Frequently Asked Questions About Water Discharged at Pilgrim Nuclear Power Plant

Life cycle timeline consisting of 6 various stages of status (Pre-Licensing, Licensing, Construction, Operating, Operating with Intent to Decommission, Decommissioning) with the current status(s) shown in color, and the other available status are greyed out


The controlled releases of effluent at nuclear power plants, within specified regulatory limits designed to ensure protection of the public health and safety and the environment, is an activity that occurs throughout the operation and decommissioning of a facility. The authority and responsibility to regulate the effluent from these activities is split between two federal agencies, with the NRC regulating radioactive materials under the Atomic Energy Act of 1954 and the U.S. Environmental Protection Agency regulating pollutants under the Clean Water Act.

Regulatory Guide 1.109 (ML003740384) is an NRC guidance document that provides the NRC’s methodology to calculate annual radiological doses to the public from effluent releases from nuclear power plants.

Frequently Asked Questions related to Potential Radioactive Liquid Effluent Releases from Pilgrim Nuclear Power Station

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What is an effluent release?

Generally, when the NRC refers to effluent releases, it refers to radioactive material released into the environment as a gaseous or liquid discharge. Environmental discharges (liquid and airborne) are subject to a variety of regulations, depending upon the nature of the discharge, including by the NRC, the EPA, and potentially, state and local laws.

Who is responsible for determining how the liquid effluents at Pilgrim are removed from the site?

Holtec Decommissioning International (HDI) is responsible for determining how it will manage radioactive material in its liquid effluent. HDI may elect to use any of the methods allowed under the NRC's regulations, which allow discharge, shipment for disposal, or evaporation of the liquid and disposal of the resulting solid waste. HDI is required to keep records of releases, along with documentation that demonstrates that it is meeting license conditions and applicable regulations for the releases. The NRC reviewed and approved Pilgrim's Off-Site Dose Calculation Manual, which HDI uses to comply with its license. The NRC also routinely inspects HDI’s compliance with NRC regulations, their license, and approved manuals and procedures. In addition, EPA Region 1 and the Commonwealth of Massachusetts' Department of Environmental Protection jointly issued a National Pollutant Discharge Elimination System permit for Pilgrim that establishes requirements for non-radiological constituents of wastewater discharges.

How is effluent release monitored?

NRC-licensed facilities may discharge radiological wastes (i.e., gases, liquids, or particulates) into the environment provided that dose limits to members of the public (see 10 CFR 20.1301) are not exceeded and that doses are maintained As Low As is Reasonably Achievable (ALARA). The most common method for monitoring liquid discharges at Pilgrim is via effluent monitors.

Effluent radiation monitors are used at facilities, such as Pilgrim, with discrete discharge points, such as the plant stack for airborne releases or a discharge conduit for liquid releases. The licensee samples the releases and measures the radiation in the samples at the release points, where the concentration is the highest. In addition, the NRC provides oversight, through its inspectors, of Holtec’s compliance with the NRC regulations related to effluent release, monitoring, and reporting to ensure public health and safety associated with operation of the facility. As part of the monitoring process, the NRC also requires annual reports from Holtec that itemize shipment of radioactive waste to licensed waste repositories.

Do nuclear power plants typically release effluents?

Yes; the controlled release of liquid effluents at nuclear power plants, within specified regulatory limits, is an activity that occurs throughout the operation and decommissioning of a facility. The NRC’s regulations and licensing reviews for the facility consider such releases as part of the agency’s safety and environmental determinations, ensuring that it is safe for people and the environment.

Is the release of radioactive material in liquid effluent hazardous to the environment of the Cape Cod Bay?

The NRC has evaluated the environmental impacts of operation and decommissioning of Pilgrim Nuclear Power Plant, including impacts to the ecology of Cape Cod Bay, in several different environmental analyses. Most recently, Holtec assessed the potential impacts of its planned decommissioning activities on ecological resources in its post-shutdown decommissioning activities report (PSDAR) submitted to the NRC on Nov. 16, 2018 (ML18320A040). In 2019, the NRC staff reviewed Holtec’s PSDAR and found that the potential environmental impacts associated with the Pilgrim decommissioning activities are bounded by the Decommissioning GEIS and the SEIS and that the PSDAR meets the requirements of 10 CFR 50.82(a)(4)(i).

Additionally, the PSDAR evaluates the impacts of decommissioning activities on threatened and endangered species, which the Decommissioning GEIS identifies as a site-specific issue. See the question below concerning North Atlantic right whales for more information on this topic.

How far into Cape Cod Bay is the plant owner required to go before they can discharge effluent water and is this common practice at other nuclear power plants?

The regulations do not specify a particular distance before discharge, but do require any discharge location be evaluated to determine whether a potential discharge meets applicable requirements. Pilgrim’s release point is in the recirculatory cooling discharge channel located at the shore. Discharged effluent water quickly dissipates near the discharge point. As part of the licensee’s radiological environmental monitoring program (REMP), Holtec samples a variety of environmental sampling media in the vicinity of Pilgrim and at distant locations, including air particulate filters, seawater, sediment, shellfish (including mussels and clams), American lobster, and fishes. The NRC will continue to inspect Pilgrim until the plant is completely decommissioned and ensure that all activities are conducted in a manner protective of public health and safety.

