Secondary Chemical Addition Systems Flashcards
Why is hydrazine added to the CD system?
To scavenge oxygen (reduce the potential for corrosion in the steam generator and feed piping
Why is ammonia added to the CD system?
Elevate pH and minimize corrosion
Where is hydrazine and ammonia added into the CD system?
Downstream of the Condensate polishing demin resin traps
Where else can chemicals be added?
Into the suction lines of the AF āNā pump, blowdown system and SG upper feed lines
Which unit has been modified to inject hydrazine down stream of #5 and #7 HPFW heaters? Why?
Unit 3
Help reduce the iron carry over in the secondary
What system provides the normal supply of dilution water for ammonia?
What is the alternater?
DW
Condensate service header
What is used as the driving force to move ammonia from the truck to the bulk storage tank?
Service air
The hydrazine and ammonia addition pumps can discharge to how many points in the S/Gs and where are they?
2 points
1st downcomer feed line between the FW regulating valves and the FW isolation valve
2nd downcomer feed line downstream of the isolation valves and upstream of the double check valves
What does QM do for the system?
Heat trace
What is the purpose of the ammonia addition tanks?
Supplies ammonia to the condensate to maintain pH at 9.3 - 9.6
What stops the ammonia transfer pumps automatically?
Low low in bulk tank or an electrical trip
What ammonia pump can pump to high pressure of the steam generators?
SCN-P11
What dictates the concentration of chemicals in the day tanks?
CCI chemistry control instruction
What affect would a loss of ammonia have on the plant?
loss of pH control
What affect of loss of hydrazine have on the plant?
loss of oxygen control, increased corrosion rates
