Analysis of Abnormal Rise of Fluorion in the Primary Circuit of PWR

In view of the abnormal increase of fluorion in the primary circuit of a PWR nuclear power plant after overhaul, in this paper, the interference factors of chemical analysis, the representative verification of sampling, reconnaissance of RCS makeup water quality, additives in the process system, impurities in fuel cladding, the use of chemical auxiliary materials, and water quality of related systems are investigated, the results show that the acid pickling passivation paste used for pickling passivation of stainless steel surface in the refueling pool and spent fuel pool during during construction and installation is not cleaned thoroughly and remains on the surface of stainless steel. The fluorion generated after irradiation decomposition pollutes the primary water, and causes the fluorion in the purification ion bed to be saturated, losing the purification ability of fluorion, and continuously releasing fluorion into the primary water during water exchange.