Reply #29: Even if a US reactor COULD operate at minimum power NRC regulations prohibit it.

[Statistical]

As you are aware but others reading might not be the reactor will trip automatically when any abnormal condition is detected. A whole host of conditions can lead to a reactor trip but loss power from any one of four sources is one condition that will lead to a trip.

Equipment senses loss of power or loss of connectivity to one of its primary sources
1) reactor main turbine
2) grid-intertie
3) diesel generator
4) off-site diesel generators

Technically with loss of grid a reactor COULD operate normally on diesel generators. The turbines could be disconnected and cooling system used to remove 100% of thermal output (turbine only removes about 30% of thermal output at peak load anyways). Alternatively reactors could be designed with a secondary turbine to provide station power and divert most of coolant around that secondary turbines (i.e. 980MW straight to cooling, 20MW to secondary turbine).

Still NRC regulations would prohibit that. Any loss of primary requires initiates an automatic trip.