United States Nuclear Regulatory Commission - Protecting People and the Environment

Technology, Safety and Costs of Decommissioning Reference Nuclear Research and Test Reactors (NUREG/CR-1756, Volume 1)

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Publication Information

Manuscript Completed: February 1982
Date Published: March 1982

Prepared by:
G. J. Konzek, J. D. Ludwick, W. E. Kennedy, Jr., R. I. Smith

Pacific Northwest Laboratory
Richland, WA 99352

Prepared for
Division of Engineering Technology
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
NRC FIN No. B2117

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Abstract

Safety and cost information is developed for the conceptual decommissioning of two representative licensed nuclear research and test (R&T) reactors. Three decommissioning alternatives are studied to obtain comparisons between costs (in 1981 dollars), occupational radiation doses, potential radiation dose to the public, and other safety impacts. The alternatives considered are: DECON (immediate decontamination), SAFSTOR (safe storage followed by deferred decontamination), and ENTOMB (entombment).

DECON for the reference'research reactor is estimated to cost $0.85 million, to require about 1 year for planning and preparation prior to final reactor shutdown, to require about 0.7 years of active decommissioning, following reactor shutdown, and to-result in radiation doses to decommissioning workers of about 18 man-rem.

SAFSTOR for the reference research reactor with decontamination after 10, 30, or 100 years is estimated to cost $1.64, $2.24, or $4.5 million, respectively . Safe storage is estimated to cost $33,000 per year and would continue until the facility is decontaminated. It is estimated to require about 1 year for planning and preparation prior to final reactor shutdown, to require about 0.5 years to place the facility in safe storage, and to result in accumulated radiation doses to decommissioning workers of about 14 man-rem. Deferred decontamination is estimated to require a time span equivalent to DECON and to result in radiation doses to decommissioning workers of 1.5, 0.11, or <0.01 man-rem after safe storage periods of 10, 30, or 100 years, respectively.

ENTOMB for the reference research reactor after removing the activated reactor vessel internals is estimated to cost $0.56 million, to require about 1 year for planning'and preparation prior to final reactor shutdown, to require about 0.5 years of active decommissioning following reactor shutdown, and to result in radiation doses to decommissioning workers of about 17 man-rem.

The costs of continuing care-during entombment of the reference research reactor are estimated to be $6,100 per year. These costs would continue until either-the radioactivity can be shown to have decayed to unrestricted release levels, or until the facility is dismantled and decontaminated. The costs of dismantling the entombment structure are not analyzed.

DECON for the reference test reactor is estimated to cost $15.6 million, to require about 2 years for planning and preparation prior to final reactor shutdown, to require about 2.1 years of active decommissioning following reactor shutdown, and to result in radiation doses to decommissioning workers of about 322 man-rem.

SAFSTOR for the reference test reactor with decontamination after 10, 30, or 100 years is estimated to cost $17.6, $20.0, or $27.2 million, respectively. Safe storage is estimated to cost $120,000 per year and would-continue until the facility is decontaminated. It is estimated to require about 1.5 years for planning and preparation prior to final reactor shutdown, to require about 0.6 years to place the facility in safe storage, and to result in accumulated radiation doses to decommissioning workers of about 118 man-rem. Deferred decontamination is estimated to require a time span equivalent to DECON and to result in radiation doses to decommissioning workers of 86, 6, or <1 man-rem after safe storage periods of 10, 30, or 100 years, respectively.

ENTOMB for the reference test reactor after removing the activated reactor vessel internals is estimated to cost $14.6 million, to require about 2 years for planning and preparation prior to final reactor shutdown, to require about 2.1 years of active decommissioning following reactor shutdown, and to result in radiation doses to decommissioning workers of about 425 man-rem.

The costs of continuing care during entombment of the reference test reactor are estimated to be between $13,000 and $41,000 per year, depending on the security program (if-needed) and the requirements of the environmental monitoring program imposed by the amended nuclear license. These costs would continue until either the radioactivity can be shown to have decayed to unrestricted release levels, or until the facility is dismantled and decontaminated. The costs of dismantling the entombment structure are not analyzed.

For both of the reference R&T reactors studied, the safety impacts of the decommissioning operations on the public are found to be small, with the principal impact on the public being the radiation dose resulting from the transport of radioactive materials to a disposal site.

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