ML082880498

Nine-Month Response to NRC Generic Letter 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems'

ML082880498
Person / Time
Site:	Palisades
Issue date:	10/14/2008
From:	Schwarz C J Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-08-001
Download: ML082880498 (18)

Text

Entergy Nuclear Operations, Inc. Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043 Tel269 764 2000 October 14, 2008 10 CFR 50.54(f) U. S. Nuclear Regulatory Commission ATTN: Document Control Desk 1 1555 Rockville Pike Rockville, MD 20852 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Nine-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emer~encv Core Cooling, Decay Heat Removal, and Containment Sprav Svstems"

References:

1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 1 1, 2008 2. Entergy Nuclear Operations, Inc. letter dated May 13, 2008, "Three-Month Response to NRC Generic Letter 2008-01, 'Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"' Dear Sir or Madam, The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 (Reference

1) to request that each licensee evaluate the licensing basis, design, testing, and corrective action programs for the emergency core cooling system, residual heat removal system, and containment spray system, to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified.

GL 2008-01 requested each licensee to submit a written response in accordance with 10 CFR 50.54(f) within nine months of the date of the GL to provide the information summarized below:

a. A description of the results of evaluations that were performed pursuant to the requested actions; b. A description of all corrective actions, including plant, programmatic, procedure, and licensing basis modifications that were determined to Document Control Desk Page 2 be necessary to assure compliance with the quality assurance criteria in Sections Ill, V, XI, XVI, and XVll of Appendix B to 10 CFR Part 50 and the licensing basis and operating license as those requirements apply to the subject systems; and, c. A statement regarding which corrective actions were completed, the schedule for completing the remaining corrective actions, and the basis for that schedule.

In summary, Entergy Nuclear Operations, Inc. (ENO) has concluded that the subject systems at Palisades Nuclear Plant (PNP) are in compliance with the Technical Specification definition of Operability and capable of performing their specified safety function.

PNP is also in compliance with 10 CFR 50, Appendix B, criteria in Section Ill, V, XI, XVI and XVII, with respect to the concerns outlined in GL 2008-01 regarding gas accumulation in the accessible portions of these systems.

In Reference 2, EN0 committed to complete walkdowns of the inaccessible portions of the GL 2008-01 subject systems during the 2009 refueling outage, complete evaluations and provide a supplement to this report within 60 days from startup of that outage describing any remaining corrective actions and their schedule for completion.

EN0 is revising the commitments to complete the evaluations and provide a supplement to this report within 90 days from startup of the 2009 refueling outage describing any remaining corrective actions and their schedule for completion. Enclosure 1 to this letter contains the nine-month response to NRC GL 2008-01 . Enclosure 2 contains new and revised commitments. I declare under penalty of perjury that the foregoing is true and correct.

Executed on October 14,2008 Site Vice President Palisades Nuclear Plant Enclosure CC Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC ENCLOSURE 1 NINE MONTH RESPONSE TO NRC GENERIC LETTER 2008-01, MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING, DECAY HEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMS Entergy Nuclear Operations, Inc. (ENO) is providing this nine-month response to the Nuclear Regulator Commission (NRC) Generic Letter (GL) 2008-01 "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008, for Palisades Nuclear Plant (PNP).

In GL 2008-01, the NRC requested that each addressee evaluate its emergency core cooling system (ECCS), residual heat removal (RHR) system, and containment spray system licensing basis, design, testing, and corrective actions to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified. The following information is provided in this response: a. A description of the results of evaluations that were performed pursuant to the requested actions (see Section A of this enclosure), b. A description of the corrective actions determined necessary to assure compliance with the quality assurance criteria in Sections Ill, V, XI, XVI, and XVII of Appendix B to 10 CFR Part 50 and the licensing basis and operating license with respect to the subject systems (see Section B of this enclosure), and

