THE GOVERNMENT AND YUCCA MOUNTAIN: AN EXERCISE IN MAKING THE (RADIOACTIVE) SHOE FIT….

Since the rock at Yucca Mountain is like a sieve-fractured throughout--a protective radiation standard will almost certainly disqualify it from use as a high-level nuclear waste dump. Among those who honor the 1987 political decision to send all the nation's civilian and military high-level waste to this site on Shoshone lands and "Screw Nevada" no matter what, the problem is one of how to "make the shoe fit."
The alchemists of the past had a device called an 'alembic' in which magic transformation reportedly occurred. Today's alchemists have another device where hocus-pocus is also practiced - the calculation of radiation dose given a certain amount of radioactive release into the environment (or other exposure). All of today's radiation dose standards are based on assumptions, including how radiation affects the body, size of the body, how long this body is exposed, and an incredibly long list of other variables. Then these assumptions are plugged into arbitrary scenarios. There is uncertainty associated with every one of these estimates, and they multiply as the calculations are made. While all radiation regulation is hocus-pocus (unless the standard is zero), some standard setting processes have more integrity than others.
The Nuclear Waste Policy Act of 1982 directed the Environmental Protection Agency (EPA) to set a radiation standard that a permanent high-level nuclear waste repository would have to meet. After EPA issued their standard in the 1980's, it was returned to them by a federal judge through a successful challenge from the Natural Resources Defense Council because the standard did not include specific groundwater protection. EPA inserted the Safe Drinking Water Act groundwater protection standard of 4 millirems/year, to be measured at the waste site boundary. This provision is today a line of battle between those who want to ensure that the site will "pass" and those who would ensure protection first.
The original EPA standard had multiple ways to assess whether the site would protect us from the deadly waste that would be buried there for the rest of time. The groundwater standard was part of a total dose to a "maximally exposed individual." There was also a "population dose limit" that set a limit on the projected total dose to humanity over time and globally. This makes sense since there will be a significant amount of radioactive gas released from the waste, some of which will persist in the environment for many millennia. There were also release limits for each radionuclide; recognition that the site would leak some, but these set a limit on the total amount that would be acceptable.
The concept of the first EPA standard was that regulation would limit the number of people who would die from cancer due to radiation from the dump to a maximum of 1000 people over a period of 10,000 years. We now know that the peak doses from waste leaking from the site into ground water will be many times higher than this. Of course the number of deaths are tied to the number exposed, but under some scenarios that doses go so high that anyone who drank the water would get cancer, not an increased risk of it. It has also been estimated that the Carbon-14 releases alone at this site would cause a global population dose resulting in more than 25,000 cancer deaths over time.
But in 1992 Congress exempted Yucca from the original EPA standard as part of the Energy Policy Act. This major "shoe horn" was applied because it was known by then that the fractures in the Yucca Mountain rock would allow much more Carbon-14 to escape from the mountain than the EPA population dose and release limits would permit. Nonetheless, Congress directed EPA to do something that has never been done: write site-specific radiation standards. The standard is to be based on a report that the National Academy of Sciences (NAS) would write. Congress also specified that EPA was to worry only about the dose to an individual rather than the entire exposed population. In this action, 49 states told Nevada, "we are going to try to make this shoe fit!" The concept of a scientific basis for Yucca Mountain decisions was left behind-not for the last time.
The NAS panel had a number of former government officials, members of academia and the nuclear industry. A panel member from the Edison Power Research Institute introduced a methodology that became the basis for their report. This approach was completely radical in radiation standard setting. They advocated use of a series of successive approximations of multiple scenarios. Contrary to conventional radiation safety practices, the average of all the values was then taken, not the maximum scenario. A group of hypothetical average individuals is generated this way to form a "critical" group. The average member of this group is then the "dose receptor." The individual considered in this standard--by definition an average--cannot be the person who gets the highest dose of radiation. Previous radiation standard setting has acknowledged that it is essential to look at the "maximally exposed individual." The EPRI approach also has a much higher level of uncertainty because of the large number of calculations.
In the meantime, the Department of Energy has slowly come to admit that the main barrier to prevent radiation release from Yucca Mountain is not the mountain itself, but the man-made casks that would be placed inside the mountain. While this reality does not affect standards, it does greatly influence assumptions about the timing and magnitude of the inevitable radiation leaks.
Once a container-similar to a dry cask storage unit--starts to leak, radioactivity will move fairly quickly to the groundwater. DOE projects less than 500 years from container failure to detectable radioactivity in monitoring wells. New findings recently published in Science Magazine on the solubility of plutonium raise questions about what fraction of the waste would be leaking. The migration is due to the fracture of the soft volcanic rock by ongoing seismic activity at the site, coupled with the fact that water is continuously moving through the mountain, which is much like a sponge in how it retains water.
In light of the quality assurance problems seen recently in dry cask containers, this is very disturbing. The design and materials would be different for a Yucca container, but the same fabricators, methods and quality assurance processes will be used. DOE unrealistically projects no container failures for 1,000 years, and then only one failure for the rest of time. Given actual experience, it's more likely that some of the tens of thousands of containers that would be loaded into a repository will be ready to leak immediately, and far more than one man-made container will leak in the future.
Congress has been busy attempting to influence radiation standards at Yucca Mountain as well. The various versions of the Mobile Chernobyl legislation since 1994, (all revisions of the Nuclear Waste Policy Act) are attempts to insure that Yucca will be the waste disposal site, no matter what. The bills have taken several tacks including: Congress setting a dose limit (as high as 100 millirems to the average person); directing EPA to set a standard using a specified risk range; prohibiting EPA from having anything to do with Yucca Mountain and giving all authority to the Nuclear Regulatory Commission. All of these bills have passed, but none have been able to get beyond President Clinton's promised veto and the one third of the Senate + 1 who will uphold that veto.
While that battle has raged on Capitol Hill, there have been a lot of behind the scenes maneuvers among EPA, NRC and DOE. It took over three years for a draft EPA rule to be published. The new rule for Yucca is similar to the old standard, which remains for all other repository sites, but in accordance with the 1992 Act has no population dose and no release limits. There is also quite a bit of wishy-washyness on where the groundwater standard is to be applied. However, inside sources indicate that the huge squabble between the agencies is because NRC and DOE do not want a specific groundwater standard at all. Former Senate Energy Committee Chairman Bennett Johnston--with Rep. John Dingell (D-Mich.), the "fathers" of the Yucca Mountain project--has said recently that the 4 millirem groundwater standard will stop Yucca.
NRC plans to use the NAS model, a critical group and no groundwater provision if it gets to set the standard. It does not seem to bother NRC or DOE that the uncertainties (the "plus or minus") associated with the NAS approach are many times greater than any dose limit that would compare with other radiation standards in use today. For instance 25 millirems a year, plus or minus 300 millirems is well within the range of uncertainty of this method. Using the NAS approach, the actual dose in the end may be even hundreds or thousands of times higher than the stated limit. NRC has stated that they prefer establishing a standard that can be "implemented" for licensing of this site. What ever happened to using a standard to select the site? What happened to isolating the waste for as long as it is hazardous? So the real issue is whether standards mean anything in a picture where sheer brute politics - "stick it to Nevada" is driving the train (carrying high level waste across 43 states!). -Mary Olson