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Tech Specs 2 Flashcards

Containment

1
Q

3.6.1 Containment Systems

List the sections and subsections of the containment systems chapter.

A

3.6.1.x - Primary Containment & Supporting Systems
3.6.1.1 - Primary Containment – Operating
3.6.1.2 - Primary Containment Air Locks
3.6.1.3 - Primary Containment Isolation Valves
3.6.1.4 - Primary Containment Pressure
3.6.1.5 - Primary Containment Air Temperature
3.6.1.6 - Low-Low Set Valves
3.6.1.7 - RHR Containment Spray System
3.6.1.8 - Feedwater Leakage Control System
3.6.1.9 - MSSVs
3.6.1.10 - Primary Containment – Shutdown
3.6.1.11 - Containment Vacuum Breakers
3.6.1.12 - Containment Humidity Control

12 LCOs in this section

3.6.2.x - Suppression Pool & Supporting Systems
3.6.2.1 - Suppression Pool Average Temperature
3.6.2.2 - Suppression Pool Water Level
3.6.2.3 - RHR Suppression Pool Cooling System
3.6.2.4 - Suppression Pool Makeup

4 LCOs in this section

**3.6.3.x - Hydrogen Control **
3.6.3.2 - Primary Containment and Drywell Hydrogen Igniters
3.6.3.3 - Combustible Gas Mixing System

2 LCOs in this section

**3.6.4.x - Secondary Containment & Supporting Systems **
3.6.4.1 - Secondary Containment
3.6.4.2 - Secondary Containment Isolation Valves
3.6.4.3 - Annulus Exhaust Gas Treatment System

3 LCOs in this section

3.6.5.x - Drywell & Supporting Systems
3.6.5.1 - Drywell
3.6.5.2 - Drywell Air Lock
3.6.5.3 - Drywell Isolation Valves
3.6.5.4 - Drywell Pressure
3.6.5.5 - Drywell Air Temperature
3.6.5.6 - Drywell Vacuum Relief

6 LCOs in this section

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2
Q

3.6.1.1 Primary Containment - Operating

List the LCO, Applicability, and all 1 Hour or less actions.

A

LCO
Primary Containment Shall Be Operable

Applicability
Modes 1, 2, & 3.

1 Hour or Less Actions
Condition A - Primary Containment inoperable
Restore Primary Containment to Operable Status in 1 Hour.

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3
Q

3.6.1.1 Primary Containment - Operating

What exceptions does the Tech Specs make for containment operability?

A

Applicable and Required Actions are not required to be entered for the IFTS penetration for up to 20 hours per 12 month period when the IFTS blind flange is unbolted.

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4
Q

3.6.1.1 Primary Containment - Operating

What is the function of the primary containment?

A

Isolate and contain fission product release from the RCS during DBA LOCA and to confine the postulated release of radioactive material to within limits.

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5
Q

3.6.1.1 Primary Containment - Operating

What criteria are established to ensure primary containment maintains a leak tight barrier?

A

A. All primary containment penetrations required to be closed during accident conditions are either capable of being closed by an operable automatic isolation or closed by manual valves, blind flanges, or deactivated valves except as provided by LCO 3.6.1.3.
B. Primary containment air locks are operable except as provided by LCO 3.6.1.2.
C. The equipment hatch is closed and sealed.
D. The leakage control systems associated with penetrations are OPERABLE except as provided by LCO 3.6.1.8.
E. Containment leakage rates are in compliance with TS 3.6.1.1 & 3.6.1.3.
F. Suppression Pool is operable
G. Sealing mechanism associated with each primary containment penetration is functional.

Abridged List
A. Penetrations closed or can close.
B. Air Locks operable.
C. Equipment hatch closed & sealed.
D. Penetration Leakage Control Systems operable.
E. Leak Rates satisfactory.
F. SP Operable.
G. Penetration seals functional.

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6
Q

3.6.1.1 Primary Containment - Operating Bases

What does compliance with 3.6.1.1 LCO ensure?

