Many of the milestones in Canadian nuclear history that are being celebrated this year (NRT 27 April 2022) were well recorded with photographs of the people present during the event. This is the case for the start-up of the NRU and PTR reactors at Chalk River, the NPD reactor at Rolphton and the WR-1 reactor at Whiteshell. Unfortunately, that is not the case for the first large Canadian reactor, NRX, which went critical at 6:22 am on July 22, 1947. No photographer was present to record the event.
Various versions of the events that happened at the start-up of NRX have been written with the most complete given in the July 1967 issue of AECL Research, the AECL employee newsletter. This version names the main people in the Control Room; B.W. Sargent (In-Charge), D.G. Hurst, B. Pontecorvo, D.D. Stewart and G.M. James. In addition, a number of Operators were present to perform duties and provide readings.
Another group composed of senior staff was located in a room directly below the Control Room. The 1967 version has these people communicating with the Control Room by telephone as the heavy water level was raised. In an April 1977 article in the AECL Review, written by B. W. Sargent, he states that this second group “could learn of happenings only by a one-way communications system.” It would appear that little outside advice was welcome!
The leader of this second group was W.B. Lewis. He received the readings and recorded them on a slate blackboard. He also generated a plot as the slow increase in water level and approach to criticality progressed. There is no known record as to how large this group of senior staff was but four names have surfaced. They were G.W. Hatfield, D.A. Keys, K.F. Tupper and W.H. Watson.
Although no photograph was taken of the personnel, a photograph was taken of the blackboard and has been published in numerous documents. In addition to the data, four single letters on the blackboard stand out, H, T D and W. There appears to be a link drawn between the H and T as well as another between the K and W. The 1967 version of the story has it that during the slow overnight approach to criticality the four persons listed above enjoyed a bridge game with Hatfield and Tupper forming one pair and Keys and Watson the other. No point in wasting an opportunity.
Despite the “DO NOT ERASE” notice seen prominently on the blackboard, this piece of important history was not only erased, but the blackboard itself was discarded at some later date. While the Society for the Preservation of Canada’s Nuclear Heritage Inc. cannot claim to have the original blackboard, it has recently mounted on its walls a genuine AECL slate blackboard with a reproduction of the famous board. A number of years ago Dave Lee rescued from the Plant a blackboard slated for the landfill and stored it in his workshop. Mike Milgram used not only his carpentry skills to reframe the unit but also his chalk artistry. A relatively accurate reproduction of the board now can be viewed by visitors to the Society’s collection.
