Combustible gas Flashcards
Do hydrogen igniters auto start?
no
What are hydrogen ignitors made of?
they are a glow plug
Do the hydrogen recombiners auto start?
no
When should the hydrogen recombiners be started?
> 1% hydrogen
When should they be secured? why?
Prior to 6% before they become overloaded and could damage the unit
How many hydrogen analyzers are there?
4 (2 in ctmt and 2 in DW)
Where are the hydrogen analyzers?
2 in ctmt and 2 in the DW
Do the hydrogen analyzers auto start?
YES! on a LOCA
When do the hydrogen analyzers start?
on a LOCA
If CTMT pressure is lower than drywell pressure, what position are ALL vacuum breakers in?
closed??
When will CTMT purge isolation valves F009/F010 close?
LOCA signal
NSSSS LOCA
CTMT/DW exhaust HI-HI Rad 3.6 mr/hr
Manual isolation pushbutton
When will filter train exhaust isolation valve F036/F037 close?
NSSSS LOCA Initiation
SBGT initiation HI-HI Rad or manual
Which systems are safety related and which are not?
Safety - Post LOCA vacuum relief, Hydrogen control, Drywell purge
Non Safety - CTMT purge, Normal drywell vacuum relief
After a LOCA signal, with signal still present, when can CTMT isolation valves be re-opened?
24 hours after receiving the signal
What will happen if DC power is lost while drywell purge compressor is running?
nothing dude
What percent do the hydrogen recombiners maintain hydrogen levels in CTMT/DW?
< 4%
What are the flammable and explosive ranges of hydrogen
< 4% Non combustible
4 - 18% Combustible/flammable
18 - 59% Explosive/detonable
59% - 75% Combustible/flammable
> 75% Non-combustible
What is the primary use of CTMT purge subsystem
backup to hydrogen recombiners
What’s the purpose of combustible gas?
- Control the concentration of hydrogen that may be released into CTMT/DW following a LOCA
- Prevents a vacuum from being drawn into the drywell
- Relieve a vacuum that could occur due to failure of normal ventilation and air conditioning
What are the auto starts of the drywell purge compressors?
LOCA and 30 seconds and Drywell > .87 psig above CTMT pressure
What are the trips to the drywell purge compressors?
Low oil pressure < 15 psig bypassed unless in test
High oil temp > 155 deg F bypassed unless in test
MPD
ESF load shed
Local breaker pushbutton
When will post LOCA vacuum relief valves open?
LOCA
and
30 seconds
and
Drywell .88 psig below CTMT pressure
and
Drywell < .87 psig above CTMT pressure or CGCS manual initiation
What’s the logic for normal vacuum relief operation?
HS permissive met (auto and back to auto)
> 60 psig instrument air (F020 only)
NO LOCA
DW < .186 below CTMT (contact is reclosed < 1.6 below CTMT
when all of the contacts are closed, valve is open (F007 and F020)
