VERNON — Vermont Yankee administrators say they’re getting a stubborn groundwater intrusion problem under control and are no longer pursuing a proposal to discharge radioactive water into the Connecticut River.
While liquid continues to seep into the shut-down nuclear plant’s turbine building, that’s happening at a greatly reduced rate, spokesman Marty Cohn said.
So there is no current need to consider discharging the water, Cohn said. Vermont Yankee has been sending the contaminated liquid out of state by tanker truck for the past several months, but Cohn said the company is cutting back on those shipments.
“We had a plan, we implemented the plan, and the plan worked,” he said.
Entergy ceased power production at Vermont Yankee in December 2014, and administrators say they had a comprehensive water management plan for the Vernon site. But at some point, groundwater began leaching into the lower level of the turbine building at much greater rates than had been expected.
Due to its contact with the turbine building, the groundwater became contaminated with low levels of radioactivity, according to Entergy and federal officials.
The issue first came to light in a federal Nuclear Regulatory Commission inspection report this year. Within weeks, photos submitted to VTDigger showed that some of the water was being stored in open, commercially available swimming pools — an NRC-approved measure that illustrated the severity of the problem.
Those pools were a short-term solution. Eventually, Entergy deployed a series of industrial-sized bladders and steel tanks to hold the water, and the company hired a contractor to begin shipping it to out-of-state disposal sites.
In June, officials disclosed that Entergy also was considering asking for state permission to discharge some of the water into the nearby Connecticut River. At the time, Entergy had begun sharing some analytical data with state regulators regarding contaminants in the water.
But the discharge proposal has stagnated over the past few months, said George Desch, deputy commissioner of environmental conservation.
Entergy has not “submitted any additional data or a formal request to discharge,” Desch said. “Consequently, we have not been reviewing the data that they submitted with respect to the intrusion water.”
Cohn confirmed the discharge discussion is “on hold.” One reason, he said, is that preliminary examinations of discharge permit protocols discouraged Entergy from pursuing the idea.
“It was getting to be too complicated, so we decided to continue shipping” the water, Cohn said.
But more importantly, Cohn said, the water problem has abated. The rate of intrusion has dropped under 700 gallons a day — a big improvement, given that Entergy disclosed at a February meeting that it had seen influxes as high as 2,500 to 3,000 gallons daily.
Entergy has said it enlisted experts to advise on water control measures, and Cohn said those appear to be working. Simply sealing “a number of cracks” in the turbine building has helped, he added.
With flows decreasing and tanker shipments continuing, Entergy has been able to make a big dent in the amount of contaminated water stored on site. After shipping about 300,000 gallons off site, workers have emptied all water storage bladders and are planning to cut back from five storage tanks to one, Cohn said.
“What that means is that we’ve got a really good handle on our stored inventory,” he said.
As a result, Utah-based disposal contractor EnergySolutions is not sending as many trucks to Vermont Yankee these days. The company had been handling four 5,000-gallon shipments of Vermont Yankee water a week, but that has decreased to two a week and is expected to drop to one weekly shipment in September, Cohn said.
“By the end of this month, we will have caught up and will be cutting back on our shipments,” Cohn said.
That will save money. While Entergy has not released a total dollar figure for dealing with the groundwater intrusion problem, officials have said each tanker truckload costs about $20,000 — cash that comes from the plant’s decommissioning trust fund. Final cleanup of the idled plant won’t begin until the fund grows enough to cover the cost.
Entergy has been pursuing federal approval of a second water disposal contractor that could handle both intrusion water and so-called process water — liquid that had been used in plant operations. But there now appears to be less urgency behind that request.
“We still haven’t heard back from the NRC,” Cohn said. “But there’s no rush, and we’re not pushing.”