Text

Ninety-Day Supplemental Response to NRC Generic Letter 2008-01 (Charging System Walkdown), Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems.
	ML091750097
Person / Time
Site:	Saint Lucie
Issue date:	06/17/2009
From:	Johnston G; Florida Power & Light Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	GL-08-001, L-2009-142
	Download: ML091750097 (10)
	v • d • e

Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 0 June 17, 2009 F IPIL .. L-2009-142 10 CFR 50.4 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike, Rockville, MD 20852 Re: St. Lucie Unit I Docket No. 50-335 Ninety-Day Supplemental Response to NRC Generic Letter 2008-01 (Unit I Charging System Walkdown), "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"

References:

1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated January 11, 2008.

2. FPL Letter L-2008-070, Three-Month Response to NRC Generic Letter 2008-01 "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated May 12, 2008.

3. FPL Letter L-2008-221, Nine-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated October 14, 2008.

4. St. Lucie Units I and 2 - Re: Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" Proposed Alternative Course of Action dated September 24, 2008.

5. FPL Letter L-2009-034, Ninety-Day Supplemental Response to NRC Generic Letter 2008-01 (following the Unit 1 Fall 2008 Refueling Outage), "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated February 9, 2009.

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 systems (ECCS), decay heat removal (DHR) 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.

As requested in Reference 1, Florida Power & Light (FPL) provided a nine month response letter (Reference 3). Additionally, after the St. Lucie Unit 1 refueling outage, FPL provided a 90-day post outage response (Reference 5) as committed in References 2 and 3. After the 90-day post outage submittal, FPL determined that some actions deemed necessary to address the issues requested in the GL had not been.completed. Specifically, walkdowns of portions of the St.

A1IL5 an FPL Group company

L-2009-142 Page 2 Lucie Unit 1 charging system had not been completed as intended. This supplemental response describes the results of the additional actions that were performed with respect to the Unit 1 charging system.

In summary, FPL has concluded that the subject systems and functions at St. Lucie are operable and that St. Lucie is currently in compliance with the licensing basis documentation and applicable regulations, including 10 CFR 50 Appendix B, Criteria III, V, XI, XVI, and XVII, with respect to the concerns outlined in GL 2008-01.

There are no revisions to regulatory commitments previously made by FPL for St. Lucie in this letter and this letter does not contain any new NRC commitments.

The attachment to this letter contains the FPL supplemental response to NRC GL 2008-01 for portions of the St. Lucie Unit I charging system.

Please contact Ken Frehafer at (772) 467-7748 if you have further questions regarding this matter.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on 2009.

Very truly yours, CGordon L. Johnstol Site Vice President St. Lucie Nuclear P GLJ/KWF Attachment

St. Lucie Unit 1 L-2009-142 Docket No. 50-335 Enclosure 1 Page 1 of 8 St. Lucie Unit 1 Supplemental Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" (St. Lucie Unit 1 Charging System)

This attachment provides a supplemental response to Generic Letter (GL) 2008-01 for actions that were performed subsequent to the last St. Lucie Unit I refueling outage for the charging system.

The following information is provided in this attachment:

a) A description of the results of evaluations that were performed pursuant for GL 2008-01 on the previously incompleted activities, such as system piping walkdowns and ultrasonic testing, at St. Lucie Unit I (see Section A of this attachment).

b) A description of any additional commitments determined necessary to assure compliance with the quality assurance criteria in Sections III, V, XI, XVI, and XVII of Appendix B to CFR Part 50 and the licensing basis and operating license with respect to the subject systems, including a schedule and a basis for that schedule (see Section B.l of this attachment).

The original conclusions documented in the nine-month response with respect to the licensing basis evaluation, testing evaluation, and corrective action evaluations have not changed. This supplement will only discuss the results of design evaluation reviews associated with walkdowns of previously uncompleted activities.

St. Lucie Unit I L-2009-142 Docket No. 50-335 Enclosure 1 Page 2 of 8 A. EVALUATION RESULTS

1. Design Basis Documents As discussed in Reference 3, the Unit I charging system is included within the scope of GL 2008-01 as it is credited in the small break loss of coolant accident (SBLOCA) accident analysis. The evaluation principally focuses on the charging pump suction piping from the inventory sources credited in the SBLOCA analysis to preclude gas binding. The design basis evaluation of this system has not changed since Reference 3 and Reference 5 were submitted. The evaluation has been revised to confirm a maximum 20% void fraction is provided upstream of the vertical pump suction down-legs to support self-venting criteria.

Principal revisions to the evaluation address results of the recent Unit 1 charging system walkdowns, determination of maximum potential void sizes, results of ultrasonic testing (UT) inspections, and recommendation for an additional vent valve. The walkdown and UT results are summarized in Sections A.2 and A.3 below.

