Lower Mode Functional Recovery Flashcards
What are the Entry Criteria for the Lower Mode Functional Recovery Procedure?
Entry Criteria:
* Mode 4 - 6 with LTOP in service and an EOP is NOT currently in use. (need both LTOP’s)
* And ANY of the following exist:
o CRS directs entering the LMFR
o Any Lower Mode SFSC Acceptance Criteria NOT met
o AOP or ARP directs entry
o Condition not being mitigated by procedure(s) in use (AOP, ARP, OP) or no procedural guidance can be identified
What are the three “Sets” for the LMFRP?
LMFR Sets
* Split into 3 sections based on initial plant conditions. Remain in same set for duration of the event. Each set has SFSC acceptance criteria.
* Set 1 PZR Manway On
o RCS is intact
o No opening has been provided that meets the LTOP requirements or NO RCS breach event.
o RCS considered intact if the RCVGS vents are open.
* Set 2 PZR Manway Off
o RCS is NOT intact
o An opening has been provided (16 in2) that meets LTOP requirements or an event has caused a breach in the RCS.
* Set 3 Reactor Vessel Head Removed
o NOT correct section if the Head is only de-tensioned.
o Removed: Head is no longer being supported by the Core Support Barrel and there is a gap between the Head and the Core Support Barrel such that there is NO flow restriction which would impede water from flowing back into the RCS via the Core Support Barrel in the event of a Gravity Feed or Safety Injection
What actions (in the LMFRP) should be taken if a Shutdown Cooling Pump is cavitating?
SDC Cavitation
* SDC pump flow or amp oscillations at < 1 minute intervals
* If two SDC Pumps are in service, stop one pump
* If oscillations are still present, reduce SDC flow to 3780 gpm.
* If oscillations are still present, stop the affected pump and perform applicable HR success path.
* ↓ SDC flow will ↑ pump suction pressure and minimize the potential for vortexing.
o Higher inventory required for 2 pumps.
* Ensure inventory control is adequately addressed prior to leaving this success path, or it may hamper efforts to restore HR
What is the minimum HPSI hot leg injection flow in the LMFRP?
- HPSI pump injection to hot leg or cold legs
o HPSI Hot leg minimum flow is 260 gpm (pump protection and matches boil off)
o CL Injection: SDC lost and any SG Cold Leg Manway is removed and nozzle dam is NOT installed
HL injection NOT used because it assumed water is lost out of the hot legs.
o HL Injection: SDC lost and any RCP impeller removed and RCP Plug is NOT installed
CL injection is NOT used because of the RCP opening so hot leg injection is used to keep the core covered
In the LMFRP, what are the gravity feed paths?
- Gravity feed paths:
o SDC suction lines via LPSI pump suction piping
o Hot leg injection path via HPSI pump piping
o Cold legs via HPSI, LPSI or CSP piping
o Flow is throttled to ensure RWT level drops ~ 3% every 15 minutes (conserves water)
What are the RCS level requirements for SDC pumps (LMFRP)?
≤ 107’ 6” and two SDC Pumps running in parallel: stop one pump
≤ 104’ 6” and two SDC Pump running on opposite SDC loops: stop one pump
≤ 101’ 4”: stop all running SDC pumps
When can the LPSI pump be put in service for Shutdown Cooling? Containment Spray?
LPSI pump may be placed in service on SDC:
* PPZR < 385 psia (below pressure which SDC can be placed in-service)
* RCS Temp < 335°F (minimize pump mechanical seal degradation)
CS pump may be placed in service on SDC:
* PPZR < 210 psia
* RCS Temp < 185°F
* Protects SDC discharge piping from exceeding design limits
What are the Shutdown Cooling flow limits (LMFRP)?
SDC flow limits:
* Mode 4: 4000-4750 gpm
* Mode 5: 3780-4750 gpm
* ≤ 4600 gpm max if RCS level is < 103’ 1” to 102’
* ≤ 4150 gpm max if RCS level is < 102’
What is the minimum Condensate Storage Tank level to support Auxiliary Feed pumps?
- CST > 9’ to support AFW pump operations
What is the flow path for HR-5 (SG Cold Leg Manway Removed, No Nozzle Dam) in the LMFRP?
- Establishes cold leg injection at ≥ 100 gpm per cold leg.
o Analysis is based upon two days post shutdown.
o ~ 142 gpm is required to compensate for boiloff.
o 100 gpm to each cold leg ensures ≥ 142 gpm through the core for cooling and boiloff makeup. - Cold leg injection with a SG cold leg manway open will still put water through the core.
o Water will spill out through the SG hot leg manway
o Assumed that if the cold leg manway is open, the hot leg is open as well
While using gravity feed in the LMFRP, what position should the gravity feed valve be throttled to initially?
HR-7: Gravity Feed (Set 2 or 3)
* Ensures adequate flow is provided from the RWT to RCS Hot Leg to compensate for boil off.
* Used when a pumped path is not available.
* Guidance is given for throttling the Gravity Feed Valve to an initial position of 30% such that RWT level drops ~ 3%/15 minutes.
* CETs available: maintain < 10°F superheat
* CETs NOT available: RWT level drop will be compared to the Boil-off curves in the SAOD book.
When are Long Term Actions performed in the LMFRP?
Long Term Actions (LTAs)
* Implemented after all selected success paths in use have been performed AND SFSC acceptance criteria for selected success paths are being satisfied.
In the LMFRP, what are the level requirements for the RCS to use LPSI per Standard Appendix 229/230 (LM - Placing LPSI on SDC)?
Appendix 229/230 (LM - Placing LPSI on SDC)
* If SBOG is supplying power, the associated MDAFW pump and HPSI pump must be secured
* LPSI pump cannot be required to support another success path
RCS < 385 psia and < 335°F
≥ 101’ 6” minimum level to operate SDC
≥ 104’ 6” minimum level to operate two SDC loops
What are the RCS temperature and pressure requirements for placing a Containment Spray (CS) pump on SDC per Standard Appendix 239/240? Can a CS pump be used for SA 239 if LPSI is available?
- Requires RCS < 185°F and < 210 psia
- While in mid-loop, CSPs should only be used if LPSI pumps are unavailable to provide cooling flow during functional recovery.
When NC is cross tied to EW (Essential Cooling Water) per Standard Appendix 243, (LM - NC Cross Tie to Train A) does the EC (Essential Chill Water) Heat Exchanger receive cooling?
No
Appendix 243/244 (LM - NC Cross Tie to EW Train A/B)
* Allows NC to provide EW Train A/B cooling loads.
* Alignment only provides NC flow to the EW HX (EC HX isolated)
