Main circulating water

Question 1

Purpose of CW

Answer 1

• Remove cycle waste heat from the steam cycle in order to optimize plant efficiency by producing a low pressure area for main LP turbines and TDFW pps.
• Provides a heat sink for the steam dumps during plant cooldown.

Question 2

Circ water pump trips

Answer 2

Manual
Phase OC
Ground OC
Loss of exciter field
4kv bus UV

Question 3

CW pump classification

Answer 3

6000 HP

214500 GPM

Question 4

CW pump interlocks (to start)

When does discharge valve start to open after pump start?

Answer 4

1. To start pump
   a. Discharge valve closed
   b. Cooling and seal water supply pressure >15 psig
   c. Discharge valve begins to stroke open 8 sec following pump start(Momentarily place C/S in close to stop valve stroking full open)

Question 5

Avoid throttling discharge valve to ______ to ensure min flow through the pump.

Answer 5

<40%

Question 6

Discharge valve _____ on pump trip. CW breaker position input to _____.

Answer 6

Closes

C-9

Question 7

Close discharge to ______ prior to tripping CW pump to ______.

Answer 7

25%

Prevent excessive backflow

Question 8

Power supplies of the CW pumps is 1A____1B_____1C_____.

Answer 8

A and C 143

B 144

Question 9

_____normally supplies the CW pps oil cooler and seal water.

_____ discharge header provides a backup supply

Answer 9

WS

CW

Question 10

Natural draft cooling tower turbine trip interlock:

Answer 10

1. On a turbine trip all the riser valves close and all the bypass valves open.
2. Prevents over cooling circ water, possible tower icing.
3. Interlock is bypassed by going to override on turbine trip interlock switch on 0PM01J.

Question 11

The NDCT turbine trip interlock is normally ______ to prevent______.

Answer 11

Bypassed to prevent stirring up debris and clogging cold water basin screens.

Question 12

To reopen the riser valves, must have _____ and _____.

Answer 12

Turbine trip signal removed

Turbine throttle valves reopened

Question 13

CW low discharge pressure will alarm at _____.

Answer 13

35#

Question 14

C-9 (condenser permissive) to be made up must have _____ and any _______.

Answer 14

<7.0 in HgA -and- any 1 of 3 CW pump breaker closed

Question 15

The function of C-9 is to ______ and can/can not be bypassed.

Answer 15

Block normal steam dump ops

Can not

Question 16

Sodium hypochlorite can only be in service for _______ hours, per _____ per _____.

Answer 16

2 hours per unit per day

Question 17

Sodium bisulfate must be added any time sodium hypochlorite in service or ______violation will occur.

Answer 17

NPDES

Question 18

Blowdown flow must be maintained ______ gpm for dilution when _______.

Answer 18

> 10,000

releasing a radwaste release tank to the river

Question 19

Traveling screens are on an automatic timer to run for ______ for 0A and _____ for 0B once every _____.

Answer 19

25 minutes
55 minutes
12 hours

Question 20

Traveling screens also operate on high DP of ______ in slow and shifts to _______ at _______.

Answer 20

6” H20
Fast
12” H20

Question 21

CW makeup pump trips 6

Answer 21

-Phase or ground OC
-Bus UV
-Manual
-Emergency trip PBs (MCR or local)
-15 seconds after pump start if
a. Discharge valve has not come off of closed seat
b. Discharge valve closes
0B pump only: trips on both sliding gates closed

Question 22

0CW220 is the _______ and maintains flume and intake bay level at setpoint from controller in ______.

Answer 22

Makeup valve

MCR

Question 23

If you emergency trip any one ______, you should trip all running______ to help prevent _______ damage.

Answer 23

CW MU pump
CW MU pump
Backflow