Spray Pond Chemical Addition

Question 1

What is the purpose of the Spray Pond Chemical Addition system ?

Answer 1

Used to maintain our ultimate heat sink chemistry in order to optimize heat transfer of DG Coolers & Essential Cooling Water HEX

Question 2

What is the reason for adding Sodium Hypochlorite?

Answer 2

-Minimize bacteria & algae growth

Question 3

Why is Sulfuric Acid added to Spray Pond ?

Answer 3

Adjusted pH to prevent scale & corrosion

Question 4

Why is dispersant added to Spray Ponds?

Answer 4

Provides colloidal suspension of scale forming ions, silt,& algae, for ease in filtering

Question 5

Why is Biocide added to Spray Pond ?

Answer 5

Added to minimize Microbiological Influenced corrosion

Question 6

Why is Copper Corrosion Inhibitor (CCI) added to the Spray Pond ? What is negatively affected by ?

Answer 6

-Sodium Tolytriazole is a film forming anole that binds with copper to protect heat exchangers tubes
-Negatively affect by chlorine & UV light

Question 7

Why is Mild Steel Corrosion Inhibitor(MSCI) added to Spray Pond ?

Answer 7

Maintains protective film in HEX from residual concentrations

Question 8

When is Mild Steel Corrosion Inhibitor addition started/stopped ?

Answer 8

Started- 15 minutes before securing SP pump
Stopped- 30 minutes after pump has been secured

Question 9

Why does HMI have software interlocks ?

Answer 9

The software interlocks prevent undesired chemical interactions

Question 10

Are HMI interlocks still active when manually adding chemicals ?

Answer 10

No, they’re not active & this could cause mixing chemicals which leads to localized high concentrations of chemicals

Question 11

What is the High Flow Rate Valve(FCV) interlocked with ?

Answer 11

It’s interlocked with Spray Pond pump to prevent valve from opening, while the SP pump is running

Question 12

Why is the Hypo additions High Flow Rate Valve interlocked with SP pump ?

Answer 12

If SP pump is running while adding high flow rate hypo, could cause hypos being pumped through DG & Essential cooling HEX which could cause damage due to corrosion

Question 13

What’re the HMI interlocks to prevent Sodium Hypochlorite from interacting with Dispersant,CCI,MSCI?

Answer 13

Prevents incompatible Chemical Addition Pumps from starting in AUTO when Hypo is being added via automatic valve

Question 14

What is the interlock to prevent Hypo from coming into contact with other chemicals if one of the Incompatible Chemical Pumps is started MANUALLY?

Answer 14

HMI software will auto close hypo automatic valves if Incompatible Chemical Pump starts during hypo addition

Question 15

What’re the HMI interlocks to prevent Biocide from interacting with Dispersant,CCI,MSCI?

Answer 15

Interlocks to prevent incompatible Chemical Addition Pumps from being started while in AUTO, if Biocide is being added

Question 16

What is the HMI interlock if a incompatible Chemical Addition Pump is started MANUALLY,while Biocide is being added ?

Answer 16

Biocide pump will trip, IF incompatible Chemical Addition Pump is started MANUALLY

Question 17

What’re the HMI interlocks to prevent Dispersant from interacting with Biocide, CCI, Hypo?

Answer 17

Interlocks prevents incompatible Chemical Addition Pumps from AUTO starting,& Hypo Automatic valves is opened, DURING Dispersant addition

Question 18

What does HMI interlock do when incompatible Chemical Addition Pump is started manually or Hype Automatic Valve is opened, DURING Dispersant addition ?

Answer 18

HMI interlock will trip Dispersant pump, IF incompatible Chemical Addition Pump is started manually OR Hypo automatic valve is opened

Question 19

When can CCI only be added to Spray Pond ?

Answer 19

Can only be added when associated SP pump is running

Question 20

What chemical is allows to be added with other chemicals ?

Answer 20

Sulfuric acid is only chemical allows to be added in conjunction with other chemicals

Question 21

How many gallons are the Dispersant, CCI, MSCI, & Biocide tanks ?

Answer 21

1000 gallons for each tank

Question 22

How does hanging lever detector work for the chemical tanks ?

Answer 22

It’s reverse indications as LVL does down with the float, it’ll pull the level indicator up higher

Question 23

How’re chemicals added to Chemical Tanks ?

Answer 23

Utilities load a barrel onto forklift raised above tank and a hose is installed to gravity feed to Chemical Tank

Question 24

How is the chemical fed to the associated Pump Skid ? What is the putout for each pump ?

Answer 24

-Chemical is gravity feed to two 18gph pumps for each spray pond

Question 25

What is the cylinder on the pump skid used for ?

Answer 25

It’s filled and aligned to either pump for pump capacity testing

Question 26

Where do the chemical pumps discharge to ?

Answer 26

They discharge into recirculation header

Question 27

Are the chemical pumps on each pump skid able to be cross connect to each others spray pond?

Answer 27

Yes

Question 28

What does the three position handswitch (Hand/Off/Off) on each chemical pump skid mean ?

Answer 28

Hand- Turns associated pump on &removes control from HMI PLC Auto-Gives control of pump to HMI PLC Off- Turns pump off & removes control from HMI PLC

Question 29

What helps mix chemical into the recirculation header ?

Answer 29

A quill is used to create turbulent flow in Recirc header, which is then dispensed into ponds

Question 30

What needs to be running for Chemical Addition pump to operate ?

Answer 30

Need Recirculation Pump must be running & aligned mechanically & electrically to be able to operate Chemical Addition Pump

Question 31

How many Recirc pumps are usually running ?

Answer 31

-Two are usually running aligned to each spray pond -Third pump is a backup which can be aligned to either spray pond

Question 32

Where is Sodium Hypochlorite supplied from ? How is it transported ?

Answer 32

-Supplies to each unit from Water Resources -Transports it through common header outside PA, which then it breaks off to each units common header, then the units common header is split into two headers

Question 33

What’re the 5 valve entry points for Hypo into its spray pond ? What’re the valves rated for ?

Answer 33

-Two manual valves One rated for .5gpm flow rate Other rates for 10gpm flow rate Three automatic air operated valves -Low flow rate .25gpm -Medium Flow Rate .50 -High flow rate 5gpm

Question 34

What is different about Low Rate FCV than the other valves ?

Answer 34

Can also be operated via clutch & manual hand wheel

Question 35

How big is the acid chemical tank ?

Answer 35

2500gallons and it’s a double walled tank

Question 36

What does the Acid Chemical Tank feed ?

Answer 36

It feeds the Chemical Addition skids that has two pumps rated for 6gph & will discharge directly to SP

Question 37

What is the HMI PLC used for ?

Answer 37

It is used on the Spray Ponf Chemical Addition subsystem

Question 38

When must the schedule for the HMI PLC for the Chemical Addition system be verified by the area operator ?

Answer 38

-Must be verified by AO within 3 hour window -Starting 2 hours before & end on hour AFTER Trigger Time for daily chemical addition

Question 39

What is the alarm associated with Chemical Addition system ?

Answer 39

A local yellow strobe & horn on outside of building

Question 40

What do the HMI alarm on, for the Chemical Addition system ?

Answer 40

-High & Low level on tanks -Any non-normal condition from PLC -Pump Skid level alarm