Combating Radioactive Risks and Isolation in Tajikistan

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Science  01 Jul 2005:
Vol. 309, Issue 5731, pp. 44-45
DOI: 10.1126/science.309.5731.44

The science academy of this war-weary country is reaching out for help in tracking down lost radioactive sources—and restoring scientific vitality

FAIZABAD, TAJIKISTAN—In the early 1990s, as civil war raged in this mountainous land, a terrorist's prize was here for the taking. Powerful radioactive sources lay buried in an open-air, gravel-covered pit on a compound ringed by a dilapidated concrete wall and chain-link fence. During the 5-year war, villagers and fighters pillaged nearby apple orchards and industrial sites. But the makings of dirty bombs—including radioisotopes such as cesium, cobalt, and americium in old Soviet gauges and other devices—remained untouched. “We were lucky,” says Gennady Krivopuskov, manager of the 6-hectare waste storage facility 50 kilometers northeast of the capital, Dushanbe. “Maybe the radiation hazard signs kept looters away.”

How long the rad cops' luck will last is an open question. One or two derelict radioactive generators, which produce electricity from the heat harnessed from the decay of strontium-90, were never moved to this storage facility and remain unaccounted for, experts say. Each radioisotope thermoelectric generator (RTG) packs a whopping 40,000 curies—equivalent to the radioactivity from strontium-90 released during the 1986 Chornobyl explosion and fire. “How serious is it that they aren't secured? Well, that depends on who has them,” says a Western diplomat. Last month, a U.S. Department of Energy (DOE) team was in Dushanbe to train specialists at the Nuclear and Radiation Safety Agency of the Academy of Sciences of the Republic of Tajikistan (AST) on how to detect abandoned sources. Search efforts are about to get under way.

Concern about RTGs as a serious proliferation threat first got attention 3 years ago, when the International Atomic Energy Agency (IAEA) in Vienna helped secure a pair of abandoned generators in the Republic of Georgia (Science, 1 February 2002, p. 777). IAEA has since learned that more than 1000 such generators were produced in the Soviet Union; the vast majority stayed in Russia, where they were used primarily to power Arctic lighthouses. But in recent years scores have gone astray or been vandalized for scrap metal. In Tajikistan, where the generators were used to power remote weather stations, four RTGs have been recovered and are awaiting transfer to Russia for disposal, says Ulmas Mirsaidov, director of the radiation safety agency. Although Mirsaidov told Science that all RTGs in Tajikistan are now secured, DOE officials and a Western diplomat in Dushanbe say that units are missing; one or two is the best estimate based on present information.


Barriers have been upgraded at the Faizabad radwaste site, with help from the U.S. Department of Energy.


Tajikistan's radiation agency is now working with IAEA to compile an inventory of radiological sources. “We're helping them make sense of their records and develop a search plan,” says Carolyn MacKenzie, a radiation source specialist with IAEA. There's no indication that any RTGs have fallen into the wrong hands. Still, there's a disconcerting lack of knowledge about where precisely to look. “When the Soviets left, the records weren't passed on,” MacKenzie says. “We don't have definite information,” adds Roman Khan, a health physicist at Argonne National Laboratory in Illinois. DOE's Search and Secure Program, Khan says, has provided Mirsaidov's agency with a suite of instruments—including a portable radiometer capable of detecting alpha and beta particles and gamma rays, a hand-held gamma ray spectrometer, and a broad energy germanium detector—for tracking down orphan sources.

The hope is that the loose RTGs can be located and stored as soon as possible at the Faizabad facility, a hilly territory alive with discus-sized tortoises, a cacophony of sparrows, and a riot of bright-red poppies. A short walk up the road, through an inner fence patrolled by a machine gun-toting guard, is a whitewashed building with a massive gray steel door. Buried here, 9 meters beneath the dirt floor, are a variety of radioactive sources, including x-ray fluorescence instruments containing americium-241 that were used for geological surveys, radiotherapy canisters filled with cobalt-60, and four RTGs recovered so far.

The repository was rebuilt last year with DOE and U.S. State Department support. The previous structure was frail indeed: On several occasions, high winds that sweep down from the mountains from September to March tore off the corrugated steel roof, says Krivopuskov, who after 26 years of service receives a salary of $12 per month. Thanks to the renovations, he claims, the sources “can stay here safely for 1000 years.” In the meantime, though, he and his colleagues must contemplate the fate of the sources that haven't yet been secured.

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