On Synergy Between a High Temperature Gas-Cooled Reactor and a LNG Vaporization Plant

The Liquefied Natural Gas (LNG) chain of processes consumes the equivalent of 10% of initial natural gas flow for liquefaction, transportation and regasification of the natural gas. It is possible with the right process to recover some of this lost investment during the regasification process. The High Temperature Gas Cooled Reactor (HTGR) nuclear power plant appears to possess the characteristics needed to accomplish this recovery. This synergy of processes and fluid properties between an LNG regasification plant and an HTGR provides an opportunity to enhance an already efficient nuclear power generation scheme. Boiling LNG (112 K) provides an ideal cold side heat sink for the helium based Brayton cycle of the HTGR. Helium remains in the gas phase at these low temperatures. The resulting large temperature difference (1000 K) between the high temperature and low temperature sides of a thermal cycle means Carnot efficiencies approach 90%. Achievable efficiencies approach 77%, an increase from 48% for current ambient temperature cooled HTGR designs. Thus a LNG/HTGR plant can deliver half again more power for similar capital investments and operating costs. In addition, boiling LNG with helium saves fuel gas costs for the regasification plant. This paper will show that this combination is feasible and economic. Since both processes are designed to run at maximum capacity, duty cycles and plant availability criteria match. For coastal locations, both processes possess similar site selection criteria. Finally, combining the processes will impose no unmanageable safety constraints on either system and in fact could make safe operation easier to attain. This paper will provide general overviews of an HTGR power plant and of the LNG-to-market sequence, concentrating on regasification plants. The paper will then describe a process that combines an HTGR power plant with an LNG regasification facility to the advantage of both. At full load, the economic benefit for a dual installation supporting what would be a 1.1 GWe power plant before improvement would be approximately $423 million per year.