Systems Exam 3 - Station Service Water Flashcards
(34 cards)
Tech Spec 3.7.9 SSI Requirements
→maintain max expected inlet temp ≤102°F
→level maintained ≥770’, restore within 7 days or shutdown (required level based on 30 days for accident unit and safe shutdown of other unit)
→if SSI inoperable for reasons other than level (e.g. temp >102° or dam degraded), be in mode 3 in 6 hrs, mode 5 in 36 hrs
Modes 1-4
TR 13.7.33 SSI Sediment
→average sediment depth shall be ≤1.5 ft; if not, take immediate action to reduce sediment level
→dam shall have no abnormal degradation or erosion; if not, immediately enter TS 3.7.9 for SSI inop
Cross connecting SSW trains…
…will inop both Trains, cross connecting SSW between units will inop both unit’s affected trains
→between units is desirable to only supply each unit’s CCW HX and opposite unit’s CCP
→accomplished by sending discharge of one pump through the cross connect and
→manually throttling the other unit’s discharge valve to
→limit total flow to 18,600 gpm
To prevent Chloride infusion if a CCW HX tube leak exists…
→the CCW HX Shell side should be filled, vented, and pressurized prior to operating SSW
OR
→the CCW HX Shell side shall be isolated and drained with the drain valves open
SSW Pump Auto Starts
- SI
- BO - train associated
- Low Pressure opposite train <10 psig off of the 10” header (safety loop)
- Start of train associated CCW Pump, in auto or manual
(SSW pumps powered from uEA1 & uEA2)
SSW Pump discharge MOV close position
→discharge MOV only closes to 10% open position, must be manually closed 8 turns for isolation
→if manually closed, must be opened 8 turns from closed (10% open) before cycling electrically
Note: if valve has been fully closed manually, there will be no position indication on MCB because power has been removed. Position indication lights will be dark.
(MOVs powered from MCCs located adjacent to associated pump, uEB3-3, uEB4-3)
SSW Screenwash pump power supplies
Normally from U2; ABT used
(XEB3-3; ABT is preferred power seeking)
SSW Screenwash Pump Auto Stops
(not including screenwash timer or differential level auto-stops)
→pump will trip on low discharge pressure of 85 psig which causes screens to stop (7 sec TDPU after pump start, bypassed if started in manual)
→SI on unit supplying power; traveling screens also stop and screenwash valve fails open on SI
→trip of U1 and U2 train related SSW pumps (X-01 Train A, X-02 Train B); prevents auto start of screenwash pump for that train and closes screenwash valves
On a loss of the CST, SSW can serve as…
SSW can serve as the AFW backup
→must have shift manager approval
→must be in ERG network
→minimized to supplying one SG, if possible, to limit SG damage from dirty SSW water
Screenwash Auto Starts
Auto Starts
→Hi differential level across screens: 15.25”; runs until D/L is ≤8.25” (minimum runtime of 25 mins)
→Every 4 hours; runs for 16 mins
Which fluid is at a higher pressure, CCW or SSW in CCW HX?
Why?
→CCW is higher (≈140 psig)
→SSW is lower (≈40 psig)
→don’t want SSW leaking into CCW
Which SSW components can be controlled from the RSP?
→Both trains of SSW pumps
→Train A discharge valves only
What are the SSW loads?
10-inch Line:
→SIP lube oil coolers
→CCP lube oil coolers
→CSP bearing lube oil coolers
→EDG jacket water coolers
30-inch Line:
→CCW HX
Can be AFW backup during loss of CST
Which SSW Pumps does Screenwash pump X-01 supply?
What about X-02?
→Screenwash Pump X-01 supplies Train A pumps for both units (1-01, 2-01)
→Screenwash Pump X-02 supplies Train B pumps for both units (1-02, 2-02)
Does closing the EDG outlet valves for SSW inop the EDG?
No. Valves receive auto open signal on EDG start.
(valves normally maintained open to prevent stagnant water corrosion)
Tech Spec 3.7.8 Station Service Water System (SSWS)
Two trains and an SSW Pump on the opposite unit with its associated cross-connects shall be operable (Modes 1-4).
TR 13.7.34 Flood Protection
→flood protection shall be provided for all safety-related systems, components, and structures when SCR exceeds 777.5 ft
→applicable at all times
→initiate action to be in lower mode in 1 hr, mode 3 in 7 hrs (only applies if flood protection not in place)
SSW to AFW Supply Valves u-HV-4395/4396
→u-HV-4395/4396
→tapped off 10” safety header downstream of EDG jacket water cooler to provide some preheating if EDG is operating
→powered from uEB3-1 (4395) and uEB4-1 (4396)
When does the alarm come in for low SSW return flow to any CSP?
→ ≤10.2 gpm
→indicative of bearing cooler strainer clogging or SSW pump malfunction
When does the alarm come in for low SSW return flow to a CCP?
→ ≤33 gpm
→indicative of bearing cooler strainer clogging or SSW pump malfunction
→separate alarm for each pump
CCP rhymes with 33
When does the alarm come in for low SSW return flow to an SIP?
→ ≤12 gpm
→indicative of bearing cooler strainer clogging or SSW pump malfunction
→separate alarm for each pump
DG Jacket Water Cooler EDG SSW Return Valves u-HV-4393 & u-HV-4394
→3-position handswitch: open-auto-close; spring return to auto
→maintained open to reduce potential for stagnant water corrosion
→interlock: receives open signal on EDG start
When does the alarm come in for low SSW return flow to an EDG jacket water cooler?
How long can an EDG run without SSW flow to cool jacket water?
→ ≤1350 gpm
→EDG can only run for ≈1 minute loaded with no SSW flow
→EDG can only run for ≈15 minutes unloaded with no SSW flow
When does the CCW HX Low SSW Return Flow alarm come in?
<14,000 gpm
