Nuclear Waste Disposal

Experts in nuclear waste disposal have grown used to shallow analyses in the news media, but it's depressing to see this in a technical magazine (C&EN, May 5, page17). A weakness in the U.S. that is obvious to everyone else in the world is the notion that if something is difficult to do in the U.S., it must be impossible. Thus, if there are inherent uncertainties with Yucca Mountain, there must be no geology suitable for nuclear waste disposal.

The lack of perspective regarding proposed solutions in other countries is unfortunate. For example, Finland has a site license for a repository in crystalline rock, and Sweden will apply for one within one to two years. Both have developed long-lived copper canisters (greater than 100,000 years) that have low susceptibility to corrosion under the reducing conditions of deep groundwater. France and Switzerland have site license applications planned for about 2015. There, the host rock layer for the repository has very low permeability clay stones in which transport is diffusion controlled. The geochemical and hydrologic principles of these systems are well defined, and there doesn't seem to be much disagreement about them here in Europe among scientific and engineering specialists.

Note that the isolation principles for these repositories are based on physical and chemical principles of very slow corrosion of canisters in reducing environments or low groundwater transport rates in saturated low hydraulic gradient systems. Yucca Mountain is an indefinitely oxidizing environment and is an unsaturated rock in which flow may (or may not) be rapid. It may be possible to make the case for Yucca Mountain, but the residual uncertainties are likely to remain greater than for some other geological environments.

Specialists agree there is no hurry regarding implementing disposal. Interim storage is very safe. However, the idea of stewardship forever on Earth's surface is absurd given the need for the wastes to decay for tens of thousands of years. Thanks to vagaries of nature and human behavior, monitoring and guarding the waste for such time frames will simply not be achieved. Despite recycling of fuel, wastes with radioactive inventories that preclude surface or shallow disposal will still exist, so this is not an argument to stop moving forward with suitable repository sites. Surely, terrorists would have a difficult time excavating wastes out of a repository 500 meters deep without being noticed.

Finally, I continue to be surprised by those who argue that the issues of intergenerational equity and long-term hazards of toxic materials are unique to nuclear waste. Is not the rapid depletion of the world's oil and gas reserves an intergenerational equity issue? In addition, we continually mine metals and make them into products that are carelessly disposed of. Consider, for example, hazardous and carcinogenic metals such as cadmium and emissions of mercury from coal-fired power stations (ironically, discussed in the same issue). Perhaps you should check their half-lives. "Forever waste," indeed.

Lawrence Johnson
Wuerenlos, Switzerland