Nah, those (if legitimate) aren’t tarpits. We’ve had, at various times, approved locations for waste, and we actually still approve the storage of waste on site - indefinite storage of ‘temporary waste’. Paying into an insurance fund in case of a nuclear disaster would be far cheaper than what has been happening.
What happens instead is 1) a set of requirements is made, 2) someone spends years figuring it out. 3) it gets approved, 4) before it finishes getting built (or started to be built in some case), someone files a lawsuit causing it to stop or changes the rules, 5) rinse and repeat, or;
Someone gets the bright idea to try something new and unproven, and then they pay all the R&D time, and then the first thing starts happening, and then you’re tarpitted again.
In California it even appears to be part of the plan for high speed rail; as the engineering firms get paid every time the plan needs to get redrawn, and they can keep juking between plans forever until the funds are gone. This happened with Caltrain electrification for a decade. Billions spent for literally a 45 miles’ish stretch of track to electrify it, with zero progress over that time.
If folks are being paid to make plans instead of make a project, that’s usually what they are going to do.