c. A statement regarding which corrective actions have been completed, the schedule for the corrective actions not yet complete, and the basis for that schedule (see Section B of this enclosure). The following systems were determined to be in the scope of GL 2008-01 for PNP High pressure safety injection (HPSI) system Low pressure safety injection (LPSI) and shutdown cooling (SDC) systems Containment spray (CS) system A. EVALUATION RESULTS I. Licensina Basis Evaluation The PNP licensing basis was reviewed with respect to gas accumulation in the water filled HPSI, LPSI, SDC and CS systems. This review included the Technical Specifications (TS), TS Bases, Operating Requirements Manual (ORM) and ORM Bases, Updated Final Safety Analysis Report (UFSAR), responses to NRC generic Page 1 of 14 communications, regulatory commitments, and Renewed Facility Operating License (RFOL) conditions.

1. Summary of the results of the licensing basis documents review The above documents and regulatory commitments were evaluated for compliance with applicable regulatory requirements. The following is the result of the review. The TS, TS Bases, ORM, ORM Bases, UFSAR, and RFOL conditions contained no requirements for filled components or piping or venting of accumulated gases in the subject systems except for provisions in a TS surveillance requirement and in the TS Bases. The surveillance requirement, SR 3.6.6.3, is to verify the CS piping is full of water to the 735 foot elevation in the CS headers.

The TS requirement is not related to gas accumulation in the system.

The provision is to ensure containment cooling response time is within the analyzed time in the containment response analysis and containment post accident pressure is within the containment design requirements. The surveillance is performed within its 31 -day required frequency.

The review did not identify any specific regulatory commitments including commitments made in response to NRC generic communications with respect to gas accumulation within the HPSI, LPSI, SDC, and CS systems

2. Summary of changes to licensing bases documents (Corrective Actions) The UFSAR will be revised to state that the subject piping systems, including applicable suction and discharge piping, are kept sufficiently filled with water to ensure the systems remain operable and perform properly.

TS improvements are being addressed by the Technical Specifications Task Force (TSTF) to provide an approved TSTF traveler for making changes to TS related to the potential for unacceptable gas accumulation.

The development of the TSTF traveler relies on the results of the evaluations of a large number of licensees to address the various plant designs.

EN0 is continuing to support the industry and Nuclear Energy Institute (NEI) Gas Accumulation Management Team activities regarding the resolution of generic TS changes via the TSTF traveler process.

3. Schedule for addressing changes to licensing bases documents The UFSAR revision described in item 2 above will be updated per 10 CFR 50.71 (e). After approval of the TSTF traveler related to the potential for unacceptable gas accumulation, EN0 will evaluate its applicability to PNP, and evaluate adopting the traveler. These evaluations of the industry TSTF traveler will be completed within three months after NRC approval of the TSTF traveler.

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11. Design Evaluation

1. Summary of Design Basis Review The PNP design basis was reviewed with respect to gas accumulation in the HPSI, LPSI, SDC, and CS systems. This review included design basis documents, calculations, engineering evaluations, and vendor technical manuals. The results of the review identified the following: There are no "keep full systems" at PNP that automatically maintain the subject systems in a filled and vented configuration. The HPSI, LPSI, and CS pumps are located in the lowest level of the auxiliary building to maximize the available net positive suction head (NPSH) for the pumps. Normally, the HPSI, LPSI, (LPSI pumps also perform as SDC pumps) and CS pumps are aligned to the safety injection and refueling water tank (SIRWT) that is located approximately seventy feet above the pumps. At the initiation of containment sump recirculation, following a design basis event, the suction for the pumps is realigned from the SIRWT to the containment sump. The containment sump piping is sloped downward to the pump suctions. Calculations have confirmed that realignment to the containment sump is made when there is sufficient water remaining in the SIRWT to prevent unacceptable vortexing and potential air entrainment. Additionally, engineering analysis demonstrates acceptable operation of the LPSI pumps in the SDC mode at mid-loop operations.

EN0 has contracted a vendor to develop a walkdown procedure, conduct the walkdown, assess the results, analyze for potential void size, evaluate for pressure transients, assess piping systems for structural integrity and develop a report. EN0 is continuing evaluation of the draft report for the outside containment piping assessment at this time.

