Factual error: After the turbine trip, Godell says that the reactor water level was "almost up to the steam lines." The fictional Ventana nuclear plant is described as being a pressurized reactor plant and could not possibly have such a problem.
Factual error: When Godell takes over the control room, his colleagues are out in the plant trying to shut it down. In actuality, anyone, especially a trained operator, can do this easily from virtually anywhere in the plant.