When referring to storage containers, the vendors are now trying to call their thin canisters “thick canisters” and “robust cask systems”, so it’s important to be more specific. 

Technically, the term “canister” is not used to define thick metal casks, but most people don’t know the difference between the word “canister and “cask”, so I always include the word thin and thick.  

When the public learns thin-wall canisters are only 1/2″ to 5/8″ thick and thick-wall metal casks are 10″ to 19.75″ thick, it is intuitively obvious to them that thick is better than thin when you’re storing nuclear waste. This has been very effective in messaging to the public and elected officials.
I don’t use the term “safer”, because it implies the thin-wall canisters are safe. The thin-wall canisters are unsafe. 

The words “safe” and “robust” are not measurable and are subject to interpretation. 

It is also common sense to most people that all nuclear waste containers must be designed to be inspected (inside and out), maintained and monitored in a manner to PREVENT radioactive releases and explosions. No thin-wall canister meets those critical common sense safety requirements.

Canisters and casks are pressure vessels, yet only thick wall casks have pressure monitoring and pressure relief valves. Most engineers do not know the nuclear waste containers are pressure vessels. They are shocked to learn the thin canisters don’t have pressure monitoring and pressure relief valves, needed to prevent hydrogen gas explosions. This is one of many basic ASME safety requirements where the NRC allows exemptions.  
If the NRC required ASME N3 Nuclear Pressure Vessel certification, no thin-wall welded canisters would ever be approved. 

Ralph Nader was shocked to learn the NRC is approving nuclear waste containers that don’t meet all ASME requirements.  He told me ASME are minimum standards set by the manufacturers, so are even low standards. He gave me a copy of a good article he wrote about ASME standards. Here’s a link to the article. 


Regarding decommissioning, the most important thing is to not allow them to destroy the pools unless they have a hot cell on site. The real reason Holtec and the utilities want to rush fuel out of the pools is because of the high overhead cost to keep the pools. They also want to spend the Decommission Trust Fund. 

Regarding transport, the legislators think the timeline to transport fuel is solely based on having a location. However, with canisters now loaded with so many fuel assemblies (e.g. 37 fuel assemblies instead of 24), the minimum cooling time before transport goes from 20 years to at least 40 years from the time the fuel came out of the reactor. There’s a direct correlation between cooling time and level of radiation that is released through the walls of any transport cask. 

I suggest including this 2-page inventory of commercial canister and casks stored in each state be included in the legislative package. It’s been very popular with elected officials and others. It includes the type of canister or cask and how long it’s been used in their state. The DOE is suppose to update this inventory data soon, but have not given a date. 


Donna Gilmore