TC- Turbine Cooling Water

Question 1

What is the capacity [TC] pumps?

Answer 1

2 100% in parallel

Question 2

[TC] pumps location?

Answer 2

NE TB 100’

Question 3

Where can the pumps be started from?

Answer 3

Control Room

Local - at the breaker

Question 4

What happens if header pressure drops to 55 psig?

Answer 4

Standby pump will auto start

Question 5

What is TC maximum allowed temperature? What is the Hi-alarm setpoint?

Answer 5

105F

120F

Question 6

What are the TC pump power supplies?

Answer 6

‘A’ – NBN-S01

‘B’ – NBN-S02

Question 7

What is the capacity of the TC heat exchangers?

Answer 7

100% each

Question 8

What is the heat sink for TC?

Answer 8

PW system

Question 9

Where are the TC HXs located?

Answer 9

The north yard just north of the Turbine building

Question 10

What is the purpose of the TC Surge Tank?

Answer 10

Accommodates changes in system volume due to temperature changes

Provides NPSH for the TC pumps

Provides means of detecting leakage into or out of the TC system

Question 11

Where is the Surge Tank located? What is its capacity?

Answer 11

140’ Turbine Building above the TC pumps

500 gallons

Question 12

Why is Nitrogen used in the Surge Tank? What is the nitrogen pressure kept at? How else is the surge tank protected?

Answer 12

To prevent oxygen intrusion that could lead to corrosion

~25psi

over and under pressure protection
local level and pressure indication

Question 13

What system provides makeup water to the TC surge tank? What is the maintained level band?

Answer 13

Demineralized Water

45-51”

Question 14

Where is the TC Chem Add Tank located? What is the capacity?

Answer 14

100’ turbine building just north of the pumps

11 gallons

Question 15

During normal operations, how far open is the PW outlet valve for the TC HXs?

Answer 15

33%

Question 16

Why are the vent valves on top of the hydrogen coolers cracked open during normal ops?

Answer 16

To keep air out of the system high point

Question 17

Is the turbine cooling system safety related equipment?

Answer 17

no

Question 18

How does the turbine cooling water surge tank maintain level?

Answer 18

provided with a level control that signals a demin water make up line control valve to actuate open or closed

Question 19

What system powers the TC pumps?

Answer 19

NB

Question 20

How does the TC system interface with NH?

Answer 20

powers TC pump motor space heaters

Question 21

How does TC interface with CW?

Answer 21

cools the CW pump lube oil coolers

Question 22

Where are the TC system drains routed to?

Answer 22

OW system via turbine building drains

Question 23

What type of seals do the TC pumps have?

Answer 23

mechanical seals

Question 24

What is the discharge capacity of the TC pumps? Where are they located?

Answer 24

17,500 gpm

100’ turbine building north east side

Question 25

What type of heat exchangers are the TC HXs? Is TC in the tubes or shell side?

Answer 25

single-pass, counter-flow, shell and tube type

shell side

Question 26

Each TC HX has a relief valve for both the shell and tube side of the HXs. Where is the discharge routed to if there was over-pressurization?

Answer 26

the ground

Question 27

What is the required status of the TC HX outlet valve and TCHX bypass valve during operation?

Answer 27

one is required to be full open at all times to ensure good system flow

Question 28

What is the normal operating temp. for the TC system?

Answer 28

~90-95*F

Question 29

What is the most restrictive HX in the TC system?

Answer 29

main turbine lube oil cooler

Question 30

What does keeping TC temp. < 85F ensure?

Answer 30

temp. oscillations in support system does not occur

Question 31

How are temperature adjustments made in the TC system?

Answer 31

manually at the direction of the control room by adjusting TCHX outlet valve or bypass valve

(when approaching upper limit in the summer, adjustment to the PW outlet valve can be made)

Question 32

When will the TC surge tank pressure relief valve open? When will the safety valve open? Under pressure relief valve?

Answer 32

30 psi

100 psi

2” HG or .98 psi

Question 33

What is the impact of the plant if TC system is lost?

Answer 33

if TC can not be restored, plant must trip

Question 34

What are the loads cooled by the TC system?

Answer 34

CW pump motor lube oil coolers
generator hydrogen coolers
stator coolers
CD pump lube oil coolers
isophase bus duct cooling
gland steam packing exhauster
main turbine lube oil coolers (2)
main feed pump turbine lube oil coolers (2)
control oil coolers (2)
heater drain pump lube oil coolers (2)
Instrument (3) and service air compressors
secondary sample coolers (4)

Question 35

If there was a tube leak in the TCHX, what system would leak into the other due to higher pressure?

Answer 35

PW would leak to TC because the HX is the point in the system where PW is higher pressure than TC