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Flashcards in Spent Fuel Pool Deck (34):
1

What is the purpose of the SFP system?

To remove decay heat from spent fuel stored in the spent fuel pool.

Designed to .maintain the temperature less than 150°F with a minimum of one spent fuel cooling pump operating.

2

In relation to time to boil, what is the design?

The system is designed such that for a loss of cooling, the time to boil is 8 hours for ⅓ of the core off loaded and 3 hours for a full core off loaded.

3

What is the safety related portion of SFP?

Designed based on removing 1/3 of an infinitely irradiated core removed from the reactor within 36 hours following a reactor shutdown.

  • Spent Fuel Pool Cooling Pumps (P-51A/B)
  • Spent Fuel Pool Heat Exchanger (E-53A/B)
  • Spent Fuel Pool

4

What is the capacity and power supply for the Spent Fuel Pool Cooling Pumps (P-51A/B)?

1700 gpm

MCC-7 - P-51A

MCC-8 - P-51B

5

What is on the shell side or tube side of the SFP Heat Exchanger?

What is its design?

Tube Side - SFP

Shell Side - CCW

  • Max flow - 1840 gpm

Designed to withstand a temperature transient of 60°F to 212°F in 5 seconds.

6

What is the capacity and design of the spent fuel pool?

Reinforced concrete walls with varying thickness from 41/2 to 6 feet with a stainless steel liner.

Operational volume is 186,300 gallons.

7

What are the Non-Safety Related portions of the SFP system?

The Non-Safety Related function of the Spent Fuel Pool Cooling System is the filling, draining and water cleanup functions.

Spent Fuel Pool Recirc. Booster Pump

  • 160 gpm

Spent Fuel Pool Demineralizer

  • Design flow of 150 gpm a design pressure of 200 psig and a design temperature of 220°F and contains 50 cubic feet of resin.

 

8

What design features prevent water loss from the SFP?

Design features that prevent the loss of water in the Spent Fuel Pool:

  • Maximizing water level in the Spent Fuel Pool minimizes the spent fuel pool radiation levels.
  • There are no drains in the main pool.
  • Failure of the outlet piping would only result in a loss of water only to the level of the outlet piping (3'7" below skimmers).

9

What controls and indications are in the control room?

  • P-51A and P‑51B start/stop switches on C-08
  • FI-0404 RECIRCULATION TO SIRW TANK FLOW INDICATOR
  • CV-0944A SFP Hx Supply
  • Spent Fuel Pool Temperature
  • Spent Fuel Pool Level

10

What Remote Shutdown Panel Controls, Alarms, and Indications are available?

SFP at C-40

11

How does SFP interact with the following systems:

  • Instrument Air
  • Component Cooling Water (CCW) System
  • Shutdown Cooling System
  • Safety Injection Refueling Water (SIRW) Tank
  • Fire Protection System
  • Primary Makeup Water (PMW)
  • Radwaste Systems
  • Station Power System

Instrument Air

  • SFP System has NO air operated valves
  • Loss air = CV-0944A closed

Component Cooling Water (CCW) System

  • SFP rides with CCW temp.

Shutdown Cooling System

  • SDC HT Exch can spare

Safety Injection Refueling Water (SIRW) Tank

  • Refill source
  • Recirc (fast or slow) with SFP pumps
  • Clean SIRW via T-50

Fire Protection System

  • Backup supply of makeup

Primary Makeup Water (PMW)

  • Makeup source

Radwaste Systems

  • Rebat can be makeup source
  • Tilt Pit/Cavity drains via SFP system to DWDT

Station Power System

  • P-51A is powered from Breaker 52-717
  • P-51B is powered from Breaker 52-817
  • P-82 is powered from Breaker 52-839

12

What are the PPC temperature alarms?

TIA-0925, Main Pool and TIA-0926, North Tilt Pit have a range of 50°F to 250°F and transmit to PPC points TIA_0925_D and TIA_0926_D respectively.

LO at 75°F

HI at 125°F

HI HI at 140°F

13

What are the SFP Temperature Limits?

