Text

Nine-Month Supplemental (Post-Outage) Response to NRC Generic Letter 2008-01
	ML100640545
Person / Time
Site:	Waterford
Issue date:	03/04/2010
From:	Murillo R; Entergy Nuclear South, Entergy Operations
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	GL-08-001, W3F1-2010-0017
	Download: ML100640545 (8)
	v • d • e

Entergy Nuclear South Entergy Operations, Inc.

17265 River Road Killona, LA 70057-3093 Tel 5047396715 Fax 504 739 6698 rmurill@entergy.com Robert J. Murillo Licensing Manager Waterford 3 W3F1-2010-0017 March 4, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Nine-Month Supplemental (Post-Outage) Response to NRC Generic Letter 2008-01 Waterford Steam Electric Station, Unit 3 Docket No. 50-382 License No. NPF-38

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. Entergy letter W3FI-2008-0036 to the NRC, "Three-Month Response to Generic Letter 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated May 12, 2008.

3. NRC Letter to Nuclear Energy Institute, Dated July 8, 2008 (ML0818305557).

4. NRC letter to Kevin Walsh, Waterford Steam Electric Station-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 9, 2008.

5. Entergy letter W3F1 -2008-0064 to the NRC, "Response to Request for Additional Information regarding Generic Letter (GL) 2008-01 Proposed Alternative Course of Action and Request for a Revised 3-Month Response Letter Waterford Steam Electric Station, Unit 3,"

dated September 23, 2008.

6. Entergy Letter W3F1-2008-0068 to the NRC, 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.

W3F1-2010-0017 Page 2

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 actions for the emergency core cooling (ECCS), decay heat removal (DHR),

and containment spray systems 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 5, please find attached Entergy's supplemental response to the nine month response letter (Reference 5). This supplemental response is being submitted within 90 days of startup from the outage in which the deferred actions were completed.

In summary, Entergy has concluded that the subject systems at Waterford-3 are operable and that Waterford-3 is currently in compliance with GL 2008-01 regarding managing gas accumulation in these systems/functions.

This letter contains no new NRC commitments.

Please contact Mr. Robert J. Murillo, Manager, Licensing at (504) 739-6715 if there are any questions concerning this matter.

ttherely, JM/M ' MEMW Attachment Nine-Month Supplemental (Post-Outage) Response to NRC Generic Letter 2008-01.

W3F1-2010-0017 Page 3 cc: Mr. Elmo E. Collins, Jr.

Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop 08B1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004

Attachment I W3FI-2010-0017 Nine-Month Supplemental (Post-Outage) Response to NRC Generic Letter 2008-01 to W3F1-2010-0017 Page 1 of 4 This attachment provides the Nine-Month Supplemental (Post Outage) Response to Generic Letter 2008-01 for actions that were deferred until the next refueling outage as requested by the NRC in Reference 5 of the cover letter.

This attachmrent addresses the following:

A description of the results of evaluations that were performed pursuant to Generic Letter 2008-01 on the previously incomplete activities, such as system piping walkdowns, at Waterford-3 (see section A of this attachment), identification of any additional corrective actions determined necessary to assure system operability and compliance with the quality assurance criteria in Sections III, V, Xl, XVI, and XVII of Appendix B to 10 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 B1 of this Attachment),

and summary of any changes or updates to previous corrective actions,. including any schedule change and the basis for the change. (See Section B2 of this Attachment).

The original conclusions documented in the 9 month response with 'respect to the licensing basis evaluation, testing evaluations, and corrective action evaluations have not changed. This supplement will only discuss the results of design evaluation reviews conducted during the recent refueling outage associated with previously uncompleted activities.

to W3F1-2010-0017 Page 2 of 4 A. EVALUATION RESULTS

1. Design Basis Documents No changes to the Waterford-3 Design Basis Documents were made.

2. Confirmatory Walkdowns As identified in the Waterford 3 Three-Month response to NRC GL 2008-001, Waterford 3 committed to perform any necessary confirmatory walkdowns or evaluations of inaccessible piping in the containment during the next Refueling Outage which began in Fall 2009. Entergy completed a walkdown of the piping inside containment during Refuel 16. The walk down confirmed general piping installation per isometric drawings, and the installation of vents as depicted on the isometric drawings.

The piping inside containment for High Pressure and Low Pressure Safety Injection (HPSI and LPSI) consists of injection lines from HPSI and LPSI inside containment isolation valves (CIV) to the Reactor Coolant System (RCS). These lines combine shortly after the inside CIV into 4 injection headers and are encased in mirror type insulation. There are no other valves in the piping from the inside CIVs to the RCS boundary check valve for each injection line. Each injection line includes a Safety Injection Tank (SIT) which is pressurized with nitrogen to a range of 600 to 670 psig.

This SIT pressure maintains the injection line pressure at the same nominal value.

