ET 15-0008, Response to Request for Additional Information Regarding License Amendment Request to Revise Technical Specifications to Adopt TSTF-523, Revision 2, Generic Letter 2008-01, Managing Gas Accumulation.

Response to Request for Additional Information Regarding License Amendment Request to Revise Technical Specifications to Adopt TSTF-523, Revision 2, Generic Letter 2008-01, Managing Gas Accumulation.

ML15084A104
Person / Time
Site:	Wolf Creek
Issue date:	03/18/2015
From:	Mccoy J Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ET 15-0008
Download: ML15084A104 (13)

Text

W&6-F CREEK ' NUCLEAR OPERATING CORPORATION Jaime H. McCoy Vice President Engineering March 18, 2015 ET 15-0008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter ET 14-0034, dated November 20, 2014, from J. H. McCoy, WCNOC, to USNRC

2) Letter dated February 10, 2015, from C. F. Lyon, USNRC, to A.C.

Heflin, WCNOC, "Wolf Creek Generating Station - Request for Additional Information Re: License Amendment Request to Adopt TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation" (TAC NO. MF5280)"

Subject:

Docket No. 50-482: Response to Request for Additional Information Regarding License Amendment Request to Revise Technical Specifications to Adopt TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation" Gentlemen:

Reference 1 provided the Wolf Creek Nuclear Operating Corporation (WCNOC) application to revise the Wolf Creek Generating Station (WCGS) Technical Specifications (TS). The proposed amendment would modify the WCGS TS requirements to address Nuclear Regulatory Commission (NRC) Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," as described in Technical Specification Task Force (TSTF) Traveler TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation." Reference 2 provided a request for additional information related to the application. The Attachment provides WCNOC's response to the request for additional information.

The additional information does not expand the scope of the application and does not impact the no significant hazards consideration determination presented in Reference 1.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," a copy of this submittal is being provided to the designated Kansas State official.

P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831 An Equal Opportunity Employer M/F/HC/VET A & -

ET 15-0008 Page 2 of 3 This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4156, or Mr. Steven R. Koenig at (620) 364-4041.

Sincerely, 6!/71 Jaime H. McCoy JHM/rlt Attachment cc: T. A. Conley (KDHE), w/a M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. F. O'Keefe (NRC), w/a Senior Resident Inspector (NRC), wla

ET 15-0008 Page 3 of 3 STATE OF KANSAS ))s COUNTY OF COFFEY )

Jaime H. McCoy, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the contents thereof; that he has executed the same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

6 Jaime/-. McCoy /

Vice resident Engineering SUBSCRIBED and sworn to before me this /642 day of 2~a4 LL ,2015.

I GAYLESHEPHEARD] NotryFylic Notary Public -State of Kansas]

jAppt. Expircs 7A/l p-A-11, Expiration Date

Attachment I to ET 15-0008 Page 1 of 10 Response to Request for Additional Information Reference 1 provided the Wolf Creek Nuclear Operating Corporation (WCNOC) application to revise the Wolf Creek Generating Station (WCGS) Technical Specifications (TS). The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification. The changes are being made to address the concerns discussed in Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," (Reference 1).

Reference 2 provided a request for additional information related to the application. The specific NRC question is provided in italics.

1. What were the historic void volumes found that are applicable to performance of TS surveillance requirements (SRs) 3.5.2.3 and 3.6.6.9, and how did these compare to the acceptance criteria? How do those void volumes compare to follow-up calculations that were performed if the originalcriteriawere not met?

Response: The historic void volumes found that are applicable to the performance of Surveillance Requirement (SR) 3.5.2.3 are as follows. Note that the Allowable Volume (Allowable Vol.) is the acceptance criteria at the time the void was discovered.

