JPS6367597A - Method of washing spent fuel aggregate - Google Patents
Method of washing spent fuel aggregateInfo
- Publication number
- JPS6367597A JPS6367597A JP21303386A JP21303386A JPS6367597A JP S6367597 A JPS6367597 A JP S6367597A JP 21303386 A JP21303386 A JP 21303386A JP 21303386 A JP21303386 A JP 21303386A JP S6367597 A JPS6367597 A JP S6367597A
- Authority
- JP
- Japan
- Prior art keywords
- spent fuel
- cleaning
- fuel assembly
- cleaning tank
- gas
- 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
- 239000002915 spent fuel radioactive waste Substances 0.000 title claims description 59
- 238000000034 method Methods 0.000 title claims description 42
- 238000005406 washing Methods 0.000 title 1
- 238000004140 cleaning Methods 0.000 claims description 76
- 239000007789 gas Substances 0.000 claims description 32
- 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 claims description 26
- 229910052708 sodium Inorganic materials 0.000 claims description 26
- 239000011734 sodium Substances 0.000 claims description 26
- 230000000712 assembly Effects 0.000 claims description 23
- 238000000429 assembly Methods 0.000 claims description 23
- 239000011261 inert gas Substances 0.000 claims description 21
- 238000009423 ventilation Methods 0.000 claims description 18
- 239000000446 fuel Substances 0.000 claims description 16
- 229910001338 liquidmetal Inorganic materials 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 3
- 239000003595 mist Substances 0.000 description 10
- 230000006837 decompression Effects 0.000 description 6
- 238000010407 vacuum cleaning Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 230000002285 radioactive effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000010795 gaseous waste Substances 0.000 description 2
- 238000011086 high cleaning Methods 0.000 description 2
- 239000002901 radioactive waste Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000005253 cladding Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Landscapes
- Solid Fuels And Fuel-Associated Substances (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
この発明は、１次冷却材としてナトリウム等の液体金属
を使用する高速増殖炉の使用済燃料集合体を対象とした
使用済燃料集合体の洗浄方法に関する。The present invention relates to a method for cleaning spent fuel assemblies of fast breeder reactors that use liquid metal such as sodium as a primary coolant.
周知のように頭記した原子炉から取出した使用済燃料集
合体は、燃料貯蔵プール内に保管する前段階の工程で燃
料集合体に付着しているナトリウム等の液体金属を洗浄
することが一般に行われている。
この場合の使用済燃料集合体の洗浄法として、従来より
使用済燃料集合体を洗浄槽内に収容した状態で使用済燃
料集合体に蒸気を含む湿潤ガスを吹付け、さらに水で洗
浄した後に、燃料集合体を温風等で乾燥させる蒸気−水
洗浄法が知られている。しかしてかかる蒸気−水洗浄法
は１本の使用済燃料集合体の洗浄に１．５時間にも及ぶ
長時間を要する他、さらに洗浄に伴って使用済燃料集合
体１本当たりで約１．５トンにも及ぶ放射性クラッド。
放射性腐食生成物等を含む多量の放射性洗浄廃液が発生
するために、廃液処理系設備の大形化、および放射能汚
染の増加などの廃棄物処理上での厄介な問題がある。
一方、前記した従来の蒸気−水洗浄方式の難点を解消し
、放射性廃液の発生を伴わずに使用済燃料集合体に付着
している液体金属を排除する洗浄方式として、まず使用
済燃料集合体をナトリウム等の液体金属の溶融温度以上
の温度まで予熱昇温し、この予熱済みの使用済燃料集合
体を洗浄槽内に収容した状態で洗浄槽内の雰囲気を前記
の予熱温度に対する液体金属の飽和蒸気圧以下に減圧さ
せることにより、燃料集合体に付着している液体金属を
蒸発させて排除するようにした乾式減圧洗浄方法が提唱
されている。かかる乾式減圧洗浄方法によれば洗浄過程
で蒸気、水等を使用しないので洗浄に伴う放射性廃液の
発生が無く、僅かな量の排ガスを処理するだけで使用済
燃料集合体を効果的に洗浄することが可能となる。
次に１次冷却材としてナトリウムを使用した高速増殖炉
の使用済燃料集合体を対象とする前記乾式減圧洗浄方式
の概要を第２図により説明する。
図においてｌは頂部にドアバルブ２を装備した洗浄槽、
３が洗浄槽内に収容された使用済燃料集合体であり、こ
こで前記洗浄槽１に対しては、ブロア４．ガス加熱器５
．ガス冷却器６．ベーパトラップ７等を具備して洗浄槽
１との間に接続配管したガス循環ライン８、および該ガ
ス循環ライン８に接続された例えばアルゴンガスの不活
性ガス源９を含めた使用済燃料集合体の予熱手段と、洗
浄槽１より真空タンク１０．真空ポンプ１１．ベーパト
ラップ１２等を経て気体廃棄物処理系１３に通じる減圧
排気ライン１４として成る減圧手段が装備されている。
さらに洗浄槽１および真空タンク１０にはその底部より
