Gas Core Reactor-MHD Power System with Cascading Power Cycle
- Innovative Nuclear Space Power and Propulsion Institute, University of Florida, PO Box 116502, Gainesville, FL, 32611 (United States)
The US Department of Energy initiative Gen-IV aim is to produce an entire nuclear energy production system with next generation features for certification before 2030. A Generation 4 capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors. A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and cascading power cycle forms the basis for a Generation IV concept that is expected to set the upper performance limits in sustainability and power conversion efficiency among all existing and proposed fission powered systems. A gaseous core reactor delivering 1000's MW fission power acts as the heat source for a high temperature magnetohydrodynamic power converter. A uranium tetrafluoride fuel mix, with {approx}95% mole fraction helium gas, provides a stable working fluid for the primary MHD-Brayton cycle. A helium Brayton cycle extracts waste heat from the MHD generator with about 20% energy efficiency, but the low temperature side is still hot enough ({approx}1600 K) to drive a second conventional helium Brayton cycle with about 35% efficiency. There is enough heat at the low temperature side of the He-Brayton cycle to generate steam, and so another heat recovery cycle can be added, this time a Rankine steam cycle with up to 40% efficiency. The proof of concept does not require a tremendously efficient (first law) MHD cycle, the high temperature direct energy conversion capability of an MHD dynamo, combined with already sophisticated steam powered turbine industry knowledge base allows the cascading cycle design to achieve break-through first law energy efficiencies previously unheard of in the nuclear power industry. Although simple in concept, the gas core reactor design has not achieved the state of technological maturity that, say, molten salt or high-temperature gas-cooled reactors have pioneered. However, even on paper the GCR-MHD concept holds considerable promise, for example, like molten salt reactors the fuel is continuously cycled, allowing high-burnup, and continuous burning of actinides, and hence greatly improved fuel utilization. The fuel inventory is two orders of magnitude lower than LWR's of comparable power output and fissile plutonium production is likewise lower than in spent LWR fuel. Besides these features this paper discusses specific GCR-MHD design challenges such as fission enhanced gas conductivity in the MHD channel, GCR safety issues and related engineering problems. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21167909
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BRAYTON CYCLE
DESIGN
DIRECT ENERGY CONVERSION
ENERGY EFFICIENCY
FISSION
HELIUM
HTGR TYPE REACTORS
MAGNETOHYDRODYNAMICS
MOLTEN SALT REACTORS
PLUTONIUM
POWER SYSTEMS
REACTOR CORES
TEMPERATURE RANGE 1000-4000 K
TURBINES
URANIUM TETRAFLUORIDE
WASTE HEAT
WATER COOLED REACTORS
WATER MODERATED REACTORS