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 next day, Ilkaev introduced Hecker to a pair 

of scientists who were well informed about what 

had unfolded at Semipalatinsk. They were Yuri 

Styazhkin and Viktor Stepanyuk, both of whom 

had worked at the test site in earlier years. Styazh-

kin knew the whole story, but he did not reveal it 

all at once. “There are a lot of things we did out 

there,” he told Hecker, “and it wasn’t just the hy-

dronuclear experiments.” 

This was the second turning point. Thanks to Il-

kaev’s apparent pressure on Moscow overnight—

he had clearly taken a risk—and Styazhkin’s sense 

of personal responsibility, Hecker had broken 

through Russia’s wall of silence. 

‘Who is Ever Going to Go 

Out There?’

Hecker next went to the second former Soviet 

nuclear weapons laboratory, known as Chely-

abinsk-70 in Soviet times, located in the Ural 

Mountains. This laboratory was started nine years 

later than Arzamas-16. In the Soviet era, the two 

labs competed, working on different warhead 

designs. Hecker had also built bridges in the early years to Chelyabinsk-70 and was welcomed 

there, as well. He went to see Boris Litvinov, the chief weapons designer for 31 years, who was 

one of Hecker’s early contacts in the Soviet nuclear weapons establishment. Hecker showed Lit-

vinov the photographs from Semipalatinsk; both Soviet laboratories had carried out experiments 

on the test site. 

Hecker recalled that Litvinov:

...explained to me how they did the hydronuclear tests. He said, ‘We didn’t bury it the 

way you guys did. We did [tests] out on the surface. We dug a little trench. We put our 

experiments in there. And we just blew it up. Then we took bulldozers and bulldozed that 

over, and we took care of it. We thought, who is ever going to go out there?’

In the meeting with Litvinov, Hecker learned that the Soviet tests were not only hydronuclear. 

The weapons designers had also carried out studies known as “equation-of-state” experiments to 

probe the behavior of plutonium. While the hydronuclear explosions probably had blown up the 

metal and dispersed it, the other experiments were done in shallow bore holes, and whole pieces 

of plutonium, rather than residue, may have been left in the ground, which would be even easier 

for someone to recover. 

Yet another revelation followed. When Hecker asked Litvinov whether all of the Soviet nuclear 

Source: Siegfried Hecker

Trenches dug by scavengers to extract copper cables 

from the test site.

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

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explosions conducted in the tunnels had actually detonated, Litvinov said they had not. This 

added a new concern: the plutonium (or highly enriched uranium) that remained in the test tun-

nels from those duds, especially now that it appeared the scavengers were re-entering some of 

the previously-sealed test tunnels. 

Lastly, Litvinov told Hecker that some of the tests had been carried out in large tank-car sized 

metal containers known as “Kolbas.”

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 Where were they now? Still in place, at Semipalatinsk. 

Some were deep inside the tunnels at Degelen Mountain, others were outside.

These discussions with the scientists convinced Hecker that any hope of dealing with the plutoni-

um at Semipalatinsk would have to involve the Russians. They had the knowledge of what tests 

had been carried out and what might have been left behind. “What tunnels actually still contained 

stuff that we should be worried about?” Hecker recalled asking. “Without the Russians, we have 

no chance whatsoever. It would be like looking for a needle in a haystack.”

It would not be easy. Even in 1998, seven years after the Soviet collapse, suspicions from the 

Cold War still ran strong. While at Chelyabinsk-70, Hecker went to see Evgeny Avrorin, who 

had twice served as scientific director of the laboratory. Although he had extensive contacts with 

westerners over the years and had come to Los Alamos to help the lab celebrate its 50

th

 anniver-

sary in 1993, Avrorin was still cautious and suspicious. The nuclear weapons laboratories had 

been secret kingdoms for so long that the mindset was hard to change. 

Hecker showed the photographs from Semipalatinsk to Avrorin, and implored him to support 

some effort to deal with the plutonium. Hecker recalled that Avrorin replied, “It sounds like intel-

ligence to me.” 

Hecker added,

What he was concerned about is that the work that they did there… the plutonium chemistry, 

the plutonium isotopics, are classified secret in Russia. …The type of test that they did, 

whether it was in the tunnels, whether it was in the Kolbas—that’s all part of their trade, of 

the nuclear weapons trade. They don’t want to give out that information.  And Avrorin was 

concerned that I was doing this for intelligence collection. 

Hecker recalled telling Avrorin that he was not spying but was concerned about the nuclear ma-

terials spread across the steppe, unprotected. Nonetheless, the Chelyabinsk-70 scientists decided 

to hold back, to see if Moscow allowed the project to move ahead, and to let Arzamas-16 go first. 

They eventually joined the project. 

Next, Hecker came back to the United States and briefed high-level officials in the government 

about what he had found. He showed them photographs of the unmanned guard gate, of the 

trenches, and maps of the various sites at Semipalatinsk where the fissile material might be lo-

cated. He urged them to join Russia and Kazakhstan in an effort to do something about the prolif-

eration risks at Semipalatinsk. 

Hecker warned them that the amount of recoverable plutonium was not trivial. He said there 

was perhaps as much as 200 kilograms, or about 441 pounds, enough for at least a dozen nu-

clear weapons and maybe more, given the quality of the material. And it was all lying about, 

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   “Kolba” is a term of art in chemistry to refer to containment chambers.

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