Academic Environmental Studies
Environmental Studies

The Yucca Mountain Nuclear Controversy

Discovery of Chlorine-36 at Yucca Mountain

The federal government selected Yucca Mountain as a potential site for a repository largely because of its forbidding geology. The mountain, they argued, would shield the waste from natural forces, in particular water. In 1996, however, scientists discovered that water was infiltrating Yucca Mountain far faster than they had thought possible. The discovery seemed to mandate that the government find another site. Instead, DOE changed the siting rules to accommodate the new discovery, and pressed forward with development of the repository.

These events gave Yucca Mountain opponents a coherent conceptual framework with which to fight the repository, centered on the idea that the government had prioritized politics over science. For the next decade and a half, this framework would shape the debate around Yucca Mountain. The framework, as it developed in the chlorine-36 affair, had two components. The first was scientific: the Precautionary Principle mandated that Yucca Mountain be removed from consideration, given the uncertainty surrounding the science at Yucca and the immensity of the risks involved. (The Precautionary Principle is the informal notion that we should not pursue a course of action with the potential to cause great harm unless we are absolutely confident that we understand how to avoid that harm.) The second component, following directly from the first, was political: the federal government had written scientific standards and the Precautionary Principle into its own regulations, but when evidence turned up that would violate these regulations, the DOE bureaucracy simply pushed on. Politics had trumped science.


Yucca Mountain’s resistance to water infiltration was one of the key features the government used in selling the site. DOE scientists argued that the nature of the rock at Yucca Mountain, coupled with the dry climate in the surrounding desert, would minimize the rate of water infiltration. They believed that rainwater would require hundreds or thousands of years to penetrate the mountain. The amount of water traveling through the mountain, then, would not be sufficient to corrode waste containers and carry waste into groundwater supplies.16

Yucca Mountain Tunnel A tunnel at Yucca Mountain. (Source: United States Nuclear Regulatory Commission)

DOE’s own scientists undermined these arguments, however, when they discovered chlorine-36 deep beneath Yucca Mountain. Chlorine-36 is a radioactive isotope introduced into the atmosphere by atomic bomb testing in the Pacific during the 1950s, and now distributed throughout the world. The scientists found this 50-year-old chlorine in a test tunnel they dug through the middle of the mountain—at the level where the waste would be stored. The only way the chlorine could have reached that depth is if rainwater carrying it had seeped through the mountain much faster than anticipated. The discovery seemed to strike a blow at the core of the argument for Yucca Mountain.16 The chlorine-36 also, by the government’s own rules, appeared to disqualify the site. The NWPA in 1982 mandated that the DOE develop a number of regulations—pertaining to climate, security, etc.—to ensure that the chosen site would truly isolate nuclear waste. The violation of any one of these rules would require the Secretary of Energy to disqualify the site immediately.4 The new discovery, however, violated one such rule, which stated that rainwater could not penetrate the site in less than 1,000 years.4 The state of Nevada, among many others, demanded that the Secretary of Energy disqualify Yucca Mountain on this basis.16

Instead, the DOE changed the rules, so that Yucca Mountain was no longer in violation. The revisions related to the chlorine-36 issue began soon after the discovery4 and continued for several years8 as scientists discovered more damaging evidence. They made exceptions that accommodated the chlorine-36, and lessened the importance of geological considerations in siting requirements. Joan Claybrook, the president of the nonprofit Public Citizen, observed in 2001 that the revised regulations had led to an odd circumstance: “DOE’s repository design proposals rely more than 99% on engineered barriers for containment. The geology of Yucca Mountain contributes less than 1%.”8 The DOE, it seemed, had almost written Yucca Mountain itself out of the rules in its attempts to accommodate the chlorine-36 discovery.

These events catalyzed the development among activists of a framework centered on the notion that politics had trumped science that explained why they opposed Yucca Mountain. The politics-over-science framework, as it took shape during the chlorine-36 controversy, had two parts. In the first, activists argued that the science around Yucca was so uncertain, and the risks so great, that the Precautionary Principle demanded Yucca be rejected. In the second, opponents claimed that the government had allowed political and bureaucratic considerations to trump science and the Precautionary Principle, and therefore had no credibility. These two components are explained further below.

Yucca Mountain and the Precautionary Principle

The discovery of chlorine-36 deep in Yucca Mountain led activists to argue that science and the Precautionary Principle demanded that Yucca be stopped. The fundamental notion behind the Precautionary Principle is that if we are not completely sure that we will succeed in a given course of action, and if the damage associated with failure is great, we must not move forward. Opponents adapted the Principle to Yucca Mountain by arguing that the science around Yucca was so uncertain, and the risks so unimaginably broad in scope, that Yucca would never be viable.

