Structural Issues


   Radioactive Waste
   Structural Issues
   Emergency Planning
   Energy Alternatives

   Take Action!





Nuclear reactors are similar to cars or any other piece of complicated machinery in that they have limited shelf life. When they get old, they break down more often and maintenance activities become too costly and difficult. Pilgrim is old and no exception - time to quit.
More than 30% of nuclear power reactor equipment failures can at least be partly attributed to age-related degradation (Stephen Koff, “Nuclear Plant equipment Problems Worsening as reactors Age,” Newhouse News Service, December 9, 2002).

Current federal regulations governing reactor re-licensing allow owners to ignore the realities of age-related degradation that base risk calculations on the assumption that all equipment fails at the same rate. This ignores hundreds of technical reports by the NRC about age degradation of specific components such as valves, pipes, motors, cables, concrete, and switches.

These reports indicate that failure rate of these parts follows a standard bathtub curve (Susan Stanahan, “Reactor Revival; Old Reactors Being Re-licensed,” Mother Jones, November 2001). This means a high rate of failure at the beginning of the license, followed by a low and rather constant failure rate, concluding with a wear-out period showing an increased rate of failure as the original license is coming to a close.

Vermont Yankee Cooling Tower Collapses. A portion of a cooling tower at the Vermont Yankee reactor collapsed Wednesday, August 22. A broken 52” pipe was photographed spewing water into the ground, in the latest embarrassment for Yankee owner Entergy Corporation, the nation’s second-largest nuclear utility.


Just because the NRC has re-licensed old reactors does not mean that they are fit; rather it means that NRC’s re-licensing process does not take a hard look; assure that the current licensing basis shall be maintained during license renewal; and fails to even look at key areas.

OIG Report: Audit of NRC’s License Renewal Program, OIG-07-A-15, (Sept. 6, 2007), available at ADAMS accession number ML072490486. The Office of Inspector General in its Audit of the NRC’s License Renewal Program, 016-07-A-15, dated September 6, 2007, said that there was little documentary evidence that NRC staff has performed any meaningful independent review of the technical information provided by applicants in support of their license renewal requests. In numerous cases, NRC staff has simply copied extensive portions of the plant operator’s applications into agency decisions and reports without any indication that the staff has conducted any technical verification or review. Also the OIG found that the NRC Staff does not maintain its audit records in a way that would permit verification that the audits have been performed adequately. And by failing to retain the licensee documents that it audits, the Staff frustrates the public’s ability to challenge the adequacy of license renewal applications.

Based on the OIG report, environmental citizen groups filed petitions with the NRC to overhaul its review process before processing applications for license extensions by reactors in Vermont, Massachusetts, New York and New Jersey because the Commission does not have sufficient information to support a finding of “reasonable assurance” needed to protect public safety over the license renewal period for any audited plants (See NRC’s Electronic Library Adams). The NRC Commission rejected the petition, Commissioner Gregory B. Jaczko respectfully dissents, in part: Commission Memorandum and Order (CLI-08-23) at

Petitioner's Filings in License Renewals: See Petitioner's filings in Pilgrim's, Vermont Yankee's, Indian Point's, and Oyster Creeks' license renewal adjudications for specific examples of failures in the license renewal process. Outside the Northeast, the NRC inspected, gave a clean bill of health and issued a re-license to the Oconnee reactor. Shortly after it passed the re-licensing process, workers discovered the reactor’s cooling system, critical to preventing a meltdown, had sprung a leak – due to aging metal on nine nozzles (NRC Information Notice 95-17;NUREG/CR-6677-01).

Important Reports on Aging

1. U.S. Nuclear Plants in the 21st Century: The Risk of a Lifetime - A report by the Union of Concerned Scientists

2. Nuclear Information Resource Service: Aging Reactors -

3. NRC and Oak Ridge National Laboratory Report, “Boiling Water Reactor Internals Degradation Study” NUREG/CR-5754, September, 1993; NRC/BWORG Meeting, “Core Shroud and Vessel Internals Concerns,” Rockville MD, June 28, 1994  Source: Fact Sheet, Nuclear Resource Service, Paul Gunter

Deterioration of BWR Systems and Components: It is becoming increasingly clear that aging of reactor components poses serious economic and safety risks at BWRs. Pilgrim is a Boiling Water Reactor (BWR).

A report by NRC published in 1993 confirmed that age-related degradation in BWRs will damage or destroy many vital safety-related components inside the reactor vessel before the forty year license expires. The NRC report states "Failure of internals could create conditions that may challenge the integrity the reactor primary containment systems." The study looked at major components in the reactor vessel and found that safety-related parts were vulnerable to failure as the result of the deterioration of susceptible materials (Type 304 stainless steel) due to chronic radiation exposure, heat, fatigue, and corrosive chemistry.

Core Shroud Cracking: One such safety-related component is the core shroud and it is also an indicator of cracking in other vital components through the reactor made of the same material. The core shroud is a large stainless steel cylinder of circumferentially welded plates surrounding the reactor fuel core. The shroud provides for the core geometry of the fuel bundles. It is integral to providing a re-floodable compartment in the event of a loss-of-coolant-accident.
Cracking of circumferential welds on the core shroud has been discovered in a growing number of U.S. and foreign BWRs – including Pilgrim. A lateral shift along circumferential cracks at the welds by as little as 1/8 inch can result in the misalignment of the fuel and the inability to insert the control rods coupled with loss of fuel core cooling capability. This scenario can result in a core melt accident.
A German utility operating a GE BWR where extensive core shroud cracking was identified estimated the cost of replacement at $65 million dollars. The Wuergassen reactor, Germany's oldest boiling water reactor, was closed in 1995 after wary German nuclear regulators rejected a plan to repair rather than replace the reactor's cracked core shroud.

Rather than address the central issue of age related deterioration, U.S. BWR operators now opt for a dangerous piecemeal approach of patching cracking parts at least cost but increased risk. Pilgrim opted to patch their cracks instead on following the German, safer example of replacement. See: NRC and Oak Ridge National Laboratory Report “Boiling Water Reactor Internals Degradation Study” NUREG/CR-5754, September, 1993; NRC/BWORG Meeting, “Core Shroud and Vessel Internals Concerns,” Rockville MD, June 28, 1994

More Structural Issues