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.AR LOIT Systems: Welch's Highlighted Notes > .AR SP-Essential Spray Ponds (Welch's Highlighted Notes) > Flashcards

.AR SP-Essential Spray Ponds (Welch's Highlighted Notes) Flashcards

1
Q

Function / Design Basis:

  • ?
A

Function / Design Basis:

  • Cools EW and DG support systems during normal or emergency operations.
  • Maintains EW temperature to Essential Chiller ≤ 135°F following a DBLOCA.
  • 26 days of cooling without makeup water
    • EOP actions ensure continued cooling capability beyond the 26-day period.
  • Provides back-up cooling (with EW) to the SFP.
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2
Q

Essential Spray Ponds (UHS) Levels:

15’ 6” - ?

14’ 8” - ?

14’ 5” - ?

14’0” - ?

13’ 11” - ?

13’ 7.5” - ?

13’ 6” - ?

5’ 6” - ?

1’ 6” - ?

0’ 0” - ?

-6’ 0” - ?

A

Essential Spray Ponds (UHS) Levels:

15’ 6” - Top of Spray Pond wall

14’ 8” - High level alarm (“Clogged Weir Alarm”)

14’ 5” - Weir overflows to sump

14’0” - MCR LI Tech Spec minimum level (LCO 3.7.9 bases)

13’ 11” - Low level alarm

13’ 7.5” - SP Filter Pump start interlock / trip

13’ 6” - Local Tech Spec minimum for 12’ usable volume [1’ 6” (Min pump op level) + 12’ 0” = 13’ 6”]

5’ 6” - Spray flow must be reduced prior to level going < 5’ 6”. Ensures cavitation will not occur at 1’ 6”.

1’ 6” - Minimum level for spray pond pump operation (NPSH)

0’ 0” - Bottom of spray pond

-6’ 0” - Bottom of spray pond at pump intake

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3
Q

Spray Nozzles:

  • ?

Spray header (49A/50A) and Bypass header valves (49B/50B)a:

  • ?

HCV-207 and HCV-208 (cross-ties):

  • ?

Flow orifice bypass MOVs (HV-75A / HV-76B):

  • ?
A

Spray Nozzles:

  • 4 spray headers / 20 risers each (80 total). 320 spray nozzles per spray pond. Even flow through spray nozzles.
  • Design bases assumes spray flow at beginning of the accident.

Spray header (49A/50A) and Bypass header valves (49B/50B)a:

  • Manually operated MOVs (Local hand wheel ONLY)
  • Motors disconnected (App. R)
  • Use of bypass header places SP outside design basis (inoperable)

HCV-207 and HCV-208 (cross-ties):

  • Locked-closed, manually operated butterfly valves.
  • Equalize level between the ponds
  • Provide the combined inventory of both ponds to the operating SP train for the 26 day period following a LOCA.
  • Opened within 24 hours from start of LOCA (1 train of ESF equipment is stopped)

Flow orifice bypass MOVs (HV-75A / HV-76B):

  • Bypass lines with MOVs installed around flow orifices.
  • Normally open. Stay open for first 6 days post-LOCA (higher flow and thermal performance).
  • Closed when heat load is reduced for post-LOCA heat loads. (if no SP M/U for 6 days)
  • MOV breakers normally locked open. Controlled from the MCCs.
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4
Q

Essential Spray Pond Pumps (SPA-P01 / SPB-P01):

  • ?
  • Auto-start signal from BOP-ESFAS (25 sec TD):
    • ?
    • ?…
  • ?
A

Essential Spray Pond Pumps (SPA-P01 / SPB-P01):

  • PBA-S03 / PBB-S04
  • B train pump has App. R local-remote switch
  • Auto-start signal from BOP-ESFAS (25 sec TD):
    • DG running
    • SIAS
    • LOP
    • AFAS (1 or 2)
    • CSAS
    • CREFAS
    • CRVIAS
  • Auto starts (HS to start) or pump trip (HS to stop) can be overridden from the MCR
  • Pump house exhaust fan:
    • Auto start – pump breaker closure
    • Auto stop – 5 minutes after pump breaker opens
  • Intake sump: screens and stop-gates for pump isolation and sump draining for maintenance.
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5
Q

MCR Alarms:

  • ?

