In 2006, the author published his research on characteristics of boron co-deposition with crud experienced in AOA and crud deposition anomaly (CDA). These anomalous crud deposition phenomena are contrary to the general theory of mineralogy where hydrothermal growth of crystals was widely used and therefore, the crud should not deposit on fuels where the reactor water is at the highest temperature. Significant quantities of meta-ZrO_2 and nickel iron oxyborates (bonaccordite), notably Ni_2FeBO_5 have also been found in deposits on cores with AOA. On the basis of the general characterization information released by EPRI, the author has constructed a potential-pH diagram of Ni_2FeB(OH)_<10>, which is a hydrated state of FeNi_2(BO_3)O_2. However, the theoretical results were not consistent with the reported phenomenology since the removal of excess electrons is needed for metallic cations (e.g. Fe^<++>, Ni^<++> and Cr^<++>) to deposit as CRUD on the fuel's surface. This indicates that the reactor fuels must be cathodic, thus demonstrating that further investigation of the radiation effects on electrochemical reactions are indispensable. This is the main agenda of this paper. Since the author's last paper the author has confirmed that 'long-cell action' corrosion plays a pivotal role in practically all unresolved corrosion issues for all types of water-cooled reactors. Some of these unresolved issues are IGSCC, PWSCC, AOA and FAC. In conventional corrosion science, established by US NBS in 1958, it is well known that 'long cell action' can seriously accelerate or suppress the local cell corrosion activities. The author believes that the omission of this basic corrosion mechanism is the root cause for practically all un-resolved corrosion issues. The long-cell action corrosion mechanism is induced in water-cooled reactors as demonstrated with potential differences between irradiated- and un-irradiated reactor water. The author recently developed a unified theory, which enables the estimation of redox potential differences induced by radiation. The author's previous calculations through modifying the Nernst equation revealed a reasonable agreement with the published in-pile experimental results when a "fitting parameter" is introduced. Based on these new findings this paper revisits previous E-pH diagrams to investigate the effects of radiation. The Nernst equation, applied to reactor water, determines the actual in-core operational environment with a potential shift from the electrochemical potential due to solute species such as dissolved hydrogen and oxygen in the reactor water.
