CD Demins Flashcards
(38 cards)
What is the purpose of the CD Demins?
to maintain required condensate chemistry
What size leak can the demins handle?
1 GPM on a continuous basis
What do cations and anions remove?
Cation - +M
Anion - -M
What type of resin do we use in the demins?
Mixed bed H-OH resin
What happens to the H & OH that is released from the resin in the ion exchange?
They combine to make H2O
What is it called when all exchange sites have the same form?
The resin is saturated, spent, or exhausted
What is the release of unwanted contaminants into the system from resin called?
Throwing ions
What is the relative attractiveness for one ionic species over another called?
Affinity
What does high D/P across a vessel indicate?
a clogged resin trap
What does low D/P indicate?
Channeling in a resin bed
What provides clean water for the CD demins for transferring, cleaning, and rinsing resin?
CT (the CST)
What does the CI (chlorine injection system) do for the CD demins?
it provides the sulfuric acid for demin regeneration. Only for the Cation bed
What is used to regenerate the anion bed?
caustic (sodium hydroxide) from the CC system
Where can the low TDS sump be pumped to?
the LR system if there is evidence of radioactive contamination, but normally it’s pumped to the circ water canal
Where is the high TDS sump pumped to?
to the CM system’s chem waste neutralizing tank
Where can the demin vessels be isolated from?
the control room or the Demin panel
What happens when the switch for the inlet valve to a demin vessel is taken to open?
a bypass valve opens. the D/P across the valve is sensed by a D/P switch and when it reaches a set value, the inlet valve opens and the bypass closes.
What happens if you release the switch from the open position before the D/P switch gets its signal?
The bypass will close and the valve will not open.
Which of the 6 lights that indicate the status of a demin vessel are used?
Rinse, Resin transfer (red)
Standby (white)
In service (Green)
Which regen vessels can take a full resin load?
Cation and the mixing & holding vessel
Where is all resin added?
Into the hopper that goes to the Cation Regen vessel
How many positions are there for the bottom water flow valve on the cation regen vessel?
4 positions that control air to the valve and thus control water flow.
What interlock is there for the vent valve on the cation regen vessel?
if pressure gets too low on the inlet to the cation vessel, a pressure switch will close the valve. This happens because the low pressure is an indication of failure of the resin trap
What does the Acid Day Tank do?
it holds 96% sulfuric acid that is used to regenerate the cation resin.