A

Structural integrity of Containment during DBA LOCA and leakage limited to rates assumed in the safety analysis.

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7
Q

3.6.1.2 Primary Containment Air Locks

List the LCO and Applicability

A

LCO
Two primary containment air locks shall be operable.

Applicability
Modes 1,2, & 3, and movement of RIF.

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8
Q

3.6.1.2 Primary Containment Air Locks

Describe the provisions afforded regarding inoperable doors for conditions & actions of this LCO.

A

If a containment air lock is inoperable, its counterpart door has to be shut and locked. The LCO gives allowance for entering through this door under control of a dedicated individual to perform repairs.

When a door is inoperable, its counterpart operable door must be locked and verified locked on a regular periodicity. Doors in HRAs can be administratively verified.

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9
Q

3.6.1.2 Primary Containment Air Locks

List conditions of the LCO that require actions in 1 hour or less.

A

Action A
If an airlock has an inoperable door, the operable door in that airlock must be closed within 1 hour.

Action B
If an airlock interlock mechanism is inoperable, an operable door in that airlock must be closed within 1 hour.

Action C
If primary containment airlock is inoperable for any reason other than an inoperable door or interlock mechanism;
Immediately initiate action to evaluate containment leakage rate using current air lock test results
&
Verify a door in the affected airlock is closed within 1 hour.

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10
Q

3.6.1.2 Primary Containment Air Lock Bases

What purpose do the air locks serve?

A

Limits release of radioactive material to environment from normal operation up to Design Basis Accidents.

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11
Q

3.6.1.2 Primary Containment Air Locks

What constitutes an operable air lock?

A

Airlock interlock mechanism operable, air lock in compliance with Type B air lock leakage test, and both air lock doors operable.

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12
Q

3.6.1.3 PCIVs

List the LCO and Applicability

List any conditions with actions required to be performed in 1 hour or less.

What provisions does this LCO allow for failures in different PCIVs?

A

LCO
Each PCIV, except containment vacuum breakrer, shall be operable.

Applicability
Modes 1, 2, 3, and when associated instrumentation is required to be operable per LCO 3.3.6.1 “Primary Containment and Drywell Isolation Instrumentation.”

Condition B: One or more penetration flow paths with two PCIVs inoperable except due to leakage not within limits
Within 1 hour, isolate the affected penetration flow path by use of at least one closed and deactivated automatic valve, closed manual valve, or blind flange.

Provisions
Separate condition entry is allowed for each penetration flow path.

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13
Q

3.6.1.3 PCIVs

This LCO makes provisions to allow intermittent operation to unisolate all flow paths except for one. Which valve does not fall under this provision?

A

The inboard 42” inboard purge valve.

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14
Q

3.6.1.3 PCIVs Bases

What system must be available to satisfy this LCOs requirements for Outboard MSIVS?

A

The “B” train of the SRIA system is required to ensure leak tightness of the OTBD MSIVs following an accident.

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15
Q

3.6.1.3 PCIVs Bases

Which accidents were considered for the basis of this LCO regarding release of radioactive material?

A

LOCA and Main Steam Line Break

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16
Q

3.6.1.3 PCIVs Bases

What factors were considered in the analysis to establish this LCO?

A

Two major factors were required be met: minimize the loss of reactor coolant inventory and establish primary containment boundary during major accidents.

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17
Q

3.6.1.3 PCIVs Bases

What constitutes an operable automatic PCIV?

A

Isolation time within limits.
Actuate on signal.

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18
Q

3.6.1.3 PCIVs Bases

SR 3.6.1.3.4 provides provisions for the IFTS blind flange to not be installed.
What is the maximum duration this blind flange can be removed and what is the basis of this provision?

A

IFTS blind flange can be removed for up to 60 days per operating cycle.

This provides the option of performing testing and maintenance of the IFTS during Modes 1-3 prior to an outage. It is not intended for the movement of fuel.

