SEABROOK — The Nuclear Regulatory Commission has issued a report on NextEra Energy Seabrook nuclear power plant's application to extend its operating license 20 years, finding that if seven still outstanding issues are fixed, the power plant will have met the requirements needed for a new license.
The 770-page report is a technical review of safety concerns at Seabrook Station required in the commission's lengthy process of reviewing licensing at the nation's nuclear power plants. The safety evaluation report is one of two license-related reviews; the second review is a environmental review, which has not yet been issued.
NextEra Energy Seabrook is trying to have its operating licence extended from 2030 to 2050.
According to NRC Region 1 spokesman Neil Sheehan, the focus of the license renewal process is on the aging management programs for key safety systems, structures and components.
"We seek assurance that the systems, structures and components will be able to continue to safely perform their functions for an additional 20 years of operation," he said. "Such plans may include replacement of a component, such as a pump or electrical system, at some point during the license renewal period."
For nearly all the systems reviewed, commission staff concluded that Seabrook Station demonstrated that it met the NRC's requirements. However, seven issues remain open and must be resolved before the NRC can make a final determination on its safety evaluation, according to the letter sent to Seabrook Station by Brian Holian of the license renewal division of the NRC.
As expected, one of the seven open items relates to concrete degradation found in some areas of Seabrook Station's subterranean walls, due to alkali-silica reaction within the concrete. ASR is more commonly found in transportation structures like bridges and roads, where it has been successfully mitigated. But Seabrook Station is the first nuclear power plant to discover and report its presence within parts of the plant's structure.
Occurring when moisture is present, alkali-silica reaction is a slow chemical reaction between the alkaline cement and reactive silica found in some aggregates used to make concrete. ASR forms a gel that expands, causing micro-cracks that affect concrete properties, but which can take five to 15 years to show up.
According to Debbie Grinnell, of Seabrook Station's citizen watchdog group C-10, the ASR issue at the plant is a perfect example of why relicensing of nuclear plants should not occur 20 years in advance of license expiration. Seabrook Station is the first nuclear plant in the nation to deal with ASR degradation during a license renewal, and there are no NRC guidelines to address it, she said.
"The NRC's 770-page evaluation of Seabrook (Station's) license renewal, which lists open and unresolved safety items two years after NextEra applied for a license renewal 20 years in advance of their license expiration, identifies two critical weakness in the federal government oversight," Grinnell said. "The NRC license renewal allowance 20 years in advance of a license expiration must be changed to no more than 10 years, as it is unsafe, unreasonable and unacceptable, and routine NRC inspections done at US plants are inadequate."
According to NextEra Energy Seabrook spokesman Alan Griffith, the license renewal process is extremely rigorous and designed to thoroughly evaluate every aspect of a license renewal application.
"Addressing and closing open safety evaluation report items is an expected part of this comprehensive process," Griffith said.
According to the report, an item is considered open if, in the staff's judgment, "it does not meet all applicable regulatory requirements at the time of the issuance of the" report.
Sheehan said the commission always issues safety evaluation reports with open items, but some reports have had fewer by the time they get to this point.
"Typically, we issue the report with open items," Sheehan said. "It gives all of the parties a chance to see what areas we've identified that need addressing, and it gives them time to weigh in on the report."
According to the safety evaluation report, the other six open items include:
Staff concern that Seabrook Station has not, until now, implemented procedures and inspections to keep space between containment and containment enclosure buildings in a dewatered state. Accumulation of water in the space can potentially degrade the containment liner plate.
NextEra did not fully describe how it will use future operating experience to ensure the aging management program will remain effective for managing the aging effects during the period of extended operation, nor make clear how it intends to implement monitor operating experience on an ongoing basis to ensure effectiveness.
Sufficient information was lacking to evaluate pressure-retaining bolting and component external surfaces surrounded by seal cap enclosures that may be submerged due to ongoing leakage within the exposure.
Sufficient information was lacking to judge if treated borated water environments will be controlled sufficiently to determine if components will be adequately managed.
NRC staff had concerns whether the methodology used to develop pressure-temperature limits is consistent with requirements.
NRC staff is concerned with the management of cracking due to primary water stress corrosion cracking on the primary coolant side of steam generator tube-to-tubesheet welds that are made or clad with nickle alloy.
Sheehan said all of the open items must be resolved before the NRC will be able to issue a final decision on Seabrook Station's application to operate for an additional 20 years.