Main Steam Flashcards
(24 cards)
Describe the purpose of the main steam system
Conveys steam from steam generators to the turbine generator and reheaters.
Provides steam for auxiliary services, including main and auxiliary feed water pump turbines, turbine gland sealing steam, and auxiliary steam.
Provides pressure relief protection for steam generators
Provides a means of controlled heat release from the reactor during normal operation, start up, hot shut down, cool down, and reactor physics testing.
Provides a means to minimize the effects of steam flow transients, preventing reactor trips during rapid load reductions and load rejections.
What are some other things the main steam system does?
- The main steam system contains and transports saturated steam from the steam generators to the main turbine, where steam is utilized to produce electricity.
- To meet heat sink requirements for steam generators, the main steam system provides a means to remove energy via safety valves when steam dumps (turbine bypass valves), or atmospheric relief valves are not available.
- Main steam also supplies steam to moisture separator reheaters (MSRs), auxiliary steam system (ASS), turbine driven main feed water (TDMFW) pumps and the turbine driven auxiliary feed water (TDAFW) pump, as well as the gland sealing steam system.
- During normal operation, steam from MSS passes through four main steam isolation valves (MSIVs) to four turbine main stop valves and four control valves into the high pressure (HP) turbine.
Describe the function and location of the Steam Generators. How many are there?
- Transfers heat from primary to secondary side
- Converts feedwater to steam for driving turbine
- Separates radioactive primary fluid from non radioactive secondary
There are 4 of them
Describe the function and location of the SG Flow Restrictors
designed to limit steam flow in the unlikely event of a break in the main steam line.
Describe the function and location of the Rad Monitors (MSS-RE75-79)
monitor the pipes through collimating windows in the shielding
Describe the function and location of the SG Code Safety Valves
ensures secondary system pressure will be limited to 110% of design pressure during the most severe anticipated system operational transient, which is based upon a turbine trip from 100% rated thermal power, without a reactor trip, coincident with an assumed loss of heat sink (i.e., no steam dumps or atmospheric relief valves available).
Describe the function and location of the SG Atmospheric Relief Valves (MSS-PV20 - D)
Describe the function and location of the SG Atmospheric Relief Bypass Valves (MSS*MOV74A – D)
ensure a secure path around atmospheric pressure relieving valves in the event the primary path is not available
Describe the function and location of the SG Atmospheric Relief Isolation Valves (MSS*MOV18A – D)
provide design basis safety function remaining open during normal operation, providing a flow path to the safety grade cold shut down paths via atmospheric relief valve or bypass valve.
Additionally, the valves are designed to close during a postulated faulted or ruptured steam generator if the respective atmospheric relief or bypass valve cannot be closed. They are designed to open with maximum operating differential pressure, if needed to establish a path to the relief or bypass valve.
Describe the function and location of the Steam Flow Detectors
Describe the function and location of the Steam Pressure Detectors
Describe the function and location of the Main Steam Isolation Valves (MSIV) (MSS*CTV27A - D)
To preserve containment structure integrity and prevent uncontrolled blow down of more than one steam generator
Describe the function and location of the Main Steam Isolation Valve Bypass Valves (MSS*HV28A - D)
permit control of steam flow around MSIVs for warming steam lines and equalizing pressure around MSIVs
Describe the function and location of the Main Steam Manifold Pressure Detector (MSS-PT507)
Describe the function and location of the Main Turbine Bypass Control Valves (MSS-PV47A/B/C, PV48A/B/C, PV49A/B/C)
Describe the operation of the main steam system under the following normal, abnormal, and emergency condition: Main Steam System Startup
Describe the operation of the main steam system under the following normal, abnormal, and emergency condition: Inserting Steam Generators with Nitrogen
Describe the operation of the main steam system under the following normal, abnormal, and emergency condition: Opening Main Steam Isolation Valves
Describe the operation of the main steam system under the following normal, abnormal, and emergency condition: Receipt of a Main Steam Isolation Actuation Signal
Describe the operation of the main steam system under the following normal, abnormal, and emergency condition: Gagging Steam Generator Safety Relief Valves
Describe the operation of the Steam Generator Atmospheric Relief Valves (MSS*PV20A - D)
Describe the operation of the Main Steam Isolation Valves (MSS*CTV27A - D)
Describe the operation of the Main Steam Isolation Bypass Valves (MSS*HV28A - D)
Describe the system response to loss of electrical power
