In light of the recent problems that continue to arise at Pilgrim Nuclear Power Plant, residents and local officials are turning an eye toward possible contamination of the area’s ground water.

Meg Sheehan, Plymouth native and environmental attorney, said a major issue with the nuclear power plant is ground water pollution. Studies by the Department of Public Health have shown high levels of tritium, a radionuclide, in ground water wells.

Tritium is most commonly used as a component in the triggering mechanism in thermonuclear, or fusion, weapons.

At the Pilgrim plant, Sheehan said tritium is somehow being leaked into the ground water.  “Tritium cannot be removed once it is in the water,” Sheehan said.

The United States Environment Protection Agency states that there is no threshold of tritium in water below which there is no health risk. Therefore, there should be no tritium at all in the drinking water. According to the USEPA, exposure to tritium increases the risk of developing cancer. However, due to its low radiation emission, it is one of the least dangerous radionuclides.

In 2006, the Nuclear Energy Institute proposed that nuclear power plants begin a voluntary groundwater protection initiative to monitor groundwater for tritium. In response to reports of an unusually high level of tritium in May 2010, the Mass. Department of Public Health recommended Entergy install additional monitoring wells and begin collecting surface water samples. According to the DPH, the site currently has 21 monitoring wells.

Sheehan said the DPH reported 11 locations at the Pilgrim site that are potential sources for the tritium leak. For example, buried pipes, storage fuels and different drainage systems may contribute to the leakage.

Sheehan said her major concern, and the concern of many others, is that neither the state nor Entergy Corporation, the company that runs the station, have adequately studied which direction the ground water flows from the station. The Plymouth/Carver Sole Source Aquifer covers a large number of towns over 100 square miles and, although the water is assumed to be running toward Cape Cod Bay due to the pitch of the land, there is a possibility the contaminated water could be flowing into the aquifer.

Mary Lampert, Duxbury Nuclear Advisory Committee chair and member of Pilgrim Watch, an organization that aims to serve the public interest with regards to the nuclear power plant, said the organization would like to see monitoring wells installed onsite to sample the ground water and publicly report water contamination levels. Additionally, the organization would like to see off-site monitors installed to measure how much radiation is emitted into the air.

“It’s necessary for Entergy to put in more wells to figure out where the leak is,” she said. “We need to know whether it’s coming from the waste water treatment plant, the reactor itself or a crack somewhere on site.”

The site was re-licensed in May 2012 after 40 years of operation. The Nuclear Regulatory Commission allowed the Plymouth station to continue operations for another 20 years. 

Lampert said she is also concerned about the fact that there have been three issues with the plant in the first 21 days of the year. She cited many possible reasons for the various problems, including poor training and aging structures.

On Monday, Pilgrim Station operators manually shut down the reactor at 5:45 a.m. to investigate a leak associated with safety relief pilot valve RV-203-3B. In a press release, Entergy said the plant was in a safe, stable condition and there was no threat to public safety.

Lampert said it is evident the plant is showing age-related deterioration, as many reactors were designed 40 years ago.

David Lochbaum, director of the Nuclear Safety Project at the Union of Concerned Scientists, said on Dec. 21, 2012, Entergy submitted a report to the Nuclear Regulatory Committee about shutting down safety relief valve RV-203-3D due to indications that it was leaking. Entergy informed the NRC that its testing of the valve failed to identify any reason for the leak; no design problem, no assembly problem and no material degradation problems were found.

“Because no cause for the December 2011 leaking valve was identified, no steps could be taking to prevent future leaks,” Lochbaum said. “Now, they have a second valve to examine for potential causes. They will either figure it out or continue to shut down every year or so to replace leaking valves.”

On Thursday, Jan. 10, both recirculation pumps, which adjust power levels at the plant, stopped working, causing an unplanned shut down. On Tuesday, Jan. 15, the station had a bottom head drain valve leak that delayed the plant from going online. The station returned to service on Wednesday afternoon, Jan. 16, six days after the initial shut down. Before the shutdown, the plant had run continuously for 230 days.

Lochbaum said the NRC will examine the collection of shut downs to determine if there is a common cause such as insufficient funds for work, inadequate procedures or training, or whether it is simply “bad luck.” If the number of unplanned shut downs exceeds six in two years, the NRC will send more inspectors to the site.

“The NRC is undoubtedly curious about the recent string of problems and will be probing for common causes, if any are present,” he said.