2. Gas Volume Acceptance Criteria

a. Pump Suction Piping The interim allowable gas accumulation in pump suction piping is based on limiting the gas entrainment to the pump after a pump start.

A Pressurized Water Reactor Owners Group (PWROG) program established interim pump gas ingestion limits. The interim criteria address pump mechanical integrity only and are, for the pump types applicable to PNP, as follows: Page 3 of 14 PNP procedures provide assurance that the volume of gas in the pump suction piping for the subject systems is limited. Qualitative assessments based on system walkdowns and review of piping isometrics show that gas ingestion is limited by the piping arrangements that ensure large quantities of air cannot be trapped. Pump gas ingestion is being evaluated at PNP based on detailed piping survey measurements. The evaluation is being conducted in accordance with the above PWROG program established interim criteria. The PWROG evaluation will be applied in support of system operability until further data supports a change. Steady-State Transient*

QB.E.P. Range Pump Type (transient data)

b. Pump discharge piping that is susceptible to pressure pulsation after a pump start A joint PWROG and Boiling Water Reactor Owners Group program evaluated pump discharge piping gas accumulation. Gas accumulation in the piping downstream of the pump to the first closed isolation valve or the reactor coolant system (RCS) pressure boundary isolation valves will result in amplified pressure pulsations after a pump start. The subsequent pressure pulsation may cause relief valves in the subject systems to lift, or result in unacceptable pipe loads. The joint Owner's Group program establishes a method to determine the limit for discharge line gas accumulation to be used by the member utilities. *The transient criteria are based on pump test data and vendor supplied information.

QB.E.P. = flow at best efficiency point WDF and CA are pump model type designators Single-Stage 2% 5% for 20 sec. 70%-120% WDF The method uses plant specific information for piping restraints and relief valve set points in the subject systems to determine the acceptable gas volume accumulation such that relief valve lifting in the subject systems does not occur and pipe loading is within acceptable limits, i.e., axial forces that are less than the design rating of the axial restraint(s).

Multi-Stage Stiff Shaft 2% 20% for 20 sec. 70%-140% CA EN0 will implement this methodology for PNP and establish the applicable limits for gas accumulation in the discharge piping of the subject systems. PNP procedures combined with qualitative assessments of the piping based on system walkdowns and review of piping drawings provide assurance that any gas accumulation in the subject systems discharge is limited. The joint Owner's Group program methodology will be applied in support of system operability until further data supports a change.

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c. Pump discharge piping that is not susceptible to water hammer or pressure pulsation following a pump start

i. The PWROG methodology for CS evaluates the piping response as the CS header is filled and compares the potential force imbalances with the weight of the piping. The net force resulting from the pressurization of the CS header during the filling transient is a small fraction of the dead weight of the filled piping, and therefore the filling transient is well within the margin of the pipe hangers. The PNP CS system discharge header piping is being evaluated using the PWROG methodology described above. Using this methodology, it is anticipated that the force imbalances on the CS system discharge header piping are well within the margin of the pipe hangers. ii. A PWROG methodology has been developed to assess when a significant gas-water waterhammer could occur during switchover to hot leg injection. The methodology concludes that: If the upstream valve has an opening time of approximately 10 seconds and the downstream path to the RCS is only restricted by check valve(s), no significant waterhammer would occur, i.e., none of the relief valves in the subject systems would lift, or none of the piping restraints would be damaged. The PNP ECCS flow path for switchover to hot leg injection has an upstream valve that has an opening time approximately ten seconds and the downstream path to the RCS is only restricted by check valves. Therefore, consistent with the PWROG program methodology, no significant waterhammer would occur.

