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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sequence of somewhat mysterious events. Trailers were brought to a remote area in Semipala-

tinsk known as Aktan Berli. Some kind of test was conducted, then the Soviets scraped the 

ground in the immediate vicinity. The material scraped from the site was deposited in trenches 

located several hundred meters downwind.

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 What the satellites did not show—and what U.S. of-

ficials did not know precisely until later—is what kind of tests the Soviet scientists were carrying 

out.

Siegfried S. Hecker became the fifth director of Los Alamos in January, 1986. At the time, he 

was told that some plutonium from the U.S. hydronuclear tests remained in the holes at Technical 

Area 49 on the grounds of the installation in New Mexico. While at first the U.S. hydronuclear 

experiments were carried out in deep holes, over the years, the study of the properties of pluto-

nium and HEU became more refined. The experiments could be conducted in the equivalent of 

glove boxes, without high explosives. 

Hecker recalled, 

If you want to study the shock-loading characteristics of plutonium, you take a little pellet 

of plutonium, you put it in a gas gun and you fire a projectile at that plutonium. And on the 

other end of the plutonium, you put a number of gauges, which tell you how the plutonium 

responds to that shock insult. That’s how we studied the shock behavior.

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In most of the American hydronuclear tests, the plutonium was not removed from the hole after 

the test. It was just left there. Hecker knew that plutonium from these tests could be recovered 

and used for making a nuclear weapon—the United States had once done it. In 1958, amid 

concerns that the U.S. faced a plutonium shortage, U.S. specialists performed an experiment in 

which they recovered plutonium from two safety tests and used the material to build another 

bomb.

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 In another example, British scientists were forced to return to their test site in Maralinga, 

Australia in 1979 to collect plutonium, as well as highly-secret components used during a series 

of six experiments in 1962, although in that case there was not enough plutonium left behind to 

construct a bomb.

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Scientist-to-Scientist

A metallurgist trained at Los Alamos, Hecker appreciated the physics—and perils—of the nucle-

ar age. His personal story was also caught up in the convulsions of the 20

th

 century. His father, an 

Austrian who had been drafted into the German army, was lost at the Russian front in World War 

II. As a young boy in Austria, Hecker had grown up with only dark impressions of Russia, rein-

forced by the few male teachers who returned from the front with grim war stories. He emigrated 

to the United States in 1956 when he was 13 years old, and later earned a doctorate in metallurgy 

and materials from Case Western Reserve University before going to Los Alamos as a student 

17

   Memorandum, “Project Amber: Elimination of a Potential Source of Special Nuclear Materials,” November 13, 1995, pro-

vided by Hecker to the authors. 

18

   Interview with Siegfried S. Hecker, November 29, 2012, Stanford University, Calif.  

19

   Interview with Ristvet, October 2012. 

20

   Interview with John Carlson, the former director general of the Australian Safeguards and Nonproliferation Office, September 

2012.  See also, H.A.S. Bristow and S.A. Flook, “Repatriation of Plutonium Residues from Maralinga February/March 2012,” 

Procurement Executive-Ministry of Defense of the United Kingdom, AWRE Report No. 24/80.

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

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and later for post-graduate work. Hecker saw himself as a scientist, fulfilling his patriotic duty 

for his adopted country. He was never a weapons designer.

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In 1988, Hecker, then the Los Alamos director, and other U.S. scientists carried out a joint nucle-

ar weapons verification experiment with Soviet scientists, a result of the Reagan-Gorbachev 1986 

Reykjavik summit, and an important early bridge across the Cold War chasm of mistrust. Then, 

in February, 1992, just after the Soviet collapse, Hecker made a ground-breaking visit to Arza-

mas-16, which had been established as the first Soviet nuclear-weapons laboratory. These were 

the breathtaking days of a sudden openness between old adversaries, and Hecker used it to build 

trust with the Russian scientists. At Arzamas, on the tarmac upon his arrival, he met Yuli Khari-

ton, who had designed the first Soviet atomic bomb under Igor Kurchatov, and who later became 

the first scientific director of Arzamas-16. Khariton extended his hand and said, “I’ve been wait-

ing forty years for this.” With the Soviet Union gone, the Russian scientists were suffering eco-

nomically, but they told Hecker they saw themselves as equals of the Americans and only wanted 

to take part in scientific cooperation on that basis. Hecker established a vital line of communi-

cation to the Soviet weaponeers, a lab-to-lab program of joint projects that helped to overcome 

Cold War mistrust.

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 Other efforts later provided millions of dollars to Russia to assist in helping 

secure nuclear materials and find ways for weapons scientists to shift to civilian projects.

On November 3, 1997, Hecker completed his term as director and became a senior fellow at 

Los Alamos. He decided at the time to continue his work securing nuclear materials around the 

world. He knew plutonium and highly-enriched uranium—how they were made and why.  But 

with the Cold War now over, he hoped to use his knowledge to improve global nuclear security 

and prevent fissile material from falling into the wrong hands. 

Hecker knew that security at Russian nuclear installations at the time was often woeful. He and 

others had led a lab-to-lab effort to secure and account for nuclear materials, ultimately con-

vincing the U.S. Department of Energy and Russia’s Minatom to launch a broad program called 

Materials Control, Protection and Accounting, or MPC&A, to deal with the problem. But he was 

concerned that despite plans for security upgrades at the known sites, there might be material that 

remained completely off the radar—overlooked or forgotten, and therefore a greater risk. 

Kazakhstan was known to be riddled with nuclear materials from the Cold War. In 1994, the 

United States airlifted out of Kazakhstan about 604 kilograms (1,332 pounds) of highly-enriched 

uranium left behind by the Soviet Union in an elaborate operation known as Project Sapphire, 

one of the most important and dramatic attempts to secure these materials. 

The early 1990s were focused primarily on removing nuclear weapons and delivery vehicles 

from the three former Soviet republics outside of Russia where they were located: Kazakh-

stan, Ukraine, and Belarus. Among them, Kazakhstan had been most eager to denuclearize. The 

country’s strongman leader, Nursultan Nazarbayev, who had been a member of the last Soviet 

Politburo, decided to give up nuclear weapons on his soil at least in part because of his horror at 

the ecological legacy left behind by the testing program at Semipalatinsk.

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 Encouraged by the 

21

   Interview with Hecker, November 29, 2012.

22

   David E. Hoffman, The Dead Hand: The Untold Story of the Cold War Arms Race and Its Dangerous Legacy, (New York: 

Doubleday, 2009), p. 413.

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   See, for example, Nursaltan Nazarbayev, Epicenter of Peace (Hollis, N.H.: Puritan Press, 2001).

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