stainless steel. The cavity heat exchanger is assumed to cost 20$/kWt. The 36 ft. diameter dish delivers 52 kWt to the cavity receiver making the cost of each receiver $1040. The total cost of each collector and receiver is $13,800. When the NaK heat transport cost is corrected for 1975 dollars and adjusted for a 150 MWe system, the cost is 190$/kWt. The pumping power is 2.9% and the heat leak is 12.6%. Based on delivering 379 MWt to the heat engine, the cost of the engine becomes 480$/kWe. A summary of these results is shown in Table 14. The total system cost using NaK fluid transport is 1431$/kWe. The helium transport subsystem has more severe losses with the pumping power at 11.1%, and the heat leak at 19.4%. The cavity receiver heat exchanger for this case is assumed to cost 33$/kWt which brings the cost of each collector and receiver combination to $14,476. The heat transport cost is 174$/kWt, which when adjusted becomes 194$/kWt. The results of this system cost evaluation is also shown in Table 14. The overall system efficiency is only 19.5% as shown in Table 12. The last heat transport system uses the chemical approach (CH^ + H20 <->- 3H2 + CO). This approach has negligible heat leak and requires only 2% pumping power. Due to the high thermal decomposition temperature (700°C), the collector efficiency is only 72%. The Rankine heat engine is also considered to be 41.5% efficient if the thermal recombination occurs at 565°C, and a 540°C turbine inlet temperature is achievable. Each collector delivers 49.6 kWt to the fluid. The gas heat exchanger is assumed to cost 33$/kWt (without catalyst). The cavity receiver costs $1640 so that the cost of each collector and receiver combination becomes $14,400. When 376 MWt are collected, 7580 collectors are required. Thus, the total cost of the field of collectors with receivers is $109 million or 727$/kWe. The heat transport cost is 30$/kWt; 10$/kWt is added for two catalyst beds for a total of 40$/kWt. Adjusting for 1975 dollars and size, the transport cost becomes 44.4$/kWt. Based on 376 MWt delivered to the central Rankine plant, the
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