Systems Exam 4 - Condensate Flashcards
(21 cards)
Condensate to Gland Steam Condenser Unit Difference?
→U1 - GS Condenser uses orifice to direct flow thru condenser
→U2 - uses valve locked in place, air operator disabled, to throttle flow
Main Condenser Level / Vacuum Alarms
→Hi-Hi Hotwell Level 6’
→Lo Hotwell Level 1.2’
→0.2’ Hotwell Lo-Lo Level trips condensate pumps (2/3)
→Lo Condenser Vacuum 24” Hg (starts standby CEV Pump)
→an SG tube leak will adversely affect vacuum due to an increase in non-condensable gases
Condensate Transfer Pump
→powered by uEB1-3
→200 gpm discharges upstream of CP system for initial system fill
→Auto stops on Low Suction Pressure 7 psig
→Load shed on SI
Main Condenser Interlocks
→Main Turbine Trip: 21” Hg if >900 rpm (2/3 on either condenser)
→Steam Dump Actuation Block (C-9): 12.3” Hg (2/2)
→Lo-Lo Level Condensate Pump Trip: 0.2’ Hotwell Level
→Main Feed Pump Trip: Low Vacuum in Aux Condensers (2/3); 2 sec TDPU
→ ≤17.5” Hg on 2 detectors
OR
→ <21” Hg on one detector and 17.5” Hg on another detector
u-LV-2217A & B Hotwell Makeup Valves
→fail closed valves
→Lo flow u-LV-2217A (4”) opens 4-12 milliamps
→Hi flow u-LV-2217B (8”) opens 12-20 milliamps
→Controller output = 4-12ma for 0-100% on 2217A, 12-20ma for 2217B 0-100%
→maintain hotwell level at approx. 3 ft
Note: Low flow valve u-LV-2217A immediately goes full open at <1.2’ (separate solenoid drives valve full open), independent of M/A station setpoint.
u-LV-2211/12 Condensate (Hotwell) Reject Valve & Interlocks
→auto opens at Hi Level 5’6” to allow backflow through u-HV-2484 & 2485
→auto closes at Lo Level 4’
→provided w/ seal in circuit (via open LS) to keep valve open after being manually opened; still auto closes on Lo Level.
→LV-2211/12 blocked from opening (and will auto close) on any of the following:
→PV-2286 is open (>15%)
→both Condensate Pumps trip
→either HV-2484 or HV-2485 is closed (auto close on AFW start or CST Hi Level)
→Condenser Lo Level NPSH for pumps
Condensate Pumps: Motor Cooling & Seal Water
→motor cooled by TPCW
→seal water provided via demin water (gravity feed from DWST)
Condensate Pumps: Trips and Interlocks
→trip on Lo-Lo Level in (0.2’) hotwell (2/3 coincidence)
→discharge valve and pump controlled via same H/S: taking H/S to start opens discharge valve; pump starts once valve is 10% open
→if discharge valve doesn’t reach 10% open, pump won’t start
→if pump doesn’t start once discharge valve is 10% open, valve auto closes
→overcurrent must be reset locally at breaker via keyswitch (normal for most of our non-safety pumps)
Note: has been found that >80% RTP, MFPs will trip on Condensate Pump trip
PV-2286 Low Pressure Feedwater Heater Bypass Valve Interlocks
PV-2286 Interlocks: (ref: ABN-302)
→auto opens on Lo MFP Suction Pressure (2/3 < 250 psig with generator output MWe > 15%)
→will open (indirectly) if condensate pump trips
Open Valve Causes:
→LV-2211/12 Hotwell Reject Valve to close
→FV-2239 Condensate Pump Recirculation Valve to close
→alarm on ALB-8B “CNDS LP HTR BYP VLV OPEN”
Initial Action if Valve Opens:
→Verify Control Rods in Auto and MANUAL Runback to 900 MWe
→2286 is sized to provide 96% of rated flow to MFPs
How does the plant respond if PV-2286 opens?
