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Standby Gas Treatment System
ILT '09
22
Other
Not Applicable
02/16/2008

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Cards

Term
Function of Standby Gas Treatment System
Definition
"Minimize ground level releases during isolated conditions by maintaining a small negative pressure in Secondary Containment to prevent ground level escape of airborne radioactivity from the Reactor building under isolation conditions; by discharging through the off-gas stack, have filtered, elevated releases."
Term
SBGT low flow alarm
Definition
3000 cfm with a 30 sec time delay on startup
Term
SBGT normal flow
Definition
4000 cfm
Term
SBGT standby pump start setpoint
Definition
2800 cfm with a 10 sec delay on startup
Term
When can AO-2982 be opened?
Definition
Only when SCTMT is not required (unless SGTS-5 blank installed AND at least one division of primary containment valves are tagged).
Term
Function of Secondary containment
Definition
"Minimize ground level release of airborne radioactive material to environment. Controlled, elevated release from Reactor building."
Term
Design in leakage
Definition
Less than or equal to 4000 cfm (3 volume changes per day under neutral wind conditions (5 mph) and 0.25 inch vacuum)
Term
Design exfiltration
Definition
"Less than or equal to 100 percent free volume per day with 0.25 inch vacuum and 40 mph wind speed. (Exfiltration is unfiltered, ground level release)."
Term
Maximum internal pressure for secondary containment
Definition
7 inches water (blow-out panels relieve at this pressure)
Term
Secondary Containment Isolation signals
Definition
  1. High drywell pressure: 1.84 psig;
  2. Low Low Reactor Level: -47 inches NOTE: Group II signal is +9 inches.
  3. Rx Building Plenum Radiation: 26 mR/hr (1 upscale or 2 downscale);
  4. Refuel floor radiation: 50 mR/hr (1 upscale or 2 downscale)
Term
What happens on an automatic secondary containment signal?
Definition
  1. Isolates secondary containment,
  2. Initiates StandBy Gas Treatment,
  3. Initiates EFT in HIGH RAD MODE.
Term
Explain the logic required for automatic secondary containment initiation.
Definition
  • The initiation signals come from RPS which is DE-ENERGIZE to activate (failsafe);
  • The secondary containment logic is energize to activate.
Term
When is secondary containment required?
Definition
  • MODES 1, 2, 3,
  • When moving recently (w/in last 24 hours) irradiated fuel, or
  • During OPDRVs.
Term
What must be done after experiencing Tornado or high winds?
Definition
SCTMT capability test
Term
Explain the operability requirements for SBGT in terms of dilution fans.
Definition
  • V-EF-18A, stack dilution fan SHALL be operable for SBGT A train to be considered operable.
  • Likewise, V-EF-18B SHALL be operable for SBGT B train to be considered operable."
Term
What does the Ops manual list as secondary containment?
Definition
  • Rx Building closed including HPCI Room roof plugs in place;
  • Steam Chase Blowout Panels in place and not blocked;
  • At least one door in each access opening closed;
  • shield plugs in place or isolation dampers closed and wired shut and floor drain analyzed for acceptable SCTMT leakage;
  • Ventilation system isolation dampers SHALL be operable or secured in the CLOSED position;
  • Ventilation interface dampers (V-EF-26 to Plenum room) SHALL be operable or secured in the OPEN position.
Term
Precaution associated with securing a SBGT Train.
Definition
Each Train should be run for about 5 minutes after the filter heaters have been placed in OFF to provide for cooldown of the filter trains. Immediate shutdown without cooldown could result in overheating of the filter heaters or other components of the filter train.
Term
Suggested run time to minimize the amount of moisture in HEPA filters.
Definition
"Per Ops manual, 10 hours a month with heaters energized."
Term
"Power supply to SBGT A (fan, damper and control power)"
Definition
MCC-133
Term
"Power supply to SBGT B (fan, damper and control power)"
Definition
MCC-143
Term
Compare the failure mechanisms of SCTMT and SBGT dampers
Definition
SCTMT dampers fail closed on a loss of instrument air. SBGT dampers fail open on a loss of instrument air.
Term
Describe the Secondary containment airlocks
Definition
De-energize to unlatch with battery back-up
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