Extraction Steam and Drains (ED)

Question 1

What is the purpose of the ED system?

Answer 1

Preheats condensate and feedwater prior to feedwater entering the Steam Generators to increase overall plant efficiency

Question 2

What system has the ability to provide steam to the 4th point heater during startup?

Answer 2

AS

Question 3

What is the purpose of the blowdown stack?

Answer 3

Provides a collection point for various steam traps, HP heater relief valves and miscellaneous aux steam header drains

Question 4

When is DS added to the blowdown stack? What if DS is not available

Answer 4

When temperature of blowdown stack water volume exceeds 150F

If not available, there will be steam coming out of the blowdown stack and the north condenser area sump

Question 5

How does GA interact with ED?

Answer 5

During long term shutdown conditions, the GA system supplies nitrogen for blanketing of the feedwater heater shells and heater drain tanks to protect against rust and prevent oxygen from dissolving in the water

Question 6

How does IA interact with ED?

Answer 6

MT control system admits IA through Turbine Critical and Non-Critical Relay Dump Valves which provide a signal to control Bleeder Trip Valves
Provides motive force for all air operated valves in ED system

Question 7

How are BTV’s affected by a loss of IA?

Answer 7

BTVs will lose their open permissives and go partially closed

They will remain open due to the extraction steam flow

Question 8

Where are the Heater Drain Pumps powered from?

Answer 8

‘A’ from NBN-S02

‘B’ from NBN-S01

Question 9

Where does the seal water for each Heater Drain Pump come from?

Answer 9

Directly from the Condensate Header at 375-500 psig

Question 10

What provides cooling to each Heater Drain Pumps stuffing box?

Answer 10

Condensate service header at 50-100 psig

Question 11

What positions the Heater Drain Pump mini-flow valves?

Answer 11

Heater Drain Pumps flow transmitter

Question 12

What three signals would stop the Heater Drain Pumps?

Answer 12

A Heater Drain Tank lo-lo level alarm

Heater Drain Pump low flow after a time delay

Electrical protection signal

Question 13

Where are the Heater Drain Pumps located?

Answer 13

100’ Turbine Building west of the Main Feed Pumps

Question 14

Why does #5 Heater not have a level control system?

Answer 14

Does not contain a drain cooler region and drains directly to the Heater Drain Tank

Question 15

Which Low pressure Feedwater heaters have four inlets?

Answer 15

1 and #2

Question 16

Which heater has an input from S/G blowdown system?

Answer 16

3

Question 17

What is the purpose of the Bleeder Trip Valves?

Answer 17

To prevent reversed steam flow when the Turbine is tripped

Closure of these valves will ensure the Turbine does not overspeed

Question 18

What happens upon activation of the BTV test valve?

Answer 18

Valve equalizes the air pressure across the operator piston to allow partial closing of the valve disc by spring force

Question 19

Why is there two BTVs installed on #4 heater extraction line?

Answer 19

4 heater, by itself, has enough energy to cause an overspeed trip

Question 20

Which level control valves are reverse acting?

Answer 20

All of the high level control valves and #1 LP heater normal level control valves

Question 21

At what air signals are the reverse acting valves full open and full closed?

Answer 21

Full open with 3#

Full closed with 15#

(Direct acting is the complete opposite)

Question 22

What happens upon a hi-hi signal in a HP heater?

Answer 22

Isolates extraction steam

Closes the normal level control valve of the preceding heater

Opens the affected heater’s motor operated extraction steam line drain valve

In addition, for the HP heaters, the 1st and 2nd stage reheater drain tank vents isolate from the affected heater and vent to the main condenser

Question 23

What happens upon a hi-hi signal in a LP heater?

Answer 23

Isolated entire LP heater train by closing the heater train isolation valves

Isolated extraction steam to #3 and #4 heaters

Opens the extraction line solenoid operated drain valves for #3 and #4 heaters

Question 24

Below what power level may there be insufficient D/P between the heater shells to allow for proper operation of the normal level control valves?

Answer 24

20%

Question 25

When is the first heater drain pump started? Second?

Answer 25

1st = 25% power 2nd = Between 30% and 40% power

Question 26

During a plant shutdown, when are the Heater Drain Pumps secured?

Answer 26

First one at 40%, second one at 25%

Question 27

How is the ED system affected by a loss of IA?