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19
Q

3.6.1.4 Primary Containment Pressure

List the LCO and Applicability

What conditions of this LCO have actions that require response in 1 hour or less?

A

LCO
Primary containment to secondary containment differential pressure shall be ≥ -0.1 psid and ≤ 1.0 psid.

Applicability
Modes 1, 2, & 3

1 Hour or less actions
If differential pressure not within limits, restore to within limits within 1 hour.

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20
Q

3.6.1.4 Primary Containment Pressure Bases

Discuss the reasoning behind these pressure limitations.

A

The negative pressure (external pressure) is established to ensure that the containment is not damaged due to an inadvertant initiation of containment spray.

The positive pressure (internal pressure) is established to ensure that the containment does not reach its design value of 15 psig during a DBA LOCA.

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21
Q

3.6.1.5 Primary Containment Air Temperature

List the LCO and Applicability.

A

LCO
Primary Containment average air temperature shall be ≤ 95F.

Applicability
Modes 1, 2, & 3.

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22
Q

3.6.1.5 Primary Containment Air Temperature

What is the basis behidn the temperature limit established in this LCO?

A

Ensures that the peak LOCA primary containment temperature does not exceed the maximum allowable temperature limit of 185F.

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23
Q

3.6.1.6 LLS Valves

List the LCO and Applicability.

A

LCO
The LLS function of six SRVs shall be operable.

Applicability
Modes 1, 2, & 3.

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24
Q

3.6.1.6 LLS Valves Bases

What is the purpose of the LLS function?

A

Ensures that the requirement of one SRV operating on “subsequent actions” is met.

Basically, having multiple SRVs opening simultaneously after the initial opening of any amount of SRVs is not considered in the DBA analysis.

Maintaining the LLS operation functional ensures this analysis is valid.

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25
Q

3.6.1.7 RHR Containment Spray System

List the LCO and Applicability

A

LCO
Two RHR containment spray subsystems shall be operable.

Applicability
Modes 1, 2, & 3.

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26
Q

3.6.1.7 RHR Containment Spray System Bases

What is the reasoning behind requiring both containment spray systems to be operable?

A

Containment spray is required in the event of a DBA to mitigate drywell bypass leakage, reduce containment peak pressure, and scrub fission products from the containment atmosphere for dose reduction.

The worst case scenario of a failure of one ECCS system means having two operable ensures at least one is available when needed.

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27
Q

3.6.1.8 FWLCS

List the LCO and Applicability

A

LCO
Two FWLCS subsystems shall be operable.

Applicability
Modes 1, 2, & 3.

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28
Q

3.6.1.8 FWLCS Bases

What is the basis of this LCO?

A

Contain radioactive material release in a design basis accident. Without FWLCS fission product release through the secondary containment by way of Feedwater System valve bonnets is possible in an accident situation.

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29
Q

3.6.1.9 MSSVs

List the LCO and Applicability

A

LCO
The Main Steam Shutoff Valves shall be operable.

Applicability
Modes 1, 2, & 3.

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30
Q

3.6.1.9 MSSV Bases

What is the basis of this LCO?

What amount of leakage is considered acceptable through these valves?

A

When analyzing the the DBA, with a single MSIV failing to close, dose limits in the control room and off-site would be exceeded without the MSSVs closed.

With the MSSVs failing to be closed as a single failure, NOT COINCIDENT with a failure of a single MSIV closure, the DBA results in the most limiting dose.

There is no consideration for valve leakage rate in this analysis.

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31
Q

3.6.1.9 MSSV Bases

What is the time requirement for isolating the MSSVs post LOCA?

A

20 minutes to provide the manually initiated closure signal.

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32
Q

3.6.1.9 Bases

Why is there a dose concern regarding the MSSVs post LOCA?

A

The analysis assumes fission product release into the MSLs that can accumulate on the walls. With the MSSVs not closed, these fission products can be entrained and released without treatment.

