Several artifacts from the office of the late Don Charlesworth at the Chalk River Laboratories (CRL) have been donated to the Society for the Preservation of Canada’s Nuclear Heritage Inc. (SPCNHI). Among these artifacts are two identical measuring tapes manufactured for AECL by the renowned Keuffel and Esser (K&E) instrument company. The tapes, which are approximately 28 feet (8.5 m) in length, are wound on product-specific, 38 cm diameter, wooden spools.
The mystery arises when one looks at the start of the tape where a value of zero is usually seen. The start of these tapes is marked with the very specific non-zero value of 457’ 7”. Furthermore, the following marks, which number 12 in total and end at 484’ 7”, are at irregular intervals. Some are very precisely specified (473’ 5 5/8” for example). These are clearly not regular tape measures!
A topographic map showing the ground elevation contours on the CRL site offers some clues to the mystery. The 450’ contour line lies between the NRU and NRX reactors. The tapes are clearly associated with elevations in that area, but in what manner was still unclear even after the Society sought an explanation from many employees, both past and present, who had worked in the area of the reactors. Elevation drawings of NRU and NRX showed many levels in the same range of numbers but no match could be found.
In the summer of 2018 two members of the Society were invited to tour several buildings slated for demolition at CRL in the near future. One of these buildings was Building 440, where river water was filtered and treated before use in NRU and NRX. An elevation drawing showing the flow of water immediately solved some of the mystery of the measuring tapes. The bottoms of the two lowest settling tanks in the facility are at an elevation of 457’ 6”, one inch below the lowest marking on our tapes. Furthermore, the outflow level of the facility is indicated to be at 484’ 6”, an inch below the last marker on our tape. Mystery almost solved.
Although it is clear the tapes were used to accurately set or adjust water flow levels, the Society has still been unable to pinpoint how the tape was used and to what the equipment or piping the intermediate levels correspond. Any clues that anyone who worked in these areas of CRL can provide would be very welcome. Please contact J. Ungrin at 613-584-3055, ungrinjr@gmail.com or any other executive member of the Society if you can help solve the rest of the mystery.
