United States Nuclear Regulatory Commission - Protecting People and the Environment

Three Mile Island Accident of 1979 Knowledge Management Digest – Recovery and Cleanup (NUREG/KM-0001, Supplement 1)

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Publication Information

Date Published: June 2016

Division of Risk Analysis
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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The safe, expeditious recovery and cleanup of Three Mile Island Unit 2 (TMI-2), including removal of the fuel from the accident-damaged reactor, were necessary for the long-term protection of public health and safety and the environment. The cleanup campaign ensured that the TMI site did not become a long-term or permanent waste repository. The recovery activities that unfolded at TMI-2 in the weeks and months (and then years) after the March 28, 1979 accident were the result of a multi-organizational effort that included hundreds of dedicated and highly-skilled individuals. Implementation of recovery and cleanup activities was the responsibility of the licensee with support from their many contractors. Organizations that supported the licensee included the original architect engineers of TMI Units 1 and 2 (Gilbert Associates and Burns and Roe, respectively); the TMI-2 nuclear steam supply system vendor (Babcock & Wilcox); many volunteers from other nuclear power plants; the U.S. nuclear industry; and several international organizations.

The U.S. Nuclear Regulatory Commission (NRC) was responsible for the regulation of TMI-2 cleanup operations to ensure the health and safety of the public, and the TMI-2 occupational workforce, as well as the protection of the environment. The U.S. Department of Energy (DOE) was responsible for supporting an extensive research program, as directed by the U.S. Congress. In addition, DOE agreed to the removal and disposition of the entire reactor core for research, as well as certain solid nuclear wastes generated during the cleanup of TMI-2. The DOE and its national laboratories provided much-needed technical support to the licensee and the NRC in almost every aspect of the many TMI-2 research and recovery programs. The environmental agencies and nearby communities from the states of Pennsylvania and Maryland were responsible for ensuring that water qualities of the Susquehanna River and the downstream Chesapeake Bay were not adversely impacted by the damaged plant, or by the cleanup activities.

Need for Cleanup. The NRC’s Programmatic Environmental Impact Statement (PEIS) related to decontamination and disposal of radioactive waste resulting from the TMI accident (NUREG-0683) concluded that the decontamination of the TMI-2 facility, including the removal of the nuclear fuel and radioactive waste from the TMI site, was necessary for the long-term protection of public health and safety. The PEIS also concluded that methods existed, and could be suitably adapted to perform the cleanup operations with minimal releases of radioactivity to the environment.

The cleanup operations removed sources of potential radiation exposure that posed risks to the health and safety of the workers and the public. Accident-generated radiation sources were present in the form of airborne contamination; contaminated waste water; absorption of radioactive material on building and equipment surfaces; contaminated sludge in tanks, sumps, and building basement floors; contaminated filter cartridges and demineralizer resins; and damaged fuel and reactor components. As long as radioactive water occupied sumps and tanks, there existed a possibility of leakage into the groundwater, and subsequently, into the Susquehanna River. The contaminated water was also a source of direct radiation to workers requiring access to buildings in order to perform critical maintenance and repairs needed to keep the reactor in a safe-shutdown condition.

The PEIS categorized cleanup into four fundamental activities: building and equipment decontamination; fuel removal and decontamination of the primary coolant system; treatment of radioactive liquids; and packaging, handling, storage, and transportation of radioactive solid wastes.

About This Supplement.  The main objective of this supplement is to provide key historical documents in electronic format that were issued during the recovery and cleanup efforts. Brief overviews of various structures, systems, equipment, and activities that were associated with the recovery and cleanup of TMI-2 are provided in the written portion of this NUREG/KM to describe the contents of the many document collections in the accompanying DVDs.

Thorough overviews of the TMI-2 recovery and cleanup, including lessons learned, can be found in the Electric Power Research Institute (EPRI) report, "The Cleanup of Three Mile Island Unit 2, A Technical History: 1979 to 1990" and the special volume of the Nuclear Technology journal of the American Nuclear Society documenting 138 papers presented at the TMI-2 topical meeting in 1988.a

The seven major aspects of the recovery and cleanup, as presented in the EPRI report, were used to organize the contents in this supplement into the following sections: management and oversight; plant stabilization; worker protection; data acquisition and analysis; radioactive waste management; decontamination; and defueling; an additional section on after-defueling activities follows. This supplement chronicles those activities, which began a week following the accident, and ended with the completion of disposal of accident-generated water, and entry into post-defueling monitored storage in 1993.

The document collections in this supplement were mainly derived from publicly available correspondence, including attached reports, between the licensee and the NRC, and the results of research activities sponsored by the NRC and DOE. In all, the accompanying DVDs contain about 4,000 documents. Although an attempt was made to find and include a wide range of key documents, the collections provided on the DVDs are not complete. As such, a document collection might not provide a complete chronology of recovery, cleanup, and regulatory actions. A listing of documents in each document-collection folder is provided in spreadsheet format on each DVD (see the DVD folder, Common). Also, a list of more than 25,000 TMI-2 records indexed in the Public Legacy Library, dating from 1979 to 1999, is included in the spreadsheet.b

How to Use this Supplement.  A few suggestions for navigating through this supplement, and the many documents on the enclosed DVDs, are provided at the end of this NUREG/KM (see the section on DVD Navigation and Interpretation). Documents in the DVD folders, Status and Summary Reports, Licensing Actions, and Management and Oversight, might be applicable to all sections in this supplement. The historical documents provided on the DVDs are for reference only, and are not official NRC records. End notes to this supplement provide filenames of the cited documents on the DVDs. The units of measure used in this NUREG/KM reflect those used in the original source reports. In some cases, conversions were provided in the original reports. Refer to the back cover for conversion factors and formulas.

aEPRI-NP-6931 and many of EPRI’s historical reports on the TMI-2 accident and cleanup are currently (at the time of this publication) available from the EPRI’s website. Individual papers from Nuclear Technology, Vol. 87, Nos. 1 through 4, are currently available from the American Nuclear Society’s website.

bPublic Legacy Library of the NRC Agencywide Documents Access and Management System (ADAMS) provides bibliographic citations for earlier documents during the period from 1979 through 1999, which are available in microfiche formats. This library can be viewed from the NRC public website.

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