Part 2 of A Historic Review of the Canadian Nuclear Industry: Achieving Nuclear Criticality

The below is part two of a five-part series detailing the history of Canada’s nuclear industry written by Michael Alexander Sinclair. It was originally submitted as an essay on November 15, 2017 for Ryerson University’s HST 701: Scientific Technology & Modern Society, and has since been modified for publication onto the Mackenzie Institute website.

An important step to Canada achieving nuclear criticality was achieved in 1942 when Clarence D. Howe decided to move the heavy water moderated uranium research from England to Canada. American by birth, C.D Howe refe rred to himself as a “Canadian by choice”.  With origins as a grain elevator engineer, Howe became Canada’s first Minister of Transport in 1936, and then the Minister of Munitions and Supply in 1940 during the Second World War. Over his 22-year career as a cabinet Minister, Howe led major initiatives including: Trans-Canada Airlines (Air Canada); the National Harbours Board; Canadian National Railways (CN); the St. Lawrence Seaway; the Trans-Canada Pipeline; the CANDU reactor program; Canada’s first nuclear power reactor; as well as establishing the Canadian Broadcasting Corporation (CBC).^[2] In 1942, as part of his duties as the Minister of Munitions and Supply, in a monumental feat brought about by Howe’s pivotal yet simple words, “Okay, let’s go,” 185.5 kilograms of heavy water was flown   Canada now possessed the global stockpile of heavy water. To supplement it, Canada began heavy water production in 1943 through a company called Cominco , now owned by Teck Resources Ltd, located in Trail, British Columbia.^[3]

With domestic heavy water production underway, the 1930 discovery of uranium in the Northwest Territories, and expanding research partnerships with England, the stage was set for the next attempt to achieve nuclear criticality. A Canadian laboratory was established in Montreal comprised of British and Canadian scientists. Experiments conducted at this laboratory yielded results essential for fission reactor design and chemical isolation of plutonium and uranium-233 critical isotopes, the original scope of the project. The goal was to produce and separate plutonium and fissile uranium for military application in a historical example of a so called double-edged sword, where the consequences of a technology depend on how it is used; nuclear technology could be developed for war, or for peaceful, commercial applications in clean power production.

The Montreal research eventually led to the Canadian Federal government decision to build a heavy water moderated nuclear reactor in Canada, specifically in Chalk River, Ontario. Located 200 kilometres from Ottawa and on the Ottawa River, it was chosen as the suitable location due to its proximity. The proposed reactor was to be named National Research Experimental (NRX). Upon completion, it would be the largest research reactor in the world. However, NRX was not to be the first reactor in Canada to achieve criticality. That achievement belonged to a much more modest reactor.^[4]

In 1945, Canada earned the distinction of building and operating the first nuclear reactor outside of the United States. Called ZEEP (Zero Energy Experimental Pile) it achieved criticality on September 5^th. Also located in Chalk River, Canada had produced a self-sustaining critical nuclear reaction. The research team was led by Canadian inventor and engineer George Klein, who over the course of his 40-year- career was essential to the NRC’s development of the first wind tunnel, and the early space program’s Storable Tubular Extendible Member (STEM) antenna that was used in the Mercury, Gemini and Apollo spacecraft. Klein was also a key player in medical developments in the microsurgical suturing device that led to the first ever successful kidney transplant and the first ever electric wheelchair which have had a monumental impact on healthcare and the lives of people who depend on these devices.^[5]

Klien’s most relevant contribution  to the topic at hand was the ZEEP reactor, which was a heavy water moderated reactor that used natural uranium as a fuel. It proved that Canada could achieve a controlled self-sustaining nuclear reaction using a homegrown innovative design. The Canadian designed reactor was also capable of producing plutonium as a by-product of the uranium fuel irradiation. ZEEP was used to perform experiments and measurements which were critical to support the design and construction of NRX.  It was also built to allow operators to gain experience working with nuclear reactors before NRX was built. ZEEP  had a single watt design capacity  in order to eliminate much of the required shielding that a larger reactor would require and simplify the overall design for quick construction. This small reactor was run constantly, excluding Sundays, from the initial startup in 1945 until April 1947. It was eventually shut down to supply heavy water to the larger experimental reactor that it was built to support, NRX.^[6]

It was not the last time that ZEEP went critical, and until 1970 it was operated intermittently to produce valuable data to support the Canadian nuclear industry; However, it is at the end of its first operation period that the next step towards modern Canadian nuclear power reactors occurs.^[7] The accomplishment of creating such an early stage reactor, especially given C The work performed to create this reactor was a key stepping stone to Canada’s rise as a global nuclear leader. Canada became recognized as a nuclear nation and this distinction is an important one from both a scientific and a societal perspective. However, it is not nearly the last great scientific nuclear achievement Canada was to produce.

 

Stay tuned for part two of five coming soon.