[B]RATTLEBORO – Vermont Yankee administrators have hauled away nearly 700,000 gallons of contaminated groundwater as they continue to deal with leaks into the plant’s turbine building.
The problem is persistent. Joe Lynch, a senior government affairs manager for Entergy, the owners of the Vernon plant, said Thursday that the water-intrusion rate now is 600 to 800 gallons daily.
But it is a significant decrease from the thousands of gallons of water that were leaking into the building daily when the flow was at its worst a few years ago. Lynch credited ongoing efforts to identify where water is entering the structure.
“Overall, it’s been a success,” he said.
After Vermont’s only nuclear power plant was shut down in December 2014, administrators noticed increasing amounts of water appeared to be leaching into the lower level of the turbine building. The problem, officials say, had been exacerbated by the plant shutdown. The heat from power production had evaporated some of the water.
The water issue first became public in a federal Nuclear Regulatory Commission inspection report in early 2016. Soon after, photographs showing water stored in commercially available swimming pools emerged.
Entergy and federal regulators said it was a short-term solution to deal with high volumes of water. Since then, the water – which is tainted by low levels of radioactivity due to its contact with the turbine building – has been collected and shipped via tanker truck to a disposal facility in Tennessee.
Those shipments have totalled 695,000 gallons of water so far, Lynch told Vermont Nuclear Decommissioning Citizens Advisory Panel members Thursday night in Brattleboro. Another disposal truck will leave the plant with its watery load on Monday.
The current intrusion rate is a few hundred gallons higher than Lynch reported last fall. But he said that’s “primarily due to seasonal fluctuations in groundwater.”
“The (water) table does move up and down over the course of the year, and typically in the winter/springtime we see that rise,” Lynch said. “So we don’t see that as any additional water coming in from unidentified sources.”
He added that “we continue to focus our efforts to reduce the water entering into the turbine building.” That effort, Lynch said, “has shown significant decreases in the overall intrusion rate.”
Lynch offered several other updates on Vermont Yankee issues at Thursday’s meeting, including:
• Crews are continuing work on a project designed to shrink the plant’s high-security “protected area.”
State regulators last year approved the project, which will decrease the protected area from 10.5 acres to 1.3 acres. The change will take effect when all of the plant’s radioactive spent fuel is moved into casks stored on two concrete pads.
“What this will allow us to do is have security focus on fuel, which is obviously the most important asset on the site,” Lynch said.
By reducing the size of the protected area, Entergy expects to save $1.2 million per month. Lynch said the change also could make decommissioning easier because it “will allow a little bit better access to the rest of the site.”
• The effort to move Vermont Yankee’s spent fuel into sealed casks is still on hold as crews perform precautionary inspections.
The NRC and Entergy recently reported that a potential issue emerged at another nuclear site involving casks made by Holtec International, the company that manufactures Vermont Yankee’s casks.
The NRC initially reported the problem as a loose bolt, but the plant’s decommissioning director on Thursday said that’s not entirely accurate: He described it as a “small threaded component.”
At this point, no problems have been identified in Vernon.
“We’re still in that (inspection) process right now,” Lynch said. “I don’t have the expected date when we would pick up the campaign. But this is an effort that we feel is very important to make sure that we don’t have the same type of issue that was identified to us.”
• Vermont Yankee’s decommissioning trust fund – the primary source for cleanup money – grew in 2017 despite Entergy’s continuing withdrawals.
The fund started the year 2017 with $561.6 million and ended the year with $581.5 million, Lynch said.
Entergy withdrew $36.9 million last year, and there were $4.2 million in fund expenses, which are mostly taxes. But the fund grew by $61 million due to investment gains.
That continues a trend of strong market performance that has boosted the trust fund recently.