Cycle 20 Void Vol. Allowable Date Location Description (ft_) Vol. (ft) Notes 3/22/2013 EMV0257 Piggy-back line from 2 0.25 MODE 6 post fill and vent during Centrifugal Charging Refueling Outage 19. Emergency Core Pump (CCP) suction to Cooling System (ECCS) not required to Safety Injection Pump be OPERABLE in this mode. Void (SIP) A suction [vented to water solid.

Cycle 19 Void Vol. Allowable Date Location Description (ft) Vol. (ft3) Notes 12/18/2012 EMV0058 SIP discharge to hot 0.011 0.25 MODE 1. Void could not be vented.

leg (HL) injection Location was water solid at next performance of ultrasonic testing (UT) 1 month later.

10/4/2012 EMV0259 Piggy-back line from 0.005 0.25 MODE 1. Void vented to water solid.

CCP suction to SIP A suction 8/15/2012 EJV0088 Residual Heat Removal 0.003 0.59 MODE 1. Void vented to water solid.

(RHR) discharge to Loop 4 8/8/2012 EJV0088 RHR discharge to Loop 0.11 0.59 MODE 1. Gas sample taken. Approx.

4 50% hydrogen and 50% nitrogen. Void vented to water solid.

Attachment I to ET 15-0008 Page 2 of 10 Cycle 19 Void Vol. Allowable Date Location Description (ft) Vol. (ft3) Notes 7/24/2012 EJV0088 RHR discharge to Loop 1.12 (est.) 0.59 MODE 1. Volume estimated using 4 Henry's Law. Void evaluated using GOTHIC. Peak pressure from water hammer less than relief valve setting, and unbalanced load from water hammer 34% of pipe weight. RHR System would have been capable of performing its safety function if required. Void vented to water solid.

7/23/2012 EJV0088 RHR discharge to Loop 0.01 0.59 MODE 1. Void vented to water solid.

4 7/19/2012 EJV0088 RHR discharge to Loop 0.41 0.59 MODE 1. Gas sample taken. Sample 4 was contaminated with air during testing, but had high hydrogen content. Void vented to water solid.

3/26/2012 EJV0088 RHR discharge to Loop >0.59 0.59 MODE 3. Formed from accumulator 4 leakage into RHR. Present for no greater than 5.87 hours0.00101 days <br />0.0242 hours <br />1.438492e-4 weeks <br />3.31035e-5 months <br />. Void vented to water solid.

Cycle 18 Void Vol. Allowable Date Location Description (ft) Vol. (ft3) Notes 11/22/2010 BGV0496 CCP recirculation 0.01 0.25 MODE 1. Void vented to water solid.

discharge to Seal Water Heat Exchanger 11/10/2010 EJV0223 RHR suction vent on <0.001 0 MODE 1. Void vented to water solid.

check valve EJ8958B 10/22/2010 EJV0088 RHR discharge to Loop 0.29 0.59 MODE 1. UT performed due to leakage 4 from accumulator. Void vented to water solid.

8/24/2010 EJV0221 RHR suction vent on Unknown 0 MODE 1. Post vacuum fill and vent of check valve EJ8958A (vented RHR A Heat Exchanger. RHR train A 1/4 turn was out of service for vacuum fill and open for 9 vent. Void vented to water solid.

sec) 8/23/2010 EEJ01A RHR A Heat Exchanger 4.1 No MODE 1. Volume of void in RHR A Heat allowable Exchanger after vacuum fill and vent volume performed. Bounded by void found on calculated 7/2/10. Was completely removed from RHR A Heat Exchanger during dynamic vent on 10/6/10 during a forced outage.

8/23/2010 EJV0221 RHR suction vent on -0.001 0 MODE 1. Post vacuum fill and vent of check valve EJ8958A RHR A Heat Exchanger. Void vented to water solid.

Attachment I to ET 15-0008 Page 3 of 10 Cycle 18 Void Vol. Allowable Date Location Description 7 . (ft') Vol. (ft') Notes 8/23/2010 EJV0238 RHR discharge at inlet 0.01 0.25 MODE 1. Post vacuum fill and vent of to RHR A Heat RHR A Heat Exchanger. Void vented to Exchanger volume of <0.001 cubic feet. Location was water solid at next performance of UT 1 day later.

