Radiochemistry Flashcards
What are the 6 steps in the CRUD cycle
1)corrosion (outside core)
2) release
3) deposition
4) activation by neutrons
5)release
6) deposition throughout system
Discuss the hazards associated with tridium
1) Low level Beta emitter, Which becomes a radiological concern if it’s inhaled, ingested, or absorbed through the skin
2) Cannot be detected by whole body count only urinalysis
3) Is as a biological half life of 8 to 4 day’s
Discuss the method of oxygen control while starting up in mode 5 < 200ﾟF
Hydrazine is added to the RCS at between 140 and 180ﾟF to scavage oxygen
Hydrazine breaks down at >200°F
Why must the CVCS ion exchangers be bypassed when using hydrazine
Decomposition products of hydrogen will exhaust resin beds and cause release of chlorides into the RCS
State the effects of channeling in a deminalizer
1) RCS flow may not pass through any resin
2) Contact time may be reduced as to make ion exchange ineffective.
State the effects of channeling in a deminalizer
1) RCS flow may not pass through any resin
2) Contact time may be reduced as to make ion exchange ineffective.
What is general degradation
Corrosion caused by the presence of oxygen or oxygen generating contaminants
What is denting degradation
Plastic deformation occurring at the tube support plates due to corrosion buildup
Is what is wastage degradation
Localized corrosion caused by acidic attack in low flow areas
What is pitting
Localized attack at sludge sites that may penetrate steam generator tube
What is stress corrosion cracking
Tube cracking at the steam generator U bend caused by chlorides and/or stress
What is intergranular attack
Corrosion of steam generator tube grain boundaries at tube sheet crevice or dry out areas
What is fretting
Local wear from impact or sliding of tubes against support plate or the other tubes due to flow induced vibration
What is erosion corrosion
Mechanical damage from impingement of steam generator tubes from suspended corrosion products or reactive chemicals
What is fatigue
Circumferential tube cracking as a result of cyclic flow or temperature stress
