May 1 - McClatchy-Tribune Regional News - Bob Audette Brattleboro Reformer, Vt.



Vermont Yankee personnel responded to a leak of tritiated water in a timely, appropriate and effective manner, according to Nuclear Safety Associates in a supplement to the Comprehensive Reliability Assessment submitted to the state last year.

Nevertheless, it wrote, the plant is potentially susceptible to similar leaks, which could prove to be a challenge to the plant's continued reliability.

Nuclear Safety Associates was hired by the state to review Yankee's reliability, a report that was meant to inform the Legislature, the Public Service Board and the Department of Public Service in making the decision whether the nuclear power plant in Vernon should be allowed to continue to operate past its license expiration date of 2012.

Entergy, which owns and operates the nuclear power plant in Vernon, has applied to the Nuclear Regulatory Commission to extend the license to 2032, but also needs approval from the state.

 Recently, the state Senate voted 26 to 4 against continued operation. The Public Service Board is in the process of determining whether the plant should receive a certificate of public good, which every public utility in the state must have to operate.

"While the occurrence of the leaks is not in and of itself indicative of a lack of management oversight, more management attention needs to be applied to detect future leaks at an early stage," wrote NSA. Until interim and long-term corrective actions

are implemented, stated NSA, reliability of the plant could be affected.

"Although the (advanced off gas) leak investigation and repair was a significant event, it did not affect the overall reliability of the plant," it wrote. "To ensure that long-term reliability is not impacted (Yankee) should increase its focus and improve its methods and practices for identifying plant leaks at an early stage through more effective monitoring. Specifically this is associated with all underground piping (including buried piping) and piping that is not readily accessible for inspection."

Currently, Entergy is conducting a root cause analysis to identify the conditions that precipitated the leak.

By the end of June, Entergy is also expected to submit an extent of condition report "to determine the vulnerability of the plant to similar leaks " noted NSA.

It will also identify actions necessary to detect and prevent similar leaks in the future, it stated in the supplementary report.

The supplementary report followed the revelation that there is underground piping systems at the Yankee plant that carry radionuclides, contrary to testimony given by Yankee representatives during hearings before the state last year.

To fulfill the requirements set forth under Act 189, which mandated the reliability assessment, DPS asked NSA to conduct a review of the plant's off gas system.

In consultation with the Public Oversight Panel, which was tasked by the Legislature to review NSA's reliability assessment, DPS also asked for an evaluation of Yankee's buried piping and tanks inspection program.

NSA concluded that Yankee practices "meet industry standards and in some cases exceed industry standards."

Even though the areas identified need to be addressed to ensure the plant will run reliably for another 20 years, "these specific areas will not prevent (Yankee) from operating reliably over an extended operating period," wrote NSA.

In the original reliability assessment, NSA concluded that Yankee can be a reliable station beyond its current operating license providing Entergy address five areas of concern -- an upgrade of its procedures, human performance, focused maintenance to the plant's condenser, cooling towers and its spare main transformer, delays in implementing industry recognized performance metrics and an ineffective use of change management.

In the supplementary report, NSA found that "low level repetitive equipment issues on non-safety related systems are not resolved in a timely manner and could challenge future plant reliability," which was identified in the original CRA regarding the cooling towers.

During the supplementary review, NSA determined that components in the off gas system have also been affected by "long-standing repetitive issues (which) challenged operations and could have impacted station reliability."

NSA recommended that Yankee be proactive in monitoring, detecting and managing leaks in non-readily accessible piping.

NSA concluded that Yankee does not have an effective program or practices in place for early leak detection and monitoring of underground and non-readily accessible piping."

None of the three pipe leaks in steam trap drain lines that were discovered between 2004 and 2006 were discovered by routine inspections "primarily due to the fact that they were in areas that are not easily accessible."

"The fact that inspections could not detect the degradation in the pipes and could not predict or prevent the leaks points to a weakness in piping inspections and leakage monitoring."

NSA found that despite the leak discovered in the off gas system's steam trap lines this year, the off gas system is reliable.

Bob Audette can be reached at raudette@reformer.com, or at 802-254-2311, ext. 273.

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