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33
Q

3.6.1.10 Primary Containment - Shutdown

List the LCO and Applicability

A

LCO
Primary Containment shall be operable.

Applicability
During movement of recently irradiated fuel assemblies in the primary containment.

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34
Q

3.6.1.10 Primary Containment - Shutdown Bases

What does this LCO ensure?

Why is this consideration worthless?

A

Fuel handling accident involving recently irradiated fuel remains contained, limiting offsite dose.

We are prohibited from moving recently irradiated fuel, as there are no dose calculations in that window.

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35
Q

3.6.1.10 Primary Containment - Shutdown Bases

What penetrations, normally required for containment operability, are allowed to be open in this LCO?

Why is this allowed?

A

The IFTS blind flange is allowed to be removed.

Dose calculations for this accident are highly conservative, so having the flange removed still allows the containment to be considered operable.

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36
Q

3.6.1.10 Primary Containment - Shutdown Bases

Validating primary containment shutdown operability requires verifying each penetration flow path required to be closed during an accident IS closed, except for which penetrations?

A

Pathways capable of being closed by operable primary containment automatic isolation valves.

Fire Protection System manual hose real containment isolation valves.

Manual isolation valves open under administrative controls.

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37
Q

3.6.1.11 Containment Vacuum Breakers

List the LCO and Applicability.

A

LCO
Three containment vacuum breakers shall be operable and four containment vacuum breakers shall be closed.

Applicability
Modes 1, 2, & 3.
Movement of RIF.

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38
Q

3.6.1.11 Containment Vacuum Breakers

With one or more vacuum breakers inoperable, the potential exists for containment vacuum relief subsystem leakages to exceed overall containment leakage acceptance criteria.

What actions, besides actions in this LCO, are required in this situation?

A

Enter required actions of LCO 3.6.1.1 - Primary Containment Operating.

39
Q

3.6.1.11 Containment Vacuum Breaker Bases

There are four containment vacuum breaker subsystems.

How many of these subsystems are required to protect the containment from its design external pressure?

A

Two subsystems will prevent containment from exceeding its design external pressure limit during events assumed in the external pressure analysis.

40
Q

3.6.1.11 Containment Vacuum Breaker Bases

This LCO contains requirements for both vacuum breaker operability and closure. What is the purpose behind both of these requirements?

A

The three required vacuum breakers operable ensures design external pressure is not reached in the most severe analyses.

The four required closed ensures no leakage from containment during a LOCA.

41
Q

3.6.1.12 Containment Humidity Control

List the LCO and Applicability

A

LCO
Containment average temperature to relative humidity shall be maintained within limits.

Applicability
Modes 1, 2, & 3.
Movement of RIF.

42
Q

3.6.1.12 Containment Humidity Control Bases

What analysis is this LCO based off of?

A

Inadvertent initiation of containment spray.

43
Q

3.6.2.1 Suppression Pool Average Temperature

List the LCO and Applicability

A

LCO
Suppression pool average temperature shall be:
A. ≤ 95F when THERMAL POWER is > 1% RTP and no testing that adds heat to the suppression pool is being performed;
B. ≤ 105F when THERMAL POWER is > 1% RTP and testing that adds heat to the suppression pool is being performed; and
C. ≤ 110F when THERMAL POWER is ≤ 1% RTP.

Applicability
Modes 1, 2, & 3.

44
Q

3.6.2.1 Suppression Pool Average Temperature

Discuss any conditions with actions requiring response within 1 hour or less.

A

Condition A:
With suppression pool average temperature > 95F and ≤ 110F, AND > 1% RTP, AND no testing that adds heat to the SP in progress;
Verify suppression pool average temperature is ≤ 110F once per hour and every 24 hours afterwards.

Condition C:
With Suppression pool average temperature > 105F AND > 1% RTP AND testing that adds heat to the SP IS in progress, immediately suspend all testing.

