In a series of recently published papers [1,2], the author tried to elucidate on the corrosion environment of LWR cores. Through these studies, the reactor cores are found to be behaving as gigantic cathodes. He established that “long cell action” (a kin to “macro-cell”) corrosion plays a pivotal role in practically all unresolved corrosion issues, irrespective of reactor types and operation [3,4].

The author recently developed a unified theory, which enables the estimating of redox potentials for all types of LWRs (e.g., PWR, BWR, VVER, and RBMK). The author’s previous calculations are confirmed by applying a new set of g-values and reaction kinetics data set [i.e., AECL 153-127160-450-001], developed by Drs. A.J. Elliot and S.M. Bartels in 2009.

The results show reasonable agreement with the published in-pile experimental results. However, the author’s calculated DO as well as DH resulted in significant deviations from the input data. The author tried to fortify the verification through another approach in this paper, by incorporating electrolysis reactions (i.e., Faraday’s law) induced by the potential difference. By integrating the radiation-chemical rate equations with the electrolysis reactions, the electric current flowing between the in-core and the out-flux regions through structures was estimated. It was found that this configuration induces surprisingly strong “long cell” current (i.e., cathode current) outside of the regions of DH and DO commonly specified by the water chemistry conditions. This current determines many of the basic corrosion parameters, including ECP, redox potentials, pH, DO and DH, as well as over-potentials, through water chemistry specifications.

Although details are still debatable, the author believes that there is no doubt that this corrosion mechanism exists in water-cooled reactors. However it remains debatable due to the lack of basic knowledge pertaining to the chemistry of the LWR cores.

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