In 1913 in the course of a conversation with her cousin, the British radiochemist Frederick Soddy, the Scottish doctor Margaret Todd coined the term “isotope.” Soddy had found persuasive evidence that chemical elements could come in varieties that had the same chemical properties but had different masses. Therefore all these varieties would occupy the same position in the periodic table. Soddy did not know what name to give to this phenomenon. His cousin suggested from the Greek -isos—the same—andtopos—place or position. In 1921 Soddy was awarded the Nobel Prize in Chemistry for his work. Miss Todd...

In the summer of 1939 Frisch left Copenhagen for what he thought would be a short trip to Birmingham. The war broke out and he stayed in Birmingham. There he found another refugee from Germany, Rudolf—later Sir Rudolf—Peierls, who had been a professor at the University of Birmingham since 1937. He was in England when Hitler came to power and he received permission to stay. At a conference in 1930 in the Soviet Union he had met the Russian physicist Yvgenia Kanegisser. He married her. “Genia” Peierls was, as I can testify, an irresistible force. In her presence...

On May 7, 2008, Gernot Zippe died in Bad Tölz, Germany. He was ninety. I could find only one obituary for him. It was in the URENCO trade magazine—URENCO being the Europe an consortium that enriches uranium commercially with centrifuges. In fact, even though Zippe and I had been in occasional communication by phone and email for a few years before his death, I did not learn about it until some months after the fact. Through no fault on Zippe’s part, his centrifuge has been responsible for a very substantial portion of the proliferation of nuclear weapons to places...

In 1975 the Shah of Iran signed a deal with the German company Kraftwerk Union AG to build reactors some eleven miles from the city of Bushehr on the coast of the Persian Gulf. What ever the Shah’s intentions were, his action led Saddam Hussein to begin his own reactor program with the French. This was the Osirak reactor that the Israelis destroyed in 1981. This reactor, unlike most at this time, was to be fueled by highly enriched uranium, which had not yet been loaded. The uranium was not destroyed in the raid and enough was left to have...

Glenn Seaborg had something in common with many second-generation Americans. His mother tongue was not English. In his case it was Swedish. This came in handy in 1951 on the occasion of his winning the Nobel Prize in Chemistry. He was able to address the King of Sweden in their common mother tongue. Seaborg was born in 1912 in Ishpeming, Michigan. In 1922 his mother decided that she had had enough of Michigan winters and moved the family to a suburb of Los Angeles. This was the first piece of good luck in the early parts of Seaborg’s career. It...

I had the chance to meet William “Willie” Zachariasen a few times when he came to visit his son Fred in Aspen, Colorado. Like his father, Fred was a physicist—he died in 1999—and we spent several summers together at the Aspen Center for Physics. I knew at the time that Willie must have been a distinguished physicist. He was a professor of physics at the University of Chicago and for a time chairman of the department, a department that included people like Fermi. I had no idea what field Willie was in and never thought to ask. He...

Figure 7.1 shows the fragment from the fifth draft of President Eisenhower’s December 8, 1953, “Atoms for Peace” speech delivered to the United Nations General Assembly. The speech was mainly written by Eisenhower’s aide General C. D. Jackson. The handwriting is Eisenhower’s. Members of his cabinet, such as his secretary of state, John Foster Dulles, strongly opposed the speech, which he gave anyway. This proposal is absolutely remarkable both for what it says and what it does not say.¹

It is unclear to me if Eisenhower had any technical background in nuclear energy. He did have some very good advisors,...

In March 1974 the Shah declared that Iran’s goal was to produce, within a few decades, 23,000 megawatts of electricity using nuclear power. This would mean constructing twenty or so power reactors. In this context a 5-megawatt reactor at the University of Tehran—the TRR—is very small beer indeed. After Ayatollah Khomeni became the Supreme Leader in December 1979 and declared that nuclear weapons were un-Islamic, he dismantled the Shah’s program, which would seem to mean that he had doubts about its peaceful intentions. He had good reasons. Take the curious case of South Africa. In 1969 they began...

In 1993 the Iranians received 115.5 kilograms of 19.75 percent enriched uranium fuel elements for the Tehran Research Reactor—the TRR from Argentina. We do not know precisely how this reactor has been run. Its maximum power output is 5 megawatts thermal. How many days a year it has been run at this maximum, or how frequently it has been shut down, one does not know. It is also not known how the fuel has been managed. The core seems to contain eighteen fuel elements, each with 1.87 kilograms of enriched uranium, and five control elements, each containing 1.08 kilograms...