MCR Indications:

  • ?
A

MCR Alarms:

  • ESP PMP A (B) DISCH PRESS HI-LO (58 psig / 47 psig)
  • ESP SYS TRBL
    • Hi/Lo Spray Pond level (14’ 8” / 13’ 11”)
    • High Spray Pond temp (85°F)
    • Differential flow HI (1500 gpm): potential SP pipe break
    • Hi EW HX outlet temp (120°F)
    • Pump motor pre-trip / electrical trip
    • Hi Pump discharge temp (105°F)
  • Multipoint Recorders Above Setpoint (motor bearings)
  • SESS alarms (both SP Pumps)
  • (& 86 Lockout Relays can only be RESET from the MCR…but only _if_ SP-system is connected to the DGs)

MCR Indications:

  • Pump discharge pressure
  • Supply and return flow (large difference = potential SP leak)
  • Pond level
  • Pump suction and discharge temperature
  • EW HX outlet temperature
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6
Q

LCO 3.7.8 Essential Spray Pond System (ESPS):

  • ?
A

LCO 3.7.8 Essential Spray Pond System (ESPS):

  • Two trains operable in Modes 1-4.
  • One train inoperable: restore in 72 hours or RICT
    • Notes require the associated DG (3.8.1) and SDC train (3.4.6) to be declared inoperable. (3.0.6 does not apply)
  • Both trains inoperable: restore one within 1 hour or RICT (cannot voluntarily enter)
  • Isolation of DG HXs makes the DG inoperable, but not SP.
  • Isolation of EW HX is not acceptable, declare both EW AND SP inoperable.
    • Due to SP operating outside of the acceptable limits of the system.
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7
Q

LCO 3.7.9 Ultimate Heat Sink (Spray Ponds):

  • ?
A

LCO 3.7.9 Ultimate Heat Sink (Spray Ponds):

  • UHS required to be operable in Modes 1- 4
    • Usable water depth ≥ 12 ft
    • Temperature ≤ 89°F
  • If not met, be in M3 in 6 hours. M5 in 36 hours.
  • 20 minutes – max post-accident heat load (LBLOCA / RAS)
  • 26 day water supply (assumes no make-up)
    • LOCA EOP/FRP: Actions will stop one train of ESF equipment and open SP X-tie valves within 24 hours. Will also close the flow orifice bypass MOV if SP make-up not available for 6 days. Ensures UHS available for 26 days.
  • Bottom 1.5’ is required to meet pump submergence requirements (NPSH)
  • Actual depth of 13.5’ is needed to meet the 26 day requirement for inventory purposes. (13.5’ locally or 14’ in MCR)
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8
Q

Long Term Cooling Alignment (LOCA EOP or FRP):

  • ?
A

Long Term Cooling Alignment (LOCA EOP or FRP):

  • One train of safety equipment is stopped
  • Spray pond cross-ties are opened (within 24 hours)
  • Close Flow Orifice bypass if SP make-up lost for 6 days.
  • Ensures continued availability of the spray pond.
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9
Q

Spray Pond Makeup system:

Domestic Water (DS) - Preferred

  • Limitations – ?
  • Advantages – ?
  • Disadvantages – ?

Cooling Tower Makeup and Blowdown (TB) Reservoir

  • Limitations – ?
  • Advantages – ?
  • Disadvantages – ?
A

Spray Pond Makeup system:

Domestic Water (DS) - Preferred:

  • Limitations – 3 units on polishers after an outage and all 3 units using DS for ESP makeup max output from WRF is 1000 gpm, limited by RO unit capacity.
  • Advantages – maintains alkalinity / less biological activity
  • Disadvantages – higher calcium, impacts needed makeup and blowdown

Cooling Tower Makeup and Blowdown (TB) Reservoir:

  • Limitations – If WRF outage is in progress, no ability to feed hypo to the reservoir so an algae bloom is possible, complicated with continuous running ESP, no bulk hypo to ESP either.
  • Advantages – lower calcium impact to DBA, less acid required
  • Disadvantages – More biological activity / does not have the alkalinity for corrosion control/pH stability
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10
Q

Spray Pond Filter pumps, filters, and associated equipment:

SP Filter Pumps:

  • ?

Filters:

  • ?

Filter Backwash operations (manually performed):

  • ?

