Applications of Supercritical Carbon Dioxide Brayton Cycle for Nuclear Engineering: Cycle Layouts and Facilities

Background

Among various energy sources, the utilization of nuclear energy in the past decades shows the incomparable advantages, which is of the high energy density and the strong adaptability to environment and has no emission of gas pollutants and warming gas (CO₂). With the fast increasing energy needs, the reduction of the cost of electricity or the increase of system thermal efficiency is the crucial issues toward the successful future utilization of nuclear power. For this purpose, supercritical carbon dioxide (S-CO₂) Brayton cycle with high efficiency and compactness, is considered as the very promising energy conversion system in nuclear engineering.

Supercritical carbon dioxide as the heat transfer medium in nuclear power is of following advantages:

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  good chemical stability, non-toxic, easy to obtain;

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  the critical point is easy to reach because critical temperature close to ambient temperature;

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  with the increasing temperature at supercritical pressure, CO₂ is still single-phase in the process that transits from the liquid-like state to gas-like state, and its properties vary continuously along temperature;

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  there will be no boiling crisis in reactor;

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  the damage to the turbomachinery can be avoided since there is no liquid drop entrainment;

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  CO₂ near the pseudo-critical point is easy to compress, which can reduce significantly the compressing work;

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  due to the large heat transfer effectiveness of S-CO₂ benefited from its large density and thermal diffusion, the facilities of the energy conversion system such as turbine, compressor and heat exchanger are quite compact;

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  the low viscosity of S-CO₂ results into the high working capacity.