The NRC has mandated that all dry cask storage systems be evaluated for the potential to generate hydrogen. The canisters at IPEC are stainless steel rather than carbon steel and have no ability to generate H2 gas.

Numerous analyses, including terrorist scenarios, have been conducted on the ruggedness of the various dry storage containers used in the United States. One such study, conducted by Sandia National Laboratory, subjected a steel and concrete cask similar in design to the Holtec Hi-Storm, to a device 30 times more powerful than a typical anti-tank weapon. Another study illustrated the effects of a large commercial aircraft traveling low to the ground at 350mph, precisely hitting nuclear plant containment structures, used fuel storage pools and dry cask storage containers of the type chosen for IPEC. In other analyses, hypothetical F-16 strikes were launched on the Holtec casks.

In all of these analyses, it has been concluded that the robust system of concentric steel and concrete cylindrical containers will prevent radioactive material from being released to the environment. In fact, for the first two scenarios, there was no release. The NRC staff filed 9 reports on the F-16 scenario, concluding that an accidental aircraft or ordnance impact on similar casks at a proposed facility in Utah (NRC Docket 72-22-ISFSI) does not pose a credible hazard to public health and safety. Holtec’s simulated F-16 strikes showed that MPC confinement will be maintained intact. (www.nei.org/documents/SafeShipBrochure1.pdf)

The Nuclear Regulatory Commission must certify all container designs. Before approval, containers must meet rigorous engineering and safety criteria and be able to pass a series of hypothetical accident conditions that create forces greater than the containers would experience in actual accidents. The same container must, in sequence, undergo

• A 30-foot free fall onto an unyielding surface
• A 40-inch fall onto a steel rod six inches in diameter
• A 30-minute exposure to fire at 1,475 degrees Fahrenheit that engulfs the entire container
• Submergence under three feet of water for eight hours

Also, by a separate test, containers are submerged under 50 feet of water for eight hours. Engineers and scientists at Sandia National Laboratories in New Mexico have also subjected used nuclear fuel containers to actual accidents to see what would happen in real-world conditions. For example:

• A flatbed tractor-trailer carrying a container was run into a 700-ton concrete wall banked with 1,700 tons of dirt at 80 miles per hour
• A container on a tractor-trailer was broad sided by a rocket-assisted 120-ton train locomotive traveling 80 miles per hour
• A container was dropped 2,000 feet onto soil as hard as concrete, traveling 235 miles an hour at impact. In all these cases, the containers survived intact.

Post-crash assessments demonstrated that the containers would not have released their contents. (www.nei.org/index.asp?catnum=3&catid=725)

Quality assurance and control systems are in place to ensure non-conformances are identified, evaluated and dispositioned, and multiple layers of checks are required for certification of a cask. For example, Entergy observes the Holtec fabrication process through inspections and assessments at the fabrication facility. Final product acceptance and placement in service, requires verification that casks meet their design criteria. If a defect is discovered, it is fixed and re-checked. Not until the cask meets all of its requirements will it be used. The Holtec system is used at 27 plants, with no record of structural failures or radioactive releases.

There have been no substantiated quality issues with the Holtec Hi-Storm system. An alleged quality issue has been addressed by the NRC, which concluded there was no technical merit to the issue. The highly regulated nature of the cask system design and ISFSI construction provides multiple layers of redundancy in safety. Entergy will verify compliance with the cask Certificate of Compliance through a quality assurance program and operational checks and inspections as required by 10CFR72. In the 20-year history of their use, no cask has failed or had to be reopened for remediation.

Fuel will be loaded in accordance with the FSAR and the Certificate of Compliance. All fuel assemblies will be categorized according to NRC criteria. Fuel that has been identified to have damage will remain in the spent fuel pool.