A modular high-temperature gas-cooled reactor (HTGR) coupled with a closed cycle helium gas turbine is expected as one of the promising power generation plants due to inherent safety and economics. EŠects of main design parameters, particularly gas pressure, on cycle thermal e‹ciency and power generation cost were examined for the block-type HTGR power plant. A previous design of 600 MWt reactor with inlet and outlet temperatures of 460 and 850°C and a gas pressure of 6 MPa was assumed as a

more »

... rence design. A computer analysis program combining a core thermal design and a gas turbine cycle was developed. From the results of parametric analyses regarding both the pressure and the fuel channel diameter based on this program, the reactor pressure vessel (RPV) cooling ‰ow ratio of 1 was clariˆed to be su‹cient. With increasing pressure, pressure drop decreased, and consequently, a higher cycle thermal e‹ciency and a lower power generation cost were achieved. Namely, it was clariˆed that an optimal pressure exists at around 8 MPa, which is diŠerent from the existing generally employed pressure of 6 or 7 MPa. In addition, the eŠects of fuel cost escalation were examined.