Greater than 57F and less than 125F on TIA-0925 and TIA-0926 when the SFP contains irradiated fuel.

125 Limit for Demins

40F is actual min but indicator doesn't go below 50F. So 5 degrees for margin and 2 degrees for inaccuracy gets you to 57F.

140F is SOP limit.

150F is upper design limit based on SFP Ht Exchanger inlet nozzles.

14

What is the Administrative minimum limit for Spent Fuel Pool boron?

Mode 1, 2, 3, 4, 5, and 6 greater than 2550 ppm

15

What If the Plant is in Modes 1, 2, 3, or 4, and SFP level lowers below 646'?

If the Plant is in Modes 1, 2, 3, or 4, then lowering Spent Fuel Pool level below 646' may violate the assumptions of EA-SQG-04-01, Adjustment of Administrative Boron Concentration Limit for the Spent Fuel Pool.

16

What are the Spent Fuel Pool sampling requirements?

SFP shall be sampled within 24 hours prior to the start of any evolution that may change the boron concentration except for decontamination activities authorized in accordance with Attachment 2.

SFP shall be sampled in an expeditious manner after any evolution that may change the boron concentration.

17

How should irradiated material suspended in the SFP be handled?

Irradiated material that is temporarily suspended in the SFP should be at a lower elevation than the bottom of Door-950, SFP South Tilt Pit Gate, to prevent high radiation fields in the event of door failure.

18

What monitoring requirements are there for filling the SFP?

IF the Control Room TV monitor is not available to monitor SFP level, THEN a Nuclear Plant Operator, Control Room Operator, Senior Reactor Operator or a Reactor Engineering Department Engineer must be present at the SFP at all times during any SFP addition operations.

19

Technical Specification 3.7.14, Spent Fuel Pool Water Level

Technical Specification 3.7.14, Spent Fuel Pool Water Level

The SFP water level shall be ≥ 647 ft elevation.

APPLICABILITY: During movement of irradiated fuel assemblies in the SFP,
During movement of a fuel cask in or over the SFP.

SFP level may be below the 647 ft elevation to support fuel cask movement, if the displacement of water by the fuel cask when submerged in the SFP, would raise SFP level to ≥ 647 ft elevation.

 

20

Technical Specification 3.7.14, Spent Fuel Pool Water Level - Actions

The SFP water level shall be ≥ 647 ft elevation.

SFP water level not within limit.

Immediately

  • Suspend movement of irradiated fuel assemblies in SFP.

AND

  • Suspend movement of fuel cask in or over the SFP.

21

SR 3.7.14.1 Spent Fuel Pool Level Surveillance

Verify the SFP water level is ≥ 647 ft elevation every 7 Days

22

Technical Specification 3.7.15, Spent Fuel Pool Boron Concentration

Technical Specification 3.7.15, Spent Fuel Pool Boron Concentration

The SFP boron concentration shall be ≥ 1720 ppm

APPLICABILITY: When fuel assemblies are stored in the Spent Fuel Pool.

23

3.7.15 Spent Fuel Pool (SFP) Boron Concentration

The SFP boron concentration shall be ≥ 1720 ppm.

SFP boron concentration not within limit.

Immediately

  • Suspend movement of fuel assemblies in the SFP.

AND

  • Initiate action to restore SFP boron concentration to within limit.

24

SR 3.7.15.1 Spent Fuel Pool (SFP) Boron Concentration 

The SFP boron concentration shall be ≥ 1720 ppm.

Verify the SFP boron concentration is within limit every 7 days

25

What is the basis for 3.7.15 - Spent Fuel Pool Boron Concentration

The SFP boron concentration shall be ≥ 1720 ppm.

The basis for the Technical Specification limit of 1720 ppm is to ensure subcriticality is maintained in the Spent Fuel Pool for the following accidents:

  • Loading of a spent fuel assembly with improper burnup and enrichment.
  • Dropping of a spent fuel assembly.

26

What is the basis for TS 3.7.14 - Spent Fuel Pool (SFP) Water Level

The SFP water level shall be ≥ 647 ft elevation.

Meets the assumptions for the iodine decontamination factors following a fuel handling or cask drop accident.

