ML082910042
| ML082910042 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 10/13/2008 |
| From: | John Carlin Constellation Energy Group, Ginna |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-08-001 | |
| Download: ML082910042 (16) | |
Text
John Carlin R.E. Ginna Nuclear Power Plant, LLC Site Vice President 1503 Lake Road Ontario, New York 14519-9364 585.771.5200 585.771.3943 Fax John.Carlin@constellation.com 0
Cnstellation Energyl Nuclea Gr.oup October 13, 2008 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk
SUBJECT:
R.E. Ginna Nuclear Power Plant Docket No. 50-244 Nine-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"
REFERENCES:
(a)
NRC Generic Letter 2008-01, January 11, 2008, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" The Nuclear Regulatory Commission (NRC) issued Generic Letter 2008-01 (Reference a) to request that each licensee evaluate the licensing basis, design, testing, and corrective action programs for the Emergency Core Cooling systems, Decay 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.
The generic letter requested each licensee to submit a written response in accordance with 10 CFR 50.54 (f) within nine months of the date of the generic letter (October 11, 2008). The requested information is presented in Attachment (1). Also requested was a 3-month letter stating what actions required by the generic letter would not be complete by the due date of the nine-month letter. All actions required by the generic letter to be complete by October 11, 2008 were anticipated to be complete; therefore a three-month letter was not submitted.
Attachment (2) contains regulatory commitments identified in this letter.
Should you have any questions regarding the information in this submittal, please contact Mr.
David Wilson at 585.771.5219 or David.F.Wilson(@Constellation.com.
- Vyours, QCJW aýrin I oQaOcý
Document Control Desk October 13, 2008 Page 2 STATE OF NEW YORK COUNTY OF WAYNE
- TO WIT:
I, John T. Carlin, being duly sworn, state that I am Vice President, R.E. Ginna Nuclear Power Plant, LLC (Ginna LLC), and that I am duly authorized to execute and file this request on behalf of Ginna LLC.
To the best of my knowledge and belief, the statements contained in this document are true and correct.
To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Ginna LLC employees and/or consultants. Such information has been reviewed in acc
- ance with company practice and I believe it to be reliable.
Subscribed and sworn before me, a Notary Public in anvor the State of New York and County of IAGOnOc
_,this 1 "3 day of C
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(, 2008.
WITNESS my Hand and Notarial Seal:
My Commission Expires:
Date N
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I SHARON L. MILLER Notary Public, State of New York Registration No. 01MI6017755 Monroe County
,,ommission Expires December 21, 20 1o
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JC/MR Attachments: (1)
R.E. Ginna 9 Month Response to Generic Letter 2008-01 (2)
List of Regulatory Commitments cc:
D. V. Pickett, NRC S. J. Collins, NRC J. P. Spath, NYSERDA Resident Inspector, NRC (Ginna)
P. Eddy, NYS Dept. of Public Services
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 R.E Ginna October 13, 2008
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 This attachment contains the R.E. Ginna Nuclear Power Plant (Ginna) nine-month response to Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems."
The following information is provided in this response:
a) A description of the results of evaluations that were performed pursuant to the actions requested by the generic letter. This description includes information to demonstrate compliance with the quality assurance criteria in Sections III, V, XI, XVI, and XVII of Appendix B to 10 CFR Part 50 and the licensing basis and operating license.
b) A description of any corrective actions that were determined necessary to ensure compliance with the quality assurance criteria in Sections III, V, XI, XVI, and XVII of Appendix B to 10 CFR Part 50 and the licensing basis and operating license with respect to the systems in question, 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.
The following systems (hereinafter referred to as the "subject systems") were determined to be in the scope of the generic letter for Ginna:
" Safety Injection System (SI)
Residual Heat Removal System (RHR)
Containment Spray System (CS)
For the purposes of this submittal, the term Emergency Core Cooling System (ECCS) refers to the combination of the SI and RHR systems in the emergency injection or emergency recirculation alignment.
