Hydrogen Addition Flashcards
What is the purpose of the Hydrogen Addition System?
Supplies h2 to Rx coolant to minimize free oxygen available to primary system, resulting in decreased susceptibility of reactor materials to IGSCC
Where is H2 Addition Injected?
CB Booster
What is the H2 Excess Flow Check Valve Trip Point?
600scfm
What is the purpose of the H2 add Excess Flow Check Valve?
Protects on loss of inventory on rupture, can be reset with equalizing valve
What is the H2 Add FCV controlled by?
IA to valve
What is the impact of a leak downstream of the H2 EFCV on the FCV?
It will throttle closed
What happens to the H2 Add FCV on loss of IA or HAS trip?
FCV closes
What position will the HAS Solenoid Isolation Valve be in on HAS Trip?
auto isolates
What will cause a HAS Trip?
U2 & 3:
H2 at 50% LEL at 1 out of 8 switches for 5 seconds
Rx Scram
O2 <5% dwnstrm of Recombiner for 10 seconds
O2 >45% dwnstrm Recombiner for 10 sec
Manual Trip
Feedwater Flow 3 scfm over required for 10 sec
U3 Only
Closure of Chimney Isolation Valve
O2 <2scfm below 0.5 H2 Injection Rate for 60 sec
What else does H2 feed besides HAS?
Generator atmosphere
Where are the HAS Detector switches?
8 - 4 by bus ducts, 4 by C/CB Pps
At what point does the O2 EFCV trip?
300scfm
What does O2 addition do in response to HAS trip?
Maintains O2 flow at 7.5scfm for 5 minutes, ramps closed 3-5 min after trip
Where does O2 Injection tap into system?
Traps into OG prior to Preheater and recombiner.
What is the drawback of H2 addition?
Can increase rad levels by factor of 5 due to increased N-16 concentration