Condition D
With suppression pool average temperature > 110F but ≤ 120F, IMMEDIATELY place the mode switch in shutdown, and verify suppression pool average temperature is ≤ 120F every 30 minutes.

45
Q

3.6.2.1 Suppression Pool Average Temperature

What is required when suppression pool average temperature exceeds 120F?

A

Depressurize the reactor and move to cold shutdown.

46
Q

3.6.2.1 Suppression Pool Average Temperature Bases

Discuss the basis of the temperature limitations of this LCO.

A

These limits are established to ensure peak primary containment pressures and temperatures do not exceed the max allowable values during a postulated DBA.

The limit of 95F ensures that the initial conditions of the licensing analysis are met.

Extending the limit to < 105F when testing allows for plant flexibility while maintaining a margin to the 110F shutdown requirement.

Limiting temperature to ≤ 110F ensures that the suppression pool is capable of absorbing decay and sensible heat and stay within the design limits.

47
Q

3.6.2.1 Suppression Pool Average Temperature Bases

When performing testing that adds heat to the suppression pool, how often should suppression pool average temperature be monitored?

What is the basis of this time requirement?

A

Every 5 minutes.

With the rate at which testing will heat up the suppression pool, this time requirement ensures that the allowable pool temperatures are not exceeded provided actions are taken IAW the LCO.

48
Q

3.6.2.2 Suppression Pool Water Level

List the LCO and Applicability

A

LCO
Corrected suppression pool level shall be ≥ 17ft 9.5in and ≤ 18ft 6in when the reactor well to steam dryer storage pool gate is not installed.
OR
Corrected suppression pool water level shall be ≥ 18ft 3.2in and ≤ 18ft 6in when the reactor well to steam dryer storage pool gate is installed.

Applicability
Modes 1, 2, & 3.

49
Q

3.6.2.2 Suppression Pool Water Level Bases

What do these LCO values assume?

What must be done to the indicated value to ensure SP level is within LCO limits?

A

There is zero differential pressure between containment and drywell.

The dp between the containment and drywell must be accounted for with a table from the PDB that corrects the value of suppression pool level.

50
Q

3.6.2.2 Suppression Pool Water Level Bases

Why are the values different with the well to dryer gate installed and uninstalled?

A

SPMU is considered in the DBA analysis. With the dryer gate installed, a significant volume (7472 cubic feet) is lost to the suppression pool during a SPMU dump.

Therefore, when the dryer gate is installed, suppression pool minimum level must be more conservative.

51
Q

3.6.2.2 Suppression Pool Water Level Bases

There are five criteria/constraints satisfied by maintaining suppression pool volume within this LCOs bands.

What are they?

A

1. Maintain a 2 foot minimum post-LOCA horizontal vent coverage to assure steam condensation/pressure suppression, and maintain coverage of the RHR A test return line.
2. Adequate ECCS pump NPSH.
3. Adequate depth for vortex prevention.
4. Adequate depth for minimum recirculation volume.
5. Minimizing hydrodynamic loads on submerged structures during SRV and horizontal vent steam discharges.

52
Q

3.6.2.3 RHR Suppression Pool Cooling System

List the LCO and Applicability

A

LCO
Two RHR suppression pool cooling subsystems shall be operable.

Applicability
Modes 1, 2, & 3.

53
Q

3.6.2.3 RHR Suppression Pool Cooling Bases

What considerations does the DBA analysis make that require RHR SP Cooling?

A

In order to satisfy the DBA, one SP cooling system must be able to remove heat from the suppression pool to ensure peak primary containment temperature and pressure are below design limits.

54
Q

3.6.2.4 SPMU

List the LCO and Applicability

A

LCO
Two SPMU systems shall be operable

Applicability
Modes 1, 2, & 3.

55
Q

3.6.2.4 SPMU

What is temperature requirement for the upper pool to ensure SPMU operability?

A

≤ 110F

56
Q

3.6.2.4 SPMU

The SPMU system requires the upper pool have a minimum inventory in various configurations. What are these levels?

