[PreciousLiberty]

“Possibly a dumb question, but why can’t they replace the reactors when the old cores wear out..”

Just a guess, but it probably has to do with the extensive cutting that would have to be done on the pressure hull. Possibly the hull and other parts of the sub are also wearing out in the same time frame and it’s just not cost-effective (or safe) to overhaul the old sub compared with building a new one.

“Am I correct in assuming that the reactors cores become degraded over time by the nuclear energy.”

It’s that the reactor core’s energy potential is being used up as the fissionable elements fission. It is possible to replace the cores in general, since that’s what’s done every ten years with our nuclear carriers. Clearly the issues are a lot different with the subs.

[ken5050]

If the cut the sub open to add a new segment to increase the length, I assume they can cut the hull where the reactor is to remove it, and swap in a new one..

I expect the experst here will let us know soon enough..