Based on the below information, the subject systems at Ginna are in compliance with the Technical Specification definition of Operable, i.e., capable of performing their intended safety function, and that Ginna is currently in compliance with 10 CFR 50, Appendix B, Criterion III, V, XI, XVI and XVII, with respect to the concerns outlined in GL 2008-01 regarding gas accumulation in the subject systems.
LICENSING BASIS EVALUATION The Ginna licensing basis was reviewed with respect to gas accumulation in the SI, RHR, and CS systems. This review included the Technical Specifications (TS), TS Bases, Updated Final Safety Analysis Report (UFSAR), the Technical Requirements Manual (TRM) and TRM Bases, responses to NRC generic communications, NRC Commitments, and License Conditions. The review verified that the quality assurance requirements and design criteria applicable to gas management in the subject systems, as discussed in the "Applicable Regulatory Requirements" section of GL 2008-01, were maintained. There are no periodic venting requirements in the Ginna current licensing basis (CLB).
1
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01
- 1. TS and TS Bases:
Standard Technical Specifications Westinghouse Plants, NUREG-1431, Surveillance Requirement (SR) 3.5.2.3, which verifies that the ECCS piping is full of water, is not included in the Ginna TS. Ginna's TS were converted to improved technical specifications with Amendment 61. Since SR 3.5.2 was bracketed in NUREG-1431, and the requirement was not included in the original TS, the surveillance was not included in the Ginna conversion.
Rather, the more generic definition of operability listed in TS 1.1, Definitions, is applied.
Although no specific requirement for minimum voiding is indicated, and voiding is not specifically discussed in the bases for operability of the ECCS trains, it is inherent in the definition of OPERABLE that voiding sufficient to prevent the system from delivering the flow assumed in the safety analysis, and thereby performing its safety function, would result in the system being inoperable.
The Bases for TS Section 3.5.4 discusses Refueling Water Storage Tank (RWST) volume by stating: "Insufficient water in the RWST could result in inadequate NPSH for the RHR pumps when the transfer to the recirculation mode occurs."
The TRM does not currently address gas accumulation issues. No change is anticipated at this time.
- 3. UFSAR:
The UFSAR was reviewed for information on Gas voiding. The following sections contain information relevant to GL 2008-01:
" Section 5.4.5.4 discusses the actions associated with Generic Letter 1988-17 (Reference 1). This section contains information on Generic Letter requirements, containment closure, instrumentation, mitigation equipment, procedures and analysis.
Section 6.3.3.9 discusses the actions associated with Generic letter 97-04 (Reference 2).
The NPSH for the Safety Injection Pumps, RHR Pumps and Containment Spray Pumps is discussed in Section 1.8.1.1.
" The RHR NPSH requirements associated with Generic Letter 04-02 (Reference 3) are discussed in section 6.3.2.
The possibility of water hammer in the RHR system during a LOCA in Mode 4 is discussed in Section 6.3.3.11.
No deficiencies were found that required immediate revision to the UFSAR.
2
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01
- 4. Correspondence:
A search and review of regulatory correspondence related to gas intrusion into plant systems was performed. Specific correspondence was primarily related to Generic Letter 1988-17 (Reference 1) and Generic Letter 97-04 (Reference 2). All regulatory commitments identified in this correspondence were closed. There were no issues identified as a result of this review.
A search of regulatory commitments related to the issues addressed in GL 2008-01 was performed. Other than those identified in the above correspondence related to GL 1988-17 and GL 97-04, no additional regulatory commitments were identified.
- 6. Licensing Bases Pending Corrective Actions:
- a. Upon completion and approval of the new industry generic Technical Specifications currently under development by the Tech Spec Task Force, Ginna will review these requirements and submit a License Amendment Request as appropriate. See Commitment 2, Attachment 2, List of Regulatory Commitments.
- b. Until we have reviewed the new generic Technical Specifications, Ginna will develop and implement interim surveillance measures in owner-controlled document(s) to address gas accumulation management in the subject systems. See Commitment 1, Attachment 2, List of Regulatory Commitments.