A
57
Q

3.6.2.4 SPMU Bases

What factors render the SPMU system operable?

A

Upper pool water temperature ≤ 110F, piping in tact, system valves operable, combined water levels of upper pool and SP within limits.

58
Q

3.6.2.4 SPMU Bases

What accidents are considered for the SPMU analysis?

What purpose does SPMU serve for these accidents?

A

Both large and small break LOCAs.

For the small break LOCA, SPMU is required to act as an adequate heat sink to maintain containment temperature and pressure within limits.

For the large break LOCA, SPMU is required to maintain coverage of the weir wall vents.

59
Q

3.6.3.2 Primary Containment and Drywell Hydrogen Igniters

List the LCO and Applicability.

What conditions have actions that require completion in 1 hour or less?

A

LCO
Two divisions of primary containment and drywell hydrogen igniters shall be operable, each with ≥ 90% of the associated igniter assemblies operable.

Applicability
Modes 1 & 2.

1 Hour or Less Actions
With two primary containment and drywell hydrogen igniter divisions inoperable, verify by administrative means that the hydrogen control function is maintained within 1 hour.

60
Q

3.6.3.2 Primary Containment and Drywell Hydrogen Igniters Bases

What do the hydrogen igniters ensure?

A

Combustion of hydrogen is in a controlled manner such that containment overpressure failure is prevented as a result of a postulated degraded core accident.

61
Q

3.6.3.2 Primary Containment and Drywell Hydrogen Igniters Bases

In order to satisfy this LCO, each division requires 90% of its igniters to be operable.

How many igniters can be inoperable and still satisfy this LCO?

A

5 per division.

62
Q

3.6.3.2 Primary Containment and Drywell Hydrogen Igniters Bases

Why does this LCO require two divisions to be operable?

What do these igniters prevent?

A

The worst case accident analysis assumes a single failure. With both igniter systems operable, the plant still falls within the assumptions as one division of igniters is sufficient to control hydrogen below the lower explosive limit (LEL) of 4%.

63
Q

3.6.3.2 Primary Containment and Drywell Hydrogen Igniters Bases

This LCO contains a 1 hour action requiring verification that the hydrogen control function is maintained by administrative means.

What does this mean?

A

The hydrogen control function is simply the ability to maintain hydrogen below the LEL in the worst case accident. If igniters are unavailable, verification of other methods of hydrogen control must be performed.

To satisfy this requirement, one hydrogen recombiner and one combustible gas mixing system must be operable.

Verification may be performed by examining logs or other information to determine the availability of the alternate hydrogen control capabilities.

64
Q

3.6.3.3 Combustible Gas Mixing System

List the LCO and Applicability.

What conditions of this LCO require action in 1 hour or less?

A

LCO
Two combustible gas mixing subsystems shall be operable.

Applicability
Modes 1 & 2.

1 Hour or Less Actions
With two combustible gas mixing subsystems inoperable, verify by administrative means that the hydrogen control function is maintained within 1 hour.

65
Q

3.6.3.3 Combustible Gas Mixing System Bases

How does the combustible gas mixing system prevent hydrogen explosions?

A

The system ensures a uniform mix of gases in the post accident containment atmosphere, minimizing the potential for localized hydrogen concentrations that exceed the LEL.

66
Q

3.6.3.3 Combustible Gas Mixing System Bases

Discuss how the combustible gas mixing system functions regarding drywell integrity.

A

The combustible gas mixing system provides the capability to reduce drywell hydrogen concentration to approximately the bulk average primary containment concentration following a DBA.

67
Q

3.6.3.3 Combustible Gas Mixing System Bases

How many combustible gas mixing subsystems are required to operate to maintain hydrogen concentration within limits?

A

Only 1 subsystem is required to maintain this concentration, thats why this LCO requires two operable (assume 1 fails in the analysis).

