Nuclear Steam Supply Systems - NCYCLE
1 - Generic NSSS. With this system, the steam turbine throttle pressure and enthalpy are specified. Miscellaneous heat losses, blowdown systems, and NSSS auxiliary power consumption may also be specified.
2 - Boiling Water Reactor. The turbine throttle pressure and reactor outlet moisture are specified. Control rod drive flows, blowdown systems, reactor water cleanup systems, miscellaneous heat losses, and NSSS auxiliary power may also be specified.
NCYCLE models four types of Nuclear Steam Systems:
3 - B&W type Pressurized Water Reactor with Once-Thru steam generators. The turbine throttle pressure and the steam generator outlet temperature are specified (either as a curve or as a constant). CVCS heat losses, miscellaneous heat losses and NSSS auxiliary power may also be specified.
4 - Westinghouse/Combustion Engineering type Pressurized Water Reactor with U-Tube type steam generators. The steam generator outlet moisture and the steam generator outlet pressure are specified (either as a curve or as a constant). CVCS heat losses, miscellaneous heat losses, a blowdown system and NSSS auxiliary power may also be specified. The user may also specify design and actual reactor coolant temperatures and flows, and steam generator cleanliness factor. NCYCLE will determine the design heat transfer coefficient in the steam generator, adjust it for changes in reactor coolant flow and cleanliness, and perform a heat transfer calculation using the actual reactor coolant temperature and flow to determine steam pressure.
Except for B&W type PWR's, the steam generator may have a blowdown system that can include, at the user's option, multiple flash tanks and/or a blowdown cooler.