Other consequences of an abnormal level in the Spent Fuel Pool is flooding or a loss of suction to the Spent Fuel Pool Cooling Pump.

Shielding and minimizes general area dose.  Loss of level raises area dose rates.

27

Operating Requirements Manual 3.17.6 Fuel Pool Area Radiation Monitors

Operating Requirements Manual 3.17.6 (19) Fuel Pool Area Radiation Monitors

If a Fuel Pool Area Radiation Monitor becomes inoperable, fuel moves in the SFP are to be stopped until monitoring capability is restored.

  • Within 72 hours restore the monitor or provide equivalent monitoring.
  • The basis for this ORM requirement is to ensure the monitors are available to provide a warning in the event of a release due to a Spent Fuel Handling accident.

28

Operating Requirements Manual 3.17.6 Fuel Pool Area Radiation Monitors Channel Checks

Channel Checks

Requires a channel check to be performed every 24 hours on the Fuel Pool Radiation Monitors (RIA-2313 and RIA-5709).

Done Shiftly

29

ORM section 3.24.3 - Primary and Back-up Spent Fuel Pool Level Instruments

ORM section 3.24.3 - Primary and Back-up Spent Fuel Pool Level Instruments

SHALL be FUNCTIONAL

The Primary OR Back-up Spent Fuel Pool level instrument does not meet FUNCTIONAL requirements.

  • Fix in 90 days.

The Primary AND Back-up Spent Fuel Pool level instruments do not meet FUNCTIONAL requirements. 

  • Initiate actions to restore in 24 hours AND Implement compensatory measures in 72 hours.

Required Action and associated Completion Time of Condition 1 not met – Implement compensatory measure such as use of alternate suitable equipment - Immediately

30

ORM 3.24.3 Basis - SFP Level Instruments

ORM section 3.24.3 bases states:

Surveillances or testing to validate the functionality of the installed instrument channel shall be performed within 60 days of a planned refueling outage

Considering normal testing scheduling allowances (e.g., 25%).

  • This is not required to be performed more than once per 12 months.

31

EK-1307, "FUEL POOL CLG PUMPS P51A AND/OR P51B TRIP"

EK-1307, "FUEL POOL CLG PUMPS P51A AND/OR P51B TRIP"

Breaker 'b' contact and control switch in AFTER START position

Send NPO to Check

Start Alternate Pump per SOP-27

32

EK-1308, “Fuel Pool Clg Pumps Disch Lo Press”

EK-1308, “Fuel Pool Clg Pumps Disch Lo Press”

Sensor:

  • PS-0926, Spent Fuel Pool Circulating Pumps Pressure

Trip Setpoints:

  • 30 psig

Mechanical shock (ie, securing a CCW pump) or SFP sampling may result in a spurious alarm.

CHECK Spent Fuel Pool level normal.
CHECK Spent Fuel Pool Cooling system lineup normal per SOP-27.
PLACE standby Spent Fuel Pool Cooling Pump in service per SOP-27.

33

EK-1309, “Spent Fuel Pool HI/Lo Level”

EK-1309, “Spent Fuel Pool HI/Lo Level”

Sensor:

  • LS-0924, Spent Fuel Pool Level Switch

Trip Setpoints:

  • Elevation 647 feet 10 inches
  • Elevation 646 feet (35 feet from pool bottom)

Alternate Indication:

  • SFP level on camera
  • LI-2141, Spent Fuel Pool Level (CR)
  • LI-2142, Spent Fuel Pool Level (C-40)

34

What are the two means of cooling the spent fuel pool with SDC and the monitoring requirements?

SOP-27 has two ways of cooling the Spent Fuel Pool with the Shutdown Cooling System.

  • Full Core Offloaded and no flow through the normal SDC system
  • Fuel Pool and Reactor Cavity cross tied and flow continuing through the normal SDC flow path while still cooling the Spent Fuel Pool

With the full core offloaded and the SDC system being used to cool the SFP, the Fuel Pool level and the LPSI pump operating conditions are monitored:

  • Continuously until stable for 10 minutes
  • Hourly after that.