The Cold War rivalry between the United States and the Soviet Union lasted for much of the
second half of the 20th Century. While the superpowers never engaged directly in full-scale
armed combat, a nuclear arms race became the centerpiece of a doctrine of mutually assured
destruction, and prompted a mass production of plutonium, and the designing, building, and
testing of large numbers of nuclear weapons. In more than 50 years of operation, the Cold War
battlefields created over 100 metric tons of plutonium, produced tens of thousands of nuclear
warheads, oversaw more than 1000 detonations, and left behind a legacy of contaminated
facilities, soils, and ground water.
The extent of long-term adverse health effects will depend on the mobility of plutonium and
other actinides in the environment and on our ability to develop cost-effective scientific
methods of removing or isolating actinides from the environment. Studying the complex
chemistry of plutonium and the actinides in the environment is one of the most important
technological challenges, and one of the greatest scientific challenges in actinide science today.1
I will summarize our current understanding of actinide chemistry in the environment, and how
that understanding was used in the decontamination and decommissioning of the Rocky Flats
Site, where plutonium triggers for U.S. nuclear weapons were manufactured. At Rocky Flats,
synchrotron radiation measurements made at the Stanford Synchrotron Radiation Laboratory
were developed into a science-based decision-making tool that saved billions of dollars by
focusing Site-directed efforts in the correct areas, and aided the most extensive cleanup in the
history of Superfund legislation to finish one year ahead of schedule, ultimately resulting in
billions of dollars in taxpayer savings.2
Figure. (Top), A 1995 Aerial photograph of the Rocky Flats Site showing the Industrial Area. (Bottom), A 2011 Aerial photo of the remediated Rocky Flats Site.
1. Clark, D. L., Hecker, S. S. Jarvinen, G. D., Neu, M. P., “Chapter 7, Plutonium” in The Chemistry of the
Actinides and Transactinides, 3rd Edition, Lester R. Morss, Norman M. Edelstein, Jean Fuger, Eds. 2006,
Springer, New York, 813-1264.
2. Clark, D. L., Janecky, D. R. and Lane, L. J. Phys. Today, 2006. 59(9): p. 34-40.