Maurice E. Indig

Electrochemical measurements and modeling predictions in boiling water reactors under various operating conditions

Abstract One important issue for providing life extension to operating boiling water nuclear reactors (BWRs) is the control of stress corrosion cracking in all sections of the primary coolant circuit. This paper links experimental and theoretical methods that provide understanding and measurements of the critical parameter, the electrochemical potential (ECP), and its application to determining crack growth rates among and within the family of BWRs. Measurement of in-core ECP required the development of a new family of radiation-resistant sensors. With these sensors, ECPs were measured in the core and piping of two operating BWRs. Concurrent crack growth measurements were used to benchmark a crack growth prediction algorithm with measured ECPs. Future studies obtaining in situ crack growth measurements with measured and calculated ECPs are necessary to increase both capability and confidence in using the predictive approach. The modeling of the concentration of potential-determining species in various par...

The application of noble metals in light-water reactors

Corrosion potential is a primary determinant of the stress-corrosion cracking susceptibility of structural materials in high-temperature water. Efforts to minimize stress-corrosion cracking in light-water reactors include adding hydrogen. In someplants’ out-of-core regions, the hydrogen required to achieve the desired corrosion potential is relatively high. In-core, more hydrogen is needed for an equivalent reduction in corrosion potential. Additionally, sIDe effects of high hydrogen-addition rates, including increased 16N turbine shine and 60CO deposition, have also been observed in some cases. An approach involving noble-metal coatings on and alloying additions to engineering materials dramatically improves the efficiency with which the corrosion potential is decreased as a function of hydrogen addition, such that very low potentials are obtained once a stoichiometric concentration of hydrogen (versus oxygen) is achieved.

Effects of Impurities and Supporting Electrolytes On SCC of 304 Stainless Steel in High Temperature Aqueous Environments

Abstract The effects of impurities in high temperature water has been examined on sensitized 304 stainless steel under both constant temperature and transient temperature conditions. As-welded, low...