Valve control for low temperature overpressure protection in a nuclear power plant

Patent · Tue Apr 22 04:00:00 EST 1986

OSTI ID:5707573

McMullin, C W; Weismantel, S E

In a nuclear power plant having a reactor coolant system and associated coolant pressure boundary, a control system is described for overpressure protection of the reactor coolant boundary to prevent violating a prescribed pressure-temperature relationship. The control system consists of: a relief nozzle connected to the reactor coolant boundary; a fluid collector remote from the reactor coolant boundary; first and second system relief lines connected in parallel between the nozzle and the collector, the relief lines having respective first and second power operated relief valves; control means for operating each of the power relief valves, the control means including logic means responsive to signals indicative of the pressure and temperature of the reactor coolant, a mode selector switch for selecting either normal or low temperature overpressure protection, and a function selector switch having an off position and a position for selectively introducing a simulated overpressure signal to the logic means; wherein the control means opens the first relief valve when (a) the function selector switch is off and (b) the mode selector switch is in the normal position and (c) the coolant pressure is greater than a set point value P/sub FP/ above the pressure corresponding to full power operation; and wherein the control means opens at least the first relief valve when (a) the function selector switch is off and (b) the mode selector switch is in the lower temperature overpressure protection position, (c) the temperature of the coolant is less than a preselected value T/sub M/ and (d) the pressure of the coolant is greater than a preselected value P/sub 1/ less than P/sub FP/ whereby the opening of the first or first and second valves provides a conduit path to discharge coolant from the reactor coolant system to the fluid collector for reducing the pressure in the coolant system.

• Assignee: Combustion Engineering, Inc., Windsor, CT
• Patent Number(s): US 4584164
• OSTI ID: 5707573
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200* -- Nuclear Reactor Technology-- Components & Accessories
220400 -- Nuclear Reactor Technology-- Control Systems
CONTROL
CONTROL EQUIPMENT
CONTROL SYSTEMS
COOLANTS
COOLING SYSTEMS
ELECTRICAL EQUIPMENT
ENERGY SYSTEMS
EQUIPMENT
FLOW REGULATORS
NOZZLES
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
PRESSURE CONTROL
PRESSURE DEPENDENCE
REACTOR COMPONENTS
REACTOR CONTROL SYSTEMS
REACTOR COOLING SYSTEMS
RELIEF VALVES
SIGNALS
SWITCHES
TEMPERATURE DEPENDENCE
THERMAL POWER PLANTS
VALVES