Thank you Dr. Holdren, Dr. Koonin, Dr. Brinkman, Secretary Chu and distinguished guests. I am deeply honored and humbled by this award in recognition of Enrico Fermi. I also want to congratulate John Goodenough – it’s a special honor to be co-recipient with you. I would like to pay tribute to Enrico Fermi by focusing on the indirect impact he had on my career and my life; I say indirect, because I never met Fermi. He died two years before I came to the United States. I will briefly mention two areas – Los Alamos and plutonium.
Laura Fermi pointed out in her wonderful book Atoms in the Family, that Fermi loved Los Alamos – the stimulating intellectual environment, the scenic beauty and outdoor adventures, including hiking, skiing and he even took up fishing (although his physics theory of fishing was his least successful). Fermi’s work on chain reactions and neutrons set the stage for Los Alamos and the Manhattan Project. Fermi came to Los Alamos from the University of Chicago in the summer of 1944. He was one of the “oracles” of Los Alamos – the person anyone could seek out to answer any question on physics (by the way, the other oracle was John von Neumann, who did the same for mathematics).
Fermi was given the title of Associate Director and leader of F (or Fermi) division. In addition to having the challenging job of “supervising” talents like Edward Teller, and answering physics questions, he also built a small uranium-salt homogeneous reactor in one of the Los Alamos canyons. Even the wartime was an exciting time for new reactor concepts at Los Alamos.
The Fermis left Los Alamos on Dec. 31, 1945, to return to Chicago. But, Fermi returned most summers to Los Alamos to continue his research. What drew him back were many friends, the attractive surroundings and the best computers of the time. He needed those to analyze his experimental work on pion-nucleon scattering.
Fermi had left his mark on the Los Alamos I first joined as a summer graduate student in 1965. It was intellectually exciting; one could find expertise in every field of science, including mine – metallurgy and materials. Altogether, I spent 34 years at Los Alamos, before joining the faculty at Stanford in 2005. It was the best place in the world for combining fundamental science with challenging national and international problems – ranging from nuclear weapons, to energy, to the human genome project.
Immediately after the discovery of fission in 1938, Fermi and others in the United States realized that in addition to Uranium-235, the 239 isotope of element 94 should fission with slow neutrons. Fermi played a role with Glenn Seaborg and company at the Berkeley cyclotron in their discovery of element 94, which they later called plutonium. Fermi then took charge of creating the first man-made chain reaction at the University of Chicago on Dec. 2, 1942. He followed that by leading the effort to build the wartime production reactors for plutonium.
Fermi’s interest and fascination in plutonium arose from its nuclear properties – the fact that it fissions with slow neutrons and sustains a chain reaction, thereby liberating millions of times the energy one can extract from conventional energy sources – all of which rely on electrons.
My interest in plutonium stems from its electronic structure, not its nucleus. I conducted my first plutonium experiments in glove boxes at Los Alamos in 1965. Plutonium is one of the most complex and fascinating elements in the periodic table because of its electronic structure. The metal exhibits six solid crystallographic phases at ambient pressure and a seventh under pressure; and these phases are notoriously unstable with temperature, pressure, chemical additions, and time. With little provocation, the metal can change its density by as much as 25 percent. It can be as brittle as glass or as malleable as aluminum; it expands when it solidifies, and its freshly machined silvery surface will tarnish in minutes. It is highly reactive in air, has five chemical oxidation states, and can form numerous compounds and complexes in the environment and during chemical processing. Because of its continuous radioactive decay it transmutes itself with time and causes self-irradiation damage in its metal lattice, or modification of solutions containing plutonium ions. It defies conventional metallurgical wisdom – one has to understand the physics of 5f electrons.
Plutonium marks the transition point in the actinide series where the 5f electrons change from being bonding to being localized (or chemically inert). In the delta phase, the electrons seem to be in a unique state of being neither fully bonding nor localized, a property that leads to novel electronic interactions and unusual physical and chemical behavior. This position in the periodic table challenges our understanding of relativistic electronic interactions and the nature of chemical bonding in heavy element metals, compounds, and complexes. I should add that Fermi played an indirect role in understanding these issues through his development of Fermi statistics while he was still in his twenties. Sixty-nine years after its discovery, we still do not fully understand the physics of plutonium. We may consider it a physicist’s dream because it offers new and novel physics, but it remains an engineer’s nightmare.
