Considering the military is the worst pollution offender, I'm wary of how they'd handle nuclear waste.
260,000 shaft horsepower for 20 years between refueling.
I'd be curious how much oil would need to be burned instead of this (bunker fuels tend to be HIGHLY polluting).
Both sites have been visited every few years since they were located to check on the reactors. The design on both is working as intended, and no radioactive material has been detected to be leaking from either wreck. US naval nuclear reactors are (supposedly) designed such that they shouldn't lose containment if the vessel either sinks from an accident or is destroyed by enemy activity.
What would be an accident in the civilian space would be a state secret in the military.
If you know of a way to hide it, Jong-un Kim would like to talk to you.
2. Which non-US agencies monitors radioactivity levels in the air and water in the middle of the pacific ocean, with the resolution necessary to detect a small naval accident, before it gets diluted, or lost in the background noise?
It's obvious that the Navy has not had a Chernobyl accident. It's less obvious that it has had no accidents.
The USS Puffer [1], Proteus [1], Dace [1], California (twice) [2], Truxton [2], Gurnard (twice) [3], Hawksbill [3], and Abraham Lincoln [3] have all unintentionally leaked nuclear waste into the various bodies of water [1].
The USS Guardfish managed to irradiate it's own crew enough that 4 of them were sent to the hospital, and later managed to contaminate the submarine again while dumping radioactive resin into the wind. The latter form of incident is described as "quite common" [2].
The USS Aspro [2], Sam Houston [3], etc managed to leak radioactive water internally.
The USS Sam Rayburn "is mildly radioactive when it returns from patrol in February 1984. The Navy says this radiation is so mild it cannot be detected by a Geiger counter. " [3] (whatever that means)
(I make no claim that this is a complete list, or even a particularly reliable list since I didn't check my sources sources or anything like that, the point is there have definitely been accidents).
It's true that "there have been no spectacular meltdowns", but you're also talking about operating in an extremely controlled environments of a ship that you control. I don't think the army is going to have as an easy a time at it.
[1] https://en.wikipedia.org/wiki/List_of_military_nuclear_accid...
[2] http://www.chris-winter.com/Digressions/Nuke-Goofs/Refs-70.h...
[3] http://www.chris-winter.com/Digressions/Nuke-Goofs/Refs-80.h...