ECCS Flashcards
What are the ECCS Injection order with pressures?
- CCP 2600#
- SI Pumps 1560#
- Accumulators 600#
- RHR Pumps 210#
What is the ECCS Acceptance Criteria per 10CFR50.46?
- Peak clad temp < 2200°F
- Max cladding oxidation < 17%
- H2 concentration < 1%
- Core maintains cool able geometry
- Long term cooling provided
When does the ECCS injection phase end?
When RWST reaches low level (20%) and transfer to Recirc Sump
What is the RWST Tech Spec Limit?
- 375,500 gallons
- 2400-2600 ppm boron
- 70-100°F
When are the accumulators outlet valves open and deenergized?
Modes 1and 2
Mode 3 when Pzr # > 1000#
When do the accumulator outlets get an open signal?
SI sends signal to open outlet valves (IMO-110 thru IMO-140) to ensure any close valves will open
How many accumulators are necessary to inject into the core? (FSAR Assumption)?
3 accumulators contain enough borated water to fill volume outside of the reactor core barrel, below nozzles, bottom plenum, and portion of the core
Assumes one falls to the floor
What is the runout flow of the SI Pump?
700 gpm
What is the normal position of IMO-262 and IMO-263 (SI Pump to RWST recirc valves)?
OPEN for standby readiness (for injection phase)
When would you close IMO-262 and IMO-263 (SI Pump to RWST recirc valves)?
Closed for cold leg recirc to prevent pumping recirc sump to RWST
When are IMO-270 and IMO-275 (SI train x-tires) open and when are they closed?
- Normally open for standby readiness to provide 4 loop injection on 1 SI Pump failure
- Closed during hot lleg recirc to prevent loss of both trains from single passive failure of SI pump discharge piping
What will give you an SI signal?
- Pzr # Low - 1775# (2/3)
- Containment # High - 1.0# (2/3)
- S/G # Low - 500# (1/1 on 2 S/G)
- 1 S/G 100# ΔP lower than 2 others (2/3)
What is the Tech Spec Basis for the RWST Level?
Level 375,500 gal - min level for recirc sump
When do you align Hot Leg Recirc?
between 5.5 - 7.5 hrs after the LOCA.
What is the reason for the time limitations associated with Hot Leg Recirc?
- Waiting at least 5.5 hours avoids core uncovery due to boil off. Enough decay heat has been removed
- Not exceeding 7.5 hours prevent boron precipitation in the reactor
When do we initiate RHR Spray after an accident?
- Must be on the recirc sump AND > 50 mins after accident (ensures adequate injection for decay heat removal)
- If < 2 CTS running, the RHR Spray must be I/S in 75 minutes (limits can # and keeps CR dose < 5 rem TEDE.)
What is the ECCS Leakage limits?
- Total unfiltered leakage from Recirc Loop < 0.1 gpm for Control Room dose
- < 2.0 gpm for containment sump water level analysis
What are the applicable modes forTS 3.5.1 (Accumulators)?
Modes 1-3 with RCS Pressure > 1000#
Per TS 3.5.2 (ECCS, operating), what must be done if 1 of the ECCS flow is < 100% equivelant to a single Operable ECCS train available for reasons other than having 1 or more SI Systems x-tie valves closed ?
- IMMEDIATELY enter LCO 3.0.3
What does TS 3.5.3 (ECCS, Shutdown) direct if rquired ECCS Train subsystem is inoperable in Mode 4?
IMMEDIATELY initiate action to restore required ECCS RHR/CCP subsystem to OPERABLE status
What does TS 3.5.4 (RWST) direct if the RWST is inoperable for reasons other than boron concentraion or temperature?
WITH IN 1 Hr, restore RWST to OPERABLE status.
Per TS 3.5.1 (Accumulators), what are the Accumulator parameters that must be maintained?
- Volume 921-971 cubic feet
- 585-658 psig
- 2400-2600 ppm Boron Concentration
What is the the tech spec basis for the RWST Temperature band?
- Temp 70°F - Lower ΔP rcs vs cntmt - backpressure
- Temp 100°F - Prevents Peak # in Ctmnt to < 12#
What is the tech spec basis for the RWST Boron Concentration band?
- Boron > 2400 ppm - ensure subcriticality
- Boron < 2600 ppm – max time to HL recirc
When is RHR spray not required?
If containment # < 1.5#
What are the ECCS Auto Actions on a Safety Injection?
- RWST to CCP isolation valves open; VCT outlet valves close
- CCPs start
- CCP ELOs close
- Charging header isolation valves close
- BIT inlet and outlet valves open
- SI pumps start
- RHR pumps start
- Any closed accumulator isolation valve opens
Where do the Charging Pump ELOs receive their pressure signals from?
East Charging Pump - QMO-225 from NPP-151
West Charging Pump - QMO-226 from NPP-153
What is filtered leakage?
There is communication with AES Fan.
If in the applicable modes, what does TS 3.5.1 (Accumulators) direct if 2 or more accumulators are inoperable?
IMMEDIATELY enter LCO 3.0.3
Per TS 3.5.2 (ECCS - Operating), what is considered a Train for OperabilitY?
CCP, SI and RHR
Per TS 3.5.3 (ECCS - Shutdown), what is considered a Train for Operability?
CCP and RHR