引出して、ナトリウムのドレンタンク１５、 ナトリウ
ム送液ポンプ１６を経てナトリウム回収系１７に通じる
ナトリウムドレンライン１８が接続配管されている。な
お１９〜２９は前記したガス循環ライン、減圧排気ライ
ン、ドレンラインの系内に介挿した開閉バルブである。
次に上記構成による使用済燃料集合体の洗浄操作の手順
に付いて説明する。まず原子炉より取り出した使用済燃
料集合体３をドアバルブ２を通じて洗浄槽１内に収容す
る。ここでバルブ１９〜２１を開放し、不活性ガス源９
より所定量のアルゴンガスを系内に導入し、さらにブロ
ア４．ガス加熱器５を始動して加熱されたガスを洗浄槽
１内に循環送流し、崩壊熱を発生する燃料ピン、および
燃料ピン以外の非発熱部を含む使用済燃料集合体３の全
長域をナトリウムの溶融温度以上の所定の予熱温度（好
ましくは４５０〜５５０℃程度）まで加熱昇温させる。
またこの予熱工程の過程で使用済燃料集合体３の温度、
特に崩壊熱を発生する燃料ピンの表面温度が許容温度ま
で達するようになった場合には、一時的にガス循環ライ
ン８のガス冷却器６を始動して循環ガス温度を下げ、使
用済燃料集合体３を所定の予熱温度に維持させるように
温度調節を行う、一方、この予熱工程を行っている期間
にバルブ２２．２３を閉じたまま真空ポンプｌ’ｌを始
動して真空タンクｌＯを減圧して置く。
ここで前記した予熱工程により使用済燃料集合体３が所
定の予熱温度に到達した時点でブロア４゜ガス加熱器５
を停止し、かつバルブ１９．２０を閉じ、しかる後にま
ず真空タンク１ｏに通じるバルブ２２を開放して洗浄槽
１の内部を急激に減圧させる。続いてバルブ２２を閉じ
て真空タンク１０との間を切離した後に、バルブ２３を
開放して真空ポンプ１１により洗浄槽ｌ内をさらに真空
引きし、洗浄槽内の内圧がその温度に対するナトリウム
飽和蒸気圧以下。
例えば４〜１０Ｔｏｒｒ程度となるように減圧排気させ
る。これにより使用済燃料集合体３の表面、内部に付着
したいたナトリウムは蒸発促進され、ナトリウム蒸気、
ミストの形で使用済燃料集合体３より洗浄除去されるよ
うになる。なおこの過程で生じたナトリウム蒸気、ミス
トは大半が洗浄槽１゜および真空タンク１０の内部に移
行して付着し、残りの浮遊蒸気、ミストは排ガスに同伴
して減圧排気ライン１４中のペーパートラップ１２に吸
着除去され、洗浄槽１の内容積に見合う量の排ガスのみ
が気体廃棄物処理系１３に送出されて処理される。
なお上記の洗浄操作を必要により数回繰り返して行い、
使用済燃料集合体３を充分に洗浄して一連の洗浄工程が
終了する。また前記の洗浄に伴って洗浄槽ｌ、真空タン
ク１０に蒸着したナトリウムは、洗浄槽、真空タンクに
装備した図示されてない加熱ヒータ、および使用済燃料
集合体自”身の崩壊発熱により加熱してナトリウムを溶
融□させた上で、バルブ２６．２７を開放してナトリウ
ムをドレンタンク１５へ排出し、ここからナトリウム送
液ポンプ１６によりナトリウム回収系１７に送出して回
収する。
ところで上記した乾式減圧洗浄方法では、減圧工程の際
に使用済燃料集合体３の表面より蒸発したナトリウム蒸
気、ミストを排除するための輸送を主として燃料集合体
周辺における蒸気の濃度勾配によって行うようにしてい
る。一方、多数本の燃料ビンをラッパ管内に密に並べて
収容した構造の燃料集合体ではラッパ管内の隙間が非常
に狭いことから、前記の洗浄方法のままでは減圧゛工程
で蒸発したナトリウム蒸気、ミストをラッパ管内から外
部へ排除することが困難であり、この結果として高い洗
浄効果が得られない。As is well known, spent fuel assemblies taken out from the above-mentioned nuclear reactors are generally cleaned of liquid metals such as sodium adhering to them in the process before being stored in a fuel storage pool. It is being done. In this case, the conventional method for cleaning spent fuel assemblies is to blow wet gas containing steam onto the spent fuel assemblies while they are housed in a cleaning tank, and then wash the spent fuel assemblies with water. A steam-water cleaning method is known in which fuel assemblies are dried with hot air or the like. However, such a steam-water cleaning method requires a long time of up to 1.5 hours to clean one spent fuel assembly. Five tons of radioactive cladding. Since a large amount of radioactive cleaning waste liquid containing radioactive corrosion products is generated, there are troublesome problems in waste treatment, such as an increase in the size of waste liquid treatment equipment and an increase in radioactive contamination. On the other hand, as a cleaning method that eliminates the drawbacks of the conventional steam-water cleaning method described above and removes liquid metal adhering to spent fuel assemblies without generating radioactive waste, we first clean the spent fuel assemblies. The preheated spent fuel assembly is preheated to a temperature higher than the melting temperature of liquid metal such as sodium, and with this preheated spent fuel assembly housed in the cleaning tank, the atmosphere in the cleaning tank is adjusted to the temperature of the liquid metal at the preheating temperature. A dry vacuum cleaning method has been proposed in which liquid metal adhering to a fuel assembly is evaporated and removed by reducing the pressure to below the saturated vapor pressure. According to this dry vacuum cleaning method, no steam, water, etc. are used in the cleaning process, so there is no radioactive waste liquid generated during cleaning, and spent fuel assemblies can be effectively cleaned by only treating a small amount of exhaust gas. becomes possible. Next, an outline of the dry vacuum cleaning method for spent fuel assemblies of fast breeder reactors using sodium as the primary coolant will be explained with reference to FIG. In the figure, l is a cleaning tank equipped with a door valve 2 at the top;
