Mechanical aging trend in ethylene propylene rubber-insulated safety cables sampled from bwr nuclear power containment
Mechanical aging trend in ethylene propylene rubber-insulated safety cables sampled from bwr nuclear power containment
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DOI：
10.1109/tdei.2014.004464
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发表时间：
2014-10
影响因子：
3.1
通讯作者：
N. Fuse;M. Kanegami;H. Misaka;H. Homma;T. Okamoto
中科院分区：
文献类型：
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作者：
N. Fuse;M. Kanegami;H. Misaka;H. Homma;T. Okamoto
对从沸水反应堆型安全壳中取出的电缆上不同老化的乙丙橡胶绝缘进行了统计分析。这种电缆的温度和剂量率条件并不相同。因此，在60 ° C、10 mGy/h条件下，将观察到的这种绝缘的断裂伸长率数据转换为每个等效周期。发现老化趋势比加速老化试验结果预期的老化趋势大约慢一半。此外，将该老化趋势用作拟合每个伸长率值的参考，并外推拟合曲线以找到使用寿命的终点，其定义为绝对伸长率的70%。在Arrhenius图上比较了通过该方法估计的寿命和通过加速老化试验预测的寿命。建议后者寿命估计比实际短。温度依赖性还表明两种老化条件下基本化学反应的差异，这导致活化能和指前因子的明显差异。
Statistical analysis has been performed on variously aged ethylene propylene rubber insulation on cables removed from boiling water reactor-type containment. Temperature and dose rate conditions of such cables are not identical. Therefore, elongation at break data observed for such insulation are converted to each equivalent period under 60 °C, 10 mGy/h condition. The aging trend is found to be approximately slower by half than that expected from accelerated aging test results. Furthermore, this aging trend is used as a reference to fit to each elongation value, and the fitted curve is extrapolated to find the end of service life, which is defined as 70 % of absolute elongation. Lifetimes estimated from this method and from predictions by the accelerated aging test are compared on an Arrhenius plot. It is suggested that the latter lifetime estimation is shorter than actual. The temperature dependence also suggests a difference in a basic chemical reaction under the two aging conditions, which results in apparent differences in activation energies and pre-exponential factors.