Patent Number: 054917310
Section: claims

1. An automated method for maintaining pressure within a nuclear power plant primary loop, the method comprising the steps of: partially filling a portion of a pressurizer vessel, in fluid communication with the primary loop, with a liquid for maintaining pressure in the primary loop;  circulating a primary coolant through the primary loop with a reactor coolant pump while controlling the pressure in the pressurizer vessel bye:  circulating the primary coolant through the primary loop with a reactor coolant pump after:  sensing the pressure of the primary coolant circulating through the primary loop by the first automated device; and  initiating or terminating said injection step by the first automated device in response to the sensed pressure of the primary coolant.  sensing the pressure of the primary coolant circulating through the primary loop by the second automated device; and  initiating or terminating said venting step by the second automated device in response to the sensed pressure of the primary coolant. 2. The method as in claim 1, wherein nitrogen is injected into the pressurizer vessel. 3. The method as in claim 2, wherein said injecting of step (i) includes: 4. The method as in claim 3, wherein said venting of step (ii) includes: 5. The method as in claim 1, wherein the inert gas is injected by the first automated device at a first predetermined pressure of about 380 psig. 6. The method as in claim 5, wherein the inert gas is vented by the second automated device at a second predetermined pressure of about 400 psig. 7. The method as in claim 18 wherein the pressure is automatically controlled within a range of about 20 psi.