The Nuclear Regulatory Commission has directed its technical staff to improve venting pressure during potential accidents at 31 U.S. reactors, including Oyster Creek Generating Station.
The Commission’s decision comes two years after the Fukushima meltdown in Japan and requires hardened venting systems at boiling-water reactors with Mark I and Mark II containments.
“In reaching this decision, the Commission engaged in thoughtful deliberation with each other as we each considered these important issues in our post-Fukushima accident review process,” said NRC Chairman Allison Macfarlane.
Since Fukushima, local advocates have petitioned to shut down U.S. nuclear plants with the same type of reactor as the Japanese plant.
In 1972, several years after Oyster Creek came online, the containment structures of Mark 1 boilers were deemed likely to fail under a severe accident, Paul Gunter, Director of the Reactor Oversight Project for Beyond Nuclear previously explained. Beyond Nuclear, an anti-nuclear organization, headed a petition that called for the immediate suspension of 17 nuclear facilities with General Electric (GE) Boiling Water Reactors Mark I Units, the same type of reactors at Fukushima that experienced a meltdown following an earthquake and tsunami.
It was later confirmed that there is a 90 percent failure rate under severe conditions, Gunter said. In 1989 the NRC approved the voluntary installation of vents, which would vent open containment to the atmosphere.
The same vents installed at Oyster Creek, were installed at Fukushima in 1991. When Japan was hit with a devastating earthquake and tsunami in March, those vents had a 100 percent failure rate on three reactors, Gunter said.
Oyster Creek, along with other Mark I and II Boiling Water Reactors, was already required under an NRC order issued in March 2012 to ensure that the plant has a reliable hardened vent system, which vents combustible gases from the plant’s containment following a severe accident, NRC spokesman Neil Sheehan said.
Exelon Generation, the operator of Oyster Creek, recently filed an integrated plan for addressing that requirement, he said.
Under the order the Commission issued this wee, the vent requirement is now being enhanced, Sheehan said.
NRC staff will have 60 days to finalize the order, which will require the vents to handle the elevated pressures, temperatures and radiation levels from a damaged reactor. The Order will also ensure plant personnel can operate the vents safely under these accident conditions.
NRC staff will also have a year to produce a technical evaluation to support rulemaking on filtering. Additional public input will be gathered during that time to complete analysis.
“Exelon fully supports the Nuclear Regulatory Commission's decision to use the rulemaking process to identify the most effective way to reduce radiation releases in extreme situations,” Oyster Creek spokesperson Suzanne D’Ambrosio said. “Like our many stakeholders and industry partners, we want the very best strategy available and we continue to advocate for an effective site-by-site solution.”
The Commission directed the staff to consider both the use of a filter to be placed on the vent, as well as a more performance-based approach using existing systems to achieve a similar reduction in radioactive release during an accident, a news release from the NRC said.
“With respect to the latter, it involves, among other things, plant operators using containment sprays and flooding to deal with the aftermath of a severe accident,” Sheehan said. “Also, Mark 1 Boiling Water Reactors can use the torus to help filter radioactive gases.”
A draft rule and final rule must be developed by March 2017.
“We recognize this as a very dangerous half measure,” Gunter said.
Essentially, the NRC has rejected its Japan lessons learned project directorate and senior management who recommended that the Mark I and Mark II containments be equipped with a severe accident capable vent and a high capacity radiation filter, he said. Although the venting systems will be improved, the filter aspect has been rejected.
Gunter related the NRC’s order to putting a screen door on a submarine. The order requires operators to vent pressure and hydrogen gas while ignoring that they will “fire hose” communities with radiation release without a filter in the case of a severe accident, he said.
“The order as it stands and proceeds does not provide for the best interest of the public health and safety but a financial agenda for the industry,” he said.
The NRC also rejected a prompt order, Gunter said.
“The commission voted with the industry to pursue further study and to explore rulemaking. This will add years if not outright kill the filter concept,” he said. “Essentially, Oyster Creek is going to be closed before they even begin to come up with a concept and we think this is incredibly disingenuous on the part of the Commission.”
Beyond Nuclear is now calling on the NRC for the revocation of Oyster Creek’s operating license, having filed a petition on Thursday. The New Jersey Environmental Federation has also signed on.