DESIGN EVALUATION The Ginna design basis was reviewed with respect to gas accumulation in the SI, RHR and CS Systems. This review included Design Basis Documents, Calculations, Engineering Evaluations and Vendor Technical Manuals.
- 1. Design Basis Documents The UFSAR defines the ECCS as RHR (Low Head Injection) and SI (High Head Injection).
RHR is also the decay heat removal system. The UFSAR assumes at least one train for each of the three systems (RHR, SI, and CS) to be available and able to perform its safety function.
Seismic Isometric and Piping & Instrument Drawings (P&ID) were reviewed for as built configuration. The isometric and P&ID review identified several discrepancies between the isometric drawings and the P&IDs. Typical errors on the isometric drawings were detail labeling errors, valve labeling, and valve location. Typical errors on the P&IDs were mislabeling of vent lines as drain lines and the order of piping connection along a horizontal run. These errors have been entered into the Corrective Action Program (CAP).
System operating and maintenance procedures were reviewed for consistency with design requirements and adequacy in addressing system voids. This review yielded several 3
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 opportunities for procedural enhancement, the most common of which were improvements in the venting of systems, the venting process, and the flushing of systems, which were captured in the CAP. Procedure Change Requests (PCRs) have been drafted. The operations test procedures also yielded many opportunities for enhancements. The most common changes are to ensure segments of piping are refilled after containment isolation valve leak rate testing. Some of the refilling process will be enhanced by linking the test procedure to the system alignment procedure, ensuring the system is flushed or fully vented prior to declaring the system operable. These deficiencies were captured in the CAP. See Commitment 3, Attachment 2, List of Regulatory Commitments.
Review of the above documents and drawings indicates that the RHR, SI, and CS are interconnected through the RWST and the RHR supply to the SI and CS for Containment Sump Recirculation phase of an accident. Portions of the Chemical and Volume Control System (CVCS) and part of the waste processing system (in particular portions connecting to the Reactor Coolant Drain Tank pumps) are also connected to the subject systems.
The pump vendor manuals were reviewed but lacked the detail to provide acceptance criteria for the generic letter evaluation.
Ginna uses a common Constellation fleet design process when making design changes to plant systems. The process is being revised to address gas intrusion issues, and is currently scheduled to be complete in May, 2009.
- 2. Design Calculations Design analysis was previously performed to address concerns of NRC Information Notice (IN) 2006-21 for high pressure containment atmosphere leaking into the ECCS and/or CS systems through valves. This analysis determined that the only system directly impacted by this source of gas is the RHR system through the pipe connections to Containment Sump
'B'. The analysis concluded that air in containment can not leak into the RHR system before the Sump 'B' suction lines are covered with water. Gas intrusion from containment atmosphere is not of concern at Ginna for the subject systems.
Design analyses were reviewed to ensure potential sources of gas introduction have been addressed. There are two primary sources of water for the RHR, SI, and CS systems. The two primary sources of water are the RWST and the containment sump (Sump 'B'). RHR has a third source of water for its Shutdown Cooling (Decay Heat Removal) function, as it takes suction from the RCS for shutdown cooling purposes. CS also has a third source of water for addition of sodium hydroxide (NaOH). The analysis for RWST, Sump 'B', and RCS suction sources address vortex formation, and the procedures reflect the assumptions in the analysis. NaOH tank vortexing was not addressed in the analysis at the time of the review.
This deficiency was entered into the CAP and vortexing has since been addressed in the analysis. Currently all sources of water for the subject systems (RHR, SI, and CS) have procedure guidance to preclude the formation of a vortex, therefore gas intrusion from vortex formation is precluded at Ginna for the subject systems.
The change over from the injection phase of an accident to the recirculation phase has been evaluated in current analyses to preclude the introduction of voids into the subject systems by maintaining sufficient water levels in the RWST and Sump B during the transfer.
