Concerns spread over "Baffling Reactor Vessel Bolts" in aging U.S. PWRs

This image, used by Lochbaum at UCS in his "All Things Nuclear" blog post, as well as his NIRS-hosted Webinar, shows the location of former plates and baffle plates at the heart of PWR reactor pressure vessels. The baffle-former bolts play a critical safety role in directly cooling water flow through the reactor core.As reported by Aaron Larson at POWER, degraded baffle-former bolts at the core of U.S. pressurized water reactors (PWRs) has raised the specter of an industry-wide safety problem. As the article reports, Salem Unit 1 in NJ has at least 18 bolts exhibiting degradation, upon visual inspection. Indian Point Unit 2 in NY, however, exhibited 227 degraded bolts, upon more rigorous Ultrasonic inspection -- a whopping 27% of the bolts there.

Such problems with bolts, the article reports, date back to the 1980s in France. However, it stands to reason that age-related degradation -- specifically, irradiation-assisted stress corrosion cracking -- contributes significantly to the bolt problems.

Both inspections -- at Salem 1 and Indian Point 2 -- resulted from 20-year license extension aging management plans. In the case of Indian Point, this was forced by the State of New York Attorney General's office, leading the state's intervention against Indian Point's license extension.

Despite the problems found at Indian Point 2, Entergy Nuclear has refused to inspect Indian Point Unit 3 to determine how bad the degradation is there. Nor does it plan to until 2019.

As reported by POWER above, PSEG has moved up its Ultrasonic inspections from 2019 to now, given the disconcerting bolt degradation revealed upon visual inspection.

As explained on April 28th by Dave Lochbaum at Union of Concerned Scientists (UCS), on a Nuclear Information and Resource Service (NIRS) sponsored Webinar (entitled "Indian Point's Baffling Reactor Vessel Bolts"), baffles and formers play a critical safety role, in directing coolant flow through PWR reactor cores:

April 28, 2016. NIRS webinar on investigation of reactor pressure vessel bolts at New York's Indian Point reactors, which revealed numerous deficiencies and failures. The webinar examines those failures and explores the implications for reactors across the U.S. and world. Full video/audio of webinar. Slides only from presentation by David Lochbaum of Union of Concerned Scientists.

In an April 7 blog post at All Things Nuclear, Lochbaum praised NY Governor Cuomo and NY Attorney General Schneiderman for thier leadership in the Indian Point license extension interventions, that forced the baffle-former bolt inspections, that revealed the widespread degradation.