Evaluation of the effect of ion exchange resin on feeder integrity

Point Lepreau核电站（PLNGS）在出口给料机上安装了一个在线氢渗出监测器（来自UNB的CNER的HEPro），以监测氢渗透速率，从而监测给料机变薄的速率。初步结果表明，大修期间安装的高铬给料管的总体腐蚀率明显低于之前安装的低铬管道。监测氢渗出率表明，探针对主要热传输系统中的化学变化敏感（例如，在加燃料期间引入低浓度的溶解氧）。这些最近的观察结果之一是在PHT纯化回路中安装新鲜的锂化IX树脂床之后氢渗出速率的显著增加（超过两倍）。观察结果表明，由于这种化学变化，馈线稀疏率发生了显着变化。腐蚀率升高（仍远低于翻新前）持续了一个月，直到计划大修，并在电厂重启后以较高的速度恢复，但此后一直在下降。初步计算表明，新鲜的离子交换树脂以足够快的速率从溶液中去除铁，以显著影响堆芯出口处的欠饱和程度，从而改变流动加速腐蚀速率。 本项目的目的是评估当前离子交换树脂实践对进料器完整性的影响，并确定是否可以优化使用中的树脂混合物，以降低从溶液中去除的铁的量，同时满足放射性运输要求。范围包括对PLNGS HEPro数据（2006年至今）的全面分析，以评估离子交换树脂实践与FAC率之间的联系。这项工作的第二个方面将进一步评估离子交换树脂对铁物种和成膜胺的吸收特性，这些胺可用作电站二次系统的添加剂。

Point Lepreau Nuclear Generating Station (PLNGS) has installed an online hydrogen effusion monitor (HEPro from CNER at UNB) on an outlet feeder to monitor the hydrogen permeation rate and hence the rate of feeder thinning. Initial results have shown that the general corrosion rate of the higher chromium feeders installed during the refurbishment outage is significantly lower than the previously installed low chromium pipes. Monitoring the rate of hydrogen effusion has shown that the probe is sensitive to chemistry changes in the primary heat transport system (e.g. the introduction of low concentrations of dissolved oxygen during fueling). One of these recent observations was a significant increase (more than double) in the hydrogen effusion rate following the installation of a fresh, lithiated IX resin bed in the PHT purification circuit. The observation suggests that the feeder thinning rate changed significantly due to this chemistry change. The elevated corrosion rate (still much lower than pre-refurbishment) persisted for a month, until a planned outage and resumed at the higher rate following plant restart but has since been decreasing. Preliminary calculations suggest that the fresh ion exchange resin is removing iron from solution at a fast enough rate to significantly influence the degree of under-saturation at the core outlet and hence change the flow accelerated corrosion rate. The objective of this project is to evaluate the influence of current ion exchange resin practices on feeder integrity and to determine if the resin mixtures in use can be optimized to lower the amount of iron being removed from solution while meeting activity transport requirements. The scope includes a full analysis of the PLNGS HEPro data (2006 - present) to evaluate the link between ion exchange resin practices and FAC rates. A secondary aspect of this work will further evaluate the absorption characteristics of ion exchange resins for iron species and for film forming amines that may be used as additives to the station's secondary system.