Radioactive Waste Focus of Future NRC Inspection at Plant
Although the Nuclear Regulatory Commission found no significant safety issues at the Oyster Creek Generating Station during its first inspection as a decommissioning power reactor, its staff found a large number of issues dealing with radioactive waste facilities, processing systems and equipment.
“The inspectors toured radwaste facilities, including the new radwaste (NRW) building and low level radwaste (LLRW) building. The inspectors found degraded conditions, including poor material conditions, lighting, heating, and housekeeping and storage in both facilities,” according to the Feb. 19 inspection report summary. The report also noted inspectors expressed their concerns at a debriefing with plant officials.
NRC staff conducted the on-site inspection Dec. 17-20 for the purpose of reviewing radioactive waste treatment and effluent and environmental monitoring. The inspection included observation by NRC personnel, discussions with Exelon staff, and a walk-down of the site. All of the monitored activities were to determine the effectiveness of the plant’s radiological programs.
During a follow-up call with Exelon Generation, which owns and maintains the permanently shuttered nuclear power plant, the company described its recovery plans. The plans and associated action items will be part of a follow-up inspection in 2019. Still, no significant findings were identified in the inspection.
The inspectors noted the licensee planned for a significant amount of output from these facilities during the transition from an operating nuclear power plant to the safe storage of spent fuel (SAFSTOR) decommissioning.
During SAFSTOR, a facility is left intact or may be partially dismantled, but the fuel is removed from the reactor vessel and radioactive liquids are drained from the systems and components then processed.
“Radioactive decay occurs during the SAFSTOR period, lowering the level of contamination and radioactivity that must be disposed of during decontamination and dismantlement,” according to the May 2018 Post-Shutdown Decommissioning Activities Report Exelon filed with the NRC.
In its report, the utility company said the primary objectives for decommissioning the plant are to take it out of service, reduce residual radioactivity to levels permitting unrestricted release, restore the site, perform the work safely, and complete the work in a cost-effective manner.
“The selection of a preferred decommissioning alternative is influenced by a number of factors at the time of plant shutdown,” the May 2018 report read. “These factors include the cost of each decommissioning alternative, minimization of occupation radiation exposure, availability of high-level waste (spent fuel) repository or a Department of Energy interim storage facility, regulatory requirements and public concerns.”
In 2011, the NRC revised its regulations governing spent fuel rods, allowing for initial and renewal terms of up to 40 years rather than 20-year terms for dry cask storage. The regulations do not limit the number of times an applicant can request renewal of a cask or storage system certificate, provided the applicant demonstrates the effects of aging on the components are adequately addressed in accordance with the regulations.
Federal law requires decommissioning to be completed within 60 years of a nuclear plant being taken permanently offline. Under this method, a nuke is placed and maintained in safe storage, allowing radioactivity levels to decrease through decay. It’s followed by decontamination and dismantlement, according to the report. A license termination plan will be developed and submitted to the NRC at least two years prior to termination of the license.
In addition to environmental monitoring, inspections included safety reviews, design changes, self-assessment, corrective actions, decommissioning performance, maintenance, and spent fuel pool safety. Inspectors performed document reviews, observations and spoke directly with plant personnel to assess decommissioning performance and status reviews.
The process included “verifying licensee activities were in accordance with license and conditions and docketed commitments, as well as within the bounds of the docketed post shutdown decommissioning activity report,” according to the Feb. 19 summary of the inspection report.
Some of the items assessed during the review were the operability and functionality of systems necessary for safe decommissioning through the control room. Plant walkdowns included radioactive effluent monitoring, spent fuel pool cooling, level and temperature control, as well as equipment important to emergency planning. NRC staff also ensured appropriate plant staffing and management oversight.
“During the inspection period the inspectors observed portions of the 230kV line removal, control rod drive mechanisms removal, and spent fuel pool level and temperature indication changes. The inspectors determined through the plant tours and activities observed that Exelon conducted activities in accordance with the regulatory requirements and plant procedures,” according to the report.
As part of its inspection at the permanently shutdown nuclear reactor, NRC staff also confirmed the safe wet storage of the spent fuel in the spent fuel pool, according to the inspection report issued Feb. 19. The review included siphon and drain down protection, instrumentation, alarms, leak detection systems, cleanliness controls, and electrical power supply adequacy. The NRC found Exelon employees adequately managed the spent fuel pool within technical and procedural requirements for water level, chemistry and temperature.
Inspections of a spent fuel pool post-shutdown do not differ significantly from those at operating nuclear reactors, according to Neil Sheehan, public information officer for the NRC Region 1 office. Guidance calls for inspectors to ensure permanent and temporary modifications, post-shutdown, do not adversely impact the spent fuel pool cooling system, he said.
“But the other basics are the same: chemistry, temperature indications, level indications, system configuration, pump surveillances, etc.,” he said, noting that the spent fuel pool cooling system is the most safety-significant system at a decommissioning power plant and receives more attention. “Our inspectors almost always meet with the system engineer and perform system walkdowns (visual assessments).”
This is the first time such inspections were conducted since Oyster Creek was permanently taken offline in Sept. 17, 2018, more than a year prior to a previous agreement with the state of New Jersey so Exelon Generation didn’t have to retrofit the site with cooling towers.
Plant employees completed the final transfer of spent fuel from the core reactor to the spent fuel pool, following the beginning of an outage that took the plant to permanent shutdown. Mike Gallagher, vice president of license renewal and decommissioning for Exelon Generation, made the official notification to the Nuclear Regulatory Commission in a Sept. 25 letter.
Along with its formal notification to the NRC on the permanent shutdown of the nuke plant and transfer status of the spent fuel, Exelon Generation is no longer authorized to operate the reactor.
“We will keep a residential inspector on site at the plant for several months after shutdown,” Sheehan said, noting the inspector will focus on the site’s safe transition from an operating reactor to one entering the decommissioning phase of its life cycle. “Once we no longer have a resident inspector present, we will continue to perform reviews of decommissioning activities at the plant. A key focus in the next several years will be on the transfer of spent nuclear fuel from the spent fuel pool to dry cask storage.”
Dry cask storage has been in use at nuclear power plants for more than three decades, beginning with the Surry Power Station in Virginia. At one time, it was thought to be a temporary solution to house spent fuel. That changed when the idea of using the Yucca Mountain repository, located about 90 miles from Las Vegas, was shelved. Currently, the NRC is reviewing applications for two potential interim sites to house spent nuclear fuel, one in Texas and the other in New Mexico. In the meantime, the only option for U.S. nuclear power plants is to store spent fuel from the reactor vessel on site, federal officials have said.
The Atomic Safety and Licensing Board, an arm of the NRC, last month said it would render a decision on standing and contention admissibility in the New Mexico application within 45 days of its review of all motions and contentions. The board held a two-day legal proceeding in January on the application, submitted by Holtec International, the Camden-based company seeking to kickstart decommissioning at Oyster Creek should a license transfer be granted by the federal government. The board may hold adjudicative hearings on major licensing actions by the NRC but is independent of the NRC staff. A board’s rulings may be appealed to the commission, a five-member board that sets NRC policy.
Reposted from The Sandpaper