7/4/2010 EJV0059 RHR suction 0.09 0.1 MODE 1. Void is gas from the RHR A downstream of Heat Exchanger which has been recirculation sump transported back to the pump suction isolation valve through the miniflow line and collected at the recirculation sump isolation valve.

Void vented to water solid.

7/4/2010 EJV0221 RHR suction vent on 0.03 0 MODE 1. Void is gas from the RHR A check valve EJ8958A Heat Exchanger which has been transported back to the pump suction through the miniflow line and collected at the check valve. Void vented to water solid.

7/3/2010 EJV0059 RHR suction 1.35 0.1 MODE 1. Gas sample taken. Void was downstream of determined to be 91.7% nitrogen, 7.3%

recirculation sump oxygen, and 0.9% hydrogen. Void is gas isolation valve from the RHR A Heat Exchanger which has been transported back to the pump suction through the miniflow line and collected at the recirculation sump isolation valve. Void vented but small volume remained.

7/2/2010 EEJ01A RHR A Heat Exchanger 9.8 No MODE 1. Maximum calculated initial allowable volume in the tube side of RHR A Heat volume Exchanger of 9.8 ft 3 present since calculated Refueling Outage 17. Detailed evaluation showed that there was reasonable assurance that RHR System, SIPs, and CCPs would have been able to perform safety functions. Void could not be completely flushed from RHR Heat Exchanger since 3500 gpm flow required for dynamic venting. A volume of 6.2 cubic feet of gas remained in the RHR A Heat Exchanger after 7/4/10.

7/2/2010 EJV0059 RHR suction 0.64 0.1 MODE 1. Gas sample taken. Void was downstream of determined to be 94% nitrogen. Void is recirculation sump gas from the RHR A Heat Exchanger isolation valve which has been transported back to the pum~p suction through the miniflow line and collected at the recirculation sump isolation valve. Void vented but small volume remained.

Attachment I to ET 15-0008 Page 4 of 10 Cycle 18 IVoid Vol. Allowable Date Locationj Description (ft Vol. (ft3) Notes 7/2/2010 EJV0059 RHR suction 0.02 0.1 MODE 1. Void is gas from the RHR A downstream of Heat Exchanger which has been recirculation sump transported back to the pump suction isolation valve through the miniflow line and collected at the recirculation sump isolation valve.

Void vented but small volume remained.

7/2/2010 EJV0134 RHR discharge to Loop 0.01 0.25 MODE 1. Void is likely a result of running 2 the RHR A pump with a large void in the RHR A Heat Exchanger. Void was located in containment, and was not vented due to high local temperatures.

When location was checked again on 7/4/2010, void had dissolved.

4/29/2010 EJV0088 RHR discharge to Loop 0.006 0.25 MODE 1. Void vented to water solid.

4 4/22/2010 EJV0088 RHR discharge to Loop 0.008 0.25 MODE 1. Void vented to water solid.

4 4/14/2010 EJV0088 RHR discharge to Loop 0.59. 0.25 MODE 1. Gas sample taken. Void was 4 determined to be >98% nitrogen. Void evaluated using GOTHIC. Peak pressure from water hammer less than relief valve setting, and pressure rise due to pressure pulsations from water hammer was determined to be insignificant. RHR system would have been capable of performing its safety function if required.

Void vented to water solid.

11/8/2009 EJV0221 RHR suction vent on -0.001 0 MODE 6 post fill and vent. ECCS not check valve EJ8958A required to be OPERABLE in this mode.

Void vented to water solid.

11/8/2009 EJV0241 RHR discharge vent on Unknown 0.25 MODE 6 post fill and vent. ECCS not check valve EJ8969A (20 - 30 required to be OPERABLE in this mode.

to CCP suctions sec. vent) Void vented to water solid.

