Initial Soil and Groundwater Remediation Work Now Underway

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View the animation of the recently stopped tritium pathway

Vernon, VT -- Entergy Corporation today announced it has identified and stopped the source of tritium leakage at its Vermont Yankee nuclear power plant and has begun initial work to support the remediation of soil and groundwater at the plant site.

The successful effort to identify the source of the leakage, fix the problem and prevent a recurrence capped an intense and rigorous effort by Entergy with the oversight of state and federal regulators that began in January when elevated levels of the radionuclide tritium were detected in monitoring wells built for that purpose.

In a special briefing for key stakeholders, Entergy’s Executive Vice President, Operations Mark Savoff expressed regret that the leak occurred. At the same time, Savoff announced that the company has embarked on a six-point, fleet-wide initiative to become an industry leader in tritium leak prevention, detection, and mitigation. The six-point initiative includes benchmarking industry best practices, prioritizing structures, systems and components, improved inspection techniques, and improved strategies for prevention, monitoring and mitigation of leakage.

Vermont Yankee engineers involved in the tritium investigation said the leakage came from two separate pipes inside a concrete tunnel. A floor drain that normally would have taken the water from the Entergy tunnel for normal processing was found to be clogged with debris and mud. This allowed the tritiated water to seep through an unsealed joint in the tunnel wall to the soil and eventually the groundwater.

The pipes, which drain moisture from the plant’s Advanced Off Gas (AOG) system, have since been rerouted. After identifying where the leakage to the soil occurred, workers continued efforts to identify other such pathways to the soil and found none.

Groundwater remediation to remove tritium will begin today with the pumping of shallow groundwater into above-ground containers for processing and reuse in the plant. The pumping will greatly reduce the concentration of tritium in groundwater. Also, planning is underway to remove about 150 cubic feet of soil that contains small amounts of other contaminants such as manganese and cobalt. The soil will be disposed of at a federally licensed disposal facility.

Since the elevated tritium concentration was first confirmed at Vermont Yankee in early January, an intense investigation has been underway by a multi-disciplined technical team including Vermont Yankee engineers, chemists and environmental monitoring specialists. In addition, individuals and organizations from outside the company that have expertise in hydrology, well drilling and robotics assisted in the effort.

Entergy Site Vice President Mike Colomb expressed gratitude to the investigation team for the dedicated, careful, and thorough approach it took in investigating, identifying and stopping the tritium leak. “This team has proven that a difficult problem can be solved with the right combination of expertise, experience and willingness to work day and night to see the project through to successful completion.”

There has been no detectable tritium level found in any drinking water well samples at the Vermont Yankee site or in the Connecticut River. Both the U.S. Nuclear Regulatory Commission and the Vermont Dept. of Health have said that the tritium in the groundwater at Vermont Yankee has not been a threat to public health and safety. Tritium is a radioactive form of hydrogen that occurs naturally and is also a byproduct of nuclear plant operations.

Entergy Corporation is an integrated energy company engaged primarily in electric power production and retail distribution operations. Entergy owns and operates power plants with approximately 30,000 megawatts of electric generating capacity, and it is the second-largest nuclear generator in the United States. Entergy delivers electricity to 2.7 million utility customers in Arkansas, Louisiana, Mississippi and Texas. Entergy has annual revenues of more than $10 billion and over 15,000 employees.

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