E-0.2 (Nat Circ c/d) Flashcards
E-0.2
Major action catagories of Natural Circulation Cooldown?
- try start RCP
- c/d and depress w/o head void growth
- block SI and isolate accumulators
- place RHR i/s
- c/d to coldshutdown
E-0.2
max c/d rate during Natural Circ C/D?
is there a difference between units?
if so why?
What if you have an inactive loop?
what about Pzr?
- U-1 = 25 deg F/ hr
- U-2 = 50 deg F/ hr
yes, U-2 has a cold head design upper internals (more bypass flow so it cools down faster and can go faster without void formation)
per Appx SL
200 deg F in any 1 hour period
E-0.2
What is an inactive loop?
What is a stagnant loop?
inactive - not available for cooling (loss of feed or steam ability)
stagnant - uncoupled (not cooling down with rest of RCS)
- hL not all cooling down at same rate
E-0.2
What is the impact of not having two CRDM fans operating during Natural Circ c/d?
2 CRDM fans on
- subcooling > 70 deg F
< 2 CRDM fans on
- subcooling > 200 deg F
- 9 hr soak time
E-0.2
During Natural Circulation c/d what is your SI actuation criteria?
What parameters validate Natural Circulation?
SI
- Lpzr < 6%
- Subcooling < 20 deg F
N.C.
- subcooling > 20 deg F
- CET stable or lowering
- hL stable or lowering
- P s/g stable or lowering
- cL @ saturation temp for P s/g
