[cocoablazing]

To what end?

The USN has, to a material degree, perfected the compact PWR.

Their experience in fuel design, materials, cooling, support systems, control systems, and processes pose an enormous barrier to new systems other than those that could truly radically simplify the reactor system and yield a huge gain in reduced manpower and increased reliability.

I think the best marginal gains are coming and will come from developments in tactical and ISR systems.