Spent nuclear fuel canisters vulnerable to failure as they age

Premature failure of U.S. spent nuclear fuel storage canisters, San Onofre Safety.org, by Donna Gilmore “……Stainless Steel Dry Canister Problems Darrell Dunn, an NRC materials engineer, stated stainless steel dry storage canisters are vulnerable to failure within about 25 – 42 years. If any of the fuel cladding in the canister fails, there is no protective barrier and we could have a serious radiation release.

The NRC said they have no current mitigation plan for that consequence. They suggested we MIGHT be able to put the fuel back in the spent fuel pool. However, Edison plans to destroy the spent fuel and transfer pools. And there is no technology to repair the canisters. The NRC said they HOPE there will be a solution for mitigation in the future. Even an NRC May 2nd High Burnup Fuel letter admits there are mitigation problems.

No Inspections of Stainless Steel Canisters EPRI 2012 presentation To make matters worse, these stainless steel canisters are not inspected after they are loaded into the unsealed concrete overpacks (Areva NUHOMS) or concrete casks (Holtec and NAC Magnastor). The NRC proposed having each nuclear plant inspect the outside of only ONE stainless steel canister before they receive a license renewal and then do that once every 5 years. The industry balked at having to even check one canister at every plant. The problem with the stainless steel canisters is they do not protect against gamma rays; so it’s not a simple task to remove a canister from the concrete overpack/cask to examine the exterior for corrosion or other degradation. And since welded canisters do not have monitoring for helium leaks, we may not have any warning of an impending radiation release.

Concrete Overpack Corrosion Problems Darrell Dunn discussed serious corrosion problems with the concrete overpacks/casks, especially in coastal environments…….. https://sanonofresafety.org/2014/08/21/premature-failure-of-u-s-spent-nuclear-fuel-storage-canisters/