芯块年龄对燃料棒富集度检测的影响研究

为保证核电站运行安全，反应堆装入核燃料组件的²³⁵U富集度具有严格的设计要求。因此，反应堆燃料棒均必须经过100%富集度及装料均匀性无损检测。已有富集度检测包括有源法和无源法，通过对有源法、无源法两种富集度检测方法中UO₂芯块年龄现象的研究，发现有源检测法在较低活度下，受UO₂芯块年龄影响，使得燃料棒富集度无法正确检测，需采用被动放置等待的方式解决芯块年龄问题。无源法可在检测中直接校正芯块年龄，满足生产检测要求，已得到工程化应用。

Influence of Pellet Age on Fuel Rod Enrichment Detection

In order to ensure the operation safety of nuclear power plant, the ²³⁵U enrichment of nuclear fuel assembly in reactor has strict design requirements. Therefore, all reactor fuel rods must undergo 100% enrichment and loading uniformity nondestructive testing. The enrichment detection methods include active method and passive method. Through the research on the age of UO₂ pellets in the active method and passive method, it is proposed that the active detection method is affected by the age of UO₂ pellets at a lower activity, which makes the fuel rod enrichment cannot be detected correctly. The passive-placement-waiting method is needed to solve the problem of pellet age. However, the passive method can directly correct the pallets age in the detection, which meets the requirements of the detection and has been applied in engineering.