Las Vegas Weekly

News: Yucca Mountain Exposure Limit Questioned

By Rob Bhatt


An official with the state agency most vocally opposed to nuclear waste storage in Nevada contends that the Nuclear Regulatory Commission's proposed limit on radiation exposure contradict existing federal laws.

Steve Frishman, technical planning coordinator for Nevada Agency for Nuclear Projects, says the 25 millirem (mrem) dosage limit proposed by the NRC is six times greater than limits authorized by the Environmental Protection Agency under the Safe Water Drinking Act.

It's also the standard rule that the NRC- has adopted for cumulative exposure emanating from low-level waste storage facilities and represents an internationally accepted standard, notes John Greeves, the director of NRC's division of waste management.

The proposed rule could apply to the potential nuclear waste repository at Yucca Mountain if the Department of Energy determines the site, about 100 miles northwest of Las Vegas, is suitable to house the nation's nuclear waste.

The EPA limit on annual radionuclide exposure from drinking water is 4 mrem. The NRC's proposed 25 mrem limit would apply to the cumulative level of radionuclides transmitted through all potential routes including air, soil, ground water and other sources. NRC officials say that the most likely path for radioactive particles to reach humans would probably occur through ground water.

"It doesn't make any sense," Frishman says of the proposed NRC rule. "Nowhere else in the country would anyone be able to knowingly contaminate the water to a level that was more than 4 mrem of radionuclides a year."

Based on current development patterns, a Nye County farming community about 12 miles from the proposed Yucca Mountain site would likely be the closest point from the facility where humans would be exposed to radioactive particles originating at the site.

Greeves points out differences between the drinking water law and the proposed nuclear waste storage rule. For starters, the drinking water law applies. to water after it is treated for use, he says, Also, radionuclides can be removed during the treatment process, and the drinking water law includes varying standards for a range of specific nuclides, including some standards that exceed a 50 mrem annual dosage.

"The Safe Water Drinking Act is applied to tap water; it wasn't designed to apply to a disposal site," Greeves adds,

Yucca Mountain is currently the only repository site under consideration by the DOE. The DOE is expected to make its recommendation about the suitability of Yucca Mountain to the president in July 2001.

Ultimately, the NRC has licensing and regulatory authority over nuclear storage facilities. That means DOE would have to demonstrate that the design of any storage facility it pursues will comply with standards stated in the proposed NRC rule.

And the NRC guidelines will need to comply with standards set by EPA. If that's not confusing enough, the NRC released its proposed rules in February, while the EPA has yet to make its rules public. In fact, the NRC released its rules despite a request from EPA Administrator Carol Browner last fall to wait until after the EPA standards come out.

NRC officials describe their proposed guidelines as a "placeholder." They promise to modify their guidelines if the EPA standards are more restrictive than its proposed rule. Federal laws require the NRC and EPA to each base their respective guidelines on research completed in 1995 by the National Academy of Sciences,

At this point, it is not clear whether the EPA standard will tolerate the 25 mrem level or set a more restrictive limit.

The federal environmental agency will likely release its standards "this spring," says Frank Marcinowski, associate director with the agency's radioactive protection division. He does not elaborate on a specific date nor a range that the EPA is considering for exposure limits.

"There's a potential that the NRC (proposed rule) would allow concentrations that exceed levels allowed under the Safe Water Drinking Act," he adds. "They (NRC) would have to amend their rule based on what our standards say."

NRC officials discussed the proposed rule during separate town hall meetings last week at UNLV and in Beatty. The commission is on schedule to respond to public comments and concerns about the rule this summer, make potential modifications and adopt a final version in the fall.

Others involved in the debate over Yucca Mountain do not think the 25 mrem dosage represents a threat to public health. Dan Kane, a DOE nuclear engineer based in Las Vegas, contends that the sun, the area's geological characteristics and other natural and man-made sources generate about 300 mrem of background radiation a year for Southern Nevada residents. That number is less than half of the roughly 650 mrem annual dosage in and around Denver, Colo. Based on these numbers, he contends that those living near Yucca Mountain would still receive less background radiation, even with the storage facility nearby, than those living in the Mile High City.

"We have a responsibility to let people know what types of radiation exposure could result (from nuclear waste storage at Yucca Mountain) and what the effects of that would be," Kane adds. "In my opinion, the radiation exposure would be low, and there would be no effects."

A DOE site assessment released in December resulted in no "show stoppers" to eliminate Yucca Mountain from consideration. Scientists for the DOE and other agencies are now focusing on geological patterns to determine the likelihood of ground-water levels rising to or above the proposed waste storage facility, some 8,000 feet below the top of Yucca Mountain. Submersion in ground water could cause the proposed double-walled, metal alloy waste storage casings to corrode sooner than expected. This could potentially result in radioactive particles seeping into the ground water sooner than expected and in greater-than-anticipated levels.