ECCS Flashcards
What are the ECCS Injection order with pressures?
- CCP 2300#
- SI Pumps 1600#
- Accumulators 600#
- RHR Pumps 200#
What are the ECCS Design Criteria from 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?
- Injection phase ends when RWST reaches low level (20%) and transfer to Recirc Sump
-Water level in Recirc Sump must be at least
602’-2 3/4”
What is the RWST Tech Spec Limit?
- 375,500 gallons - 1 Hr spec
- 2400-2600 ppm boron con - 8 Hr spec
- 70-100°F - 8 Hr Spec
When are the accumulators outlet valves open and deenergized (i.e., required to be operable)
- Modes 1-2 and Mode 3 when Pzr # > 1000#
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 are the SI pump trips?
- Load Shed
- Overload/Overcurrent
When are IMO-262 and IMO-263 (SI Pump to RWST recirc valves) open?
- Open on injection phase
When do IMO-262 and IMO-263 (SI Pump to RWST recirc valves) auto close?
- Closed for cold leg recirc to prevent pumping recirc sump to RWST
When are IMO-270 and IMO-275 (SI train x-tires) normally open and when are they closed?
- Normally open to provide 4 loop injection on 1 SI Pump failure
- Closed during cold leg recirc
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 RWST Tech Spec Basis?
- Level 375,500 gal - min level for recirc sump
- Temp 70°F - Lower ΔP rcs vs cntmt - backpressure
- Temp 100°F - Prevents Peak # in Ctmnt to < 12#
- Boron > 2400 ppm - ensure subcriticality
- Boron < 2600 ppm – max time to HL recirc
When do you align Hot Leg Recirc?
- Align before 7.5 hrs after the LOCA. (Prevent boron precipitation in the reactor)
When do you NOT align Hot Leg Recirc?
- Do NOT align < 5.5 hours after the LOCA. (Avoid core uncovery due to boil off)
When do we initiate RHR Spray after an accident and when is in required/not required?
- RHR Spray not initiated until > 50 min after accident (ensures adequate injection for decay heat removal)
- If < 2 CTS running RHR Spray must be I/S in 75 minutes (limits can # and keeps CR dose < 5 rem TEDE.)
- required for 6 hours after LBLOCA
- not required if containment # < 1.5#
