Four violations of very low safety significance were identified during the latest U.S. Nuclear Regulatory Commission inspection of Calvert Cliffs Nuclear Power Plant in Lusby.
According to the report, three of the findings — all of which were classified as “green,” or of the lowest significance — are being treated as non-cited violations, and two were self-revealed violations by plant owner Constellation Energy Nuclear Group.
The cited violation, which CENG revealed, led to a turbine building siding failure during Hurricane Irene last August, the report states. The company did not ensure the building siding was installed in accordance with design requirements, and part of the siding broke off during the storm, at wind speeds that were significantly below design standards. As a result, Unit 1 experienced an automatic trip from 100 percent power due to a phase-to-phase short circuit on the main transformer when high voltage lines were struck by the dislodged siding.
The inspectors determined that CENG missed multiple opportunities to identify the siding installation deficiencies following several high wind events throughout the plant’s 37 years in operation, but corrective actions were immediately taken, the report continues, such as restricting personnel from outside areas when wind speed was greater than 40 mph until it had been verified that siding was properly installed. Other corrective actions included testing and inspecting the main transformer, making repairs and developing new installation requirements to meet design requirements. CENG additionally inspected all building siding inside the protective area to identify other possible deficiencies.
Kory Raftery, spokesman for Calvert Cliffs, said operators returned the unit to full power on Aug. 31.
“After Hurricane Irene, Calvert Cliffs promptly made the appropriate repairs to the turbine building siding, completed a thorough examination of the siding that was damaged in the hurricane and has aggressively pursued a program to strongly enhance our siding strength,” Raftery said.
A second finding was also associated with Hurricane Irene, when plant operators did not ensure that floor drains were free to drain and clear of debris in one of the emergency diesel generator buildings, contributing to inoperability of the generator due to clogged floor drains on Aug. 28. CENG took immediate corrective actions, however, and the violation will be non-cited, according to the report.
The remaining findings in the report include a self-revealed finding that CENG did not follow procedures appropriate to circumstances associated with protected safety-related equipment on Oct. 3, 2011, and a failure to evaluate licensed operators during annual operating tests on “important tasks” that would be performed inside the facility’s auxiliary building.
“At Calvert Cliffs, we pride ourselves on our commitment to safety and finding ways to improve our performance,” Raftery said. “We are a company made up of more than 900 highly skilled and highly trained professionals who live with our families in the Southern Maryland communities we serve. As professionals, husbands, wives, parents, children and neighbors of the people of Southern Maryland, safety is our No. 1 value and priority.”
CENG has a month from the report’s release to contest any of the identified findings.
mrussell@somdnews.com
