Development of A Simple Continuous Monitoring System for Possible Fuel Failure in A Pool-type Reactor

开发一种简单的连续监测系统来监测池式反应堆中可能出现的燃料故障

• 批准号: 10680492
• 负责人: SASAKI Kenichi
• 金额: $ 0.32万
• 依托单位: RIKKYO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680492/
• 关键词: Fuel Failure Detection; FFD; Pool Type Reactor; Fission Product; Rare Gas; Kr-88; Kr-89; Xe-138

A simple and sensitive continuous monitoring system for the possible fuel failure of a pool-type nuclear reactor was successfully developed. Fuel failure detection (FFD) can be made by the detection of fission products (EP's) leaking from fuel element containers. In our system, fission rare gases (ィイD188ィエD1Kr, ィイD189ィエD1Kr, and ィイD1138ィエD1Xe) in the cooling water are collected with bubbled nitrogen gas, and then they are continuously led into a a vertical empty column (a decay and extraction chamber, φ100 mm × 2000 mm) , where they decay to yield daughter nuclides (ィイD188ィエD1Rb, ィイD189ィエD1Rb, and ィイD1138ィエD1Cs) which are extracted to aqueous phase. The radioactivity of daughter nuclides in the aqueous phase is continuously measured using a flow-through Ge-detector with excellent signal-to-noise ratios, because the collected fission rare gases are completely isolated from non-volatile background radioactive unclides in the reactor coolant. An only volatile component coming from the coolant is Ar-41, which is easily removed with bubbled nitrogen gas into the solution containing rubidium and cesium prior to detection. The newly developed continuous FFD system responded with so high sensitivity that a possible anomalous (twice) change in the concentration of FP rare gases in the coolant would be detected within about 30 minutes using the short-lived ィイD189ィエD1Kr-ィイD189ィエD1Rb pair. In addition to the above system, we tried to test, as the decay and extraction chambers, a packed column, a rotating drum, and a gas-washing bottle, which are less effective in the FFD.

成功开发了一个简单敏感的连续监测系统，用于泳池型核反应堆的燃料故障。燃料故障检测（FFD）可以通过检测到燃料元件容器泄漏的裂变产品（EP）进行。 In our system, fission rare gases (II D188 D1Kr, II D189 D1Kr, and II D1138 D1Xe) in the cooling water are collected with bubbled nitrogen gas, and then they are continuously led into a vertical empty column (a decay and extraction chamber, φ100 mm × 2000 mm) , where they decay to yield daughter nuclides (D188 D1Rb, D189 D1RB和D1138 D1CS）被提取为水相。使用具有优异信号噪声比的流直发探测器连续测量子相中的子核素的放射性，因为收集的裂变稀有气体完全从反应堆冷却剂中的非挥发性背景的放射性脱离物中完全分离出来。来自冷却液的唯一挥发性成分是AR-41，在检测前，用气泡的氮气轻松地将其取出，并在含有rubidium和cesium的溶液中去除。新开发的连续FFD系统的敏感性如此之高，以至于使用短寿命的D189IE D1KR-II D189IE D1RB对检测到冷却液中FP稀有气体浓度的异常（两次）变化。除上述系统外，我们还试图测试，因为腐烂和提取室，一个堆积的柱，旋转的鼓和洗涤瓶，在FFD中效果较低。