SBO Mechanical Flashcards
What is the purpose of the SBO?
Ensure that the plant is capable of withstanding a station blackout by providing an alternate AC power source for maitnaining adequate reactor core cooling and appropriate containment integrity for a required duration
What are the conditiosn under which the SBO must operate?
Completely Independent from plant systems
AC Power available to power shutdown equipment w/in 1 hour of event
COnnectable to to all 4 safety buses
How large are the SBO Diesels?
12 and 16 cylinder self excited diesel engines - powering a single generator per unit
What else is the air start solenoid outlet air used for?
Motive air for the governor air booster pump
What supplies the air for the SBO Air Start system?
2 compressors in the room.
system includes compressor, aftercooler, prefilters, post filters, receivers
How much air is required to be stored in the air receivers?
Enough for 5 start attempts.
What does a loss of ~10psig indicate for the SBO system?
That receiver is supplying the starting air
What is the coping duration for the SBO system?
4 hours
How is the Engine Temperature regulated?
Using the Jacket Water Cooling System - a three way AMOT valve will divert more or less water from radiators to control engine temps.
engine temp <167F - Full radiator bypass
Engine Temp >=185F - Full Engine Flow
How many jacket water cooling pumps are their and what are their power source?
2 - engine driven
What provides the initial cooling for the Jacket water system prior to radiator initiation?
1,200 gal holding tanks provide 8 minutes of cooling during SBO event using an engine driven pump
Where are main fuel oil tanks for Unit 2 and Unit 3?
Common 15,000 gallon tank located underground on east side of building
What is the capacity/duration of operation supplied by SBO Main Fuel Oil Tank?
15,000gal - supplies 24 hr full load on both SBOs
How much operation is supplied by the Day tanks?
4 hours of fully loaded run
How does the fuel get to the day tanks from the main tains?
Fuel Oil Transfer Pumps
What supplies fuel oil to the engine?
Engine Driven fuel oil pump
AC Powered backup fuel pump (auto start at >750rpm and <25psig)
What are the initiation and shutoff setpoints for the AC Powered Backup Fuel Pump?
Auto Start: >750rpm & <25psig
Auto Shutoff : <200rpm
What powers the AC powered backup fuel pump?
MCC 65-1/75-1
When is DROOP mode used?
When operating parallel to the grid
prevents overloading DG
What are the interlocks for the SBO Vent system?
First fan starts >200rpm ; outside air >60 and SBO >90
Second Fan starts >200rpm and outside air >60F
What are the lockouts on the SBO Sumps?
Engine Temp >140F
Head tank level drop >3% w/ temp <140F
Speed >200rpm
What provides power to the SBO building normally?
Bus 11 on high side of connection to Bus 16
During SBO Startup - If oil header is at 15# when DG reaches 450rpm, what will happen? If oil header is 20#?
At 450rpm, DG pauses until header reaches 20#, then goes to 900rpm. IF the pressure does not reach 20#, it will hold.
