When DOE terminated its Multi-Purpose Canister (MPC) program in late 1995, the time was right to move forward with a private sector initiative. NAC launched a program to design and license a system that could handle virtually all types of PWR and BWR fuel used in U.S. and international commercial plants. NAC based the UMS on the licensed NAC-STC basket and transport overpack designs, enabling it to push forward quickly with system development. Given the familiarity of the evolutionary design, NAC set licensing targets that would allow the UMS to meet utilities' urgent spent fuel needs before 2000.
Superior design and technology are only as good as the supplier's ability to fabricate and deliver the system on time. For the UMS, NAC implemented a comprehensive fabrication program that has led to uniformly reliable deliveries with the requisite high quality level for more than 240 systems.
- A licensed impact limiter design that uses results from comprehensive drop tests on a quarter-scale model of the NAC-STC
- Multiple basket configurations to accommodate a full range of BWR and PWR fuels
- A hands-on transport and operations-based design perspective
- A comprehensive design review by engineers and manufacturers to ensure that system component designs are easily and efficiently fabricated
- An integrated quality assurance program from start to finish.
The UMS has a capacity of 24 PWR or 56 BWR fuel assemblies. Based on its experience developing other spent fuel transport and storage systems, NAC established a capacity for the UMS that was large enough to economically meet utility needs, but within a reasonable licensing envelope to allow early deployment, a strategy that proved to be quite successful.