EN0 is evaluating the ECCS flow path in accordance with the PWROG methodology to ensure that none of the relief valves in the subject systems would lift, or none of the piping restraints would be damaged under this anticipated waterhammer.

d. RCS Allowable Gas Ingestion The PWROG qualitatively evaluated the impact of noncondensable gases entering the RCS on the ability on the post-accident core cooling functions of the RCS. This evaluation assumed that five cubic feet of noncondensable gas at 400 psig was present in the HPSI discharge piping concurrent with five cubic feet of noncondensable gas at 100 psig in the LPSI discharge piping. The qualitative evaluation concluded that the quantities of gas would not prevent the ECCS from performing its core cooling function.

PNP procedures provide assurance that the gas accumulation is limited in any sections of the LPSI injection system cold leg and hot leg piping based on qualitative assessments of the piping and review of piping drawings. PNP procedures also provide assurance that the gas accumulation is limited in any sections of the HPSl cold leg injection piping based on qualitative assessments Page 5 of 14 of the piping and review of piping drawings. The PWROG evaluation will be applied in support of system operability until further data supports a change.

3. Summary of changes to the design basis documents and the schedule for completion of the corrective actions Palisades design basis documents, including plant drawings, will be revised to incorporate changes for HPSI, LPSl and CS systems resulting from the applicable analyses from GL 2008-01 by the end of 2009. 4. Discussion of the results of the system piping and instrument drawings and isometric drawings reviews to identify all system vents and high points The piping and isometric drawings for the HPSI, LPSI, SDC and CS systems were reviewed to identify vents and high points. Specifically, the following flow paths were reviewed: Safety Injection flow path o SlRWT to the suction of the HPSl and LPSl pumps o HPSl and LPSl pumps to RCS cold legs o Safety injection tanks to the RCS SDC injection and recirculation flow path o SlRWT to suction of LPSl pumps o Containment sump to suction of HPSl and LPSl pumps o LPSl pump discharge to RCS cold legs o LPSl pump discharge crossover return to suction of LPSl pumps o SDC return from RCS hot leg to suction of LPSl pumps CS flow path o SlRWT to suction of CS pumps o CS pump discharge to the motor operated isolation valves o Containment sump to suction of CS pumps Physical walkdowns, discussed in item 6 below, along with a piping elevation survey, were conducted on all piping outside of containment.

Any required changes to plant drawings resulting from the walkdowns will be completed by the end of 2009. The evaluation of the walkdown information is not fully completed.

As identified in the EN0 three-month response to NRC GL 2008-01 for PNP, dated May 13, 2008, EN0 will perform any necessary confirmatory walkdowns of inaccessible piping inside containment during the 2009 refueling outage.

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5. ldentification of new vent valve locations, modifications to existing vent valves, or use of existing vent valves that were previously considered to be inaccessible, based on the drawing review, and summary the corrective actions, and schedule for completion of the corrective actions No new vent locations have been identified. Assessment of the need for additional vents will continue through completion of the evaluation of the containment confirmatory walkdowns and the piping elevation surveys.

6. Discussion of the results (including the scope and acceptance criteria used) of the system confirmation walkdowns that have been completed for the portions of the systems that require venting to ensure that they are sufficiently full of water The walkdowns of the PNP systems included within the scope of GL 2008-01 were performed by a qualified team of people who were trained to the requirements of the walkdown procedure. Piping isometric drawings were used to assist the walkdown team in gathering the information. The scope of walkdowns included determining the slope of the piping and the potential to accumulate gas pockets within the piping. It also included identifying the location and configuration of the existing vents. Relative pipe elevation data was obtained using the ZipLevel Pro 2000 precision altimeter. Based on the calibration report for the ZipLevel measuring device, the instrument accuracy was +I- 0.1 875 inch. The subject piping systems at PNP that are outside of containment are not insulated. Readings were taken directly against the pipe wall. Walkdown of the containment portions of the systems will be done in the 2009 refueling outage.