3 is a spent fuel assembly housed in a cleaning tank, and here, for the cleaning tank 1, a blower 4. gas heater 5
．． Gas cooler6. A spent fuel assembly including a gas circulation line 8 equipped with a vapor trap 7 and the like and connected to the cleaning tank 1, and an inert gas source 9, such as argon gas, connected to the gas circulation line 8. and a vacuum tank 10 from the cleaning tank 1. Vacuum pump 11. A decompression means is provided in the form of a decompression exhaust line 14 leading to the gaseous waste treatment system 13 via a vapor trap 12 or the like. Further, a sodium drain line 18 is connected to the cleaning tank 1 and the vacuum tank 10 from the bottom thereof and connected to a sodium recovery system 17 via a sodium drain tank 15 and a sodium liquid feed pump 16. Reference numerals 19 to 29 are on-off valves inserted into the gas circulation line, vacuum exhaust line, and drain line described above. Next, the procedure for cleaning the spent fuel assembly with the above configuration will be explained. First, the spent fuel assembly 3 taken out from the nuclear reactor is placed into the cleaning tank 1 through the door valve 2. At this point, valves 19 to 21 are opened, and inert gas source 9
A predetermined amount of argon gas is introduced into the system, and then the blower 4. The gas heater 5 is started and the heated gas is circulated into the cleaning tank 1 to cover the entire length of the spent fuel assembly 3 including the fuel pins that generate decay heat and non-heat generating parts other than the fuel pins. The temperature is increased to a predetermined preheating temperature (preferably about 450 to 550°C) that is higher than the melting temperature of sodium. Also, during this preheating process, the temperature of the spent fuel assembly 3,
In particular, when the surface temperature of the fuel pin that generates decay heat reaches the permissible temperature, the gas cooler 6 of the gas circulation line 8 is temporarily started to lower the circulating gas temperature and the spent fuel is collected. The temperature is adjusted to maintain the body 3 at a predetermined preheating temperature.Meanwhile, during this preheating process, the vacuum pump l'l is started with the valves 22 and 23 closed to reduce the pressure in the vacuum tank lO. I'll leave it there. Here, when the spent fuel assembly 3 reaches a predetermined preheating temperature through the preheating process described above, the blower 4° gas heater 5
is stopped, valves 19 and 20 are closed, and then the valve 22 communicating with the vacuum tank 1o is first opened to rapidly reduce the pressure inside the cleaning tank 1. Subsequently, after closing the valve 22 and disconnecting it from the vacuum tank 10, the valve 23 is opened and the inside of the cleaning tank 1 is further evacuated by the vacuum pump 11, so that the internal pressure in the cleaning tank becomes sodium saturated vapor at that temperature. Below pressure. For example, the pressure is evacuated to about 4 to 10 Torr. As a result, the sodium adhering to the surface and inside of the spent fuel assembly 3 is promoted to evaporate, and sodium vapor and
