EAPSI: Monitoring pipe weldments for crack formation and failure in real time in nuclear power plants

Marks Joshua A, Newark DE

Investigators

Abstract

As a country, South Korea has a high percentage of its electricity generated by nuclear power. As these nuclear power plants approach the point in their life-cycle where corrosion starts causing weldment and pipe failures, it is important to develop a detection method that works in real time and while the plant is on-line. Unexpected weldment and pipe failures that were not predicted by conventional detection methods have caused work site accidents and deaths. Improving plant safety from early on can help mitigate major system failures, and decrease the plant operation costs. This project aims to develop and implement a direct current potential drop system that is usable in the harsh operating conditions of a nuclear power plant. This research will be conducted at Seoul National University under the sponsorship of Dr. Il Soon Hwang, the leading expert in the direct current potential drop measurement technique utilized in this research. Flow accelerated corrosion (FAC) has been identified as the largest cause of secondary pipe integrity failures. Creating accurate models of pipe wall thinning and failures due to FAC is therefore an important research effort. To date, however, these models have proved to be inaccurate and pipe failures continue. The failure of the FAC models has been determined to be caused by rapid changes in the variables: pH, dissolved oxygen, or temperature, that affect the rate of FAC. In order to create accurate models the data must be sampled at a higher rate to ensure accurate representation of changing variables and pipe conditions. This project will develop, test, and characterize a laboratory system that utilizes the direct current potential drop technique to measure the change in electrical resistance for segments of piping and key weldments. The laboratory system will then be implemented in a functioning nuclear power plant. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Korea.