BRATTLEBORO — Vermont Yankee administrators have shipped 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, said Thursday that the water-intrusion rate now is 600 to 800 gallons daily.
But that's a big decrease from the thousands of gallons of water leaking into the building each day when flows were at their worst a few years ago. Lynch credited ongoing efforts to identify and address places where water is entering the structure.
"Overall, it's been a success," he said.
After Vermont Yankee shut down in December 2014, administrators noticed increasing amounts of water leaching into the lower level of the turbine building. Officials have said the problem was exacerbated by the lack of heat from power production: That heat previously had caused some water to evaporate.
The water issue first became public in a federal Nuclear Regulatory Commission inspection report in early 2016. Soon after, photos emerged showing water stored in commercially available swimming pools.
Entergy and federal regulators have said that was a short-term solution to deal with high volumes of water. Since then, the water — which is tainted by low levels of radioactivity because of its contact with the turbine building — has been collected and shipped via tanker truck to a disposal facility in Tennessee.
Those shipments now total 695,000 gallons, Lynch told Vermont Nuclear Decommissioning Citizens Advisory Panel members Thursday night in Brattleboro. Another disposal truck left the plant 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 downsizing 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 same company that manufactured 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 continuing to make withdrawals.
The fund started 2017 at $561.6 million and ended the year at $581.5 million, Lynch said.
Entergy took out $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.
Mike Faher can be contacted at mfaher@vtdigger.org.