Cycle 17 Void Vol. Allowable Date Location Description (ft) Vol. (ft) Notes 8/5/2008 EMV0257 Piggy-back line from Small 0.25 MODE 1. Gas sample taken and CCP suction to SIP A (<<0.25) determined to be 0.2% hydrogen, 25.6%

suction oxygen, and 75.2% nitrogen. Source was leftover air from fill and vent during Refueling Outage 16. Void vented to water solid.

Attachment I to ET 15-0008 Page 5 of 10 Cycle 17 Void Vol. Allowable Date Location Description ft3]) Vol. (ft 3) J Notes 6/4/2008 EJV0203 RHR A discharge to Small 0.25 MODE 1. Gas sample taken and CCP Suction (<<0.25) determined to be 2% helium, 66.1%

hydrogen, 5.75% oxygen, and 26.2%

nitrogen. Source was degassing after securing from shutdown cooling in Refueling Outage 16. Void vented to water solid.

5/27/2008 EJV0128 RHR discharge to hot Small 0.25 MODE 1. Source was degassing after leg (HL) Recirculation (<<0.25) securing from shutdown cooling in Refueling Outage 16. Void vented to water solid.

5/23/2008 EJV0128 RHR discharge to HL Small 0.25 MODE 1. Gas sample taken and Recirculation (<<0.25) determined to be 19.1% hydrogen, 15.3%

oxygen, and 65.6% nitrogen. Source was degassing after securing from shutdown cooling in Refueling Outage 16. Void vented to water solid.

5/22/2008 EJV0223 RHR suction vent on 0.13 0 MODE 1. RHR B pump out of service for check valve EJ8958B scheduled maintenance. Gas sample taken and determined to be 45.6%

hydrogen, 8% oxygen, and 46.3%

nitrogen. Source was degassing after securing from shutdown cooling in Refueling Outage 16. Void vented to water solid.

5/11/2008 EJV0128 RHR discharge to HL Small 0.25 MODE 4 during Refueling Outage 16.

Recirculation (<<0.25) Void vented to water solid.

5/6/2008 EMV0002 SI A discharge check <0.001 0.25 MODE 5 post fill and vent during valve to Loop 3 HL Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void was not vented.

5/5/2008 EJV0122 RHR discharge to HL Unknown 0.25 MODE 5 post fill and vent during Recirculation Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void vented to water solid.

5/5/2008 EJV0128 RHR discharge to HL <0.1 0.25 MODE 5 post fill and vent during Recirculation Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void vented to water solid.

5/5/2008 EJV0198 RHR B Pump casing Unknown 0 MODE 5 post fill and vent during (1 minute Refueling Outage 16. ECCS not required vent) to be OPERABLE in this mode. Void vented to water solid.

5/5/2008 EJV0223 RHR suction vent on Unknown 0 MODE 5 post fill and vent during check valve EJ8958B (1 minute Refueling Outage 16. ECCS not required vent) to be OPERABLE in this mode. Void vented to water solid.

Attachment I to ET 15-0008 Page 6 of 10 Cycle 17 1 IVoid Vol. Allowable Date Location Description (fJ Vol. (ft3) Notes 5/5/2008 EMV0078 CCP common Small 0.25 MODE 5 post fill and vent during discharge to cold leg (<<0.25) Refueling Outage 16. ECCS not required (CL) injection lines to be OPERABLE in this mode. Void vented to water solid.

5/5/2008 EMV0156 CCP A discharge to CL Small 0.25 MODE 5 post fill and vent during injection lines (<<0.25) Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void vented but small volume remained.

5/5/2008 EMV0185 SI A discharge to 0.021 0.25 MODE 5 post fill and vent during Loops 2 and 3 HLs Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void vented to water solid.

5/5/2008 EMV0242 CCP B discharge to CL Small 0.25 MODE 5 post fill and vent during injection lines (<<0.25) Refueling Outage 16. ECCS not required to be OPERABLE in this mode. Void vented to water solid.

