WASHINGTON - Scientific knowledge gaps in the management of reactor safety issues caused by aging, and acknowledged by the nuclear industry, have prompted Beyond Nuclear to challenge an application to extend the operating license for two nuclear reactors in Pennsylvania.

Beyond Nuclear, an environmental advocacy group based in Takoma Park, MD, is opposing an application from Exelon Generation, owner of the Peach Bottom nuclear power plant in Delta, PA, to extend the operating lifetime of its two reactors there for another 20 years. 

Exelon has submitted a Second License Renewal (SLR) application for an additional 20-year extension of the operating license for Peach Bottom units 2 and 3.

Beyond Nuclear submitted a request on Monday asking the US Nuclear Regulatory Commission (NRC) for a public hearing and intervention before the NRC’s Atomic Safety Licensing Board.

The hearing would address the application’s failure to comply with NRC regulations that require Exelon to demonstrate how it will manage increasing wear and tear caused by the combination of extreme heat, pressure, radiation and vibration on Peach Bottom safety systems throughout the requested 60- to 80-year extended period of operation.

Both units are GE Mark I boiling water reactors and are already operating within their first approved 20-year license extension to the original 40-year license which expired in 2013 and 2014, respectively. Exelon is now seeking NRC approval to extend the operation of Peach Bottom Unit 2 from 2033 to 2053 and Unit 3 from 2034 to 2054.

 “According to NRC regulations, the onus is on Exelon to demonstrate in its application how Peach Bottom operators will manage the destructive effects of aging on safety systems and the material reliability of structures and components for the extension period,” said Paul Gunter, Director of the Reactor Oversight Project with Beyond Nuclear. “This application fails to satisfy NRC regulations that require Peach Bottom to have effective age management programs throughout the next license renewal period,” he said.

Presently, there are as many as 16 known significant age-related degradation mechanisms (i.e. radiation and thermal induced embrittlement, stress corrosion cracking, fatigue) attacking the base metals, welds, concrete and entire systems including more than 1,200 miles of control, instrumentation and power cables at the two-unit reactor site. The industry, the regulator and national laboratories publicly acknowledge an abundance of gaps, deficiencies, and uncertainties in their present understanding of how these aging degradation mechanisms and their synergies destructively impact reactor safety and performance.

Analyzing a sufficient amount of information on the material condition of reactor systems, structures and components collected from reactor operating experience is essential, in fact required, to reasonably project Peach Bottom’s safety performance into the future. 

However, reactors in the US are closing due to a variety of economical, technological and political challenges. Several reactors have closed in just the past few years, more upcoming closures have been announced, and others could possibly close before Peach Bottom enters the proposed second license renewal period in 2033 and 2034. As currently trending, the amount of operating experience could be significantly reduced, consequentially reducing age management insights needed for the requested license renewal period.

“Exelon fails to acknowledge just how dependent its age management programs are on evidence gathered internally from Peach Bottom’s operating experience and externally from other reactors of like design and materials,” said Gunter, citing from expert testimony submitted with the legal filing to the NRC.

“Further, the application fails to address when the number of reactor closures and the associated reduction in the amount of external operating experience impairs the effectiveness of its age management programs,” he continued.

“Of more concern, the application is silent on how Exelon would provide the required operating experience gathered from alternate sources including strategic autopsies on the growing number of decommissioning reactors like Exelon’s Oyster Creek plant in New Jersey,” Gunter added.

According to Beyond Nuclear’s expert witness, David Lochbaum, a widely recognized independent nuclear engineer on reactor safety, “In order to comply with NRC relicensing regulations and protect public health and safety, Exelon needs to address several factors. First, how much of Exelon’s age management programs depends on operating experience of other reactors; second, how will Exelon determine what amount of operating experience information is sufficient to assure safety, and finally; how the required operating experience will be augmented if it is found to be insufficient,” Lochbaum said.

Beyond Nuclear concludes that without Exelon first demonstrating how it will reliably manage the increasing effects of aging during the second renewal, Peach Bottom cannot be relicensed.