Whether the standard should be written by Congress or by the Environmental Protection Agency, it must be stringent enough to build confidence in the adequacy of public health protection in the face of legal and political challenges. In these times of budgetary shortages and slow progress in waste disposal, pressures are being exerted both on Congress and scientists for more lenient standards. In my opinion this relaxation of standards is unwise and unnecessary.

The argument over safety standards centers on five key issues:

1. For how long must protection be assured? Protection must be assured for the far distant future, as long as slow continued leakage of radioactivity can contaminate ground water. It is scientifically feasible to calculate radiation exposure to people who use that ground water hundreds of millennia from now (though the uncertainty of the calculations increases as the time period becomes longer). The annual radiation dose to a person living 100,000 years from now is estimated to be about 10 million times greater than that to a person during the first 10,000 years. The present scientific consensus requires such long-term calculations for evaluating future exposures and risks. Proposals within Congress and by industry and the Department of Energy would terminate calculations at 10,000 years, long before significant exposures occur. There is no scientific basis for such an enormous relaxation of health protection.

2. Who is to be protected? To protect all future people, radiation doses to individuals who receive maximum exposure must be less than the safe and allowable doses. It is international consensus that these maximally exposed people will be subsistence farmers who draw water from wells near the waste dump, grow most of the food they eat, and live in the era of maximum releases. All other people will receive lower doses. Some congressional proposals have rejected that traditional conservative standard in favor of calculating radiation doses averaged over the general population in the vicinity. Such "population dilution" produces calculations a hundred or so times lower than those produced from the traditional approach. Protecting the "average individual" would provide no assurance that all individuals will be protected. Legislation passed by the Senate included wording that can be interpreted as specifying that future wells producing contaminated water would be no closer than present wells, about 30 miles away from the Yucca Mountain Site. This would also be a considerable relaxation in health protection.

3. How much radiation exposure is allowable? Maximum doses to the public now allowed for licensed nuclear facilities are typically 5 to 25 millirems per year to maximally exposed individuals. Corresponding annual doses averaged over populations in the general vicinity of such facilities would be much less, typically a few hundredths of a millirem. Various proposals to relax the standard have been made by the nuclear industry, the National Research Council and by Congress. One proposal would permit releases that give population-average doses as high as 100 millirems per year, an enormously permissive departure from present regulatory practice in the U.S. and abroad. The Senate bill would allow about 30 millirems using a needlessly permissive rule recommended by the National Research Council (see below).

4. Can future people be excluded from the site area? Current proposals before Congress designate the Yucca Mountain site area extending far beyond the repository itself to be controlled as an exclusion area. Future people would be prohibited from living or drawing water from within the site area. However, there is no basis for assuming that institutions can be relied on to enforce such exclusion for tens to hundreds of millennia. Ignoring the higher doses that can be received by future individuals who could use water from nearby wells is an unwarranted relaxation of protection.

5. Can habits of future people be predicted? Because we cannot predict the character and habits of people who will live tens and hundreds of millennia from now, Congress (or whoever sets the standard) needs to address how future radiation doses are to be calculated. International consensus makes the conservative assumption that some future people will use contaminated ground water to grow most of their lifetime intake of food. Doses to these maximally exposed individuals are compared with the safe and allowable level. Congress should avoid a more lenient proposal in a National Research Council report that would attempt to estimate location, occupancy, and living habits of future people.¹* Less than lifetime occupancy by subsistence farmers would reduce calculated radiation doses and allow much greater release of radioactivity to the environment. There is no scientific basis for predicting where future people will live and how much of their lifetime consumption of food and water will be contaminated, yet the National Research Council proposes to make such predictions in the guise of policy. Some occupancy factors, hypothesized but without scientific basis, would allow releases of radioactivity to the environment several thousand times greater than now allowed for waste-disposal projects. The National Research Council has failed to recognize the serious fallacies in its proposal and its many scientific errors that would introduce further relaxation of protection and safety.

On each of these issues, I believe the traditional, conservative, scientifically based alternative is the proper, prudent, and economical one. If any standard is to be relaxed, then we should require that scientific fact and logic support the change. At the present time, no scientific bases exist to support a policy less stringent than the traditional subsistence-farmer approach in effect today. Congress must reject pressures for short-term expediency and economy lest, by enacting policy that compromises scientific validity and credibility, it undermines public confidence and puts an end to all further nuclear development and research.

The scientific community and the public will find it difficult to understand why Congress would adopt a standard that is less safe in protecting public health than the traditional approach(the approach that has been adopted for all geologic disposal projects in other countries and in the United States.

Thomas H. Pigford is a professor of nuclear engineering at the University of California in Berkeley California.

1. See: Committee on Technical Bases for Yucca Mountain Standards, Technical Bases for Yucca Mountain Standards, (Washington: National Academy Press, 1995); and SDA Vol. 4 No. 4.