6. Heart

The core of a nuclear propulsion PWR is smaller than that of a land-based PWR (on the order of cubic meters), and must also meet different operating conditions ( [B 3 100] Pressurized water reactors. Description ):

• it must be able to withstand a large number of transients, including high-amplitude variations in speed (for example, variations from 10% to 100% of power in 60 seconds);

• the fuel cladding must be particularly tight, as a leaky cladding in a reactor as compact as a ship's would have far more serious consequences than in a land-based power plant, which is easier to decontaminate;

• due to the small size of the core, neutron leakage weighs heavily on the neutron balance (on the order of...