SBO Mechanical

Question 1

What is the purpose of the SBO?

Answer 1

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

Question 2

What are the conditiosn under which the SBO must operate?

Answer 2

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

Question 3

How large are the SBO Diesels?

Answer 3

12 and 16 cylinder self excited diesel engines - powering a single generator per unit

Question 4

What else is the air start solenoid outlet air used for?

Answer 4

Motive air for the governor air booster pump

Question 5

What supplies the air for the SBO Air Start system?

Answer 5

2 compressors in the room.

system includes compressor, aftercooler, prefilters, post filters, receivers

Question 6

How much air is required to be stored in the air receivers?

Answer 6

Enough for 5 start attempts.

Question 7

What does a loss of ~10psig indicate for the SBO system?

Answer 7

That receiver is supplying the starting air

Question 8

What is the coping duration for the SBO system?

Answer 8

4 hours

Question 9

How is the Engine Temperature regulated?

Answer 9

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

Question 10

How many jacket water cooling pumps are their and what are their power source?

Answer 10

2 - engine driven

Question 11

What provides the initial cooling for the Jacket water system prior to radiator initiation?

Answer 11

1,200 gal holding tanks provide 8 minutes of cooling during SBO event using an engine driven pump

Question 12

Where are main fuel oil tanks for Unit 2 and Unit 3?

Answer 12

Common 15,000 gallon tank located underground on east side of building

Question 13

What is the capacity/duration of operation supplied by SBO Main Fuel Oil Tank?

Answer 13

15,000gal - supplies 24 hr full load on both SBOs

Question 14

How much operation is supplied by the Day tanks?

Answer 14

4 hours of fully loaded run

Question 15

How does the fuel get to the day tanks from the main tains?

Answer 15

Fuel Oil Transfer Pumps

Question 16

What supplies fuel oil to the engine?

Answer 16

Engine Driven fuel oil pump

AC Powered backup fuel pump (auto start at >750rpm and <25psig)

Question 17

What are the initiation and shutoff setpoints for the AC Powered Backup Fuel Pump?

Answer 17

Auto Start: >750rpm & <25psig

Auto Shutoff : <200rpm

Question 18

What powers the AC powered backup fuel pump?

Answer 18

MCC 65-1/75-1

Question 19

When is DROOP mode used?

Answer 19

When operating parallel to the grid

prevents overloading DG

Question 20

What are the interlocks for the SBO Vent system?

Answer 20

First fan starts >200rpm ; outside air >60 and SBO >90

Second Fan starts >200rpm and outside air >60F

Question 21

What are the lockouts on the SBO Sumps?

Answer 21

Engine Temp >140F
Head tank level drop >3% w/ temp <140F
Speed >200rpm

Question 22

What provides power to the SBO building normally?

Answer 22

Bus 11 on high side of connection to Bus 16

Question 23

During SBO Startup - If oil header is at 15# when DG reaches 450rpm, what will happen? If oil header is 20#?

Answer 23

At 450rpm, DG pauses until header reaches 20#, then goes to 900rpm. IF the pressure does not reach 20#, it will hold.