Main Steam System Clause Samples

Main Steam System. The main steam system provides distribution of HP, IP / Reheat, and LP steam to the STG. High pressure steam shall flow from each HRSG through an isolation valve and into the high pressure steam header, where the steam shall be routed to the STG. Intermediate pressure steam shall be mixed with cold reheat steam from the STG and further superheated in the HRSG re-heaters. Hot reheat steam shall flow from each HRSG to the hot reheat steam header, which delivers the steam to the IP section of the STG. Low-pressure steam shall flow from each HRSG into the low-pressure steam header that delivers the steam to the LP section of the STG, where it mixes with IP exhaust steam. An STG bypass system shall provide a means to bypass the steam turbine during start-up and plant upset conditions only, including steam turbine trips. However, the bypass system is not designed to allow the plant to operate in bypass mode for long duration's. The STG bypass system shall include the necessary valves and piping to transfer steam flows from the steam turbine to the steam surface condenser. Valves and controls to protect the steam turbine shall be supplied with the steam turbine. The STG bypass shall be sized to bypass 100% of the steam from both HRSGs (without duct firing).