田湾核电站寿期中插棒试验可行性及风险分析

Feasibility and Risk Analysis for Control Rod Insertion Test of TNPS at MOL

田湾核电站为了验证是否在运行中存在控制棒落棒时间超限的问题,委托中国核电工程有限公司开展了寿期中进行控制棒手动下插试验可行性及风险分析。控制棒手动下插试验分析包括控制棒下插、提升顺序,试验时间间隔,试验步骤等,以及可能引起堆芯反应性变化及功率分布变化等堆芯参数分析。分析结果表明,堆芯功率控制在低于90%满功率,寿期中进行试验才是可行的,堆芯反应性和功率分布均在可控范围内。但存在试验期间可能发生控制棒束无法上提、下插的风险,且卡棒的位置多种多样,无法预测也无法枚举。寿期中控制棒插棒试验的成功,并不能保证或证明之后控制棒落棒时间不会超限。因此,不建议进行该试验。

In order to clarify whether there are any control rod drop time overruns at the middle of cycle （MOL）, TNPS （Tianwan Nulear Power Station） commissioned CNPE （China Nuclear Power Engineering Co., LTD. ） to launch a manual control rod insertion test for feasibility and risk analysis. The test consisted of control rods insertion and withdrawn sequence, test time interval, and test procedures, etc. The test may cause the changes in reactivity, power distribution and other core parameters. It is shown that when the core power is under 90~//oo nominal power, the test is feasible, both core reactivity and power distribution are manageable. But there may be some control rod stuck during the test. The stuck position varies and it is hard to predict and enumerate, so it is a risky test. In addition, the successful test does not mean that the control rod won＇t be stuck any more during the operation period, so the test is not recommended.