Several days before the general lockdown in Ontario in March caused by the Covid-19 pandemic Jim Ungrin received a phone call from Linda McLaren of Pembroke. She was making a visit to Deep River and would like to drop off an item to add to the collection of artifacts being accumulated by the Society for the Preservation of Canada’s Nuclear Heritage Inc. (SPCNHI). Linda, who is the daughter of the late Les Haywood, had previously donated a number of welcome artifacts.
The artifact Linda brought to 51 Poplar later that day turned out to be a very special one. It is the original draftsman’s drawing, as opposed to simply a blueprint, of the assembly of the 19-element fuel bundles used at the Nuclear Power Demonstration (NPD) reactor at Rolphton. The first version of the drawing (551C877) is dated 16 September 1959. It was drawn by G. Andrew at the “Peterboro Works” of the Canadian Atomic Power Division (CAPD) of Canadian General Electric (CGE). The drawing was released for construction 31 December 1959 and bears the Registered Professional Engineer, Province of Ontario, stamp of L.R. Haywood. A number of minor revisions to the drawing were made at CAPD over the next three years, with the 14th revision recorded on September 20, 1962.
The original design of the NPD reactor (NPD-1) was for a pressure vessel configuration with ~4 m long vertical fuel rods. This design evolved during the 1957-1958 period to the final design (NPD-2) with 132 horizontal pressure-tubes and 50 cm long fuel bundles which could be loaded/removed while the reactor was in operation – a key feature of all the CANDU reactors that followed NPD. The original loading at NPD used both 7-element bundles, with 25 mm diameter fuel sheaths, as well as 19-element bundles with 15 mm diameter fuel sheaths. The 19-element bundle featured a spiral wire spot-welded to the outside of the fuel sheath to provide correct spacing between fuel elements and to promote mixing of the surrounding heavy water coolant. This design was replaced in later fuels with bearing pads and solid spacers. On some of the elements the wires were wound in a left-hand rotation, while on others a right-handed rotation was used.
Later fuel designs for higher-power CANDU units retained the basic design of the NPD fuel with slight variations in element diameters but increased the number of elements. The CANFLEX fuel bundle, with 43 elements, was the ultimate member of the fuel-bundle series.
Numerous “dummy” fuel bundles have been manufactured over the years as presentation gifts and to mark specific events. Unfortunately, to date the Society has only been able to acquire a ½ length CANFLEX bundle which is part of a table lamp that was presented as a retirement present to Al Lane and donated to the Society by his widow, Fenella. The Society would be very pleased to provide a good home for any spare dummy bundles that may still exist in the nuclear community and any other artifacts like the Haywood drawing. Please contact us at info@nuclearheritage.ca or contact J. Ungrin via ungrinjr@gmail.com.