Blowdown:

  • ?
A

Spray Pond Filter pumps, filters, and associated equipment:

SP Filter Pumps:

  • Normally running. Provides circulation, blowdown, and filtration of the SP water.
  • Close discharge valve prior to stopping the pump. Prevents casing from draining.
  • Locally controlled (Start-Stop HS)
  • Start interlock: pond level ≥ 13’ 7.5” (Below the Low Level Alarm)
  • Pump trip: pond level < 13’ 7.5”. Pump will restart, if it was running, once level is restored.
    • Prevents further level loss if caused by malfunction at the filters, a pipe rupture or leak, etc.

Filters:

  • Two parallel sand filters per train. (Three for new filter MOD)
  • Filter pump flow enters the common head tank, then gravity drains through the filters.
  • Filtered water flows through the retention elements and then up to the upper vessel section, then to the pond.

Filter Backwash operations (manually performed):

  • Removes buildup of particulate matter.
  • Inlet flow from the head tank is diverted to the backwash sump along with the backwash water from the filter.
  • Water from the filter is driven backwards by the head of the water in the upper portion of the filter vessel, aided by eduction from the falling water from the head tank. Water flows in a reverse direction through the retention elements / sand, carrying the particulates and accumulated debris out to the backwash sump, from there it is pumped to the Circulating Water system.

Blowdown:

  • Requested by chemistry. Establish flow path by ensuring the spray pond filter pump is operating and throttling the CW Intake Blowdown Header Throttle Valve. (Feed and Bleed from DS to CW)
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11
Q

Chemical Addition System:

  • ?

Components

  • ?

Power supplies:

  • ?
A

Chemical Addition System:

  • HMI - Human Machine Interface
  • ORP - Oxidation – Reduction Potential
  • MSCI - Mild Steel Corrosion Inhibitor
  • CCI - Copper Corrosion Inhibitor

Components:

  • Chemical Pump House
  • Chemical Metering Pumps (PDPs)
  • Sulfuric Acid Pumps
  • Recirculation Skid (connected to SP filter system)
  • Hypochlorite valves (Both automatic (AOVs) and manual valves
  • Chemical Tanks
  • Instrumentation and HMIs
    • Operations verifies the CCI data that Chemistry enters into the HMI, and operates the chemical injection system.
    • Chemistry inputs CCI data into the HMI and monitors the various additives through grab sampling.
  • Alarms and Warnings (Local yellow strobe and horn on outside of building)
    • High and low level on tanks
    • Any non-normal condition from the PLC

Power supplies:

  • Normal: NHN-M30
  • Back-up: 480 Vac power from portable DG
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12
Q

(Ess. Spray Ponds) Chemical Addition System:

5 parameters with a direct impact on Essential Cooling or Diesel Heat Exchanger fouling:

  • pH - ?
  • Dispersant - ?
  • Calcium – ?
  • Phosphate – ?
  • Temperature – ?

Analysis performed

Chemicals added

Chlorine – ?

MBA (HAB) – ?

Silica - ?

Zinc ?

Specific Conductivity- ?

Isotopic & Tritium Activity - ?

A

(Ess. Spray Ponds) Chemical Addition System:

5 parameters with a direct impact on Essential Cooling or Diesel Heat Exchanger fouling:

  • pH - makes the water less corrosive by maintaining pH (7.5 - 9.5), and then to add inhibitors to control scale formation.
  • Dispersant - Provides for colloidal suspension of scale forming ions, silt and algae, for ease in filtering.
  • Calcium – aids in preventing calcium carbonate scale.
  • Phosphate – MSCI. Blend of zinc (zinc oxide) and phosphoric acid used to maintain a protective film on exposed steel.
  • Temperature – Major contributor to corrosion of metal in water.

Analysis performed

[Chemicals added]

Chlorine – minimize bacteria growth. Sodium hypochlorite

[Chlorine]

MBA (HAB) – Microbiological Activity.

[Sulfuric Acid]

Silica - < 30 ppm by backwash or feed-and-bleed.

[Dispersant]

Zinc

[MSCI (Mild Steel Corrosion Inhibitor)]

Specific Conductivity- indication of TDS.

[TTA (tolytriazole)]

Isotopic & Tritium Activity - Monitor for radioactivity release.

[Biocide]

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.AR LOIT Systems: Welch's Highlighted Notes (60 decks)

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