Does the potential release of irradiated water into Cape Cod Bay at Pilgrim Nuclear Power Station harm federally endangered North Atlantic right whales (Eubalaena glacialis) or their critical habitat?

Section 7(a)(2) of the ESA requires that Federal agencies consult with the NMFS and/or the U.S. Fish and Wildlife Service, as applicable, to ensure that any action authorized, funded, or carried out by the agency is not likely to jeopardize the continued existence of any endangered species or threatened species; or result in the destruction or adverse modification of the critical habitat of such species. During its review of an application for the renewal of the Pilgrim operating license, the NRC staff consulted with the NMFS pursuant to ESA Section 7(a)(2) to address the potential impacts of the continued operation of Pilgrim for an additional 20 years (i.e., until June 8, 2032) on federally listed species and designated critical habitats. As a result of that consultation, the NMFS concluded in 2012 that the continued operation of Pilgrim under the terms of a renewed operating license is not likely to adversely affect any listed species under NMFS jurisdiction, including the North Atlantic right whale (ADAMS Accession No. (ML12145A072). The NMFS also determined that continued operation would have no effect on North Atlantic right whale critical habitat.

In 2013, Entergy Nuclear Operations, Inc. (Entergy) submitted a regulatory commitment to the NRC to supplement Pilgrim’s environmental monitoring to include reporting of any confirmed sightings of listed whales in the vicinity of the plant (ML14007A141). As part of this commitment, Entergy developed whale sighting protocols to be included in its site procedures. Since that time, Entergy has reported the sighting of numerous North Atlantic right whales off the coast from Pilgrim. The NRC staff discusses these sightings with NMFS when they occur; none have necessitated the NRC to reinitiate ESA Section 7 consultation.

Additionally, specifically with respect to the decommissioning process at Pilgrim, Holtec assessed the potential impacts of its planned decommissioning activities on aquatic ecological resources, including federally protected species and habitats, in its PSDAR submitted to the NRC (ML18320A034 and ML19015A020). Holtec did not identify any planned decommissioning activities that would adversely affect federally listed species, designated critical habitat, or EFH. After reviewing this information; the NRC staff determined that the re-initiation of either ESA Section 7 consultation or EFH consultation with NMFS was not required. As HDI’s decommissioning plans mature, it will update the PSDAR in accordance with applicable NRC regulations and initiate any other necessary licensing actions if potential impacts to federally protected species and/or habitats are identified. At such time, the NRC staff would determine whether the updated information would necessitate the NRC to reinitiate consultation with NMFS.

Given the continuous nature of the effluent releases, how is the environmental safety at Pilgrim Nuclear Power Station ensured over time?

Holtec is required to keep records of effluent releases, along with documentation that demonstrates that it is meeting license conditions and applicable regulations for the releases. To ensure that Holtec is meeting its licensing basis relating to radioactive effluents, the NRC reviewed (and approved) Pilgrim's Process Control Program and Off-Site Dose Calculation Manual (ML16148A702). The Process Control Program establishes the requirements for processing effluents and demonstrating that all doses will be ALARA. The Off-Site Dose Calculation Manual ensures compliance with NRC regulations and the plant license.

Holtec will also continue to conduct routine environmental sampling of vegetation, water, sediment, fish, and shellfish through its radiological environmental monitoring program (REMP) to ensure there is no significant accumulation of radionuclides. The REMP results will continue to be provided to the NRC in the licensee’s annual radiological environmental operating report, which is publicly available.

In addition, EPA Region 1 and the Commonwealth of Massachusetts' Department of Environmental Protection jointly issued a National Pollutant Discharge Elimination System permit for Pilgrim that establishes requirements for non-radiological constituents of liquid effluent discharges and oversee compliance with its requirements.

Information on the NRC’s Regulations for Radioactive Release:

  • The NRC’s regulations governing radioactive releases are based on dose to the public, not the volume of the release (see 10 CFR 20.2001; 20.1301; 20.2003; 20.2004; 20.2005; and 10 CFR 35.92).
  • The same requirements apply to decommissioning and operating reactors.
  • During decommissioning, the NRC continues to inspect the licensee’s effluent and environmental programs at least annually.

Key Technical NRC Regulatory Guides (RG) on Radiological Effluents:

  • RG 1.21, Measuring, Evaluating, and Reporting Radioactive Materials in Liquid and Gaseous Effluents and Solid Waste, addresses the measuring, evaluating, and reporting of effluent releases, solid radioactive waste shipments, and public dose from nuclear power plants.
  • RG 1.109, Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I, provides the detailed implementation guidance for demonstrating that radioactive effluents conform to the ALARA design objectives of 10 CFR Part 50, Appendix I.
  • RG 4.1, Radiological Environmental Monitoring for Nuclear Power Plants, discusses principles and concepts important to environmental monitoring at nuclear power plants. The RG provides guidance on Radiological Environmental Monitoring Programs (REMP) for routinely monitored exposure pathways and annual reporting to the NRC.

Regulations on effluent releases and regulatory guides are available on the NRC public website.
For further questions regarding decommissioning activities at Pilgrim, please visit the NRC’S Frequently Asked Question about Reactor Decommissioning page.

Page Last Reviewed/Updated Thursday, August 25, 2022