Oyster Creek Nuclear Generating Station- Tritium Investigation and Remediation Project
Groundwater monitoring commenced in April 2009 upon discovery of tritium contaminated water within an onsite cable vault near the plant’s intake structure. The source of the tritium was the degradation of buried piping that leaked into the surrounding groundwater onsite. Approximately 180,000 gallons of contaminated water was released from small holes in buried pipes. The highest concentration of tritium detected in an existing onsite groundwater monitoring well was 4.5 million pCi/L prior to the initiation of remediation. The NJDEP’s Site Remediation Program and Bureau of Nuclear Engineering worked with Exelon Corporation (Exelon) to develop a Remedial Action Plan. A NJDEP Spill Act Directive was issued in May of 2010 and required additional deeper
monitoring wells in the Cohansey aquifer to better define the extent of the groundwater contamination. A remedial pumping well (MW-73) was installed in September of 2010 near the center of the onsite tritium plume in the shallow Cohansey aquifer.
Independent sampling by the BNE confirmed that the contamination was contained onsite. Results from groundwater monitoring wells indicated that tritium had not reached the clay bottom of the Cohansey Aquifer and was not detected in any of the wells in the deeper Kirkwood Aquifer. There was no evidence of any threat to private or public drinking water supplies. The pipe leaks were repaired, pipes were isolated in underground concrete vaults, and the groundwater tritium concentration was reduced to less than the New Jersey Groundwater Quality Standard of 20,000 pCi/L. The site was sold by Exelon to Holtec Decommissioning International (HDI) to accomplish decommissioning and license termination.
On November 4, 2019, pumping well MW-73 was removed from service. The decision was based on the continued decreasing trend in tritium activity during the October 2019 Radiological Groundwater Protection Program (RGPP) sampling round and recommendations by the licensee’s groundwater consultants that further removal of tritium from the groundwater at this stage is minimal.
In a letter from NJDEP to HDI on January 9, 2020, the BNE and NJDEP’s Site Remediation Program confirmed that the Oyster Creek site had complied with the requirements outlined in the Directive, thereby closing it out. While the pump and treat remediation of tritium has been completed, HDI continues groundwater monitoring as part of its Radiological Groundwater Protection Program (RGPP). The BNE continues to receive split samples from these monitoring wells for an independent analysis of tritium by the BNE’s private Radioanalytical Contract Laboratory. Presently the BNE receives split samples from twenty (20) onsite monitoring wells on a quarter-annual frequency. Sample results are available for download to the public.