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Friday, September 30, 2016

U.S. NRC Blog Update: Baffle Bolts: An Update

New post on U.S. NRC Blog

Baffle Bolts: An Update

by Moderator
Neil Sheehan
Public Affairs Officer
Region I
There have been some new developments since our last blog post, on June 1, regarding degraded reactor vessel bolts identified at a pair of nuclear power plants in the Northeast. Most notably, both the Indian Point 2 plant, in New York, and the Salem 1 plant, in New Jersey, returned to service over the summer.
BaffleBoltsGraphic1_cleanbigfontIndian Point 2 came back online in late June after 278 of the plant’s 832 baffle-former bolts were replaced. As for Salem 1, it was restarted on July 30th after changing out 189 of its 832 baffle-former bolts.
In both cases, prior to the restarts, the NRC conducted independent evaluations of analyses done for the plants’ respective owners by the reactor vendors looking at how many new, more robust bolts had to be installed to maintain safety margins and ensure the structural integrity of the baffle-former plates. The agency also had specialist inspectors at the plants for first-hand observations and information-gathering on bolt-removal and -replacement activities.
Based on those reviews, the NRC concluded that the reactors were safe to operate. The bolts will be subject to further inspections at the reactors’ next refueling outages, which typically occur about once every 18 to 24 months.
Nevertheless, the NRC identified a “green” (very low safety significance) non-cited violation at Indian Point 3 related to the bolts issue in an inspection report issued on Aug. 30th. A similar non-cited violation has also been identified at the Salem nuclear power plant, as documented in an NRC inspection report issued on Sept. 22.
In both cases, the plant owners had not completed a necessary process to document its conclusion, following identification of degraded bolts on one unit, that the second unit was safe to continue to operate. After the NRC raised concerns regarding the deficiencies, the companies undertook corrective actions, including completing and documenting the evaluations.
Looking ahead, there is still more work to be done. Bolts from both reactors have been or will be sent to labs for metallurgical analysis. Also, the NRC will continue to engage the nuclear industry on its plans for addressing the issue
An NRC web page has been updated to reflect the latest available information on this topic, including the NRC slides from a related July meeting and a summary of the session.
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