Low Pressure Demineralized Water (LDW) System

Question 1

Describe Osmosis.

Answer 1

A biological process where a dilute or lighter solution passes spontaneously through a semi-porous membrane into a more concentrated solution (seeking ion-concentration equilibrium).

Question 2

Describe Reverse Osmosis

Answer 2

An engineering method of reversing this process where a high mineral salt fluid is placed under pressure, flows through a membrane, and becomes a near mineral free solution.

Question 3

What is the conductivity and pH of Raw Water?

Answer 3

400 umhos, pH 8.1

Question 4

What is the conductivity and pH of Demineralized Water?

Answer 4

<1 umhos, pH 5.6

Question 5

Describe the general process for demineralized water production from raw water.

Answer 5

1) Antiscalant injection
2) Reverse Osmosis
3) Ion exchange beds
4) LDW storage tanks
5) LDW transfer pumps and flush pumps
6) ATR

Question 6

Describe RO Pre-filters.

Answer 6

5-micron rating filters. Normal dp <10psi. >10 psi indicates need to change filer. >15 psi requires another RO to be placed online. Last approx 3-6 months.

Question 7

Describe RO Pumps

Answer 7

9-stage HP pumps
350 psi
86 GPM
480V
RO1 is Comm/Diesel
RO2/3 Comm only.

Question 8

How many IX Polishing Tanks are there?

Answer 8

Six tanks per Bank. We have four banks, so 24 Tanks in total.

Question 9

What are the designators for LDW Storage Tanks?

Answer 9

TRA-708A, TRA-754

Question 10

Describe operation of the Demineralizer transfer pumps.

Answer 10

Three-mode control:
HAND (Manual start and run)
OFF
AUTO (Standby selection to start at 86 psig)
500 GPM @ 110PSI

Question 11

Describe Demineralizer Flush Pumps.

Answer 11

480V Commercial from 608 MCC-2
1000 GPM @ 90 psi
Used to provide high volume of LDW when needed.
Normally OFF with discharge valves SHUT.

Question 12

What is the supply valve for LDW to ATR?

Answer 12

DW-18 (Just outside of West doors of TRA-608)

Question 13

Where does LDW enter ATR?

Answer 13

10-inch LDW supply line enters ATR building in the first basement level through the East wall in the switchgear room.

Question 14

LDW Makeup FCV-8-68 will open when?

Answer 14

Low PCS Surge Tank Level
Loss of IA Pressure
Manually from RCR DCS

Question 15

What is the normal flowpath for LDW into ATR?

Answer 15

Flows through FCV-8-68 bypass GT-8-9. Provides up to 100 GPM to LDW loads. Bypass flow rate is indicated on FT-8-10B
Also flows through HVW-2 directly before FCV-8-68 to supply:
ATR Battery Rooms
ATR Diesel Jacket Water Header Makeup

Question 16

Describe LDW Storage Tanks

Answer 16

100,000 gallon tanks each for 200,000 gallon capacity total
Insulated and constructed of SS
@ 3 inches level the Transfer/Flush pumps lose suction
pH 5.2-.58 (operation) 5.0-5.5 (outage) controlled by Nitric Acid addition.

Question 17

What is the function of LDW GT-8-18?

Answer 17

Manual isolation to provide rapid makeup to the T-Section of the Canal. Normally closed. Located in Primary Pump Motor Corridor.

Question 18

What is the purpose of GT-8-20?

Answer 18

10-inch supply isolation to provide suction source to Emergency Coolant Pump Suction Header. Located in the Primary Coolant Pump Motor Corridor East Side.

Question 19

Describe the purpose of LCV-8-129?

Answer 19

Gland seal water feed tank LDW makeup control valve. Located in primary pump motor corridor, west side. Maintains gland seal water feed tank level between 40-60 inches.

Question 20

Describe LCV-1-3A.

Answer 20

Primary Coolant System Degas Tank LDW makeup control valve. Located in Primary Pump Motor Corridor, West side. Maintains PCS degas tank level between 58 and 66 percent.

Question 21

Describe BL-8-442.

Answer 21

LDW Addition Valve to Irradiated Fuel Storage Area. 16.6 gpm gravity feed rate. 82.5 gpm with transfer pump operating.

Question 22

What is normal ATR LDW usage?

Answer 22

3-5 GPM.