It comes to be cleaned and removed from the spent fuel assembly 3 in the form of mist. Most of the sodium vapor and mist generated in this process migrate to and adhere to the inside of the cleaning tank 1° and the vacuum tank 10, and the remaining floating vapor and mist accompany the exhaust gas to the paper trap in the decompression exhaust line 14. Only the exhaust gas in an amount corresponding to the internal volume of the cleaning tank 1 is sent to the gaseous waste treatment system 13 for treatment. Please repeat the above cleaning procedure several times as necessary.
The spent fuel assembly 3 is thoroughly cleaned and the series of cleaning steps is completed. In addition, the sodium vapor deposited in the cleaning tank 1 and the vacuum tank 10 during the cleaning described above is heated by a heater (not shown) installed in the cleaning tank and the vacuum tank, and by the heat generated by the disintegration of the spent fuel assembly itself. After melting the sodium, the valves 26 and 27 are opened to discharge the sodium to the drain tank 15, from where it is sent to the sodium recovery system 17 by the sodium liquid pump 16 and recovered. In the vacuum cleaning method, transportation for removing the sodium vapor and mist evaporated from the surface of the spent fuel assembly 3 during the depressurization process is performed mainly by the vapor concentration gradient around the fuel assembly. In a fuel assembly with a structure in which a large number of fuel bottles are housed closely arranged in a wrapper tube, the gaps in the wrapper tube are very narrow, so if the cleaning method described above is used, the sodium vapor and mist evaporated during the depressurization process will be removed. It is difficult to remove it from the inside of the wrapper tube to the outside, and as a result, a high cleaning effect cannot be obtained.
この発明は上記の点にかんがみなされたものであり、前
記した乾式減圧洗浄方式を改良することにより、減圧工
程で蒸発したラッパ管内部の液体金属藩気、ミストを容
易に管外へ排除させて高い洗浄効果が得られるようにし
た使用済燃料集合体の洗浄方法を提供することを目的と
する。This invention was developed in consideration of the above points, and by improving the dry vacuum cleaning method described above, the liquid metal vapor and mist inside the wrapper tube that evaporated during the pressure reduction process can be easily removed to the outside of the tube. It is an object of the present invention to provide a method for cleaning spent fuel assemblies that achieves a high cleaning effect.
上記目的を達成するために、この発明は完配した乾式減
圧洗浄方式に対し、洗浄槽内に収容した使用済燃料集合
体に向けて加熱した不活性ガスを強制的に通風する通風
手段を追加し、減圧工程の後に前記の通風手段により使
用済燃料集合体へ加熱した不活性ガスを強制的に通風さ
せることにより燃料集合体のラッパ管内に停滞している
液体金属蒲気、ミストを短時間の内にラッパ管外へ強制
排除させるようにしたものである。In order to achieve the above object, this invention adds ventilation means to forcibly blow heated inert gas toward the spent fuel assembly housed in the cleaning tank, in addition to the dry vacuum cleaning method. After the depressurization process, the heated inert gas is forcibly ventilated into the spent fuel assembly using the ventilation means to remove the liquid metal fumes and mist stagnant in the wrapper tube of the fuel assembly for a short period of time. It is designed to forcefully expel the trumpet out of the trumpet tube.
