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

Belfer Center for Science and International Affairs  |  

Harvard Kennedy School

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the Semipalatinsk operation—one 

of a dozen such bilateral meetings 

during the summit process. As it 

turned out, it was also on the top 

of the Kazakh leader’s agenda.

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Officials for the two nations met 

with their Russian counterparts. 

The United States, Russia, and 

Kazakhstan agreed in confidence 

to complete the remainder of the 

work at Semipalatinsk by the next 

Nuclear Security Summit, sched-

uled for Seoul, South Korea in 

March 2012. The high-level com-

mitment galvanized the operation. 

Kazakh crews worked through the 

winters of 2010 and 2011. DTRA 

officials stayed on site in Semi-

palatinsk with them. Increased funding from DTRA meant four crews could work simultaneously 

instead of one. Much had been accomplished over the previous decade, but there was still plenty 

to do in order to meet the deadline. “Beginning in early 2010,” Ristvet said. “We really started 

cranking.”

The Announcement

Presidents Obama, Dmitri Medvedev of Russia and Nursultan Nazarbayev of Kazakhstan an-

nounced the completion of the work as planned in Seoul, saying in a joint statement that it 

provided a “concrete example of cooperation.” Nazarbayev told reporters, “All of the threats 

have been removed.”

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 But the announcement received little attention, and was overshadowed 

by reports of an “open mic” gaffe in which Obama was overheard making unguarded remarks to 

Medvedev. 

As it turned out, work at Semipalatinsk continued until October, when Ristvet, Kutsenko, Kady-

rzhanov, Deputy Assistant Secretary of Defense Kenneth Handelman, and several dozen U.S., 

Kazakh, and Russian scientists gathered to mark the end of the Degelen Mountain operation. 

They unveiled a monument to the work, awarded medals, and made loquacious toasts over a 

make-shift picnic several hundred yards from the mountain. 

The picnic was monitored by Kazakh security officials from a state-of-the-art situation room 

at Kurchatov City that provides real time data and video on a large screen. A response force is 

stationed approximately 20 minutes away.

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 The sustainability of all this security—particularly 

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   Interview with a senior U.S. official, March 2013.

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   “’Russian-U.S.-Kazakh cooperation on Semipalatinsk site and example how to handle nuclear security’-Medvedev.” Interfax, 

March 27, 2012.

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   The security personnel are at a barracks where they are also on call in case of an incident at a nearby facility that that stores 

Source: U.S. Department of Defense

Degelen Mountain access road barrier erected in 2012.

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Plutonium Mountain: Inside the 17-year mission to secure a dangerous legacy of Soviet nuclear testing

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the hundreds of sensors and other pieces of equipment that will eventually need to be replaced—

is questionable, especially given the fact that Kazakhstan’s nuclear regulators remain relatively 

weak, and funding for the site is limited. But U.S. officials say that the cementing of the tunnels 

provides enough of a barrier so that even a basic monitoring system should suffice. 

The security at Degelen Mountain raises an uncomfortable reminder, however, of just how dif-

ficult it will be to sustain an effective security operation at Semipalatinsk for the duration that 

will be required. Plutonium’s half-life is 24,110 years.

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 The plutonium at Degelen Mountain will 

potentially pose a danger for a time frame beyond human understanding. It is certainly true, as 

the plaque at Degelen Mountain attests, that the world has become safer than it was before the 

operation, but it also remains the case that the scars left by nuclear weapons testing during the 

Cold War will last for eons. Asked at the picnic when it will be possible for security to be with-

drawn from Semipalatinsk, Sergei Lukashenko, the director of Kazakhstan’s Institute of Radia-

tion Safety and Ecology, ignored his Russian interpreter and spoke in stern, broken English. 

“Never we leave this area. Never.”

And there may yet be further surprises at the test site. Only a few months ago, Ristvet said a Ka-

zakh survey team discovered five more areas near Degelen Mountain where experiments left be-

hind plutonium residue in high enough concentrations to pose a proliferation risk. “In some cases 

[the plutonium] is such that a guy with a pickup truck and a shovel could accumulate enough [for 

a bomb], removing only a few tons of soil,” Ristvet said.  Hecker said that while there are some 

areas that need attention, existing monitoring of the site is sufficient to limit concerns about po-

tential theft. 

At the urging of Ristvet, the United States is currently negotiating a project by which it will haul 

tons of soil into an empty tunnel in Degelen Mountain and fill the tunnel with the same cement 

and iron mixture used in the other Kolba projects. However, DTRA officials say that cuts to 

CTR funding have delayed the project.  Asked how much plutonium remains at Semipalatinsk, 

even 17 years after U.S. experts first warned of the urgent need to secure the site, Ristvet says, 

“Enough.” 

Conclusions

The Semipalatinsk operation secured substantial amounts of plutonium and reduced the threat 

that it could fall into the hands of scavengers, terrorists, or a state with malevolent intentions. But 

it was a very close call. Had the governments of the United States, Russia, and Kazakhstan not 

been prodded, the large and expensive clean-up might never have been launched, or the bad ac-

tors might have arrived on the scene before the materials could be secured.  

The Degelen Mountain operation highlighted the valuable and effective role of unofficial col-

laboration and contact among scientists and others who are devoted to achieving results without 

cumbersome negotiations. Yet securing the plutonium in Kazakhstan proved to be a laborious 

and long undertaking which required 17 years, including a decade after the 9/11 attacks, which 

irradiated fuel from the old BN-350 breeder reactor, which contains tons of material near the 20% borderline of highly-enriched 

uranium, as well as tons of high-grade plutonium in spent fuel.

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   One of the ironies of nature is that Pu-239 decays to U-235 – also a potential nuclear bomb material, and with a half-life of 

three quarters of a billion years.

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