Mk1 PB-FHR Design Parameters

The Mark 1 Pebble Bed FHR (Mk1 PB-FHR) pre-conceptual design focused on questions related to coupling FHRs to air Brayton power conversion. The Mk1 PB-FHR uses a modified GE 7FB gas turbine in a conventional combined cycle configuration. This selection determined the reactor thermal power, 236 MWth, as well as the other key design parameters listed below.

Mk1 Reactor Parameters  
    Thermal power 236 MWth
    Core inlet temperature 600°C
    Core bulk-average outlet temperature 700°C
    Primary coolant mass flow rate (100% power) 976 kg/sec
    Primary coolant volumetric flow rate (100% power) 0.54 m3/sec
Mk1 Power Conversion Parameters  
    Gas Turbine (GT) model number GE 7FB
    Nominal ambient temperature 15°C
    Elevation Sea level
    Compression ratio 18.52
    Compressor outlet pressure 18.58 bar
    Compressor outlet temperature 418.7°C
    Compressor outlet mass flow 418.5 kg/sec
    Coiled tube air heater outlet temperature 670°C
    Base-load net electrical power output 100 MWe
    Base-load thermal efficiency 42.5 %
    Co-firing turbine inlet temperature 1065°C
    Co-firing net electrical power output 241.8 MWe
    Co-firing efficiency (gas-to-peak-power)† 66.4 %


†   The co-firing efficiency is the ratio of the increased power produced (total minus base load) during peaking, to the energy input from combustion of natural gas, and represents the efficiency with which the natural gas combustion energy is converted into electricity.