Pressure instruments on the injection header are monitored for pressure changes in the line. Since the pressure of the injection line is maintained at the SIT pressure, nitrogen does not come out of solution and form gas accumulations. Therefore it is judged unlikely that gas accumulations will occur in the piping previously mentioned in this

-paragraph, and further walkdowns to directly measure piping elevations were not conducted.

3. Vent Valves There were 'no new vent valve locations, modifications to existing vent valves, or utilization of existing vent valves resulting from the walkdowns during Refuel 16.

4. Procedures There were no additional procedure revisions identified following the walkdowns.

B. DESCRIPTION OF NECESSARY ADDITIONAL CORRECTIVE ACTIONS,

1. Additional Corrective Actions No additional corrective actions have been identified.

2. Corrective Action Updates The following is an update to the additional corrective actions that Entergy committed to in Reference 5.

to W3F1-2010-0017 Page 3 of 4

a. Entergy committed to evaluating piping locations identified in the post NRC GL 2008-001 plant/system walkdown as possible high points where gas accumulation could occur, and documented the evaluation in Condition Report CR-WF3-2008-4569. This action was completed.

Further walk downs of the highpoints identified in CR-WF3-2008-04569 were conducted. Insulation in these areas was removed, and UT inspections performed of the localized high point to confirm the piping was full of water.

CR-WF3-2009-1824 documents a gas accumulation found in Low Pressure Safety Injection (LPSI) B discharge piping, just down stream of the LPSI B pump. The gas accumulation was found in piping segment 2SI10-183B (reference drawing 4305-4700) near the horizontal elbow and the flow element. The gas accumulation was measured, and found to be approximately 0.09 cubic feet. This gas accumulation was within the allowable values for the LPSI A discharge, and the system remained operable.

Subsequent to the discovery, OP-903-030, Safety Injection Pump Operability Verification, for LPSI B pump was conducted to remove the gas accumulation. A UT of the location following the pump surveillance, found no gas accumulation.

Entergy conducted additional UT surveillance of the location to ensure additional gas migration or accumulation did not occur. Subsequent UT surveillances conducted for two weeks found no gas accumulation.

Since' no additional gas accumulation was found, it is reasonable to conclude the gas was not coming out of solution from a Safety Injection Tank, or other recurring means. A review of the maintenance activities for LPSI B indicated that the gas accumulation may have been introduced during a System Outage in March 2009.

Calibration of the flow instrument SI IFT1 306 occurred during this maintenance outage, and the gas accumulation is most likely the result of this maintenance.

Following calibration of this transmitter, the LPSI B pump was operated to blowdown the tubing. However, gas was apparently introduced during this evolution, and the maintenance pump run did not remove the gas accumulation.

Review of Localized High Points for Vent Installation:

The identified high points were reviewed to determine the need for new vent installations. The review considered the high point location and Ultrasonic Testing (UT) results. With no gas accumulation being found at the localized high points and post maintenance gas pockets being effectively removed through post maintenance system operation; it was concluded that no new system vents are required at this time.

b. As identified in the Waterford 3 Three-Month response to NRC GL 2004-002, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accident at Pressurized-Water Reactor," Entergy will analyze vortexing and NPSH of the LPSI, HPSI and CS systems, reference Engineering Change EC-1002.

This action has been completed.

Per EC-1002, the Safety Injection sump strainers are designed to minimize the amount of debris that enters the Safety Injection and Containment Spray systems.

Attachment 1 to W3F1 -2010-0017 Page 4 of 4 As the strainers collect debris the experienced head loss across the strainer increases which reduces the available NPSH. As long as the system available NPSH exceeds the pump required NPSH, internal cavitation of the pump should not occur. Adequate vortex protection is maintained by the use of vortex breakers and was demonstrated through testing of both the vortex breakers and the sump strainers. The minimum NPSH margins for the Safety Injection and Containment Spray pumps with suction from the Safety Injection Sump have been increased per the EC, and provide operational assurance that these safety-related pumps will perform their safety function as designed.

c. Entergy will issue Engineering Change EC-10775, which performs plant specific evaluation of the Containment Spray ring header piping in accordance with PWROG guidance provided in Calculation FAI/08-78. This action has been completed.

Calculation ECM09-001 has been prepared which concludes that no significant water hammer events will occur during the filling of the spray ring headers. The bases for the sizing of the CS System come from the sources and amounts of energy expected to be released to containment as a function of time. Calculation ECS97-001 determines that the full flow is achieved within ý0-60 seconds. The potential for a water hammer event occurs when the air pocket trapped between the last two nozzles is compressed during filling. The analysis performed in ECM09-001 conservatively shows that the resulting loads are small and have very small propagation periods. Lateral movement will be very small; even if it is assumed that r the ring headers are unrestrained and can freely move laterally to absorb the water hammer force.

Conclusion Entergy has evaluated the previously unevaluated portions of the applicable systems at Waterford-3 that perform the functions described in the GL and has concluded that these systems are operable.