Circulator Design/Technology Evolution for Gas-Cooled Nuclear Reactors

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1996

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Many variants of the nuclear closed Brayton cycle (NCBC) power plant have been studied over the last five decades, the ultimate goal being the introduction of a high efficiency and environmentally acceptable plant for electrical power generation. With an indirect cycle (IDC) plant the thermal energy from a high temperature reactor (HTR) is transferred to the helium gas turbine power conversion system via an intermediate heat exchanger. Compared with previous direct cycle variants the decoupling of the prime-mover from the reactor has the following advantages, 1) configuration flexibility (eased congestion), 2) good component access, 3) non radioactive power conversion system, 4) ease of maintenance, 5) use of conventional equipment, 6) reduced development effort, and 7) eased adaptability to a fossil-fired source. In addition to being a more practical configuration, a major attribute for the IDC is that it is compatible with long-term plans for development of a high temperature nuclear heat source (NHS) currently underway in Japan. With a NHS in place a logical progression of the HTR would be to deploy a power generation version using an IDC helium gas turbine. This paper sheds new light on the nuclear gas turbine in that it is no longer at the forefront of gas cooled reactor application studies, but rather could be a beneficiary of work currently underway in Japan to develop a nuclear heat source for high temperature process heat. The performance and major features of a future NCBC plant concept are highlighted in this paper. Depending on the market forces prevailing in Asia for small nuclear plants, the NCBC with an indirect cycle helium gas turbine could be available for service around the year 2020.

Section: Helium Circulatorsmentioning

confidence: 99%

The Indirect Cycle: A Logical and Practical Nuclear Gas Turbine Power Plant Concept

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1996

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“…Experience gained from the operation of the vertical axial flow circulators in the FSV plant is also germane (McDonald, 1992…”

Section: Helium Circulators In Gas-cooledmentioning

confidence: 99%

Helium and Combustion Gas Turbine Power Conversion Systems Comparison

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1995

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For closed-cycle gas turbines, in a size to meet utility power generation needs, the selection of helium as the working fluid represents the best solution in terms of the overall power conversion system considering the differing requirements of the turbomachinery and heat exchangers. Helium is well suited for the nuclear Brayton cycle because it is neutronically inert. The impact of helium’s unique properties on the performance and size of the power conversion system components is discussed in this paper. The helium gas turbine plants, that have operated were based on 1950s and 1960s technology, represent a valuable technology base in terms of practical experience gained. However, the design of the Gas Turbine Modular Helium Reactor (GT-MHR), which could see utility service in the first decade of the 21st century will utilize turbomachinery and heat exchanger technologies from the combustion gas turbine and aerospace industries. An understanding of how the design of power conversion systems for closed-cycle plants and combustion gas turbines are affected by the working fluids (i.e., helium and air, respectively) is the major theme of this paper.

“…Experience gained from the operation of the vertical axial flow circulators in the FSV plant is also germane (McDonald, 1992). Particularly valuable know-how associated with operating in helium included sealing techniques, which are difficult with a low molecular weight gas, and coatings application to avoid galling and self-welding in mating oxide-free surfaces.…”

Section: Rotating Machinery In Gas-cooled Reactorsmentioning

confidence: 99%

Enabling Technologies for Nuclear Gas Turbine (GT-MHR) Power Conversion System

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1994

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Since the onset of gas-cooled reactor work, almost half a century ago, the potential for direct coupling of a nuclear heat source with a gas turbine power conversion system was recognized, however, the technologies for the realization of this were not available, and the plants operated to date have used Rankine steam turbine power conversion systems. In the early 1990s, technology transfer from the gas turbine and aerospace industries, now make possible the introduction of the gas turbine modular helium reactor (GT-MHR) for utility power generation within the next decade. In this paper the enabling technologies for the helium gas turbine power conversion system are discussed, and these include the turbomachinery, magnetic bearings, compact heat exchangers, and helium system operating experience. Utilizing proven technology, the first GT-MHR plant would operate with an efficiency of 47%, and by exploiting its full potential this could perhaps reach as high as 60% early in the next century.