Helium gas turbines for nuclear power.

Abstract

In recent years great progress has been made In the gas turbine field. The improvements made in high temperature materials, compressor and turbine design, and compact heat exchangers have made the gas turbine power plant a serious competitor of steam plants and diesel engines for many applications. There are, however, many problems still existing that tend to make conventional gas turbines unattractive. The use of residual fuels in the open cycle results in ash deposits and corrosion in the turbines which seriously limits the operating life of the units. Furthermore, open cycle plants are limited in power rating since the components become too large for outputs greater than about 20,000 HP. The closed cycle gas turbine plant eliminates these problems since only clean air circulates through the cycle and high pressures permit components of a practical size for outputs much larger than 20,000 HP. For a ship propulsion unit where the power requirements vary over a wide range, the closed cycle has the additional advantage of good part load efficiency. A major factor in the slow progress of the closed cycle plant has been the inability to manufacture a reliable air heater cheaply enough to permit the gas turbine plant to compete with conventional steam plants. The future of the gas turbines may depend on how well they can be adapted for use with nuclear power. At the present time the only ship propulsion plant employing a nuclear reactor is essentially a steam plant. The size of this plant is large since a two loop system is required in order that energy may be conveyed from the reactor to the secondary working fluid.