Southern Nuclear was honored by EPRI with a 2017 Technology Transfer Award for using an EPRI report to justify to the NRC the acceptability of eliminating reactor pressure vessel threads in flange examinations.
Employees Gary Lofthus, NDE team leader for Fleet Outage Services; Tim Wells, Fleet Programs – Materials engineer; and Ryan Joyce, Nuclear Licensing engineer, collaborated with Dominion Energy employee Kevin Hacker on a recommendation to eliminate the examination requirement, which is part of the American Society of Mechanical Engineers (ASME) Section XI in-service inspection program.
Southern Nuclear and Dominion are the first nuclear utilities to implement an examination relief request using an EPRI industry report.
“When performing these examinations on reactor pressure vessel (RPV) threads in flange, there are many concerns related to personnel safety, radiation dose and outage impact,” explained Lofthus.
In an effort to address these concerns, the team conducted an industry survey to collect data and insights on the results and negative aspects of the RPV flange examination requirements. They then prepared EPRI reports to provide the technical basis and recommendation for the elimination of the examination requirement.
“By eliminating the examination requirement, we save at least two hours of critical path, reduce dose and alleviate safety concerns,” said Lofthus. “This type of work supports delivering the nuclear promise and our strategic objective of safe, reliable and cost-effective plant operations.”
Previously, the ASME examination was required once every 10 years, and is typically performed on critical path during reactor vessel disassembly. The EPRI technical report said that a survey of 168 nuclear units and more than 10,000 examinations showed no cracking and that elimination of the examination could result in significant cost and time savings, as well as simplified outage activities and increased personnel safety.
“The EPRI Technology Transfer Awards recognize utilities who have transferred research into applied results,” said Chris Comfort, SNC engineering innovation and technology manager. “This honor – and the fact that several other utilities have now submitted similar requests to eliminate these examinations – goes to show how Southern Nuclear continues to be a leader and innovator in the industry.”