George C. Laurence

(The North Renfrew Times - November 11, 1987.)

With the death last Friday of Dr. George Laurence, Canada lost another key figure in the development of the country's nuclear industry. Starting in 1930, Laurence spent his career studying the atomic nucleus and developing techniques both to harness its power and to ensure its safety. Throughout, according to one colleague, Fred Boyd, he was “a true gentleman in every sense, always concerned about others”.

Like Dr. W. B. Lewis, another nuclear pioneer who died earlier this year, Laurence's career reached back to the very origins of the nuclear age with Rutherford at Cambridge, spanned the discovery and extraordinary applications of fission, and then extended into a more cynically questioning time. Perhaps more than most, he anticipated those questions: as early as 1956, he was chairman of the Reactor Safety Advisory Committee, and for the last nine years before his retirement in 1970 he was president of the Atomic Energy Control Board. He himself considered his contributions to safety control to be his greatest.

George Craig Laurence was born in Charlottetown in 1905 when Ernest Rutherford was still a young researcher at McGill experimenting with a new physical process - radioactivity. He completed high school in Sydney in 1921 and then enrolled at Dalhousie University intending to take an arts degree. He soon switched to physics and by 1927 had received both a B.Sc. and an M.Sc. Having won an “1851 Exhibition Scholarship” he went on to Cambridge where he joined Rutherford's Cavendish Laboratory.

It was an exciting time. By then, Rutherford and his colleagues had passed far beyond the seminal McGill experiments and were really beginning to understand nuclear phenomena. It was also the end of the “sealing wax and cocoa-tin” era, as people were beginning to realise that to do physics experiments you had to spend a bit of money.

Laurence's memories of those days were peopled with historic names like Chadwick, Kapitsa, Dirac, Fowler, Thomson, and Cockcroft; and he was influenced by the metaphysics of Witgenstein. His research was to investigate the properties of alpha particles, and the penetration of positively charged ions through matter.

Return to Canada

In 1930, the National Research Council laboratories were established in Ottawa and Laurence returned to Canada to join the staff and, in the following year, to marry Elfreda Blois. His job was to set up a laboratory to study radioactivity, and especially to develop methods for measuring radiation dosage in the treatment of cancer. Although this was a new field, there was already, in his own words, an “awareness of protecting patients and practitioners from the dangers of these radiations”.

Like many other physicists in 1939, Laurence became aware of the discovery of fission and of its potential power. At once it attracted his interest and, in the following two years, he came close to generating the first man-made chain reaction an “atomic pile” at the NRC laboratory. His experiments were foiled only by the impurity of his materials, a problem not recognized by anyone at the time. In the end it was Enrico Fermi who would build the first successful “pile” in Chicago at the end of 1942.

The experience he had gained on this work was useful to Laurence when he transferred to the joint British-Canadian research laboratory in Montreal. Because many of the British scientists were in fact of European origin, the Americans considered them a security risk and were unwilling to let them participate directly in their own Manhattan project. Instead they occupied a part of the newly built University of Montreal under the directorship of the Australian exile H.H. Halban. It was Laurence's duty, as senior Canadian Technical Officer, to keep C. J. Mackenzie, the Acting President of NRC, in touch with what was going on.

He found it a frustrating time. To him, his country was being ignored and this offended his sense of pride in Canada. Though Canadians were participating and Canada was paying the bills, Halban failed to inform any Canadian about the research plans.

Chalk River

While at Montreal labs, Laurence directed a score of scientists plus their supporting technicians in developing measurement instrumentation, and later with B. W. Sargent he focused on reactor problems. It was natural then when the war was over that he and his wife and two daughters would transfer with the Atomic Energy Project to Chalk River in 1946. They occupied No. 1 Beach Avenue, which remained his home until his death.

At first he was director of the Applied Physics Division, concerned again with the development of instruments, but soon he was to contribute to the increasingly original thinking of the Canadian reactor designers. “This to me was much more exciting than directing the design of equipment”, he said a few years ago. “With Gordon Hatfield, I drew up a list of five types of reactor I thought Canada might consider … One of these I called NRU. It would use heavy water with natural uranium, it would be considerably more powerful than the NRX, and would, I hoped, avoid many of the faults.”

Following the NRX accident in 1952, Laurence headed the investigating committee, which blamed the disaster on placing too much reliance on human operators, and undue complexity in automation of control mechanisms. “I often think of this as the beginning of Canadian thinking into reactor designing that led to CANDU”, he was to say later. “The accident called attention to the need for a very critical review of features for safe and reliable operation.”

Reactor Safety

In was also Laurence's first foray into reactor safety, a field which was eventually to be his full-time concern. His conversion was further helped by a dispute he had with the project leader, W. B. Lewis, over what material should be used in reactor fuel cladding. He protested Lewis's choice so strongly that he was removed as division director - one of several occasions in his career that he demonstrated a preference for principle over power. One beneficial result was that he could devote more attention to reactor safety.

His attention was timely, since by that time Toronto and McMaster Universities were asking to install sub-critical reactors, and it would only be a matter of time before commercial power stations would be proposed. The President of the Atomic Energy Board, C. J. MacKenzie, concluded that there had to be systematic regulation of such reactors operated outside federal agencies, and he appointed the Reactor Safety Advisory Committee with Laurence as chairman in 1956.

He soon persuaded MacKenzie to add three professionals to the AECB staff and, as he said in an interview in the mid-1980's, “With their help, most of my effort for the next year was to establish rules for reactor safety. The rules we devised in the early fifties were aimed at the faults that plagued that equipment. But with appropriate changes, these rules are still essentially in use today.”

It was Laurence's nature that led to another central characteristic of Canadian regulatory strategy: let the applicant prove the safety of his proposal, rather than regulate the details of design or equipment for him in advance. “We made an effort to find solutions by common consent,” was the way he described it.

President of AECB

When MacKenzie retired as the President of AECB, Laurence became his successor, leading the agency through a period of expansion as new reactors were built and planned. Throughout it all, his style and the Board's remained unchanged, with the result that, even today seventeen years after his retirement, Canadian regulatory practice is unique in the world for its minimum of lawmaking, while the country's nuclear industry has an unrivaled safety record.

During his career, Laurence received many honours. He was made a Member of the British Empire [MBE] for his scientific work during the war; he was awarded the Canadian Association of Physicist's medal for achievement in physics in 1966 and the W. B. Lewis medal from the Canadian Nuclear Association in 1975; and he also received a number of honorary degrees.

In his own assessment, he “had the advantage of being able to live and work in a very interesting period in the history of science. My contribution to it was not important: I was a witness to it and I really enjoyed the experience. I feel I was of most help in setting the procedures and practices for safety control in nuclear power stations.” Most would say that he was too modest by far.