The historic void volumes found that are applicable to the performance of proposed SR 3.6.6.9 are as follows, Note that the Allowable Volume (Allowable Vol.) is the acceptance criteria at the time the void was discovered.

Cycle 20 SVoid Vol. Allowable Date LocationI Description (ft) Vol. (ft3) Notes 3/26/2013 ENV01 17 Containment Spray 0.005 2.75 MODE 6 post fill and vent during (CS) A suction Refueling Outage 19. CS System not downstream of required to be OPERBLE in this mode.

recirculation sump Void vented to water solid.

isolation valve Cycle 19 Void Vol. Allowable Date Location Description (ft3) Vol. (ft) Notes 1/16/2013 ENVO120 CS B suction 0.69 2.47 MODE 1. Gas sample taken and downstream of determined to be 0.1% hydrogen, 18.9%

recirculation sump oxygen, and 81.1% nitrogen. Void isolation valve vented to water solid.

Attachment I to ET 15-0008 Page 7 of 10 Cycle 19 Void Vol. Allowable Date Location Description (ft) Vol. (ft3) Notes 12/3/2012 ENVO120 CS B suction 2.75 2.47 MODE 1. Gas sample taken and downstream of determined to be 20.3% oxygen, and recirculation sump 84.1% nitrogen. Void was evaluated isolation valve using GOTHIC. GOTHIC predicted that average void fraction at pump would be 2.25% for 20 seconds, giving a factor of 2.2 below the allowable void fraction from NEI 09-10, Rev. la. Conditions on use from draft Final Safety Evaluation were satisfied. CS System would have been able to perform its safety function if required. Void vented to water solid.

Cycle 18 Void Vol. Allowable Date Location 3 Description Wft) Vol. (Wf ) Notes 8/2/2010 ENVO093 CS additive tank to CS <0.001 0.25 MODE 1. Void could not be vented.

A suction Location water solid on 9/7/2010.

7/6/2010 ENVO093 CS additive tank to CS 0.004 0.25 MODE 1. Gas sample taken and A suction determined to be 22% oxygen and 78%

nitrogen. Void vented but small volume remained. Location water solid on 7/10/2010.

7/6/2010 ENV0117 CS A suction 0.9 0.15 MODE 1. Gas sample taken and downstream of determined to be 19% oxygen and 81%

recirculation sump nitrogen. RELAP model with bounding isolation valve void size of 4.8 cubic feet used to show that void fraction at pump would be less than 5%; however, this would not satisfy the conditions on use from the Final Safety Evaluation if used today. Void vented to 0.073 cubic feet. Location water solid on 7/7/2010.

Cycle 17 Void Vol. Allowable Date Location Description (ft3) . Vol. (ft3) Notes 7/11/2008 ENV01 17 CS A suction -0.001 0.15 MODE 1. Gas sample taken and downstream of determined to be 20.2% oxygen and recirculation sump 79.8% nitrogen. Void vented but small isolation valve volume remained. Location water solid on 7/17/2008.

Attachment I to ET 15-0008 Page 8 of 10

2. Is the WCGS design basis "no gas?" If not, please provide the documentation that establishedthe design basis.

Response: The Wolf Creek Generating Station (WCGS) design basis for the ECCS and CS System is "no gas," with the exception of a portion of the CS System discharge piping. CS System discharge piping inside containment is qualified for the impulse of a water hammer at the commencement of system flow by validating that the stresses are within allowable limits.

CS System discharge piping inside containment is not required to be filled with water during normal plant operation.

3. Please provide a description of the process used to restore the plant to the design basis condition at the earliestpracticaltime following discovery of a gas volume that exceeds the design basis.