4
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01
- 3. Engineering Evaluations Evaluation of potential -gas sources To determine the scope and areas for Ultrasonic Testing (UT) inspection, Engineering evaluated the possible sources of gas intrusion into the systems of concern. The potential sources of gas for Ginna systems are:
" Vortex formation - In addition to the calculations discussed above, vortex formation is precluded at Ginna by site controls on water levels including level instrument uncertainty.
" Containment air inleakage - Containment air inleakage is not a concern since the only connection to containment Sump 'B' is covered with water before containment air pressure is higher than the static RWST pressure on the interfacing valves.
Back leakage from the RCS - Back leakage from the RCS is a potential source of gas for Ginna. The Inservice Testing (IST) Program allows for a higher leak rate from RCS boundary valves than can be tolerated over an 18 month refueling cycle. The locations subject to potential back leakage from the RCS were part of the 2008 Spring Outage inspection locations. The only void found was in a vent line where the most probable source of the gas is containment atmosphere from low loop operations conducted in a previous outage. Procedure improvements are being tracked in the CAP and potential plant modifications are being tracked by internal site tracking processes.
" Back leakage from the SI accumulators - Back leakage from the SI accumulators is a possible concern for Ginna. The locations subject to potential back leakage from the SI accumulators were part of the Spring 2008 Outage inspection locations. No voids were found from this source of gas. Since the potential for back leakage still exists, procedure changes were entered into CAP and potential plant modifications are being tracked by internal site tracking process.
Induced gas from maintenance and testing - Maintenance and testing activities during the Spring 2008 Outage on the subject systems were reviewed. Work Orders (WO) that could have introduced voids were selected for follow-up UT inspections. Some voids were found. The details on these voids are described in Section "Method of evaluation of areas of concern." Site procedures governing the initial review of WOs, WO Planner Guidance, Senior Reactor Operator Review, and System Engineer Guidelines will be changed to ensure WOs that have the potential for introducing voids into the subject systems receive a special indicator for identification, have a more focused fill and vent process, more explicit guidance for filling and venting, and have a follow up UT to confirm system is properly filled and vented. In the interim, the organization is sensitized to the GL 2008-01 issues and the need to ensure the systems are filled and vented after these activities. See Commitment 3, Attachment 2, List of Regulatory Commitments.
Vacuum dragging through instrument lines - Vacuum dragging through instrument lines is not a concern at Ginna. The RWST provides sufficient static head to ensure pressure inside the system is greater than atmospheric pressure.
5
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01
" Leakage from Air Operated Valves (AOV) - Leakage from AOVs is not a concern at Ginna. AOVs utilized on the subject systems (RHR, SI, and CS) do not create the possibility for instrument air (IA) to leak into the systems.
" Gas out of solution - Gas coming out of solution after shutdown cooling is isolated and cooled could potentially impact Ginna. If this condition existed at Ginna, then the shutdown cooling flow path should contain many voids. However, UT results before initiating shutdown cooling during the 2008 Spring Outage did not find any voids in the shutdown cooling flow path that had been isolated the previous outage. There is some internal experience documented in the CAP for abnormal sounds and pipe movements during the first RHR pump performance test following the 2008 Spring Outage. The sounds indicate possible voids traveling through the system. Although not positively identified, the likely source of these voids is degassing occurring in the RHR heat exchangers and then being swept through the system. No degradation to pump performance was observed and the pump passed its acceptance criteria. Any potential void is swept to the RWST at the end of the performance test during a high flow portion of the test. Procedure changes will be implemented to flush this segment of piping prior to declaring the RHR system operable. See Commitment 3, Attachment 2, List of Regulatory Commitments.
Drain back - Air entering the subject systems from the draining back of the system to the RWST is not a concern at Ginna. The RWST minimum water level is much higher than the system piping. This provides enough pressure to make water leak out of the subject systems, but no air can leak into the systems. During outages the RWST may be at reduced levels. In this case, the systems are restored through the system alignment procedures before they are declared operable.
" Air entrainment - Air entrainment created when the SI pump recirculation flow falls and impacts the water surface in the RWST is not a concern at Ginna. Evaluations documenting that this phenomena does not challenge the ECCS or CS systems have been completed.
