Radiation Standards:

Scientific Basis Inconclusive, and EPA and NRC Disagreement Continues

RCED-00-152: Published: Jun 30, 2000. Publicly Released: Jul 14, 2000.

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Pursuant to a congressional request, GAO examined the Environmental Protection Agency's (EPA) and the Nuclear Regulatory Commission's (NRC) radiation standards, focusing on: (1) whether the U.S. radiation protection standards have a well-verified scientific basis; (2) whether federal agencies have come closer to agreeing on standards since GAO reported on this issue in 1994; and (3) how implementing these standards may affect the costs of nuclear waste cleanup and disposal activities.

GAO noted that: (1) U.S. regulatory standards to protect the public from the potential health risks of nuclear radiation lack a conclusively verified scientific basis, according to a consensus of recognized scientists; (2) scientists have assumed that even the smallest radiation exposure carries a risk; (3) this assumption extrapolates better-verified high-level radiation effect to lower, less well-verified levels and is the preferred theoretical basis for the U.S. radiation standards; (4) some say that the model is overly conservative and that below certain exposure levels, there is no risk of cancer from radiation; (5) others say that the model may underestimate the risk; (6) interest among scientists in obtaining a more conclusive understanding of the effects of low-level radiation has been evident in recent federally funded initiatives, including a reassessment by the National Academy of Sciences of the latest research evidence on the risks of low-level radiation; (7) also, a 10-year DOE research program, begun in fiscal year 1999, has been specifically addressing the effects of low-level radiation within human cells, in part to help verify or disprove the linear model; (8) although GAO recommended as far back as 1994 that EPA and NRC take the lead in pursuing an interagency consensus on acceptable radiation risks to the public, they continue to disagree on two major regulatory applications: (a) the proposed disposal of high-level nuclear waste in a repository at Yucca Mountain; and (b) the cleanup and decommissioning of nuclear facilities; (9) centrally at issue between the two agencies is groundwater protection; (10) EPA applies community drinking water limits for radioactive substances to groundwater at nuclear sites while NRC includes groundwater and other potential contamination sources under a less restrictive limit of 25 millirem a year for all means of exposure, an approach that conforms to internationally recommended radiation protection guidance; (11) as applied in proposed standards for nuclear waste disposal at Yucca Mountain, EPA's groundwater approach has been criticized as technically unsupported by the National Academy of Sciences, which Congress mandated to recommend standards for the repository; (12) the costs of implementing different radiation standards vary, depending on the standards' restrictiveness; and (13) comprehensive estimates of overall costs to comply with current and prospective standards were unavailable.

Matter for Congressional Consideration

  1. Status: Closed - Not Implemented

    Comments: NRC published their final rule on groundwater protection standards for yucca mountain by incorporating EPA's groundwater protection standards. NRC and EPA did not resolve any disagreement between their groundwater protection standards. Instead, according to DOE "Yucca Mountain Project Site Suitability Material," NRC and EPA acted pursuant to specific directives in the Nuclear Waste Policy Act, in which Congress first assigned to EPA the responsibility to set these standards, and later in the Energy Policy Act of 1992, which directed the EPA to act in conjunction with the National Academy of Sciences and develop a standard specifically for Yucca Mountain. According to Tim McCartin, NRC, Advisor to the Director of the High Level Waste Repository Safety, no Congressional action was taken to resolve the NRC/EPA disagreement. In addition, EPA and NRC signed a memorandum of understanding on October 9, 2002, that addressed the issue of decommissioning. Again, according to Mr. McCartin, this memorandum was signed without congressional action.

    Matter: The congressional committees of jurisdiction may wish to reconcile EPA's and NRC's policy differences on groundwater protection for Yucca Mountain. Also, in connection with the two agencies' efforts to complete a memorandum of understanding relating to the cleanup and decommissioning of nuclear sites, these Committees may wish to clarify the agencies' regulatory responsibilities.


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