Design Study of Air Cooled GTHTR300A for inland installation

GTHTR300 is a design series of power and cogeneration plants based on common technologies of a high temperature gas reactor and a direct Brayton cycle gas turbine power generator. Although the series currently selects seawater cooling as the method to reject reactor waste, heat, the employment of the Brayton cycle offers potential conditions for economical dry air cooling This paper reports the results of a conceptual design study for a new plant entry in the series, namely GTHTR300A for air cooling. Dry air cooling is made to replace seawater cooling of the baseline plant without forcing major redesign and new development in the reactor or in the balance of plant as is done with previous baseline derivatives. For example, the core layout and the reactor pressure vessel dimensions are not changed from the baseline even if their optimization may produce small cost saving. It is also found that by down scaling reactor thermal power by 20%, the size for the balance of plant is unchanged while delivering the same level of plant generating efficiency. An original design feature introduced in GTHTR300A is use of an intermediate helium loop, instead of usually water, to transport waste heat from reactor to cooling tower. Water is not used so that the plant can rule out accident of water ingress into reactor. By operating at high pressure but low temperature, circulating power consumption and equipment cost are kept down for the loop. The air cooling tower employs natural draft although mechanical draft, not detailed in this paper, has also been found acceptable to this plant. A compact tower is obtained due to the high thermal efficiency of 48.2%, as opposed to 34.5% of today's nuclear plants, and to the fact that the cycle rejects waste heat in a high temperature range. The maximum design sharing, high thermal efficiency, enhanced safety, and economical dry cooling make the GTHTR300A practical for inland installation without reliance on a large source of water to reject reactor waste heat