In summary, Ginna is susceptible to the following gas sources: back leakage from the RCS, back leakage from the SI accumulators, maintenance, testing, and from cooling down and depressurizing after isolating shutdown cooling. The CS discharge piping was excluded from further evaluation due to the system being open to containment atmosphere. This is confirmed by an analysis that determined peak loads from the potential pressure pulsations in the CS pump discharge piping do not challenge operability.
Method of evaluation of areas of concern The Isometric and P&ID drawings were utilized to determine potential gas collection locations from the susceptible gas sources for the subject systems. Typical areas selected for further examination are behind isolation valves, long runs of horizontal pipe, and most of the horizontal Shutdown Cooling piping. This set of pipes was broken down into 87 pipe segments to allow for easy identification and tracking. Ginna then surveyed each horizontal segment of pipe to locate local high points. Walkdowns were also performed to verify that the subject systems are designed per the appropriate drawings and design documents.
Table 1 summarizes the system high points identified as a result of this review.
6
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 Ginna currently uses NUREG/CR -2792, owner groups' guidance, and/or vendor supplied evaluations to accept voids. Voids in the piping of the subject systems will be addressed on an as-needed basis. Ginna plans to utilize current industry guidelines for the acceptable volume of non-condensable gas injected into the RCS. Additional guidance from ongoing industry efforts to address acceptable gas volumes in the subject systems will be considered in future evaluations as appropriate.
Ginna performed 152 UT examinations just prior to and immediately following the reactor shutdown for the 2008 Spring Outage. Locations behind check valves leading to the RCS were inspected first to ensure RCS remained at normal operating pressure. These UT inspections found four (4) voids. Each void was entered into the CAP at the time of discovery.
" One void was confined to vent valve piping below the vent valve. Historically Ginna does not open this valve. When the reactor is taken to reduced inventory air can become trapped in this location and will remain. This void does not challenge operability because of the location and small size. Procedures were changed to vent this location.
" Another void was found between the RHR pump discharge cross connect isolation valves. This void does not challenge operability because the void was trapped between closed valves. The source of this void is not yet understood. Ginna is planning to inspect this location, online later this cycle and again during the Fall Outage in 2009.
This void was flushed during normal alignment of RHR for Shutdown Cooling.
" The remaining two (2) voids were found in the RHR suction piping from Containment Sump 'B'. The voids are in a section of piping between the penetrations from containment and the containment isolation boundary valves outside of containment. The RHR suction piping from containment is designed with a down slope to the RHR pumps.
This segment of pipe is normally left open to containment atmosphere. This allows the gas to flow up and out to containment atmosphere as Sump 'B' fills. The presence of this void confirms the proper pitch of Ginna's Sump 'B' suction valves (if it was pitched incorrectly, the pipes would have been completely empty). There will be some residual voids remaining after the suction piping is filled. These voids are small and have been accepted in Ginna's design basis through design analysis. These voids do not challenge operability.
Table 1 Summary Table of pre Outage UT Evaluations Number of Pre-Outage Comments System Piping Location survey (UT)
UT Findings locations One non-bounding CS NaOH supply Line 12 No Voids location was not inspected CS CS pump suction 2
No Voids header 7
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 Number of Pre-OutageCr n
System Piping Location survey (UT)
UT Findings Comments locations SI and CS and SI pump 2
No Voids CS suction from the RWST SI SI pump suction 9
No Voids headers SSI I pump discharge 33 No Voids piping SI Behind potential back 13 No Voids leakage SI valves Entered into Corrective SI valves 4
1 Void Found Action Program, no system impact RHR pump suction 2 Voids Entered into Corrective RHR from Containment 7
Found Action Program, no Sump system impact RHR RHR pump suction 4
No Voids RWST header RHR pump suction RHR Shutdown Cooling 3
No Voids header RHR RHR pump suction 2
No Voids common piping Void entered into Corrective Action Program, no system impact.
