Approaches to improve heat transport and energy conversion efficiency

Approaches to improve heat transport and energy conversion efficiency 

All small reactors without on-site refuelling have given up economy of scale benefits at the outset and seek to benefit instead from mass production of standardized, modularized plants in a factory, and from rapid site assembly. But even more can be done on the plant itself to lower capital cost by other means. One such means is improved conversion efficiency per unit of capital cost in the balance of plant. 

Almost all of the water cooled concepts use a Rankine steam cycle with saturated or slightly superheated steam for energy conversion. The energy conversion efficiency has a maximum of -33% based on reactor core outlet temperatures from 270 to 345°C. 

The nearer-term sodium cooled reactor concepts — 4S Toshiba Design (14) and MBRU-12 (16) — and the Pb-Bi cooled SVBR-75/100 (18) employ conventional core outlet temperatures in the range from 480 to 510°C and drive superheated Rankine steam cycles attaining conversion efficiencies near 39%. The number of loops transporting heat to the balance of plant never exceeds two. 

For these nearer-term plants, high priority has been placed on being first to the market therefore, traditional heat transport conditions and balance of plant designs are used. They rely on well-proven heat transport components (pumps, steam generators, pressurizes, etc ). 

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