Answer 27

Heater Drain Pump discharge valve fails closed, recirc valve fails open, putting the pump on recirc Heater Drain Tank, MSR Drain Tank, 1st and 2nd Stage Reheater Drain tank, and Feedwater heater High Level Dump valves will all fail open and the Normal Level Control Valves fail closed (Except #1 heater) Heater Drain pump will eventually trip on low flow or Heater Drain tank lo lo level signals The main steam supply to the 2nd stage reheater will isolate and the 1st and 2nd stage Reheater Drain Tanks and Tube Bundles will vent to the Condenser instead of their associated Feedwater heaters

Question 28

How do you place an ED sight glass in service?

Answer 28

- Obtain gloves, tape measure, hose/bucket, a wrench - Check for leaks and ensure drain and vent valves are closed - Remove cap off vent and make sure hose is on drain - Open lower and upper instrument valves slowly - Fill the sightglass by opening vent slighty to raise liquid level - Continue to do so until liquid is around 200 deg F - Fully open upper and lower instrument isolation valves and install vent cap

Question 29

What I&C does with the ED?

Answer 29

Operations asks them to make level controller adjustments on the robot heads

Question 30

What happens when securing HDP?

Answer 30

We have to cross tie the suctions of the pumps in order to remain >50% power but also, securing a pump can lower condenser hotwell level by as much as 9” hence why we keep hotwells at 41” and lo lo is 30”)

Question 31

What happens on a hi/hi hi HDT level?

Answer 31

Hi hi isolated all inputs into the HDT Hi should open the hi level dump and dump to the condenser

Question 32

Where does the HDT high level control valve discharge go to?

Answer 32

Condenser

Question 33

How many strings of HP heaters? LP heaters?

Answer 33

HP: 2 strings of 3 heaters LP: 3 strings of 4 heaters

Question 34

What can cause high level in a HP FW heater? LP FW Heater?

Answer 34

Both: Tube rupture in the heater Dump valves fail to open backing up the water

Question 35

What is the normal outlet temperature from #7 FW heater?

Answer 35

450 F

Question 36

How many BTVs and where are they?

Answer 36

15 BTVs HPFWH ones are on either side of the control valves LPFWH ones are on the south side of the turbine building on like 155’

Question 37

Moving high level dump valves?

Answer 37

When manually stroking the high level dump valves, you want to make sure the valve is not open or the controller being stroked. The bail on the robot head will be pressed down ¼ - 3/8 in and you will observe the air output signal lowering and let go of the bail To observe the valve locally the bail will be pressed slowly and when an operator says the valve is moving, the bail is let go If there is any problems, notify CRS, I&C and engineering

Question 38

What to do on high level MSR drain tank?

Answer 38

The turbine will trip when it reaches 3 inches below the MSR

Question 39

What are the load limits on LP heater?

Answer 39

According to 40OP-9ZZ14, Appendix I, the power limitations for one string of LPFWH out is 1109 MW (80%) and two out is roughly 50% power.

Question 40

What is some OE on robot heads?

Answer 40

The robot heads may create a crevice where the little arrow goes and it will get caught sometimes and wont move the valve The air input isn’t accurate and pressing the bail wont do anything either

Question 41

What are the level alarms for FW heaters?

Answer 41

There is a ED trouble for just a high level in any of the heaters but then there is a HiHi alarm on each of the heaters in the CR as well as the MSR drain tank and HDT

Question 42

Orientation of the FW heater within condenser?

Answer 42

LPFWH are at the top of the condenser going in horizontally with 1 and 2 on the top and 3 and 4 on the bottom although steam goes through it 4->1, the pressure difference allows flow to do so

Question 43

How do you ensure vacuum breakers are full?

Answer 43

We fill the vacuum breakers during rounds by adding seal water (condensate service header) to it and when the pipe start to feel hot, close the valve. The procedure says to close the valve when there is water discharging from the overflow, however, the temperature difference between the condensate service header and the atm is enough to feel when it is full to maintain the water air seal on the breaker

Question 44

How do the LCV and HLCV work to control ED tank levels? Interlocks?

Answer 44

Normal level control valves open based on the air input from the controller to maintain less than 4 inches. The high level control valve will open when there is a high level in the tank and dump the level to the condenser. High level control valves don’t open until the normals are completely open.

Question 45

How does colder FW affect Primary (esp RX power/Reactivity)?

Answer 45

Colder FW going in to the SG’s will pull more heat away from the RCS which then cools the RCS which then will cause power to increase. Colder water is denser which will cause more interactions with neutrons and power will increase

Question 46

Where are the normal and high level control valves for the LPFWH?

Answer 46

High Level control valves for LPFWH are on the north side by the respective heaters Normal Level control valves for LPFWH are on the south side again by the respective heaters