This is the cast-aluminum “Specifications plate” (front and back view) that had been mounted on the 22 MW, Metropolitan-Vickers, electric generator at the Nuclear Power Demonstration (NPD) reactor located at Rolphton Ontario which generated the first nuclear-based electricity in Canada. The heavy-water, natural uranium, pressure-tube based reactor started operation in 1962 and continued to operate until 1987. For much of that period it also served as a training center for many of the operators needed to staff the larger Douglas Point, Pickering and Bruce generating stations.
The plate was mounted on the side of the generator as seen in the accompanying photo. The plate itself is 35 cm by 22 cm in size and was detached from the generator during the initial phase of decommissioning. The photo at the bottom shows a long nameplate mounted below the specifications plate. It and the corresponding plate on the opposite side of the generator are discussed as Artifact 2018-004.