Response: Locations susceptible to gas accumulation are monitored by UT to verify that the ECCS and CS System are sufficiently filled with water. Locations monitored by UT have a vent valve installed. If a void is identified during performance of the surveillance procedure, the void is characterized (arc length and length) to determine the volume. A Condition Report (CR) is initiated in accordance with procedure AP 28A-100, "Corrective Action Program," to document the void. Control room personnel perform an immediate OPERABILITY determination of the identified condition. If desired by engineering, a sample of the gas can be taken to identify the composition of the gas. After the void is fully characterized, the void is vented using the vent valve. Ultrasonic testing is performed after venting to verify that the void has been fully vented and the system restored to the design basis condition (no gas).

A small number of locations (10 out of 123) are checked by venting, as UT probes are not qualified for these particular locations. For these locations, the vent valve is cracked open. If any gas is emitted from the valve, the void volume is collected in a sample bag such that the volume of the void can be determined. The void is vented until a solid stream of water issues from the vent valve.

4. Please describe the methodology used to determine gas volumes that do not jeopardize operability that are applicable to SRs 3.5.2.3 and 3.6.6.9.

Response: The methodology used to determine gas volumes that do not jeopardize OPERABILITY is based on the guidance from Nuclear Energy Institute (NEI) 09-10, Rev. la-A, "Guideline for Effective Prevention and Management of System Gas Accumulation," NRC Regulatory Issue Summary 2013-09, "NRC Endorsement of NEI 09-10, Revision la-A, "Guidelines for Effective Prevention and Management of System Gas Accumulation","

(Reference 4), and the NRC Final Safety Evaluation (SE) for NEI 09-10 (Reference 5).

Calculations were performed to determine the acceptance criteria (i.e., allowable void volume) for each location in the ECCS and CS System monitored by UT. The methodology is a mixture of Simplified Equation calculations (based on WCAP-17276-P, Rev. 1, "Investigation of Simplified Equation for Gas Transport"), Fauske water hammer calculations (based on FAI/08-70, Rev. 1, "Gas-Voids Pressure Pulsations Program"), GOTHIC computer models (incorporating appropriate factors of safety for suction locations as required by the NRC SE),

and conservative method for determining acceptable upstream void volumes as approved by the NRC SE. Qualifications from the NRC SE for suction and discharge piping and the use of computer codes were evaluated in a WCNOC Basic Engineering Disposition. In addition, for ECCS locations, the total volume of gas which can be injected into the Reactor Coolant System

Attachment I to ET 15-0008 Page 9 of 10 (RCS) from Westinghouse LTR-LIS-08-543, "PWROG Position Paper on Non-condensable Gas Voids in ECCS Piping; Qualitative Engineering Judgment of Potential Effects on Reactor Coolant System Transients Including Chapter 15 Events, Task 3 of PA-SEE-450," including the qualifications on the use of this guidance from the NRC SE, was evaluated.

5. How is potential leakage from the reactorcoolant system addressed?

Response: For potential external reactor coolant system (RCS) leakage, TS 3.4.15, "RCS Leakage Detection Instrumentation," requires instruments of diverse monitoring principles to be OPERABLE to provide a high degree of confidence that extremely small leaks are detected in time to allow actions to place the plant in a safe condition, when RCS LEAKAGE indicates possible reactor coolant pressure boundary (RCPB) degradation. Specifically, Limiting Condition for Operation (LCO) 3.4.15 requires the containment sump level and flow monitoring system, one containment atmosphere particulate radioactivity monitor, and one containment air cooler condensate monitoring system OPERABLE in MODES 1, 2, 3 and 4. Entry conditions specific to leakage into containment include increased containment humidity, pressure, or temperature; increased activity on the containment particulate or gaseous radioactivity monitors and containment area radiation monitors; and an indicated increase of the Nuclear Plant Information System (NPIS) monitored containment total unidentified leak rate. Diverse operational monitoring principles are necessary because one monitored parameter will always lead the others depending on the actual or postulated plant conditions.