(LP FWH Bypass Valve)
→efficiency goes down
→RCS T-cold goes down
→Steam Pressure goes down
→Rx power goes up
→SG Level goes up (a.k.a. swell)
PV-2242 Condensate Polishing System Bypass Valve Interlocks
→fails open
→auto opens on Hi system D/P: modulates open at 35 psid; full open at 40 psid
→auto opens on Lo MFP Suction Pressure <280 psig (2/3)
→auto opens on valve misalignment on IN-SERVICE CP Vessel (any IN-SERVICE vessel isolates at power)
FV-2239 Condensate Pump Recirc Valve Interlocks
→AOVs - fail open on loss of air; fail closed on loss of power
→power supplied from uD3
→provided with Trip to Auto Enable or Disable toggle switch on M/A station
→in Enable, valve can be manually controlled and auto open can occur
→opens <6,000 gpm
→closes >12,000 gpm
→5 sec lockout TD until valve can be switched to manual after low flow condition
→in Disable, only manual control can occur; valve will not auto open on a low flow
Interlocks:
→auto closes when 2286 opens (<250 psig MFP suction pressure 2/3 and >15% RTP)
→<190 psig 2/3 both MFPs trip after 30 sec TD (MFP A) and 45 sec TD (MFP B)
→<170 psig 2/3 with 4 sec TD, both MFPs trip
FV-2611A/B FV-2612A/B Feedwater Heater Isolation and Bypass Valves Interlocks
→auto close on Hi-Hi Level in associated heater train
→2611A/B for 5A/6A FWH, 6A Drain Cooler
→2612A/B for 5B/6B FWH, 6B Drain Cooler
→single H/S for both valves in a train
→bypass valve LV-2611/2612 opens on close signal to any of these valves
→u-LV-2611A/B - uB3-1
→u-LV-2612A/B - uB4-1
→u-LV-2611/12 - uB3-1
SOP-303 Flow Limits for Condensate Pumps
SOP-303 Flow Limits for Condensate Pumps:
→Do NOT operate two (2) Condensate Pumps until total flow is >8,000 gpm to prevent flow imbalance between the two pumps.
→A minimum flow rate of 3,000 gpm per operating Condensate Pump SHALL be maintained.
→A maximum flow rate of 14,700 gpm per operating Condensate Pump SHALL NOT be exceeded.
Tech Spec 3.7.6 CST Minimum Level (Modes 1-3)
→Minimum level of 53% (244,000 gallons)
→applicable in Modes 1-3
→ if level OOS - verify SSW backup within 4 hours AND restore within 7 days or, Mode 3 in 6 hrs & Mode 4 in 12 hours
→Bases: Volume is sufficient to hold the unit in Mode 3 for 4 hrs followed by a C/D to RHR entry conditions at 50°F/hr for 5 hrs
→To satisfy accident analysis assumptions, the CST must contain sufficient cooling water to remove decay heat following a reactor trip from 102% RTP, and then to cool down the RCS to RHR entry conditions, assuming a coincident loss of offsite power and the most adverse single active failure.
TS 3.7.18 Secondary Specific Activity (Modes 1-4)
→Specific activity of the secondary coolant shall be <0.10 μCi/gm Dose Equivalent I-131 (Modes 1-4)
→if not met, Mode 3 in 6 hrs & Mode 5 in 36 hours
Bases:
→minimizes releases to the environment because of normal operation, anticipated operational occurrences and accidents
→limit is lower than the activity value that might be expected from a 1 gpm tube leak of primary coolant at the limit of 1 μCi/gm
Condensate Storage Tank
→taps for makeup/reject located 23’9” above bottom of tank
→ensures 53% (or 244,000 gal) for Aux Feedwater following a Design Basis Accident
→ensures capability to maintain hot standby for 4 hrs, then cool down RCS from 557°F to 350°F in 5 hrs
Turbine Exhaust Hood Spray Valve
→solenoid valve opens at 194°F with >1340 rpm
→sprays condensate into the area to lower temps
→happens mostly at low power with low steam flow available to cool area
→condensate line taps off header before drain coolers
→solenoid valve must be manually closed once temp restored, but will auto close when high temp clears if LP turbine inlet steam pressure ≥7 psia
→separate MOV provided if solenoid valve insufficient to maintain temps
→if exhaust temp can’t be maintained <212°F, turbine is manually tripped
Long Path Recirc
→top of Condenser A
→after LEFM
→one Condensate Pump running
Full Flow Recirc
→bottom of Condenser
→before LEFM
→two Condensate Pumps running
What is the maximum flow through a Condensate Pump?
14,700 gpm
