Power waste heat

Average power consumption was 120 kWh/t in 1978 by 1988, it had decreased to 103 kWh/t. Maximimized utilization to off peak period (night time) power, waste heat generator and development of vertical roller mill provided great power cost saving. 

An important feature of the above potential uses of fast reactors is that in all cases the reactor cannot be considered separately form the entire nuclear fuel cycle. In any future developments the technology of the fabrication and reprocessing of the fuel and the treatment of the waste will interact with that of the reactor, and the economics and environmental impact of the whole fuel cycle, not just the reactor, will determine commercial e q)loitation. The Japanese "Self-Consistent Nuclear Energy System" (SCNES) illustrates this approach. The objective of the SCNES is a nuclear power facility, incorporating reactors and fuel cycle plants, which consumes nothing but U-238 and emits nothing but electric power, waste heat, and useful radioactive materials. This is a vision for the middle of the next century at the earliest, but in the nearer future ideas of this type are likely to become increasingly influential. 

The hot gases from the combustor, temperature controlled to 980°C by excess air, are expanded through the gas turbine, driving the air compressor and generating electricity. Sensible heat in the gas turbine exhaust is recovered in a waste heat boiler by generating steam for additional electrical power production. 

Many units have waste heat recovery systems that generate low pressure steam from reaction heat. Such steam is often employed to drive adsorption refrigeration units to cool the reactor feed stream and to increase polymer conversion per pass, an energy-saving process that reduces the demand for electrical power. 

Harvested and defivered whole, the trees are dried ia an air-supported fiber glass dome stmcture over a 30-d period by usiag waste heat from the combustioa process ia the adjaceat plant (Pig. 5). Trees leave the dome on the conveyor and, at the boiler wall, batches ate cut iato sectioas to fit the boiler. These sectioas are about 8.5 mloag for the 100-MW facility studied by EPRI and the Mianesota Power Light Company. 

L. B. Goss and L. Scott, Factors Affecting Power Plant Waste Heat Utilisation, Pergamon Press, New York, 1980. 

The combined cycle is also appHcable to dedicated power production. When the steam from the waste heat boiler is fed to a condensing turbine, overall conversion efficiencies of fuel to electricity in excess of 50% can be achieved. A few pubHc utihty power plants use this cycle, but in general utihties have been slow to convert to gas turbines. Most electricity is generated by the cycle shown in Figures 5d and 6d. 

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