The Yucca Mountain Site is unsuitable as a geologic repository. The graphs below were prepared by the DOE in response to a request from the Nuclear Waste Technical Review Board, an oversight body established by Congress. The graphs illustrate the contribution of various elements to waste isolation by evaluating the effect of each on doses.

The dose to the public without a particular element in the system is compared to the "baseline case" which includes all the elements of the system. For example, Graph A shows the projected increase in doses that would occur without the presence of the waste package (i.e., the canister). It is clear from the charts that the canister is by far the most important element in preventing doses to the public, and that the fuel itself is also important in containment. This is because the fuel is in ceramic form that would be expected to resist degradation.

The charts show that the geologic elements of Yucca Mountain are ineffective relative to the waste package. The entire aim of the repository program has been to select a site at which the geology would be the main element in waste isolation. That aim is defeated by selecting Yucca Mountain. The response of the Nuclear Regulatory Commission to evidence of Yucca Mountain's geologic unsuitability has been toto throw out its old standards, which stressed repository containment, and replace them with new ones that allow the canister to fulfill this function.

This is clearly an unacceptable response from the point of view of safeguarding public health. Because of grave uncertainties about performance over the very long term, it is important to build several levels of redundancy into any geologic storage program. For example, not only to analyses show the potential lack of effectiveness of Yucca Mountain geology in containing waste, but serious questions have also been raised as to whether the canister will perform as projected, and indeed, whether the performance of the canister can be characterized with confidence. Here is what the DOE's peer-review panels have had to say on these issues:

"Alloy C-22 [a corrosion-resistant metal (CRM) favored by the DOE for waste canisters] is susceptible to localized corrosiion only when wet in a critical temperature range. If C-22 remains passive in this range, its anticipated life, prior to penetration, is thousands of years. If it is not passive, then its life, prior to penetration, is as little as a few tens of years...The water seepage pattern during the period when a waste package is in the critical temperature range for CRM corrosion is not well defined. This is when major damage can occur. There is a need to determine the critical temperature range, and the times in this range when different scenarios can occur."

--Chris G. Whipple, Robert J. Budnitz, Rodney C. Ewing,
Dade W. Moeller, Joe H. Payer, and Paul A. Witherspoon,
Yucca Mountain Total System Performance Assessment,
Third Interim Peer Review Panel Report , 1998,
p. 20-22.

"With the benefit of hindsight, the Panel finds that, at the present time, an assessment of the future probable behavior of the proposed repository may be beyond the analytical capabilities of any scientific and engineering team. This is due to the complexity of the system and the nature of the data that now exist or that could be obtained within a reasonable time and cost."

"...assessment of the seepage and of the number of waste packages that will experience water drips is highly uncertain. For these reasons, it is not clear to the Panel that the present approach correctly captures the seepage behavior of an individual drift.

"The large uncertainty in the seepage analysis is unfortunate, because seepage into the drifts is one of the most sensitive parameters in the dose estimates presented in the TSPA-VA. Given the uncertainties described above, the long term effect of the percolating rate on seepage cannot be calculated with a reasonable degree of accuracy. In addition, the percolation rate is itself uncertain due in part to uncertainties in long-term climate predictions."

--Final Report, Total System Performance Assessment ,
Peer Review Panel, February 11, 1999, prepared by:
Bob Budnitz, Rad Ewing, Dade Moeller, Joe Payer, Chris
Whipple, and Paul Witherspoon, p. 1, 6.

Further, the DOE has settled on a "hot repository" model, in which waste canisters are packed tightly together in order to keep the repository temperature well above the boiling point for a long period of time. However, a "hot repository" could change the rock structure of the geologic system in ways that would be difficult or impossible to predict, and therefore increases risk even further. Finally, a repository that was not hot enough to keep moisture out for prolonged periods of time would run the risk of a humid environment rapidly corroding the canisters, as indicated in one of the quotes above. Such an environment also threatens rapid degradation of borosilicate glass, which has been chosen as the waste form for solidifying high-level military waste.¹

Thus, the DOE's own assessments indicate that Yucca Mountain is not capable of geologically isolating radioactive waste from the environment. It is an unsound repository location and should be ruled out before more money is needlessly expended.