Patent ID: 7809099

Claim:
A pressurized light water reactor (PLWR) having direct vessel injection (DVI) nozzles for reducing emergency core coolant (ECC) bypass through a broken cold leg comprising: a cylindrical reactor vessel having a central axis; a core support located within the reactor vessel to support a reactor core in the reactor vessel; a first hot leg ( 4 a ) and a second hot leg ( 4 b ) located on the cylindrical reactor vessel at two diametrically opposed positions along an axis and at a first height positioned above the reactor core; a first cold leg ( 3 a ), a second cold leg ( 3 b ), a third cold leg ( 3 c ) and a fourth cold leg ( 3 d ) located on the cylindrical reactor vessel each at said first height above the reactor core; the second cold leg ( 3 b ) and the third cold leg ( 3 c ) are located on opposite sides of the first hot leg ( 4 a ) and spaced from the first hot leg at an angle of 60°, and the first cold leg ( 3 a ) and the fourth cold leg ( 3 d ) are located on opposite sides of the second hot leg ( 4 b ), and spaced from the second hot leg at an angle of 60°; a first DVI nozzle ( 5 a ), a second DVI nozzle ( 5 b ), a third DVI nozzle ( 5 c ) and a fourth DVI nozzle ( 5 d ) located on the cylindrical reactor vessel wherein the first DVI nozzle ( 5 a ) and the fourth DVI nozzle ( 5 d ) are located at a distance above the axis of the first and second hot legs where said distance equals 1.5 times a sum of a diameter of the second hot leg and a diameter of the first DVI nozzle; and the first DVI nozzle ( 5 a ) is located between the second hot leg ( 4 b ) and the first cold leg ( 3 a ), and closer to the second hot leg than to the first cold leg at a first angle from the second hot leg of 10 degrees up to and including 15 degrees, the fourth DVI nozzle ( 5 d ) is located between the second hot leg ( 4 b ) and the fourth cold leg ( 3 d ), and closer to the second hot leg than to the fourth cold leg at a second angle from the second hot leg of 10 degrees up to and including 15 degrees, the second DVI nozzle ( 5 b ) is located between the first hot leg ( 4 a ) and the second cold leg ( 3 b ), and closer to the first hot leg than to the second cold leg at a third angle from the second hot leg of 10 degrees up to and including 15 degrees, the third DVI nozzle ( 5 c ) is located between the first hot leg ( 4 a ) and the third cold leg ( 3 c ), and closer to the first hot leg than to the third cold leg at a fourth angle from the first hot leg of 10 degrees up to and including 15 degrees.