RHR RHR discharge piping 31 1 Void Found One pipe not surveyed, entered into Corrective Action Program, bounding piping had no evidence of void RHR Shutdown Cooling 3
No Voids discharge piping RHR Interconnected system 4
No Voids piping RHR Behind potential back 10 No Voids leakage RHR valves 8
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 Number of Pre-Outage Comments System Piping Location survey (UT)
UT Findings locations RHR RHR supply to SI and 13 No Voids CS pumps Totals 152 4 Voids Certain locations were not inspected during the initial effort as indicated below:
One pipe segment inside containment was not surveyed or inspected because the insulation was suspected to contain asbestos. The inability to inspect this pipe was entered into the CAP. This segment is part of the RHR core deluge injection into the reactor vessel. There are two RCS isolation valves downstream of this segment of pipe.
The insulation around the valves was able to be removed. UT inspections were preformed behind the check valve and isolation valve. The check valve is located in a vertical segment of pipe closest to the RCS, ensuring the detection of any gas voids.
The segment of pipe behind the isolation valve was surveyed with a torpedo level (hand level) and the bubble was between the lines, with a slight favor to the asbestos insulation side. The slight favor would allow any voids generated from slow leakage through the check valve and isolation valve to be detected (trace voids would be found). If there was a high leakage rate through the check and isolation valves, then voids would have been found throughout the piping system. The UT inspections on both ends of the asbestos covered segment showed no evidence of voids. Therefore, there is reasonable assurance that this segment of piping is void free. This segment of pipe gets routinely flushed during outages.
One UT location was not surveyed on a piping segment due to elevated dose rates in the Non-Regenerative Heat Exchanger Room as the Letdown System (Chemical and Volume Control System) was being aligned for the Spring Outage. Evaluation of the pipe slope indicated that the high point was not at this location. Based on the UT results from the identified high point and other locations and the general slope of the pipe, there is reasonable assurance that there is no void at this location.
The RHR heat exchanger tubes are local high points that can not be inspected without opening the shell side of the heat exchanger. The flow through these tubes during quarterly pump tests is sufficient to flush any voids that may be present to the RWST where they can rise to the top of the tank.
Subsequent to the spring outage maintenance, and prior to start up, the Work Orders (WOs) that were executed on the subject systems were reviewed. Any WO that could cause voids to enter the subject systems had a follow up UT inspection on surrounding local high points.
As a result of these inspections three voids were discovered and entered into the CAP.
Extensive voiding was discovered in-the SI system discharge piping. The cause of this extensive voiding was a combination of outage maintenance and inservice testing (IST) procedures. Maintenance was conducted on some portions of the system inside containment, while the IST program conducted leak rate tests on the outside of 9
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 containment portion. The resulting effect was the SI discharge piping was drained, while the suction side was confirmed to be full of water. There were no steps to vent or fill the SI piping in the IST procedures. Attempts to vent the system were ineffective due to local high points and limited number of vent valves. The SI system was restored by a controlled full flow flush to the RCS. Ginna specific operating experience has shown that the high flow rates obtained during this flush adequately sweep the existing voids to ensure operability. A void still remains in the SI Accumulator Test line near the relief valve for that segment of the system. This segment of the system is normally isolated and not relied on for accident mitigation. This void does not challenge system operability. Procedure changes will be implemented to address the inadequacies in the IST procedures. See Commitment 3, Attachment 2, List of Regulatory Commitments.
A void was discovered in the SI Accumulator test line outside of containment. This void's location only interfaces the SI and CS pumps' recirculation line back to the RWST high in the RWST. Operating Experience from quarterly pump testing conducted after the void was detected demonstrates that this void does not impact system performance.
If the void was to move it would be discharged to the atmosphere of the RWST. This void does not challenge operability.
A void was discovered in one of the SI Accumulator's fill lines. This void is not located in the main ECCS flow stream. A breakdown orifice, elevation drop, and many feet of pipe separate this void from the main ECCS flow stream. If this void was to migrate it would be during a SI Accumulator filling sequence where the void would be transported to the SI Accumulator void space. This void does not challenge system operability.