The chlorine-36 discovery served as evidence to activists of the fundamental uncertainty behind the DOE’s science. In 1998, a coalition of 225 organizations wrote a petition to the DOE asking that the Secretary of Energy disqualify Yucca Mountain on the basis of the uncertainty around the site. The petitioners highlighted the fact that the chlorine-36 discovery starkly contradicted earlier hydrological models. Given this scientific track record, they asked whether the government could ever be sure that a site like Yucca—with many other issues, such as volcanism and scientific activity—was truly safe.4

The other side of opponents’ arguments was the risk of disaster if something should turn out unexpectedly at Yucca Mountain. Mary Olson, a scientist with the activist Nuclear Information and Resource Service (NIRS), said, “We can’t afford to make a mistake with this waste—it contains more than 95% of the radioactivity of the Nuclear Age.”2 Claybrook raised the possibility that radioactive waste might reach groundwater and thus the milk-producing areas nearby, and ultimately turn up in our children’s breakfast cereal.8 David Comarow, an environmentalist from the College of Southern Nevada, raised a more apocalyptic (and somewhat more fanciful) scenario in Congressional testimony in 2001:

Small amounts of water seeping into the containment vaults will corrode the vessels and eventually contaminate the ground water. Larger amounts of water hitting the extremely hot nuclear waste would most certainly cause a cataclysmic explosion of expanding steam, resulting in a massive escape of radioactive materials into the atmosphere. The radioactive plume would, at the very least, contaminate an entire swath of the United States, including the Midwest agricultural regions. Under the most unthinkable of events, enough radioactive materials would vent into the atmosphere to deal the same fate to the human race that an asteroid did to the dinosaurs. If it is possible, it is thinkable and such a risk is unacceptable when there is evidence of water under Yucca Mountain.9

The Precautionary Principle, then, provided a scientific basis for opposition to Yucca Mountain. It showed that Yucca Mountain should be stopped, given the uncertainty and the risks surrounding the mountain. However, the Precautionary Principle was not broadly applicable; opponents could only invoke it when truly damaging evidence turned up, such as the discovery of chlorine-36. The second, more adaptable component of the opposition’s framework argued that the government had prioritized politics over science. Though this argument was rooted in the presence of the Precautionary Principle in the NWPA, it ultimately proved applicable throughout the Yucca Mountain debates. This second component is explained in the next section.

Politics Trumps Science at Yucca Mountain

The DOE revised its regulations after the chlorine-36 discovery to accommodate the new data. To activists, this struck of hypocrisy. They noted that the NWPA, back in 1982, incorporated the Precautionary Principle with its strenuous site-qualification requirements. The DOE, they argued, was jettisoning the Precautionary Principle even though Congress itself had embedded the Principle in the law. Opponents accused the DOE of subordinating the fate of mankind to such banal considerations as bureaucratic inertia and financing, as well as to nuclear-industry lobbying. This narrative quickly took hold, and dogged the government until the day the Obama Administration finally cancelled the program.

Opponents insisted that the DOE adhere to the Precautionary Principle implicit in the NWPA. The petitioners discussed above wrote, “The NWPA envisioned a set of rules designed to protect humans by ensuring scientific credibility. The DOE, in its efforts to ensure the unsatisfactory Yucca Mountain, has laid aside this critical goal.” They insisted that the DOE comply with the NWPA’s requirement that Yucca Mountain be disqualified if it failed to meet even one condition.4 Claybrook, of Public Citizen, testified to Congress that the “dramatically flawed process railroading the Yucca Mountain Project toward approval” had undermined scientific credibility by bypassing the stringent safeguards of the NWPA.8 As the petitioners noted, “The Department of Energy has, within its possession, evidence and data that support the immediate disqualification of Yucca Mountain.”4 Why, activists asked, had the DOE sidestepped the Precautionary Principle and pushed forward?

The answer opponents gave was simple: the bureaucracy and the nuclear industry were behind Yucca Mountain, and science would not stand in their way. Olson, the NIRS scientist, argued that the DOE bureaucracy sought to maintain billions of dollars in funding by keeping Yucca Mountain moving forward. Of an interim report by the DOE to Congress, she said, “This is not a scientific assessment of the project, it is a political paper intended to keep Congress funding the radioactive waste bureaucracy.”2 Claybrook brought the attack to a personal level, noting that Bush Energy Secretary Spencer Abraham had accepted $82,728 from the nuclear industry in his failed Senate re-election campaign in 2000.8 The petitioners summed up the accusations: “A dogged belief by career DOE officials, the nuclear industry, and their Congressional allies that Yucca Mountain must be found suitable has effectively destroyed the credibility of the investigation.”4

This political attack on the DOE proved to be quite effective in damaging its credibility with the public. In the chlorine-36 controversy, this line of attack was rooted in the notion that the government was ignoring its own legislative Precautionary Principle for political reasons. Over the years, it broadened into an argument that the government prioritized politics over science in general. In this form, the politics-over-science argument became the dominant framework of the opposition. They deployed this rhetorical theme over and over again to destroy the credibility of the DOE. In the next section, I look at how activists used the politics-over-science framework to approach a DOE scandal almost ten years later.

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