Safety is built into every aspect of the transportation system. It begins with the packages used to transport used nuclear fuel. Transportation packages are designed and tested to ensure workers and the public are protected during normal conditions of transport and during accident conditions.
Package Options in Canada
Before used fuel bundles are moved, they are placed in steel tube assemblies called fuel modules. These modules are then placed in massive containers for transportation.
There are several transportation package designs certified for use in Canada. They include the Used Fuel Transportation Package (UFTP) and the Dry Storage Container Transportation Package (DSC-TP). We are assessing the transportation of used nuclear fuel using both of these package designs.
Certifying Package Designs
Before a transportation package can be used, the design must be certified by the Canadian Nuclear Safety Commission (CNSC). Certification includes meeting a number of requirements and tests to show that the package can withstand severe impact, fire and immersion.
When all requirements are met, the CNSC issues a certificate. It specifies procedures for manufacturing, operating and maintaining the package. It also defines the authorized contents the package can carry.
Used Fuel Transportation Package (UFTP)
The UFTP has three main components: the body, lid and impact limiter. The body and lid are made of solid stainless steel with walls nearly 30 centimetres thick. The lid is attached to the body by 32 bolts.
Two Viton o-ring seals are installed between the body and the lid. The first inner seal provides containment for the package contents. The second outer seal provides redundant containment in case gas somehow bypasses the inner seal.
The impact limiter has a redwood core encased in a stainless steel skin. The stainless steel body and lid provide containment, shielding and impact resistance. The impact limiter is designed to protect the body and lid closure in the event of an accident. A UFTP can carry 192 used fuel bundles. It weighs almost 35 tonnes when loaded. Two trunions are used to lift the package and provide attachment points for tie-downs during transport.