68
Q

3.6.3.3 Combustible Gas Mixing System Bases

This LCO contains a 1 hour action requiring verification that the hydrogen control function is maintained by administrative means.

What does this mean?

A

The hydrogen control function is simply the ability to maintain hydrogen below the LEL in the worst case accident. If igniters are unavailable, verification of other methods of hydrogen control must be performed.

To satisfy this requirement, one hydrogen recombiner or one division of hydrogen igniters must be operable.

Verification may be performed by examining logs or other information to determine the availability of the alternate hydrogen control capabilities.

69
Q

3.6.4.1 Secondary Containment

List the LCO and Applicability

A

LCO
The secondary containment shall be operable.

Applicability
Modes 1, 2, & 3
Movement of RIF

70
Q

3.6.4.1 Secondary Containment Bases

What constitutes an operable secondary containment?

A

1. All penetrations terminating at the secondary containment boundary are closed or flanged off;
2. Equipment hatch is closed and sealed and the shield blocks are installed;
3. Door in each access to secondary containment is closed (except for entry and exit);
4. Sealing mechanisms associated with penetrations functional;
5. Vacuum in secondary containment ≥ 0.66” H2O;
6. AEGT System is operable.

71
Q

3.6.4.1 Secondary Containment Bases

What does the secondary containment provide regarding accidents?

A

A control volume into which fission products that bypass or leak from primary containment can be diluted and processed prior to release to the environment.

72
Q

3.6.4.2 Secondary Containment Isolation Valves

List the LCO and Applicability.

A

LCO
Each SCIV shall be operable.

Applicability
Modes 1, 2, & 3.
Movement of RIF.

73
Q

3.6.4.2 SCIVs Bases

There is a note for this LCO regarding the actions that allows for intermittent unisolations of penetration flowpaths. What requirements must be satisfied to do this?

A

Unisolate under administrative controls. They require a dedicated operator who is in continuous communication with the control room at the controls of the isolation device.

74
Q

3.6.4.3 AEGT System

List the LCO and Applicability

A

LCO
Two AEGT systems shall be operable.

Applicability
Modes 1, 2, & 3.
Movement of RIF.

75
Q

3.6.4.3 AEGT System

List the conditions and required actions that must be complete within 1 hour or less?

A

Condition D:
With two AEGT subsystems inoperable in modes 1, 2, or 3, immediately enter LCO 3.0.3.

76
Q

3.6.4.3 AEGTS Bases

What is the reasoning behind requiring 2 AEGT subsystems to be operable?

A

One AEGT subsystem is sufficient to maintain negative pressure in the annulus. Assuming 1 failure, operating this LCO will maintain plant within assumptions of a DBA.

77
Q

3.6.5.1 Drywell

List the LCO and Applicability

List any conditions with actions requiring response within 1 hour.

A

LCO
The drywell shall be operable

Applicability
Modes 1, 2, & 3.

Condition A:
With the Drywell inoperable, restore to operable status within 1 hour.

78
Q

3.6.5.1 Drywell Bases

What constitutes an operable drywell?

A

A. Drywell airlock is operable except as provided by LCO 3.6.5.2 “Drywell Air Lock”
B. The Drywell penetrations required to be closed during accident conditions are either:
1. capable of being closed by an operable automatic drywell isolation valve or;
2. closed by a manual valved, flanged off, or deactivated automatic valve secured in the closed position.

79
Q

3.6.5.2 Drywell Air Lock

List the LCO and Applicability

A

LCO
The drywell air lock shall be operable.

Applicability
Modes 1, 2, & 3.

80
Q

3.6.5.2 Drywell Air Lock

Discuss the conditions with actions requiring response in 1 hour or less?

A

Condition A:
With one drywell air lock door inoperable, verify the operable door is closed within 1 hour.

Condition B:
With the drywell air lock interlock mechanism inoperable, verify an operable door is closed within 1 hour.

Condition C:
With the drywell air lock inoperable for any reason other than Condition A or B, verify a door is closed within 1 hour.