7. ldentification of new vent valve locations, modifications to existing vent valves, or use of existing vent valves that were previously considered to be inaccessible that resulted from the confirmatory walkdowns, and summary of the corrective actions, and the schedule for completion of the corrective actions No changes to the subject systems have been made at this time. The need for changes for piping outside containment is being analyzed. The need for changes to piping inside containment will be evaluated on completion of the in-containment walkdown and evaluation that will occur during and after the 2009 refueling outage.

8. Discuss the results of the fill and vent activities and procedure reviews for each system (Note that periodic surveillance testing is addressed in the Testing Evaluation section below) Following outages and maintenance activities, operating procedures are used to refill and vent the subject systems. These procedures coupled with surveillance test procedures provide the means to fill and vent the subject systems as well as purge air and other noncondensable gases from associated piping and Page 7 of 14 components. The fill and vent procedures were evaluated to determine if the sequence of steps was effective.

In each case, the sequence of steps was found to be effective. Caution statements are found throughout the procedures identifying steps that could cause possible damage to equipment or air entrainment if not followed correctly.

9. Identification of procedure revisions or new procedures resulting from the fill and vent activities and procedure reviews that need to be developed, and summary of the corrective actions, and schedule for completion of the corrective actions EN0 has not identified the need to develop new procedures. During review of the outside containment walkdown and assessment report of the subject systems, if potential areas of concern are identified, then EN0 would implement necessary actions. These actions may require the development of new fill and vent procedures. Additionally, revisions to the current procedures may include a requirement to perform ultrasonic testing (UT) after the fill and vent is completed to provide additional assurance that systems are sufficiently full of water. 10. Discuss potential gas intrusion mechanisms into each system for each piping segment that is vulnerable to gas intrusion The following potential gas sources and potential gas intrusion flow paths have been identified:

e Vortexing in the SIRWT Vortexing concerns in the suction line from the SIRWT were addressed by an analysis that concluded that pump performance would not be significantly affected by any vortexing that would occur during a loss of coolant accident (LOCA). The normal supply of water to the HPSI, LPSI, and CS pumps is the SIRWT. The source of water for emergency injection is switched from the SIRWT to the containment sump at approximately ten percent of the normal SlRWT level by the recirculation actuation signal (RAS). RAS is designed to protect the HPSI, LPSl and CS pumps from being run dry and to enable these systems to provide a continuous flow of water for core cooling. The RAS trips the LPSI pumps and transfers suction of the HPSI and CS pumps from the SlRWT to the containment sump. RAS logic is initiated by a SlRWT low level. The nominal SlRWT low level set-point for RAS ensures that there is a sufficient water supply in the SIRWT during the approximate one minute time period required to close the SIRWT suction valves and open the containment sump suction valves. The overlapping stroke during the realignment process is provided to allow mixing and assure adequate NPSH during the transfer.

Page 8 of 14 Containment Recirculation Sump Strainer Strainer performance testing addressing GSI-191 is still being evaluated.

Vortexing in the Containment Sump Vortexing concerns in the suction line from the containment sump were resolved in NUREG-0869, "Unresolved Safety Issue A-43 Regulatory Analysis," Rev 1, October 1985. This NUREG stated that the potential safety problems that could result from vortex formation and air ingestion are less than previously hypothesized and no actions are required to limit vortexing in the sump. Safety Injection Tanks The safety injection tanks (SITS) have a nitrogen blanket to keep the tanks pressurized. Plant procedures maintain the SIT pressure by venting the nitrogen if needed. SIT out-leakage can result in nitrogen gas coming out of solution and accumulating in safety injection system lines. This can result in water hammer and gas binding of safety injection system pumps.

If long term SIT out-leakage is noted (over several weeks) by a decreasing tank level trend, a condition report would be initiated in the corrective action program so that the condition may be evaluated by engineering to quantify SIT out-leakage and determine if system venting is warranted. Ongoing Industry Programs Ongoing industry programs are planned in the following areas that may impact the conclusions reached during the design evaluation of PNP relative to gas accumulation.