Plutonium also has important political and societal implications. Plutonium has come to symbolize everything we associate with the nuclear age. It evokes the entire gamut of human emotions, from good to evil, from hope to despair, from the salvation of humanity to its utter destruction. There is no other element in the periodic table that has had such a profound impact on the consciousness of mankind.
Unlike some of his colleagues, such as Oppenheimer, Szilard, Wigner and Teller, Fermi was reluctant to play a political role, but he was a strong advocate of nuclear energy and of international control of nuclear energy. My interest in the political and societal implications of plutonium and all things nuclear began largely with me taking on the responsibilities of director of Los Alamos in 1986. It was early in my tenure that the world changed dramatically when the Soviet Union collapsed and the Cold War ended. I believed it was crucial that scientists play a significant role in helping to manage the risks of all things nuclear while promoting the benefits of nuclear energy and nuclear technologies. At the time, the greatest risk was the nuclear risk posed by chaos in the former Soviet Union. This was a political and security risk recognized and addressed by Senators Richard Lugar and Sam Nunn, and Secretary of Defense William Perry. Today, we face a new set of risks, but the scientist’s role remains essential.
In addition to plutonium, these challenges have occupied much of my time during the past 20 years. I have been in Russia 41 times, in North Korea 6 times, and have made many visits to China, India and to other faraway places like Kazakhstan (in addition to more conventional places like England, France, Germany, Japan, and South Korea). As a brief aside, let me say that once we were able to get inside the Russian nuclear weapons labs, we jointly solved a 40-year old puzzle about the stability of plutonium alloys. In North Korea, I was allowed to hold 200 grams of their plutonium metal (sealed in a glass jar, of course) just to prove to the United States that they have the bomb.
Let me turn back to Enrico Fermi. He helped pave the way for my entry to Los Alamos. Fermi fled war-torn Europe with his family in 1938 and came to the United States. I was born in the middle of the war – in Poland. I grew up in Austria and came to the U.S. in 1956. Fermi was welcomed as one of the pre-eminent scientists in the world. The story is well known that he worked as an “enemy alien” in Chicago and the Manhattan Project until he could become citizen in 1944.
I was just a boy of 13 – but I was equally welcomed. Five years after my arrival, I was granted U.S. citizenship. In another three years, I was given a Q-clearance and access to the nuclear secrets at Los Alamos as a summer graduate student. Twenty years later, I was asked to direct the very laboratory that Fermi served so well during the Manhattan Project.
The moral of this story is that the U.S. government took risks – along with Fermi, came a legion of the world’s best scientists and engineers who helped to create the bomb and the rockets that propelled this country to not only a military superpower, but the leading technological and economic power in the world. The benefits of allowing these “enemy aliens” outweighed the risks. It is highly unlikely that the Manhattan Project could have succeeded without them – certainly not in time to influence the outcome of the war. This is a lesson we must not forget, including now during times when we face very different threats. I believe that our country has moved too far in the direction of becoming risk averse. This is especially acute in the nuclear field and in our nuclear laboratories.
I was fortunate to be able to follow in Fermi’s wake – he and his colleagues paved the way, but my adopted country still took an enormous risk with me and many others like me. That point was never lost on me – in fact, to this day it still inspires me to want to repay. I have always believed that “my country gave me the most demanding gift of all – it trusted me.”
So, let me conclude by saying that if sharing the Fermi Award has helped to keep alive the memory and contributions of one of the greatest physicists the world has seen, then I feel content. But whatever I accomplished was made possible only through my colleagues at Los Alamos and, now, at Stanford.
And, most of all, it was made possible by my family. I want to thank my four daughters, their families, my two grandchildren Noah and Ava, and, most of all, my wife, Nina, for having supported and encouraged me – and having put up with me. And with this trip I have finally made good on a promise I made to Noah and Ava a few years ago – that is to bring them from Colorado to Washington to show them the historical sites that should make them as proud to be an American as I am.
Thank you ladies and gentlemen.