81
Q

3.6.5.2 Drywell Air Lock

Conditions A and B have provisions for using the drywell air lock when it is inoperable. What are these provisions?

A

In Condition A, entry and exit is permissible for 7 days under administrative controls.

In Condition B, entry and exit is permissible under the control of a dedicated individual.

82
Q

3.6.5.2 Drywell Air Lock Bases

What constitutes an operable drywell?

Why is drywell air lock leakage excluded from this requirement?

A

Drywell is operable with the air lock interlock mechanism operable and both air lock doors operable.

The air lock leakage is considered part of the drywell operability in 3.6.5.1.

83
Q

3.6.5.2 Drywell Air Lock Bases

Why is operability of the drywell air lock required for operation?

A

The air lock forms an integral part of the drywell pressure boundary.

This boundary directs steam released in a DBA LOCA is directed to the containment through the weir wall vents, ensuring that containment atmosphere limits are not violated.

84
Q

3.6.5.3 Drywell Isolation Valves

List the LCO and Applicability

A

LCO
Each drywell isolation valve, except for Drywell Bacuum Relief system valves, shall be operable.

Applicability
Modes 1, 2, & 3.

85
Q

3.6.5.3 Drywell Isolation Valves

This LCO makes provisions for intermittent unisolation of drywell isolation valves under administrative control for which valves?

A

The 24 inch and 26 inch purge supply and exhaust valve penetration flow path.

86
Q

3.6.5.3 Drywell Isolation Valves Bases

What is the reasoning behidn requiring drywell isolation valve operability?

A

Ensure tha adequate drywell boundary is maintained during and after an accident by minimizing potential paths to the environment.

87
Q

3.6.5.3 Drywell Isolation Valve Bases

What safety function do the drywell isolation valves provide?

What constitutes an operable drywell isolation valve?

A

They form a part of the drywell boundary.

Power operated drywell isolation valves are required to have isolation times within limits. Automatic isolation valves are also required to actuate on an automatic isolation signal.

88
Q

3.6.5.4 Drywell Pressure

List the LCO and Applicability

What conditions of this LCO have actions required to be complete within 1 hour?

A

LCO
Drywell to containment differential pressure shall be ≥ -0.5 psid and ≤ 2.0 psid.

Applicability
Modes 1, 2, & 3.

1 Hour or less actions
Condition A
With differential pressure not within limits, restore to within limits within 1 hour.

89
Q

3.6.5.4 Drywell Pressure Bases

This LCO serves to satisfy 4 conditions.

What are they?

A

1. Ensure suppression pool water level is not forced over the weir wall.
2. Vent clearing does not occur during normal operation.
3. Containment conditions are consistent with the safety analysis.
4. LOCA Drywell pressures and pool swell loads are within design values.

90
Q

3.6.5.5 Drywell Air Temperature

List the LCO and Applicability

A

LCO
Drywell average air temperature shall be ≤ 145F.

Applicability
Modes 1, 2, & 3.

91
Q

3.6.5.5 Drywell Air Temperature Bases

What is the basis of this LCO’s temperature limit?

A

The safety analysis assumes 145F in the drywell. Maintaining at or below this value ensures that peak LOCA drywell temperatures does not exceed maximum allowable temperature of 330F.

92
Q

3.6.5.6 Drywell Vacuum Relief System

List the LCO and Applicability

A

LCO
Two drywell vacuum relief subsystems shall be operable.

Applicability
Modes 1, 2, & 3.

93
Q

3.6.5.6 Drywell Vacuum Relief System Bases

Why must these subsystems be operable?

A

Ensures that the subsequent depressurization drywell post-LOCA does not create a vacuum condition in the drywell.

94
Q

3.6.5.6 Drywell Vacuum Relief System Bases

What constitutes an operable drywell vacuum relief subsystem?

A

Capable of opening at required setpoint but maintained in the closed position during normal operation except as required to perform design function.

ILO24 (17 decks)

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