EN0 participates in and monitors these activities to determine if additional changes to the PNP design may be required or desired to provide additional margin. Gas Transport in Pump Suction Piping The PWROG has initiated testing to provide a better understanding relative to gas transport in large diameter piping. One program performed testing of gas transport in 6-inch and 8-inch piping. Another program will perform additional testing of gas transport in 4-inch and 12-inch low temperature systems and 4-inch high temperature systems. This program will also integrate the results of the 4-inch, 6-inch, 8-inch and 12-inch testing.

Page 9 of 14 Pump Acceptance Criteria Long-term industry tasks were identified that will provide additional tools to address GL 2008-01 with respect to pump gas void ingestion tolerance limits.

12. Items that have not been completed and schedule for their completion The following planned actions are part of the actions not listed in the commitments (in Enclosure 2). These actions support completion of the commitments or are related plans provided here for information. Monitor industry PWROG projects related to gas intrusion issues and incorporate into the Palisades gas intrusion mitigation strategy as applicable. Monitor industry operating experience related gas voiding and evaluate for applicability at Palisades.

Survey, quantify and resolve any identified susceptible voiding areas outside containment. Complete by January 2009.

Review and approve ECCS piping survey report for inside containment. Complete by May 2009.

Survey, quantify and resolve of any identified susceptible voiding areas inside containment. Complete by July 2009. Conduct periodic void surveys for locations that may be vulnerable to gas accumulation and that are not currently examined. Complete by July 2009. Review Operations training programs for normal, abnormal and emergency operating procedures relative to gas accumulation and update to reflect site and industry learning. Complete by August 2009.

Review engineering training programs relative to gas accumulation and update to reflect site and industry learning. Complete by August 2009. Update Design Basis Documents to reflect gas accumulation issues and mitigation strategies. Complete by December 2009.

111. Testing Evaluation

1. Discussion of the results of the periodic venting or gas accumulation surveillance procedure review Page 10 of 14 The PNP TS do not currently have any surveillance requirements for periodic venting of the subject systems.

No TS or other surveillance procedures for periodic venting or gas accumulation currently exist for these systems. Venting only occurs after maintenance, during start-up, or if a potential void is identified.

2. Identification of procedure revisions or new procedures, resulting from the periodic venting or gas accumulation suweillance procedure review, that need to be developed EN0 has not made any changes to PNP procedures resulting from this review and has determined the current procedures provide sufficient barriers to prevent gas intrusion during alignments or system maintenance. However, based on the review EN0 will develop appropriate procedures and administrative controls for the periodic monitoring and trending gas accumulation and capturing the results of venting activities. This will include, as required, documenting the condition in the corrective action program if gas is present, notification to the shift manager, trending of the venting results, evaluation of impact of gas accumulation on system operability and acceptance criteria. Gas void size would be determined by UT and post-venting UT would be performed on locations where voids were present. 3. Discussion of how procedures adequately address the manual operation of the SDC system in its decay heat removal mode of operation Station procedures for SDC operations include appropriate precautions and limitations for recognizing and avoiding potential trapped gases and water hammer in the system. The LPSl suction during normal operation is pressurized at SlRWT static pressure. Once the RCS pressure is decreased to less than 260 psia and temperature is less than 300 degrees F, the SDC isolation valves from the RCS are then opened without starting the SDC pump(s). Pressurizer level is monitored for a potential bubble from the SDC piping. The SDC pump discharge pressure is verified to equal RCS pressure and pump suction is reviewed to prevent steam binding.

After precautions have been checked, a pump is started and flow is established at all four injection valves. At this time, the SDC heat exchangers are vented by slowly opening the SDC heat exchanger outlet valve and monitoring pressurizer level.

When pressurizer level is stable, then the SDC system is placed into service. Plant procedures address loss of SDC scenarios, including system gas and/or steam binding. Instructions identify vent paths and system manipulations necessary to restore normal operations.

