A New Solution to the Nuclear Waste Problem in Canada: Near-Reactor Storage in Large-Diameter Boreholes

INTRODUCTION In the 1970s, the problem of the disposal of high-level nuclear waste, produced by Canadian nuclear reactors, was receiving increasing attention (Aikens et al. 1977). From the onset, and to the present, the preferred solution was placing the spent fuel bundles at a single (central) site somewhere in the Canadian Shield, at a depth of several hundred metres (Aiken et al. 1977; Tammemagi et al. 1977; AECL 1994; OHN 1994; NWMO 2005). Although different types of rock were considered, including limestone and shale, a large body of homogeneous granite was almost invariably viewed as being the most suitable as a repository. If adopted, the central-site concept would require major excavation of rock (site) and the transport of about 3.6 million spent fuel bundles from the reactors located in Ontario, Quebec and New Brunswick, to the central repository (Table 1). In the “Adaptive Phased Management” proposal of NWMO (2005), the fuel bundles would initially be placed at a depth of 50 m and later moved to a depth of several hundred metres, or returned to the surface for reprocessing. During the past three and a half decades, several changes have occurred in Canada and abroad that call for a re-examination of the nuclear waste problem and a critical evaluation of the central-site concept. These changes are as follows: 1) As a result of recent advances in the design of rock drills, it is now possible to drill vertical boreholes six or more metres in diameter to a depth of several hundred metres. (Franklin and Dusseault 1989; Tativa 2005), making it unnecessary to send workers underground. Drilling is relatively easy in limestone, the common rock type beneath the generating stations in southern Ontario, and the rate of drilling is about three metres an hour for large-diameter boreholes. 2) Public opposition to nuclear energy has increased as a consequence of the Chernobyl incident in 1986; this attitude was expressed repeatedly during the Seaborn hearings (Seaborn 1998). Therefore, it seems unlikely that people, who live in the transport corridors, leading from nuclear generating stations to the central site, will accept the movement of trucks or trains laden with highly radioactive waste through their communities. With 192 fuel bundles in each transport cask, three 18-wheel tractor-trailer trucks would arrive at the central site each day for 20 years. Or, if transport is by rail (10 freight cars each with three casks), 30 trains would arrive at the central site each year for 20 years. Caccia (2007) has emphasized that major socio-political problems must be expected, especially within, and adjoining, the transport corridors. 3) During the past 3 1⁄2 decades, focus on the environment has increased enormously, culminating, recently, in a concern over global warming and the role of carbon dioxide emissions from vehicles in contributing to this warming. At a time when hydrocarbon resources should be conserved and CO2 emissions need to be reduced, the central-site plan will require 18 million kilometres of truck travel, Volume 34 Numbers 3/4 September/December 2007 151

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