STABILITY AND PERFORMANCE OF THE HNPF FEEDWATER AND PLANT POWER CONTROL SYSTEMS
Analog studies demonstrated that the Plant Power Control System can maintain throttle pressure at plus or minus 2 psi for ramp changes in steam flow of 15% per minute. This steam flow rate of change is about twice that specified to meet the design load swing of 5 Mwe/min. The positive feedback introduced into the control loop by the steam flow programming. signal did not greatly affect the pressure control system performance. It was found that this system will not exhibit instability as a result of the steam flow program signal. For plus or minus 10% step changes in sodium flow, over the flow range from 20 to 100% rated, the control system will regulate throttle pressure with a maximum error of plus or minus 18 psi. The recovery rate is relatively fast reducing the pressure error to plus or minus 5 psi in less than 1.5 minutes. A plus or minus 50 deg F change in sodium inlet temperature produces a maximum pressure error of plus or minus 15 psi. The feedwater flow responds rapidly to changes in valve position. For the open loop valve positioning system, the 180 deg phase point occurs at about 2 radians per second. The high full flow gain of the present equal percentage control valve will result in control system instability unless the controller proportional band is greater than about 350. Since the present controller has a maximum proportional band of 500, and the accuracy in the upper ranges is rather poor, the present system will exhibit instabilities at all controller settings. The equal percentage valve also results in a gain change of 28 decibels from 100 to 20% rated feedwater flow. These two difficulties may be overcome by changing the valve internals to those characteristic of a 3-in. valve and changing the flow signals from the flow squared inputs to the easily available linear inputs. This system will respond rapidly to changes in feedwater pump pressure steam flow, and evaporator pressure. The level control system is rather sluggish due to the inherent low system gain. To improve system performance it is recommended that a feedwater supply pressure of 1000 psi be established as the set point of the feedwater pump system. (auth)
- Research Organization:
- Atomics International. Div. of North American Aviation, Inc., Canoga Park, Calif.
- DOE Contract Number:
- AT(11-1)-GEN-8
- NSA Number:
- NSA-16-014309
- OSTI ID:
- 4798803
- Report Number(s):
- NAA-SR-Memo-6954
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANALOG SYSTEMS
CIRCUITS
CONTROL
CONTROL SYSTEMS
COOLANT LOOPS
EFFICIENCY
ERRORS
EVAPORATION
FLOWMETERS
FLUID FLOW
GAS FLOW
HEAT EXCHANGERS
HEAT TRANSFER
HIGH TEMPERATURE
HNPF
LIQUID FLOW
LIQUID METAL COOLANT
MONITORING
PERFORMANCE
PLANNING
POWER PLANTS
PRESSURE
PROGRAMMING
PUMPS
REACTIVITY
REACTOR TECHNOLOGY
REMOTE CONTROL
SERVOMECHANISMS
SIGNALS
SODIUM
STABILITY
STEAM
TEMPERATURE
TRANSDUCERS
TRANSFER FUNCTIONS
VALVES
VARIATIONS
WATER COOLANT