4. Summary of the results of the procedure reviews performed to determine that gas intrusion does not occur as a result of inadvertent draining due to valve manipulations specified in the procedures, system realignments, or incorrect maintenance procedures Page 11 of 14 Procedures related to the subject systems for operation, maintenance and testing were reviewed. This review did not identify potential valve manipulations that could result in inadvertent draining or gas intrusion. Caution statements are found throughout the procedures identifying steps that could cause possible damage to equipment or air entrainment if not followed correctly.

5. Description of how gas voids are documented, dispositioned, and trended, if found in any of the subject systems EN0 incorporates manual venting and/or dynamic flushing in operating procedures, thus minimizing the affects of air accumulation when the system is operable. The corrective action process (CAP) is used to document gas intrusion or accumulation issues as potential nonconforming conditions.

This process ensures operability is promptly addressed, a causal evaluation is performed and corrective actions are taken to address the condition and similar conditions.

6. Provide a detailed list of items that have not been completed, a schedule for their completion, and the basis for that schedule The procedures and administrative contrdls described in item A.111.2 above will be developed prior to the 2009 refueling outage.

IV. Corrective Actions Evaluation

1. Summary of the results of the reviews regarding how gas accumulation has been addressed Gas accumulation has been addressed through industry initiatives. Resultant actions from reviews conducted under these initiatives identified the need for several procedure changes and extensive training awareness programs for operators.

Some of the other actions performed as a result of the industry document evaluations at PNP are: Reviews of piping configuration that are susceptible to gas intrusion to identify where gases may accumulate after systems are filled Installation of pump vents on both HPSl pumps and one LPSI pump Initial and continuing training on gas intrusion for personnel responsible for design, performance monitoring, operation and maintenance of safety systems susceptible to gas intrusion Changes to operating and test procedures to provide guidance for gas intrusion detection and removal Page 12 of 14

2. List of items that have not been completed, a schedule for their completion, and the basis for that schedule There are no open corrective actions in the CAP related to known gas accumulation issues in the HPSI, LPSI, SDC, and CS systems at PNP.

Conclusion Based on the evaluations summarized above, EN0 has concluded that PNP is in conformance with its commitments to the quality assurance criteria in 10 CFR 50, Appendix B, Sections Ill, V, XI, XVI, and XVII, as described in the Entergy Quality Assurance Program. B. DESCRIPTION OF NECESSARY CORRECTIVE ACTIONS AND CORRECTIVE ACTION SCHEDULE No immediate corrective actions are required to maintain the subject systems operable. The following items are to be completed:

Complete review and acceptance of the vendor's outside containment walkdown and assessment report by December 2008.

EN0 will make any necessary changes to the fill and vent procedures for the subject systems by February 2009. Prior to the 2009 refueling outage EN0 will develop appropriate procedures and administrative controls for the periodic monitoring and trending gas accumulation and capturing the results of venting activities. This will include, as required, entry into the corrective action process if gas is present, notification to the shift manager, trending of the venting results, evaluation of impact of gas accumulation on system operability and acceptance criteria. Gas void size will be determined by UT and post venting UT will be performed on locations where voids were present. Any new vent valves identified as needed for piping outside of containment will be added during the 2009 refueling outage.

The UFSAR will be revised to state that the subject piping systems are kept sufficiently filled with water to include applicable suction and discharge piping to ensure the system remains operable and performs properly. The UFSAR will be updated per 10 CFR 50.71 (e). Page 13 of 14 EN0 is continuing to support the industry and NEI Gas Accumulation Management Team activities regarding the resolution of generic TS changes via the TSTF traveler process.

After approval of the TSTF traveler related to the potential for unacceptable gas accumulation, EN0 will evaluate its applicability to PNP, and evaluate adopting the traveler. These evaluations of the industry TSTF traveler will be completed within three months after NRC approval.

A joint Owner's Group program evaluated pump discharge piping gas accumulation.

