09 | 1995-02-09 | Thermocouple type water level monitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02171095A JP3468903B2 (en) | 1995-02-09 | 1995-02-09 | Thermocouple type water level monitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08220284A JPH08220284A (en) | 1996-08-30 |
| JP3468903B2 true JP3468903B2 (en) | 2003-11-25 |
Family
ID=12062625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02171095A Expired - Lifetime JP3468903B2 (en) | 1995-02-09 | 1995-02-09 | Thermocouple type water level monitor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3468903B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009015629A1 (en) * | 2009-04-02 | 2010-10-07 | Areva Np Gmbh | Sealing device for a device for level measurement in a liquid container |
| JP5865614B2 (en) * | 2011-06-27 | 2016-02-17 | 株式会社東芝 | Water level detector for nuclear power plant |
| JP5667937B2 (en) * | 2011-07-01 | 2015-02-12 | 株式会社東芝 | In-reactor inspection method |
| JP5787729B2 (en) * | 2011-11-14 | 2015-09-30 | 株式会社東芝 | Water level temperature measuring device |
| JP5542790B2 (en) * | 2011-12-22 | 2014-07-09 | 株式会社東芝 | Reactor state monitoring device and monitoring method thereof |
| JP5829527B2 (en) * | 2012-01-05 | 2015-12-09 | 日立Ｇｅニュークリア・エナジー株式会社 | Reactor water level and temperature measurement device |
| JP6257915B2 (en) * | 2013-04-25 | 2018-01-10 | 株式会社東芝 | Water level / temperature measurement device and water level / temperature measurement system |
| US10012121B2 (en) * | 2014-05-20 | 2018-07-03 | Ssi Technologies, Inc. | Reduction of aeration interference via tortuous path and sensor boot |
| JP6653161B2 (en) * | 2015-11-10 | 2020-02-26 | 日立Ｇｅニュークリア・エナジー株式会社 | Water level measurement system |
-
1995
- 1995-02-09 JP JP02171095A patent/JP3468903B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08220284A (en) | 1996-08-30 |
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