（実施例１）
第１図で示した洗浄設備において、予熱手段としてのガ
ス循環ライン８はそのままこの発明による加熱不活性ガ
スの通風手段を兼ねている。ここで使用済燃料集合体の
洗浄時に先述と同様な操作で予熱工程、減圧工程が行わ
れると、次に通風工程に移りバルブ２２．２３を閉じて
洗浄槽１と減圧排気ライン１４との間を切離した状態で
再度バルブ１９゜２０を開放して洗浄槽ｌとガス循環ラ
イン８との間を連通させ、この状態でブロア４およびガ
ス加熱器５を始動して加熱された不活性ガスを洗浄槽ｌ
内に収容されている使用済燃料集合体３へ向けて強制通
風する。これにより前段の予熱、減圧工程で使用済燃料
集合体３より蒸発したナトリウム蒸気、ミスト、特に減
圧工程で排除し切れない燃料集合体のラッパ管内部の狭
い隙間に停滞しているナトリウム蒸気、ミストが強制的
にラッパ管外へ排除されることになる、同時に洗浄時間
も大幅に短縮することができるようになる。
（実施例２）
第２図は第１図と異なる実施例を示すものであり、この
実施例では使用済燃料集合体３の予熱手段が例えば洗浄
槽ｌと別置した加熱装置３０として構成されており、原
子炉から取り出された使用済燃料集合体３は洗浄槽１に
収容する以前の段階で前記の加熱装置３０で所定温度ま
で予熱し、しかる後に洗浄槽１内に収容される。一方、
洗浄槽１に対しては、加熱不活性ガス通風手段として不
活性ガス源９と洗浄槽１との間にガス蓄圧器３１．加熱
ヒータ３２．開閉パルプ３３を介して加熱不活性ガス通
風ライン３４が接続配管されている。
かかる構成で、ガス蓄圧器３１には不活性ガスが蓄えら
れ、かつ加熱し−タ３２により所定温度に加熱昇温され
ている。一方、使用済燃料集合体の洗浄時には、予熱済
みの使用済燃料集合体３を洗浄槽ｌ内に収容した状態で
減圧排気ライン１４により洗浄槽１内を減圧操作した後
に、バルブ３３を開放して蓄圧器３１より加熱された不
活性ガスを通風ライン３４を通じて洗浄槽１内の使用済
燃料集合体３に向けて強制通風する。これにより完配の
実施例１と同様に燃料集合体内部に停滞しているナトリ
ウム蒸気、ミストをラッパ管の内部から強制排除するこ
とができるようになる。(Example 1) In the cleaning equipment shown in FIG. 1, the gas circulation line 8 as a preheating means also serves as a ventilation means for heated inert gas according to the present invention. Here, when cleaning the spent fuel assembly, a preheating process and a depressurization process are performed in the same manner as described above, then the ventilation process is started, and the valves 22 and 23 are closed to connect the cleaning tank 1 and the decompression exhaust line 14. With this disconnected, valves 19 and 20 are opened again to establish communication between the cleaning tank 1 and the gas circulation line 8, and in this state, the blower 4 and gas heater 5 are started to supply the heated inert gas. Cleaning tank l
Forced ventilation is directed toward the spent fuel assembly 3 housed inside. This causes sodium vapor and mist that evaporated from the spent fuel assembly 3 during the preheating and depressurization process in the previous stage, and especially sodium vapor and mist that stagnates in the narrow gap inside the fuel assembly's wrapper tube that cannot be completely removed during the depressurization process. is forcibly removed from the trumpet tube, and at the same time, the cleaning time can be significantly shortened. (Embodiment 2) Fig. 2 shows an embodiment different from Fig. 1, and in this embodiment, the preheating means for the spent fuel assembly 3 is configured as a heating device 30 installed separately from the cleaning tank l, for example. The spent fuel assembly 3 taken out from the reactor is preheated to a predetermined temperature by the heating device 30 before being stored in the cleaning tank 1, and is then stored in the cleaning tank 1. on the other hand,
For the cleaning tank 1, a gas pressure accumulator 31. Heater 32. A heated inert gas ventilation line 34 is connected via the openable pulp 33. With this configuration, inert gas is stored in the gas pressure accumulator 31, and is heated to a predetermined temperature by the heater 32. On the other hand, when cleaning spent fuel assemblies, the preheated spent fuel assemblies 3 are accommodated in the cleaning tank 1, and after depressurizing the inside of the cleaning tank 1 through the vacuum exhaust line 14, the valve 33 is opened. The inert gas heated from the pressure accumulator 31 is forced to ventilate toward the spent fuel assembly 3 in the cleaning tank 1 through the ventilation line 34. As a result, the sodium vapor and mist stagnant inside the fuel assembly can be forcibly removed from the inside of the trumpet tube, as in the fully distributed embodiment 1.
