Speaker:	Don Taylor AECL Decommissioning
Topic:	The Decommissioning of ZEEP
Location:	J.L. Gray Centre Deep River, Ont.
Date:	Tuesday, December 2, 1997 (8:00 pm)

Summary published in North Renfrew Times, December 10, 1997:

ZEEP: A Look at Decommissioning

by Jeremy Whitlock

The historic site of Canada's first nuclear chain reaction is no more. Over this past summer the ZEEP building at Chalk River Laboratories was demolished, its contents carefully archived for future display. Thus, ZEEP is not only the first reactor in Canada, but also the first to be completely decommissioned. The details of this project were presented last Thursday at the J.L. Gray Bldg., in a public seminar of the Canadian Nuclear Society. The speaker was AECL's Don Taylor, project manager of the ZEEP Decommissioning Project.

ZEEP, an acronym for "Zero Energy Experimental Pile", was a low-energy (250 watts maximum) test bed for the mammoth NRX reactor that followed. Built in 1945, the flexible little heavy-water reactor was to operate for 25 years before being shut down. For most of the time since then it served as a surplus storage building, and in later years was converted into a museum for Canada's nuclear heritage. In 1966 ZEEP, also renowned as the world's first nuclear reactor outside of the U.S., was designated an historic site by the Archeological and Historic Site Board of Ontario.

Don Taylor explained that the objectives of the ZEEP Decommissioning Project were to clear the site for future MAPLE reactor construction, to archive the contents for possible reconstruction elsewhere, and to relocate site services running through the location. This scope was defined in December 1996, and a contract for the work was awarded to IDM Environmental , Inc. in April 1997.

Throughout Mr. Taylor's talk, one was struck by the remarkable speed and efficiency of the project. The work began with radiological surveys in May 1997, and ended with complete return to clean, level ground by the end of September 1997. That timeframe included an unexpected extension of scope part-way into the schedule, and a week-long strike at the plant that halted progress. In the end, the project came in a few hundred thousand dollars under its $2 million budget.

Preserved for future reconstruction are the reactor and surrounding structure, the moderator dump system, the instrumentation and control equipment, and assorted mementos deemed of historical importance. Complete records of the dismantling were also produced, including extensive photography before and during the project, and documentation of each archived component. The building itself was unfortunately deemed unsalvageable.

Mr. Taylor commented on the ease of the dismantling effort, attributed to the simplicity of the reactor's design. Only a few unexpected challenges arose, such as the undocumented complexity of the graphite block assembly surrounding the reactor, and the discovery of some control and shielding material also not evident in the drawings. In such cases new drawings had to be created to facilitate reconstruction. Only one reactor component, the moderator dump tank, was found to be slightly contaminated.

While they await a decision on their fate, the remnants of ZEEP now sit unceremoniously in storage huts at the Chalk River site. Many observers are hopeful that in time a suitable reconstruction may become a fitting testimonial to one of Canada's landmark technological achievements.