August 2013 Plutonium Mountain Inside the 17-year mission to secure a dangerous legacy of Soviet nuclear testing By Eben Harrell & David E. Hoffman Project on Managing the Atom
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Belfer Center for Science and International Affairs | Harvard Kennedy School 25 again suspended for the season, Kazakh scientists hosted a reporter from Science magazine at Semipalatinsk-21. The resulting article, “Plutonium Fields Forever,” relayed Kazakh concern over the test site and explicitly made clear that some Soviet nuclear experiments had “dispersed small chunks of plutonium” that could be a “proliferation risk.” 63
U.S. officials interviewed for this paper speculated that Kazakh scientists leaked the story to Science in order to galvanize U.S. attention, but the reporter for the story said he learned of it through his own initiative. 64 Either way, the article refocused high-level attention on the problem. The presence of plutonium at Degelen Mountain was now public information, providing new urgency to the project. A senior Pentagon official, Weber, who had been instrumental in carrying out Project Sapphire, met with Russian officials in Moscow on July 18, 2003 to rejuvenate coop- eration and extend projects to other parts of the test site, including Degelen Mountain itself. At that time, Russian officials were still reluctant to discuss Degelen Mountain. Despite clear evidence to the contrary, “the view of Minatom was that the security of these shafts was sufficiently high” following the original tunnel closure project of the 1990s, according to Stepanyuk. Minatom still suspected that the U.S. was interested in Degelen Mountain for in- telligence collection. Without Russian support, work at Degelen Mountain was impossible. In its 1997 bilateral agreement with Russia, Kazakhstan had stipulated that Russia had full ownership rights to material left by the Soviet Union in Degelen Mountain. 65 By this reckon- ing, the plutonium residue was now Russian property. Just as it proved decisive when Hecker met with Ilkaev in 1998, evidence of the successful metal scavenging at Degelen Mountain proved sufficient to overcome Russian reluctance. In 2003, Kadyrzhanov reported to his Russian counterparts that a survey of Degelen Mountain had found that over 70 percent of the tunnels at Degelen Mountain had been breached. 66 Realizing that “sooner or later we will have to return to the problem,” Minatom’s leadership agreed to move the work to Degelen Mountain itself, according to Stepanyuk, but they decided to reveal only the lo- cation of three experiments at two sites. Should work with this “sample” go well, and should the Russians feel confident that no espionage was being committed on the site, Russia would consid- er sharing further information with the Americans and Kazakhs. As it turned out, the sample locations were not in Degelen Mountain. They were in a nearby bun- ker, in three Kolbas. Kolbas are 2.4 by 7-meter metal chambers reinforced with Kevlar and fiber- glass and designed by Arzamas-16 to contain explosions up to the equivalent of 200 kilograms of dynamite. 67 They were usually placed deep within Degelen Mountain for tests. But three had been used above ground, and stored in the bunker. 63 Richard Stone, “Plutonium Fields Forever,” Science, May 23, 2003, pp. 1220-1224. 64 Stone said he met the Kazakh science minister at a conference in Brussels and expressed interest in visiting the Semipalatinsk region to learn of the health effects of nuclear testing. During reporting before his trip, a British scientist suggested to Stone in an interview that plutonium may still exist at the testing site; Stone asked his Kazakh host during his visit about this and learned about Operation Groundhog. Stone recalled, “There was a DoD researcher also visiting there at the time; we were chatting amica- bly and when I asked him about [Operation] Groundhog, he blanched —couldn’t believe the Kazakhs had told a journalist about what was meant to be a secret project.” Communication with Stone, March 2013. 65 Stepanyuk, “Liquidation of Consequences.” 66 Stepanyuk, “Liquidation of Consequences.” 67 Interview with DTRA officials. Plutonium Mountain: Inside the 17-year mission to secure a dangerous legacy of Soviet nuclear testing 26 The U.S. agreed to work on the three Kolbas, and yet again defer action on Degelen Mountain. The scientists determined that the easiest technique to secure the material would be to fill the Kolbas with a water solution containing cement and sand. The resulting grout-like mixture would be difficult to chemically separate on site, and too heavy to easily transport, providing enough of a barrier to thieves to allow for timely detection and intervention if they broke in to the site. Plu- tonium experts interviewed for this report said the cement mixture leaves the fissile material in a state that renders it very difficult to recover for use in a bomb. 68 The long-term safety of this option for the environment is open to question. Cement immobili- zation of plutonium for permanent disposal has never been proven on a large scale before—the most ambitious laboratory experiments testing cementation as a disposal option have involved only a few grams of plutonium. 69 Over the course of hundreds or thousands of years, water is likely to work its way through the metal and may begin leaching away some of the plutonium- bearing cement. While plutonium does not move very far in most chemical environments, the long-term environmental impact of this disposal has not been analysed. Before work began, Kazakh crews discovered that one of the Kolbas in the bunker had been already pried open by scavengers. 70 Again the scientists faced the prospect of theft of nuclear material, though in this case the Kolba in question did not contain enough plutonium residue for a nuclear weapon. At one point, Russian scientists inspected the inside of the Kolba unaccom- panied by U.S. officials. They reported no evidence of excavation or scraping of the plutonium residue, and concluded that no material had been stolen. It was a close call, however. The stage of the mission dealing with the three Kolbas was named Operation Matchbox and the work began in 2004; from the U.S. point of view, it proved a great success. But six years after Hecker first raised the issue with Ilkaev, Russian scientists continued to be reluctant to share information about the location of the remaining Kolbas at Degelen. The U.S. Defense Threat Reduction Agency did not have the necessary permission from Kazakhstan to search through the 116 square miles of the Degelen Mountain site to locate all the Kolbas and other containment chambers used to conduct nuclear tests. Russia continued to withhold information; in the end, it took another nine years before the United States and Kazakhstan had all the information needed to complete work at Semipalatinsk. And the timeframe may have stretched longer, were it not for the growing trust among the U.S. and Russian scientists, which included an extraordinary friend- ship between an American program manager and a Russian engineer who barely spoke each other’s language. 68 This view is not universally shared, however. A report by the British Royal Academy of Engineering in 2008 said that “Ce- ment immobilisation [of plutonium] is not particularly attractive or effective because of…relative ease with which the plutonium could be recovered.” See: The Royal Academy of Engineering, “Plutonium Management,” October, 2008. http://www.raeng.org. uk/societygov/policy/responses/pdf/PlutoniumV6.pdf (accessed on February 2, 2013). 69 See, for example, Georgette Y. Ayers, Bill McKerley, Gerald W. Veazey and, Thomas E. Ricketts, “Development of an Al- ternate Pathway for Materials Destined for Disposition to WIPP,” a paper presented at the 51st Annual Meeting of the Institute of Nuclear Materials Management, Baltimore, Maryland, July 11-15, 2010. At the Savannah River Site in the U.S., liquid waste containing mostly cesium and a little plutonium is mixed with grout and put in large concrete vaults and tanks for permanent dis- posal. This process is well underway, but there are concerns about the long-term safety of this operation. Interview with Thomas Cochran, Senior Scientist at the Natural Resources Defense Council. 70 Interview with Ristvet, October 2012. Yüklə 333,26 Kb. Dostları ilə paylaş:
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