Full-Scale External Pressure Test of Used Nuclear Fuel Container for Deep Geological Disposal – Phase 2

Abstract

In June 2007, the Government of Canada approved the Adaptive Phased Management (APM) approach for the long-term management of Canada’s used nuclear fuel recommended by the Nuclear Waste Management Organization (NWMO). In this approach, used nuclear fuel will be isolated and contained in a centralized Deep Geological Repository (DGR) located in a stable crystalline or sedimentary rock formation at a nominal depth of 500 metres below ground surface. The DGR concept incorporates multiple barriers to safely contain and isolate the used nuclear fuel over the long term. The used nuclear fuel bundles will be encapsulated in a copper-coated steel vessel referred to as the Used Fuel Container (UFC).

To verify the UFC design and validate the computer models used to evaluate the design, an external pressure test program has been executed. The program includes multiple external pressure tests at Penn. State University. In the first phase of the program, the UFC steel structural vessel (i.e., UFC without the copper coating) was tested to the onset of plastic buckling. Strain gauges were mounted on the container to gain additional data; however, all malfunctioned. In the second phase, a copper- coated UFC prototype was tested with an improved strain gauge sealing technique. In both tests the container exhibited a consistent critical buckling load when compared to the finite element analysis results. The test demonstrated that the UFC could withstand the maximum loads in the DGR. The second phase strain gauge data provided additional insight of the behavior of the container.