On Oct. 10, 2011, the NRC was informed by FENOC that its workers identified cracks in the shield building while the plant was shut down to replace the reactor vessel head. FirstEnergy consistently told the public that the cracks were confined to “architectural elements” or “decorative elements” of the wall. A team of Davis-Besse personnel and outside contractors has been conducting the analysis, said FirstEnergy.
The shield building is a 2.5-foot thick reinforced concrete building that surrounds the containment vessel that houses the nuclear reactor. The damage is extensive enough that the NRC required FirstEnergy to assume, in its calculations of the strength of the wall, that the vertical outer rebar mat did not even exist.
The NRC thoroughly reviewed the cracks after they were discovered and determined that they did not pose an imminent safety issue. The NRC held a public forum after allowing the power station to resume operations even though the causes of the cracking are unknown. On February 16th, a spokesperson for the utility said, that the report was nearing completion and due at the end of the month, adding FirstEnergy is moving ahead with its application to extend the facility’s operating license.
The Nuclear Regulatory Commission today announced it received the report and will initiated a rigorous review of FirstEnergy Nuclear Operating Co.’s (FENOC) causal analysis of cracks in the shield building at the Davis-Besse Nuclear Power Station, which was transmitted on February 28th, and will schedule a public meeting and issue an inspection report to communicate its conclusions to the public once the review is complete.
FENOC’s 119-page root cause report indicates that absence of an exterior weatherproof coating on the Shield Building allowed moisture associated with the blizzard of January 1978 to migrate into the concrete, freeze and expand, causing tight, subsurface cracks in portions of the building. The root cause report concludes that the cracking occurred following the blizzard’s combination of extreme weather conditions, which included three days of driving rain preceding a drastic temperature drop to around 0-degrees Fahrenheit and intense winds throughout the storm.
In addition to reviewing FENOC’s root cause submittal, the agency will assess the company’s proposed corrective actions and long-term monitoring program of the shield building. Four NRC inspectors have been monitoring FENOC’s investigation of the root cause since it started.
The press release published by FENOC included a disclaimer portion, that exceeded the length of text in the actual press report, warning that the statement included “Forward-Looking Statements”, which were described as statements based on information currently available to management.
The statement added such statements are subject to certain risks and uncertainties, and typically contain, but are not limited to, the terms “anticipate,” “potential,” “expect,” “believe,” “estimate” and similar words. Forward-looking statements involve estimates, assumptions, known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. FENOC did add that actual results may differ materially due to a variety of listed reasons.
When FirstEnergy made its presentation at the January 5 public hearing, its site Vice President, Mr. Barry Allen, admitted for the first time that the cracking was located along the line of the main outer rebar. But, Mr. Allen, did not mention FirstEnergy’s previous misrepresentations or explain the significance of the new description.
A coalition of environmental groups last week filed briefs with the Atomic Safety Licensing Board supporting their challenge to the request by FirstEnergy for extending the station’s operating license. The coalition contends FirstEnergy – with the complicity of NRC staff – kept the extent of the cracks from the public until pressured by Congressman Dennis Kucinich, who then pressed the NRC for a public meeting to discuss the issue.