2. Confirmatory Walkdowns As stated in Reference 3, the purpose of system walkdowns was to determine the true system high and low points for each horizontal run of piping in the subject systems (confirming the drawing reviews), determine the piping segment slopes, and identify locations where UT may be warranted to monitor for potential gas accumulation. Potential vent valve locations are also developed from the walkdown reviews.

For Unit 1, the drawing reviews, walkdowns, laser scanning, and UT inspections have been completed for those portions of the charging system within the scope of GL 2008-01. As indicated above, the walkdowns focused on the suction piping. The charging system piping downstream of the pump discharge isolation valves was screened from consideration because the system is in continuous service.

2.1. Walkdown Results Walkdowns of the charging pump suction piping from the inventory sources credited in the SBLOCA analysis have been completed using laser scanning to determine pipe segment elevations. All of these areas are located in accessible areas of the reactor auxiliary building.

Markups of isometric drawings showing elevations and unvented high point locations were produced.

Evaluation of walkdown information indicated that the as-built piping isometrics accurately depict piping layout and support locations for the subject piping scope. As expected, small local highpoints were identified within piping sections designed to be installed horizontally at a single elevation.

St. Lucie Unit 1 L-2009-142 Docket No. 50-335 Enclosure 1 Page 3 of 8 2.2. UT Results Unit I Accessible Piping UT inspections for St. Lucie Unit I accessible piping at unvented high points are complete.

The table below, previously provided in Reference 5, has been updated to include the recent charging system UT results.

St. Lucie Unit 1 UT Results - Accessible Piping'I_ _ _ _ __Side 5Suction Side Discharge Side UT UT Gas UT UT Gas Locations Complete Found CR Locations Complete Found CR 2008-32072 ECCS 2008-32077 13 13 0 SDC 7 7 0 0 0 0 CS 3 3 0 5 5 1 2008-32074 CHG 11 11 1 2009-11492 3 3 0 Three gas voids were originally identified in Reference 5 for the emergency core cooling system (ECCS), shutdown cooling system (SDC) and containment spray systems (CSS); two (2) suction side voids and one discharge side void. The voids were within the acceptance criteria of the standardized prompt operability determinations (POD)2 except for one ECCS suction side void (additional engineering analysis beyond that contained in the POD determined that the system remained operable with this gas void). All three (3) instances were tracked in the corrective actions program (CAP).

One gas void was identified within the charging system. This suction side void was within the acceptance criteria of the standardized POD. This instance is also tracked in the CAP.

In the St. Lucie nine-month submittal (Reference 3), 16 locations were identified for UT monitoring in St. Lucie Unit 1 accessible areas. Eight of those locations were check valve bonnets. It was subsequently determined that due to material and configuration issues, UT of these locations would not yield conclusive results. Four of the locations (ECCS combined suction check valves) have had vent valves installed. The other four locations are the high pressure safety injection (HPSI) and low pressure safety injection (LPSI) pump suction side swing check valves. FPL Engineering concludes that vent valve installation on these check valves is not warranted, because IST substantial flow and quarterly mini-flow testing demonstrates pump operability and indicates that post-fill and vent voids are not detrimental to pump health.

2 FPL has implemented standardized PODs in accordance with the FPL nuclear fleet procedure for establishing the acceptability of continued operation for structures, systems or components that are suspected to be degraded, non-conforming, or in an unanalyzed condition. In concert with the existing technical specifications, the PODs will ensure that the potential effects of gas voiding are adequately addressed until a license amendment is processed.

These PODs provide standardized acceptance criteria for gas voids in the suction and discharge piping of ECCS systems. If the standardized acceptance criteria are exceeded, then a specific evaluation of the location in question is performed to determine operability. Until a gas accumulation management program is implemented, any identified gas voids are documented in the St. Lucie CAP.

St. Lucie Unit 1 L-2009-142 Docket No. 50-335 Enclosure 1 Page 4 of 8 Unit 1 Inaccessible Piping UT inspections for St. Lucie Unit 1 inaccessible piping at unvented high points were performed at the beginning of the fall 2008 outage. The table below and subsequent discussion, previously provided in Reference 5, are being provided without changes.

St. Lucie Unit 1 UT Results - Inaccessible Piping Suction Side Discharge Side UT UT Gas UT UT Gas Locations Complete Found CR Locations Complete Found CR ECCS - - - 5 5 0 SDC 6 5 0 Of the 11 identified inaccessible UT locations, one was determined not to be an unvented high point (and was still inspected), and one was unable to be inspected due to interference issues. This uninspected location was evaluated as acceptable because 1) a total often (10) other SDC suction line segments were inspected (with no voids found), and 2) the SDC initiation procedure was modified several years ago to alleviate gas collection issues and operating history has shown that the current process has been effective in addressing the effects of any potential gas voids. No gas voids were identified in any of the inspected locations.

Post-Outage UT Inspections During the startup following the fall 2008 refueling outage, UT inspections were again performed on the remaining accessible and inaccessible area unvented high points that are located in ECCS pathways and not pressurized. No gas voids were found in any of those locations.

