ABSTRACT
The most serious design basis accident that can occur in a nuclear power plant is a loss-of-coolant accident (LOCA). In light water reactors, the cladding temperature is also required to stay below 2,200°F to prevent the zirconium in the cladding from oxidizing, which can lead to what is called the zirconium–water reaction. In liquid metal fast breeder reactors, the situation is somewhat different because the coolant flows through the core at pressures much closer to atmospheric pressure. A LOCA is essentially a leak in the reactor’s primary or secondary loops that results in a leak rate beyond the normal makeup capacity of the plant. In boiling water reactors, a signal is received that indicates that the water level has become unacceptably low in the reactor pressure vessel. The low-pressure injection system uses another set of pumps to pump water from the suppression pool directly into the reactor recirculation loop.
