Primary Chemistry Flashcards
What are the Four reasons for maintaining primary chemistry control?
- Maintain material integrity.
- minimize corrosion.
- reduce radioactivity.
- asist in reactor control
What is the primary source of oxygen in the RCS at power?
The radiolytic decomposition of water.
What do we use to control oxygen content in the RCS at power?
We add Hydrogen to the VCT that acts as a blanket and scavenges oxygen.
What are the two reasons for the Hydrogen limit in the RCS?
- Problem degassing (GDT space)
- Explosive problem.
How do we control oxygen while starting up in mode 5 (<200*f)
We add Hydorzine which scavages oxygen to the CVCS chemical addition pot in the BAST room.
Why do we not add Hydorzine at temperatures greater than 200*F?
Hydorzine breaks down at temperatures greater thatn 200*f.
Why must the CVCS ion exchangers be bypassed with Hydorzine present in the RCS?
The Hydroxine will exhaust the resin and the subsequent releace of undesirable chemicals into the RCS.
At what temperature are the oxygen concentration limits in effect?
Above 250*f Oxygen the limit is <.1ppm
What do we add to the RCS for pH control?
We use enriched lithium-7 to raise pH.
pH lowers when we use Boric Acid for Reactivity control.
Why do we use enriched Lithium-7 as a pH control additive?
Because natural Lithium-6 produces tritium.
How do we remove excess Lithium from the RCS?
By placing the Catbed inservice.
Why do we let the lithium concentration in the RCS lower over core life?
Later in core life we are not adding Boron for reactivity control so pH remains slightly caustic.
What two methods does a demineralizer purify water?
- Mechanical filter (captures debris)
- Ion exchanger.
How do you determine the decon factor?
Divide the input by the output.
the normal Decon factor is 25.
What type of resin is in a Mix bed?
- LiOH normaly in service.
- HOH normaly bypassed.
