Self-Driven Decay Heat Removal in a GCR Closed Brayton Cycle Power System
- Sandia National Laboratories, PO Box 5800, Albuquerque New Mexico 87185 (United States)
Closed Brayton Cycle (CBC) systems that are driven by Gas Cooled Reactors (GCR) are being evaluated for high-efficiency electricity generation. These systems were also selected by the Naval Reactor Prime Contractor team for use as space power systems. This paper describes the decay heat removal performance of these systems. A key question for such space or terrestrial based CBC systems is how to shut down the reactor while still removing the decay heat without using substantial amounts of auxiliary power. Tests in the Sandia Brayton Loop (SBL) show that the Brayton cycle is capable of operating on sensible heat for very long times ({approx} hour) after the reactor is shut down. This paper describes the measured and predicted results of generated electrical power produced as a function of time after the heat source had been turned off in the Sandia Brayton Loop. The measured results were obtained from an electrically heated closed Brayton cycle test loop (SBL) that Sandia fabricated and has operating within the laboratories. The predicted behavior is based on integrated dynamic system models that are capable of predicting both the transient and steady state behavior of nuclear heated or electrically heated Brayton cycle systems. The measured data was obtained by running the SBL and shutting off the electrical heater while adjusting the flow through the loop to keep the system operating at (or just above) its self-sustaining operating power level. During the test we were able to produce {approx}500 W of power for over 73 minutes after the heater power was turned off. Thus the Brayton loop was able to operate at self-sustaining conditions (or better) for over one hour. During this time the turbo-compressor was transporting the sensible heat in the heater, ducting, and recuperator to the waste heat rejection system for over an hour. For a reactor-driven system in space, this would give the shutdown decay power sufficient time to decay to levels where it could be removed radially through the core by conduction and then radiated to space. The model predictions show similar behavior; however, the actual generated electrical power was greater than predicted. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21016402
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AFTER-HEAT REMOVAL
BRAYTON CYCLE
BRAYTON CYCLE POWER SYSTEMS
DECAY
GAS COOLED REACTORS
HEAT SOURCES
HEATERS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
PERFORMANCE
POWER GENERATION
SHIP PROPULSION REACTORS
SHUTDOWN
SPACE
STEADY-STATE CONDITIONS
TIME DEPENDENCE
WASTE HEAT