Condensate Flashcards
Auto starts for condensate pump? (6)
- low MFP Psuct (260 psig)
- low cond Phdr (325 psig)
- MFP Trip - low level #2 HDT (21%)
- LDA (load drop anticipatory)
- UV on opposite bus (w/operating pump)
-Low #2HDT level (21%)
How can auto starts of condensate pump be defeated?
Pump in manual Pump in cutout and unit trip occurs (If in cutout and no unit trip, auto starts still work)
Automatic trips of condensate pumps? (3)
- overcurrent
- bus UV
- unit Trip in cutout (block) In auto
Describe turbine exhaust hood spray? Setpoint?
Nozzles spray discharge area of turbine (not blades), creating low pressure area (cold water), low pressure pulls steam through last stages of turbine (providing cooling). Actuated @ 160 deg (TCV-24, 25, 26)
P.S. To condensate/ booster pumps? Capacity Head
1-1. D
1-2. E
1-3. E
11,700 gpm
340”
Describe hotwell level control Why is it designed like this?
- level program ramped 55”-85” from 0-100%
- % power from Pimp (PT-505A,506A,8) med sel
- hi level, LCV-12 rejects water to CST (dnstm pol) (Intlk closed, 100# Pcond, LDA sig, MFP trip)
- lo level, LCV-8 draws water from CST (Intlk closed @ 60.8% CST lvl, preserve for AFW)
Why? Constant mass secondary, level in SG constant but as go up in power mass lowers=>goes to hotwell
Loads to miscellaneous condensate return tank? What is its function? (8)
2 HDP shaft seal leak off
SJAE after cond
GLand exhaust cond
Cond sample system
Polisher system
MFP shaft seal leak off
CO2 vaporizer
SCCW return
Super P-trap to return condensate to main condenser without damaging vacuum
Describe orientation and operation of :
TCV-23 (f/o)
FCV-31 (f/o)
FCV-30 (f/c)
TCV-23 - bypass line around H2 coolers and Stator coil coolers. Control the cold gas temp @ 115 deg (if high valve shuts forcing more cooling flow to coolers)
FCV-31 - downstream of H2 cooler and stator coil coolers. Controls flow through GSC and SJAEC (parallel flowpath) 5500-6000 gpm. (low flow -> shut, forcing more flow to loads). Mechanical stop @ 36 deg (minimum cooling to MG coolers) (also opens for 3 min on LDA and MFP trip)
FCV-30 - recirc line going back to condenser. Opens on low flow through SJAEC and GSC (4000 gpm)(also closes @ 129# cond hdr press)
How are condensate booster pumps protected from overheating on low flow conditions?
Recirc valve opens any time flow > 7000 gpm and bkr set closed
Why does it take so long for condensate pump set to indicate running?
Booster pump has aux oil pump and must establish oil pressure before booster pump will start. (If let go switch before red light, AOP and condensate pump set will turn off) When shaft driven oil pump has adequate Press AOP will S/d. When ever booster pump S/d AOP runs for 5 min
Interlocks for cond polisher valves FCV-230 bypass FCV-231 inlet FCV-232 outlet
230- opens if 231 or 232 comes off full open seat or d/p > 70 psid (> 10 sec) If signal clears , FCV-230 stops opening 231/232- will not close unless 230 full open
Describe cascading drains of LP fw htrs
2 -> #2 HDT 3 -> 4 -> 5 -> 6 -> #6 htr drn cooler Cascading drains maintain ~ 50%, all fw hts have high level dump -> condenser Htr 2,3 and 4 have non-return valves (not 5 & 6)(low energy steam) If hi-hi level received, - FCV feeding that htr is shut(cascading drain) - non return valve shut (extraction stm to htr) - Dump valve opened -> condenser
Inputs to #2 HDT (4)
Level control scheme for #2 HDT
- Fw htr #1
- Fw htr #2
- MSR LP drains
- MSR shell drains
LCV-48 discharges to feed pump suction
- 93%
- hi level Dump trip open -> MN cond
- isolate inputs (MSR LP, fw htr 1)
- 75% hi level Dump modulate -> MN cond
- 65% HLA
- 56% target
- 36% LLA
- 21% STBY condensate pump start
- 9% #2 HDP trip
2 HDP trips (5)
- O.C.
- Bus UV (4kv E)
- Main turbine Trip
- Unit trip (only if TCO cut in)
- 9% #2 HDT
What is FCV-55 What happens if opened
Bypass of all LP fw htrs Loss efficiency of plant Fw temp goes down SG shrink Cool down RCS Positive reactivity