以上述べたようにこの発明によれば、使用済燃料集合体
を収容する洗浄槽と、該洗浄槽内に収容する使用済燃料
集合体を昇温する予熱手段と、洗浄槽内を減圧排気する
減圧手段と、および洗浄槽内に収容した使用済燃料集合
体へ向けて加熱した不活性ガスを強制通風する通風手段
とを備え、予熱手段により使用済燃料集合体を所定温度
まで昇温する予熱工程と、予熱済みの使用済燃料集合体
を洗浄槽内に収容した状態で減圧手段により洗浄槽内を
減圧する減圧工程と、減圧工程の後に通風手段により加
熱した不活性ガスを使用済燃料集合体へ強制的に通風す
る通風工程とを経て、燃料集合体に付着している液体金
属を蒸発、排除させることにより、使用済燃料集合体に
付着しているナトリウム等の液体金属、特に燃料集合体
のラッパ管内部の狭い隙間に付着している液体金属を効
果的に排除して洗浄効率の向上、洗浄時間のより一層の
短縮化を図ることができる。As described above, according to the present invention, there is provided a cleaning tank for accommodating spent fuel assemblies, a preheating means for raising the temperature of the spent fuel assemblies accommodated in the cleaning tank, and a depressurizing system for exhausting the inside of the cleaning tank. Preheating means includes a pressure reduction means and a ventilation means for forcing heated inert gas toward the spent fuel assembly housed in the cleaning tank, and the preheating means raises the temperature of the spent fuel assembly to a predetermined temperature. process, a depressurization process in which the preheated spent fuel assembly is housed in the cleaning tank and the pressure inside the cleaning tank is reduced by a decompression means, and after the depressurization process, the inert gas heated by the ventilation means is transferred to the spent fuel assembly. By evaporating and eliminating the liquid metals adhering to the fuel assemblies through a ventilation process in which air is forced into the spent fuel assemblies, liquid metals such as sodium adhering to the spent fuel assemblies, especially the fuel assemblies, are removed. Liquid metal adhering to the narrow gap inside the trumpet tube of the body can be effectively removed, thereby improving cleaning efficiency and further shortening the cleaning time.
第１図、第２図はそれぞれ本発明の洗浄方法を実施する
ための異なる実施例を示す洗浄設備の系読図である。各
図において、
１：洗浄槽、３：使用済燃料集合体、４ニブロア、５：
ガス加熱器、８：予熱手段１通風手段を兼用した加熱不
活性ガスの循環ライン、９：不活性ガス源、１４：減圧
排気ライン、１８：ナトリウムドレンライン、３１：ガ
ス蓄圧器、３２：ガス加熱器、３４；加熱不活性ガス通
風ライン。
第１図FIG. 1 and FIG. 2 are system diagrams of cleaning equipment showing different embodiments for carrying out the cleaning method of the present invention. In each figure, 1: Cleaning tank, 3: Spent fuel assembly, 4 Ni blower, 5:
Gas heater, 8: Preheating means 1 Heating inert gas circulation line that also serves as ventilation means, 9: Inert gas source, 14: Decompression exhaust line, 18: Sodium drain line, 31: Gas pressure accumulator, 32: Gas Heater, 34; heated inert gas ventilation line. Figure 1
Claims (1)
の使用済燃料集合体の洗浄方法であって、使用済燃料集
合体を収容する洗浄槽と、該洗浄槽内に収容する使用済
燃料集合体を昇温する予熱手段と、洗浄槽内を減圧排気
する減圧手段と、および洗浄槽内に収容した使用済燃料
集合体へ向けて加熱した不活性ガスを強制通風する通風
手段とを備え、予熱手段により使用済燃料集合体を所定
温度まで昇温する予熱工程と、予熱済みの使用済燃料集
合体を洗浄槽内に収容した状態で減圧手段により洗浄槽
内を減圧する減圧工程と、減圧工程の後に通風手段によ
り加熱した不活性ガスを使用済燃料集合体へ強制的に通
風する通風工程とを経て、燃料集合体に付着している液
体金属を蒸発、排除させて洗浄することを特徴とする使
用済燃料集合体の洗浄方法。 ２）特許請求の範囲第１項記載の洗浄方法において、加
熱不活性ガスの通風手段がブロア、ガス加熱器等を具備
して洗浄槽に接続し、不活性ガス源から供給されたガス
を加熱して洗浄槽内との間で循環通流させるガス循環ラ
インであることを特徴とする使用済燃料集合体の洗浄方
法。 ３）特許請求の範囲第２項記載の洗浄方法において、加
熱不活性ガス通風手段としてのガス循環ラインが使用済
燃料集合体の予熱手段を兼用していることを特徴とする
使用済燃料集合体の洗浄方法。 ４）特許請求の範囲第１項記載の洗浄方法において、加
熱不活性ガス通風手段がガス蓄圧器、ガス加熱器等を介
して不活性ガス源と洗浄槽との間に接続配管された通風
ラインであることを特徴とする使用済燃料集合体の洗浄
