Wilfrid B. Lewis

Wilfrid Bennett LewisDr. Wilfrid Bennett (W.B.) Lewis (1908-1987)
The Father of the CANDU Reactor

Wilfrid Bennett Lewis was the physicist who dominated nuclear research and the development of nuclear power in Canada for nearly three decades, from the end of World War II until his retirement in 1973. The development of the CANDU reactor was his most stunning achievement.

He was born at Castle Carrock in Cumberland, England on June 24, 1908, the second of four children in a family with a long lineage of engineers.  As a child, Ben (as he was known to family and friends) enjoyed designing models out of Meccano sets and building wireless radio systems from electronic parts that he scrounged together.

After graduating from Haileybury College in Hertford, England in 1926, Lewis spent a year as a laboratory research assistant working with optical glass.   Given his profound interest in electronics and physics, it is not surprising that in the fall of 1927, Lewis chose to attend Cambridge University, the home of the World-famous Cavendish Laboratory for experimental physics.

After three years of undergraduate physics study at the Cavendish Laboratory, Lewis was approached by the lab’s chair, Ernest Rutherford, and asked to join his research group as a graduate student expert on wireless technology. Since much of the experimental equipment employed at the Cavendish in the early 1930s was increasingly electronic in nature, Lewis was often called upon as the resident expert, requiring him to troubleshoot and subsequently repair faulty electronic apparatus.

Over the next four years, Lewis absorbed the atmosphere of an academic scientific laboratory at its best, working on cutting-edge experiments dedicated to alpha particle research; specifically in the area of the electronic detection and counting of alpha particle emissions.  In 1934, he was awarded both a masters and a doctoral degree for his work.

From 1934 to 1939, Dr. Lewis served as a research fellow at Gonville and Caius College at Cambridge, working with John Douglas Cockcroft on nuclear disintegrations of particles accelerated by high voltages and, later, on the operation of the Cambridge Cyclotron. When World War II broke out in 1939, Lewis was asked by the British Government to join the Air Ministry’s Telecommunications Research Establishment to work on the development of radar systems for the purpose of defending England from German air attacks. Based on his abilities in this area, Dr. Lewis quickly rose to the position of Superintendent – a role considered by many to be that of “senior military scientist”.

Dr. Lewis had proven himself to be an able experimental physicist during his Cavendish years, but he had discovered through his work during the war on radar that his true talents lay in synthesizing the research efforts of others. In 1946, with the war over, he was offered the opportunity to do just that as the director of the National Research Council of Canada’s Atomic Energy Division (now Canadian Nuclear Laboratories) at Chalk River.

Dr. Lewis tackled both the scientific and management challenges of the new job with vigour, studying all areas of reactor design, recruiting excellent scientists, and expanding laboratories and equipment. His detailed interest and knowledge in many aspects of the research, including physics, chemistry, biology, and metallurgy made it possible for him not only to direct but inspire numerous projects.

Lewis’s drive, intelligence, and remarkable organizational skills placed him at the forefront of Canada’s nuclear program. As a proponent of pure research; existing for the simple purpose of increasing knowledge on a particular subject with no specific application in mind, Dr, Lewis encouraged the scientists working under his direction to exploit the world-class facilities at Chalk River. In the period from the late 1940s to the late 1950s the National Research Experimental (NRX) and the National Research Universal (NRU) reactors built at Chalk River were utilized for a variety of important experiments on neutron behaviour, shielding, flux and scattering.

Convinced that nuclear energy could be used economically for generating electricity, Dr. Lewis fostered a collaboration between Atomic Energy of Canada Limited (AECL, now Canadian Nuclear Laboratories) and Ontario Hydro (now Ontario Power Generation) that led to the development of the CANDU; the uniquely Canadian nuclear power reactor system. Considered by many to be the “Father of the CANDU”, W.B. Lewis was at the centre of all major planning and decisions for the project, from the conceptual phase, through proposal developments and construction, to the successful commercialization of the reactor in Canada as well as its export abroad.

After his retirement from AECL in 1973, Lewis moved to Kingston where, for the next nine years, he wrote and lectured on nuclear energy as a distinguished professor at Queen’s University. A steadfast proponent of nuclear power as a solution to the energy crises of his time, W.B. Lewis professed the energy that could be harnessed from nuclear fission was enough to sustain all of the world’s population for thousands of centuries.

In 1981, Dr. Lewis was awarded the coveted Fermi award for his outstanding lifetime contributions to energy science research. Later that same year he was diagnosed as having Alzheimer’s disease.  Dr. Lewis died in Deep River, Ontario on January 10, 1987.


Fawcett, Ruth (1994). Nuclear pursuits: the scientific biography of Wilfrid Bennet Lewis. McGill-Queen’s University Press.
Johnson, Carell B. (1983). Half a Century of Nuclear Pioneering: Profile of W. Bennett Lewis. Canadian Nuclear Association Nuclear Canada Yearbook — 1983. http://media.cns-snc.ca/history/pioneers/wb_lewis/wb_lewis.html