SURVEILLANCE TESTING PROCEDURE EVALUATION Ginna does not currently have a periodic surveillance requirement to verify the systems are sufficiently full of water. As can be seen from the above evaluation, Ginna does not have operability concerns resulting from gas intrusion into the systems addressed by GL 2008-01.
However, as a conservative measure, Ginna will develop an appropriate administrative surveillance requirement and procedure(s) to implement that requirement. In addition to describing the process for performing the surveillance, the procedure(s) will describe how gas voids are documented, dispositioned, and trended, if found in any of the subject systems. See Commitment 1, Attachment 2, List of Regulatory Commitments.
CORRECTIVE ACTION EVALUATION
- a. Results of reviews regarding how gas accumulation has been addressed at Ginna.
The Ginna CAP is used to document gas intrusion/accumulation issues as potential nonconforming conditions. Current procedures do not establish a specific threshold for documenting gas accumulation issues.
Current CAP procedures do require that any condition adverse to quality to be reported and entered into the corrective action program. Additionally, such conditions are also to be reported to the Shift Manager. Therefore, current generic station guidance implies that abnormal venting results or pipe void identification would be reported and evaluated in 10
ATTACHMENT (1)
R.E. GINNA 9 MONTH RESPONSE TO GENERIC LETTER 2008-01 accordance with the CAP which ensures those conditions are evaluated for potential impact on the station including system Operability. Therefore, Ginna's review concluded that issues involving gas intrusion/accumulation are properly prioritized and evaluated under the Corrective Action Program.
- b. Actions Actions to improve identification and reporting of gas accumulation issues are planned. This will be accomplished by incorporating specific guidance into applicable operating and test procedures for the subject systems that would provide station personal specific guidance for determining when to enter gas accumulation issues into the Corrective Action Program.
See Commitment 1, Attachment 2, List of Regulatory Commitments.
SUMMARY
Ginna has completed the evaluations required by GL 2008-01. No immediate operability issues were discovered during that evaluation. However, several opportunities for enhancement and improvement were identified. These were entered in the CAP, and either are complete or will be addressed per normal station processes. Those actions committed to in this letter are listed as regulatory commitments in Attachment 2.
REFERENCES
- 1.
NRC Generic Letter 1988-17, dated October 17,1988, "Loss of Decay Heat Removal"
- 2.
NRC Generic Letter 97-04, dated October 7, 1997, "Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps"
- 3.
NRC Generic Letter 2004-02, dated September 13, 2004, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors" 11
ATTACHMENT (2)
LIST OF REGULATORY COMMITMENTS R.E. Ginna October 13, 2008
ATTACHMENT (2)
LIST OF REGULATORY COMMITMENTS The following table identifies actions committed to in this document by R.E. Ginna NPP, LLC.
Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments. Direct any questions regarding these commitments to David Wilson at 585.771.5219, or David.F.Wilson(aConstellation.com.
Regulatory Commitment Due Date
- 1. Ginna will develop an appropriate March 31, 20091 administrative surveillance requirement and procedure(s) to implement that requirement.
In addition to describing the process for performing the surveillance, the procedure(s) will describe how gas voids are documented, dispositioned, and trended, if found in any of the subject systems.
- 2. Upon completion and approval of the new Upon NRC approval and issuance of the TSTF industry generic Technical Specifications Traveler.
currently under development by the Tech Spec Task Force, Ginna will review these requirements and submit a License Amendment Request as appropriate.
- 3. Complete the required changes to the January 31, 20092 operations, maintenance and test procedures.
1The Basis for the completion date is the time required to determine the appropriate surveillances to be performed and the applicable acceptance criteria. After the criteria are determined, additional time is required for procedure development and training. This is considered reasonable since Ginna did not identify any mechanism of gas intrusion to the suction side of the of the subject systems during normal operation, and only limited mechanisms on the discharge side.
2The basis for the completion date is the time required for drafting and processing of the changes, and training. The changes are being prioritized to support the need for the specific procedures to support plant operation.
1