方法。[Scope of Claims] 1) A method for cleaning spent fuel assemblies in a nuclear reactor using liquid metal such as sodium as a primary coolant, comprising a cleaning tank for accommodating spent fuel assemblies, and the cleaning tank. A preheating means for raising the temperature of the spent fuel assemblies housed in the cleaning tank, a depressurizing means for depressurizing and exhausting the inside of the cleaning tank, and a heated inert gas forcibly directed toward the spent fuel assemblies housed in the cleaning tank. a preheating step in which the spent fuel assembly is heated to a predetermined temperature by the preheating means; and a preheating step in which the spent fuel assembly is heated to a predetermined temperature by the preheating device; The liquid metal adhering to the fuel assembly is evaporated through a depressurization step in which the pressure is reduced, and a ventilation step in which the heated inert gas is forcibly ventilated to the spent fuel assembly by a ventilation means after the depressurization step. A method for cleaning a spent fuel assembly, which comprises removing and cleaning the spent fuel assembly. 2) In the cleaning method according to claim 1, the heating inert gas ventilation means is equipped with a blower, a gas heater, etc. and is connected to the cleaning tank to heat the gas supplied from the inert gas source. A method for cleaning a spent fuel assembly, characterized in that the gas is circulated through a gas circulation line between the fuel and the inside of the cleaning tank. 3) A spent fuel assembly in the cleaning method according to claim 2, characterized in that the gas circulation line serving as the heated inert gas ventilation means also serves as a means for preheating the spent fuel assembly. cleaning method. 4) In the cleaning method according to claim 1, the heated inert gas ventilation means is a ventilation line connected between the inert gas source and the cleaning tank via a gas pressure accumulator, a gas heater, etc. A method for cleaning a spent fuel assembly, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21303386A JPS6367597A (en) | 1986-09-10 | 1986-09-10 | Method of washing spent fuel aggregate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21303386A JPS6367597A (en) | 1986-09-10 | 1986-09-10 | Method of washing spent fuel aggregate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6367597A true JPS6367597A (en) | 1988-03-26 |
Family
ID=16632397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21303386A Pending JPS6367597A (en) | 1986-09-10 | 1986-09-10 | Method of washing spent fuel aggregate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6367597A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01189600A (en) * | 1988-01-23 | 1989-07-28 | Power Reactor & Nuclear Fuel Dev Corp | High temperature gas blow washing of spent fuel |
| CN111330905A (en) * | 2020-04-13 | 2020-06-26 | 中国原子能科学研究院 | Cleaning system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5193560A (en) * | 1975-02-15 | 1976-08-17 | Shinkujohatsunyoru natoriumukikisenjoho | |
| JPS5786800A (en) * | 1980-11-20 | 1982-05-29 | Tokyo Shibaura Electric Co | Cleaning device for decontaminated sodium instruments |
-
1986
- 1986-09-10 JP JP21303386A patent/JPS6367597A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5193560A (en) * | 1975-02-15 | 1976-08-17 | Shinkujohatsunyoru natoriumukikisenjoho | |
| JPS5786800A (en) * | 1980-11-20 | 1982-05-29 | Tokyo Shibaura Electric Co | Cleaning device for decontaminated sodium instruments |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01189600A (en) * | 1988-01-23 | 1989-07-28 | Power Reactor & Nuclear Fuel Dev Corp | High temperature gas blow washing of spent fuel |
| CN111330905A (en) * | 2020-04-13 | 2020-06-26 | 中国原子能科学研究院 | Cleaning system |
| CN111330905B (en) * | 2020-04-13 | 2021-06-29 | 中国原子能科学研究院 | Cleaning system and cleaning method |
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