TS 3.4.13, "RCS Operational LEAKAGE," specifies leakage limits to limit system operation in the presence of leakage from RCS components to amounts that do not compromise safety. SR 3.4.14.1 requires the performance of a RCS water inventory balance once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Procedure STS BB-006, "RCS Water Inventory Balance Using the NPIS Computer," or STS BB-004, "RCS Water Inventory Balance," is used to satisfy SR 3.4.13.1 and is performed once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as an industry best practice. Procedure STS CR-001, "Shift Log for Modes 1, 2, & 3,"

monitors the NPIS containment total unidentified leak rate point (LFU0769) three times per day.

If the containment total unidentified leak rate is greater than one gpm, then a RCS water inventory balance is performed per procedure STS BB-006 or STS BB-004. Within procedures STS BB-006 and STS BB-004, there are actions for a leak of >0.1 gpm (7 day rolling average),

>0.15 gpm (two consecutive measurements), and >0.3 gpm (one measurement). The actions include checking for abnormal trends on other leakage detection instrumentation and systems, commence a leakage investigation to identify and quantify the leak, perform a containment inspection for leakage, and isolate/stop the leak. Additionally, procedure OFN BB-007, "RCS Leakage High," is entered when indications of increased RCS leakage exist.

For potential RCS leakage into the ECCS and/or RHR System, leakage would be detectable by an increase in the RHR or High Pressure Coolant Safety Injection System. The pressure in the Boron Injection Tank (part of the High Pressure Coolant Safety Injection System) is recorded once per shift in accordance with procedure CKL ZL-003, "Control Room Daily Readings." If the pressure in the Boron Injection Tank is greater than 1300 psi, then the Control Room Supervisor (CRS) is to be contacted and the system depressurized prior to reaching 1500 psi. The Boron Injection Tank is depressurized utilizing procedure SYS EM-120, "BIT Depressurization," and one of the prerequisites is that System Engineering be notified. In addition, the Safety Injection System discharge header is depressurized utilizing procedure SYS EM-002, "SI System Depressurization," and one of the prerequisites is to direct System Engineering to troubleshoot the source of system pressurization if it is not known.

Attachment I to ET 15-0008 Page 10 of 10 The RHR discharge pressure is also recorded once per shift in accordance with procedure CKL ZL-001, "Auxiliary Building Reading Sheets." If the pressure in the RHR discharge is greater than 350 psi, then the CRS is to be notified. The RHR System is depressurized utilizing procedure SYS EJ-323, "RHR System Depressurization," and one of the prerequisites is that System Engineering be notified so that they can evaluate the possibility of gas buildup in the RHR System.

System Engineering is notified in the event that RCS leakage into the ECCS and/or RHR System is occurring. System Engineering evaluates the possibility of gas buildup, and determines additional actions as appropriate

References:

1. WCNOC letter ET 14-0034, "Application to Revise Technical Specifications to Adopt TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation," Using the Consolidated Line Item Improvement Process," November 20, 2014. ADAMS Accession No. ML14330A247.

2. Letter from C. F. Lyon, USNRC, to A. C. Heflin, WCNOC, "Wolf Creek Generating Station

- Request for Additional Information Re: License Amendment Request to Adopt TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation" (TAC NO.

MF5280)," February 10, 2015. ADAMS Accession No. ML15040A625.

3. NEI 09-10, Rev 1a-A, "Guideline for Effective Prevention and Management of System Gas Accumulation," April 2013.

4. NRC Regulatory Issue Summary 2013-09, "NRC Endorsement of NEI 09-10, Revision la-A, "Guidelines for Effective Prevention and Management of System Gas Accumulation","

August 23, 2013.

5. Letter from S. Bahadur, USNRC, to J. Riley, NEI, "Final Safety Evaluation of Nuclear Energy Institute Topical Report NEI 09-10, Revision la, "Guidelines for Effective Prevention and Management of System Gas Accumulation" (TAC NO. ME5291)," March 19, 2013.