3. Vent Valves As previously described in Reference 5, a total of thirteen (13) locations were selected for ECCS/CS vent valve installation at St. Lucie Unit 1. Twelve (12) vent valves were installed on Unit I accessible piping during the recently completed outage. The remaining valve has been scheduled for installation during the next Unit 1 refueling outage. This location was UT inspected during plant startup at the end of the fall 2008 refueling outage and was found to be water solid.

With respect to the recent Unit 1 charging system walkdowns, the need for an additional vent valve was identified. This valve has been scheduled for installation during the next Unit I refueling outage (spring 2010). This location was UT inspected following the April 2009 walkdowns and was found to be water solid.

4. Procedures The charging system walkdown/UT effort did not identify the need for any additional procedures or procedure changes. The charging system high points identified by the

St. Lucie Unit I L-2009-142 Docket No. 50-335 Enclosure 1 Page 5 of 8 walkdowns will be addressed in the St. Lucie gas accumulation management program being developed under commitment 5 as discussed in Section B. 1.

St. Lucie Unit I L-2009-142 Docket No. 50-335 Enclosure 1 Page 6 of 8 B. DESCRIPTION OF NECESSARY ADDITIONAL COMMITMENTS

1. Additional Commitments/Corrective Actions No additional commitments or commitment changes have been identified subsequent to the St.

Lucie Unit I and 2 nine-month response letter (Reference 3) or the Unit 1 90-day post outage response letter (Reference 5).

No additional corrective actions have been entered in the CAP to assure operability as a result of the activities being reported under this supplementary response for the Unit I charging system.

FPL will continue to address issues identified during the development of the gas accumulation management program using the CAP as discussed in Reference 3 and Reference 5.

2. Commitment/Corrective Action Updates Commitments I through 3 were provided in the FPL three-month response letter L-2008-070 dated May 12, 2008 (Reference 2).

1. FPL will provide an initial GL 2008-01 submittal by October 14, 2008 that includes the evaluation results for the completed licensing and design basis reviews, the operating and test procedure reviews, and the Unit 2 readily accessible GL piping section walkdowns and design reviews as well as the schedule for any corrective actions that may be required based on these evaluations. FPL Letter L-2008-221 (Reference 3) satisfied this commitment.

2. FPL will provide a complete Unit I GL 2008-01 submittal 90 days after the end of the fall 2008 refueling outage. This submittal will complete the design evaluation review as well as provide the schedule and basis for any corrective actions that may be required based on the detailed readily accessible and inaccessible GL piping section walkdowns performed. FPL Letter L-2009-034 (Reference 5), supplemented by this letter, satisfies this commitment.

3. FPL will provide a complete Unit 2 GL 2008-01 submittal 90 days after the end of the spring 2009 refueling outage. This submittal will complete the design evaluation review as well as provide the schedule and basis for any corrective actions that may be required based on the detailed inaccessible GL piping section walkdowns performed during the Outage.

Commitments 4 and 5 were provided in the FPL nine-month response letter L-2008-221 dated October 14, 2008 (Reference 3)

4. FPL is continuing to support the industry and NEI Gas Accumulation Management Team activities regarding the resolution of generic TS changes via the Technical Specification Task Force (TSTF) traveler process. FPL will evaluate the resolution of TS issues with respect to the changes contained in the TSTF traveler following NRC approval and the consolidated line item improvement process (CLIIP) notice of availability of the TSTF

St. Lucie Unit 1 L-2009-142 Docket No. 50-335 Enclosure I Page 7 of 8 traveler in the Federal Register. Based upon the results of the evaluation, an appropriate license amendment request will be filed with the NRC within 180 days following NRC approval of the TSTF. The appropriate bases changes associated with the potential Technical Specification will also be made.

5. FPL will develop a gas accumulation management program by 12/15/2009 to support planned TS changes (Previously referred to as a "Gas Void Management Program", this is a name change only to align with common FPL Fleet nomenclature).

All of the corrective actions described in the St. Lucie nine-month response to GL 2008-01 (Reference 3) are controlled within the St. Lucie CAP. Each corrective action has been assigned an action item (AI) within the CAP. Corrective actions are being worked in accordance with the priorities assigned by the CAP in support of the above remaining NRC commitments.

St. Lucie Unit 1 L-2009-142 Docket No. 50-335 Enclosure I Page 8 of 8 Conclusion FPL has evaluated the previously unevaluated portions of applicable system piping at St. Lucie Unit I that perform the functions described in GL 2008-01, and has concluded that the subject systems and functions at St. Lucie are operable and that St. Lucie is currently in compliance with the licensing basis documentation and applicable regulations, including 10 CFR 50 Appendix B, Criteria III, V, XI, XVI, and XVII, with respect to the concerns outlined in GL 2008-01.