In May 2017, the Mass. Department of Public Health (MassDPH) published its latest Groundwater Investigation Update for Entergy’s Pilgrim Nuclear Power Station. The reports covers testing that occurred in the the last six months of 2016.
Even though Pilgrim is scheduled to shut down in 2019, it is important to remember that there are two more years of operations. This means there will also be two more years of tritium entering the groundwater and soils on the site. It is important to understand the contamination on the site considering decommissioning is right around the corner. If Pilgrim is allowed to postpone full cleanup of the site for decades (up to 60 years is possible!), then contamination will undoubtedly migrate and flush into Cape Cod Bay over time. This is especially true given rising sea levels and storms affecting the site.
Energy collects water samples from 23 groundwater monitoring wells and two surface water locations on the Pilgrim site. The samples are split between two labs – one lab contracted by Entergy (Teledyne) and the other is the Massachusetts Environmental Radiation Lab (MERL).
Some important numbers to keep in mind are:
- 3,000 picocuries per liter (piC/L) = screening level; based on 1/10th the NRC approved level of tritium in non‐drinking water (30,000 piC/L). Anything above 3,000 piC/L is of concern.
- 20,000 piC/L = U.S. Environmental Protection Agency’s (EPA) “safe” drinking water standard for tritium.
- 0 piC/L = The level of safe exposure identified by the National Academies of Science’s 2005 report called “Health Risks from Exposure to Low Levels of Ionizing Radiation.” There is no safe level of exposure to radiation and even low doses can cause cancer. To address this, EPA set a Maximum Contaminant Level Goal (MCLG) for all radionuclides (including tritium) as ZERO. EPA defines MCLG as the “level of a contaminant in drinking water below which there is no known or expected risk to health.”
- 5-25 piC/L = Normal background levels for tritium. While this can be variable depending on soils, rock type, wind, and drainage, typically 5-25 pCi/L are found in surface water and about 6-13 piC/L in groundwater.
Overview of May 2017 Report:
According to MassDPH, 7 of Pilgrim’s wells had no detectable levels above background. Fourteen wells had stable levels of tritium (above background but similar to historical records). Two of the wells (#216 & 210) saw increases in tritium levels. Two wells (#216 and #218) had levels above the 3,000 piC/L threshold.
Monitoring Well 210 – Monitoring of well #210 will increase from quarterly to every 3 weeks until the tritium levels stabilize. This is due to levels increasing from 597 pCi/L in August to 1,180 pCi/L in November.
Monitoring Well 216 – Well #216 is historically a “problem” well. It is located on the northeast corner of the turbine/reactor building. Historically, there have been increases in tritium in well #216 during the months of September and November. Last year was no different, and the “peak” was higher in 2016 (5,756 piC/L) than it was the previous year (4,300 piC/L). Entergy and MassDPH have been trying to figure out why these spikes occur since 2013. The 2017 MassDPH report states that Entergy is still working with a consultant (ERM) to figure out the cause. It is suspected to be due to residual tritium in a seismic gap (seismic gaps are man-made spaces between building foundations that allow them to move during an earthquake). According to a 2015 MassDPH report, the gap was re-sealed that year. However, spikes in tritium are still occurring during the fall months.
Monitoring Well 218 – Monitoring well #218 has also been a “problem” well. It was installed as part of the Neutralization Sump Discharge Line Investigation in late 2013 (due to excessive levels of tritium (69,000-70,000 pCi/L) detected in monitoring well #219).
Tritium has fluctuated from about 960 pCi/L to 6,481 pCi/L since this well was installed 2013 — with the highest tritium levels occurring in 2016 (a peak of 6,481 piC/L in March). Despite this, MassDPH reports that the levels in #218 (as well as well #211) have “stabilized” after a leak in the Condenser Bay area. This leak reportedly contributed to elevated levels in both wells. The leak was detected and repaired in early 2016. MassDPH states, “Recent results are near previous levels and Entergy continues to monitor the Condenser Bay area for leaks.” It is unclear if MassDPH is referring to results from testing done in 2017 (around the time the report was published), or results from late 2016 (July-Dec 2016 results ranged from 2,230 to 4,086 piC/L).