EN0 will implement this methodology for PNP and establish the applicable limits for gas accumulation in the discharge piping of the subject systems. The joint Owner's Group program methodology will be applied in support of system operability until further data supports a change. PNP design basis documents, including plant drawings will be revised to incorporate changes for HPSI, LPSI, SDC and CS systems resulting from the applicable analyses from GL 2008-01 by the end of 2009. Complete the detailed walkdowns for the inaccessible sections of the HPSI, LPSI, SDC, and CS systems prior to startup from the 2009 refueling outage. (Refer to cover letter reference

2) Complete evaluations of GL 2008-01 subject systems within 90 days following the completion of the 2009 refueling outage.

Any other corrective actions that are identified during the 2009 refueling outage that cannot be completed during the outage will be implemented prior to restart following the 201 0 refueling outage. (Refer to cover letter reference

2) EN0 will provide a supplemental submittal within 90 days of the completion of the 2009 refueling outage describing any remaining corrective actions and their schedule for completion.

CONCLUSION EN0 has reviewed the system operating procedures, system surveillance procedures, system operation, design information, and previous evaluations of gas intrusion for those PNP systems that perform the functions described in this GL and has concluded that these systems are operable as defined in the PNP TS and are in conformance to our commitments to the applicable General Design Criteria, as stated in the PNP UFSAR. There are no known gas voiding issues in these subject systems. This conclusion applies to both the portions of the systems that have been walked down and the inaccessible portions of the systems yet to be walked down in the 2009 refueling outage. Page 14 of 14 ENCLOSURE 2 NINE MONTH RESPONSE TO NRC GENERIC LETTER 2008-01, MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING, DECAY HEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMS LIST OF REGULATORY COMMITMENTS Page 1 of 2 NEW COMMITMENTS Complete review and acceptance of the vendor's outside containment walkdown and assessment report.

EN0 will make any necessary changes to the fill and vent procedures for the subject systems.

EN0 will develop appropriate procedures and administrative controls for the periodic monitoring and trending gas accumulation and capturing the results of venting activities. This will include, as required, entry into the corrective action process if gas is present, notification to the shift manager, trending of the venting results, evaluation of impact of gas accumulation on system operability and acceptance criteria. Gas void size will be determined by ultrasonic examination (UT) and post venting UT will be performed on locations where voids were present. Any new vent valves identified as needed for piping outside of containment will be added.

The UFSAR will be revised to state that the subject piping systems are kept sufficiently filled with water to include applicable suction and discharge piping to ensure the system remains operable and performs properly.

SCHEDULED COMPLETION DATE December 2008 February 2009.

Prior to the 2009 refueling outage Prior to startup from the 2009 refueling outage The UFSAR will be updated per 10 CFR 50.71 (e).

ONE-TIME ACTION X X X X X TYPE CONTINUING COMPLIANCE Page 2 of 2 Evaluation of the industry TSTF traveler will be completed within three months after NRC approval.

Implementation will be as needed By the end of 2009. EN0 is continuing to support the industry and NEI Gas Accumulation Management Team activities regarding the resolution of generic TS changes via the TSTF traveler process. After approval of the TSTF traveler related to the potential for unacceptable gas accumulation, EN0 will evaluate its applicability to PNP, and evaluate adopting the traveler. A joint Owner's Group program evaluated pump discharge piping gas accumulation.

EN0 will implement this methodology for PNP and establish the applicable limits for gas accumulation in the discharge piping of the subject systems. The joint Owner's Group program methodology will be applied in support of system operability until further data supports a change. PNP design basis documents, including plant drawings will be revised to incorporate changes for HPSI, LPSl and CS systems resulting from the applicable analyses from GL 2008-01. X X X SCHEDULED COMPLETION DATE Within 90 days of the completion of the 2009 refueling outage. Within 90 days of the completion of the 2009 refueling

outage. REVISED COMMITMENTS Complete evaluations of inaccessible sections of the GL 2008-01 subject systems following the 2009 refueling outage detailed system walkdowns.

EN0 will provide a supplemental submittal describing any remaining corrective actions and their schedule for completion.

TYPE ONE-TIME ACTION X X CONTINUING COMPLIANCE