ML090630424
| ML090630424 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/02/2009 |
| From: | Godwin F R Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-08-001, TAC MD7799, TAC MD7800 | |
| Download: ML090630424 (9) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 March 2, 2009 10 CFR 50.54(f)U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 In the Matter of Tennessee Valley Authority))Docket No. 50-259 BROWNS FERRY NUCLEAR PLANT (BFN) UNIT 1 -NINE-MONTH SUPPLEMENTAL (POST-OUTAGE)
RESPONSE TO NUCLEAR REGULATORY COMMISSION (NRC)GENERIC LETTER (GL) 2008-01
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 [ML072910759]
- 2. 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 5, 2008 [ML081360101]
- 3. Three-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated June 6, 2008 [ML081630086]
- 4. Three-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated July 11, 2008 [ML081970084]
- 5. 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 11, 2008 [ML082890540]
- 6. Browns Ferry Nuclear Plant, Units 1, 2, and 3 -Re: Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" Proposed Alternative Course of Action (TAC Nos. MD7799, MD7800, and MD7801) dated September 25, 2008 [ML082610742]
- 7. NRC Letter to Nuclear Energy Institute dated July8, 2008[ML0818305557]
JAM Nýk U.S. Nuclear Regulatory Commission Page 2 March 2, 2009 The purpose of this letter is to provide TVA's "Nine-Month (Post-Outage)" response to NRC issued GL 2008-01, Reference 1, for BFN Unit 1. TVA's initial responses and the"Nine-Month" response were provided in References 2, 3, 4, and 5 above.The NRC issued GL 2008-01 to request that each licensee evaluate the licensing basis, design, testing, and corrective actions for the emergency core cooling, decay heat removal, 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 by NRC in Reference 6, please find enclosed TVA'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 (Unit 1 Cycle 7 Refueling Outage). GL response activities that remain to be accomplished, such as the long-term items identified in Reference 6, are considered to be confirmatory.
TVA concludes that the subject BFN Unit 1 systems are operable and that BFN Unit 1 is currently in compliance with the licensing basis documentation and applicable regulations, including 10 CFR 50 Appendix B, Criteria lll, V, Xl, XVI, and XV!l, with respect to the concerns outlined in GL 2008-01 regarding managing gas accumulation in these systems.There are no new regulatory commitments contained in the letter.I declare under penalty of perjury that the foregoing is true and correct. Executed on the 2 nd day of March, 2009.Sincerely, F. R. Go in Manager of Licensing and Industry Affairs Enclosure U.S. Nuclear Regulatory Commission Page 3 March 2, 2009 Enclosure cc (Enclosure):
Ms. Eva Brown, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Ms. Heather J. Gepford, Acting Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970 ENCLOSURE 1 BROWNS FERRY NUCLEAR PLANT (BFN) UNIT 1 -NINE-MONTH SUPPLEMENTAL (POST-OUTAGE)
RESPONSE TO NUCLEAR REGULATORY COMMISSION (NRC) GENERIC LETTER (GL) 2008-01 This Enclosure provides the TVA BFN Unit 1 Nine-Month Supplemental (Post-Outage).
Response to GL 2008-01 for actions that were deferred until the-next refueling outage as requested by NRC in Reference 6 of the cover letter.ý -The following information is provided in this response: a) 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 BFN Unit 1, (see Section A of this Enclosure), b) A description of any additional corrective actions determined necessary to assure system operability and 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 subject systems, including a schedule and a basis for that schedule (see Section B1 of this Enclosure), and c) A 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 Enclosure).
The original conclusions documented in the Nine-Month response with respect to the licensing basis evaluation, testing evaluations, and corrective action evaluations have not changed. This supplement will only discuss -the6resuts of ýdesign evaluation reviews conducted during the recent refueling outage associateld -With prev iOUsly uncompleted activities.
E-1.J .
A. EVALUATION RESULTS 1. Design Basis Documents There is no additional information or changes to report since the TVA BFN Nine-Month Response to NRC GL 2008-01 dated October 11, 2008 [ADAMS Accession No ML082890540].
- 2. Confirmatory Walkdowns Portions of the Residual Heat Removal (RHR), Core Spray, and High Pressure Coolant Injection (HPCI) Systems not previously accessible were walked down during the Unit 1 Cycle 7 Refueling Outage using the same criteria as the previous walkdowns.
The walkdown scope consisted of the RHR Loop I and II injection piping, which is downstream of the injection valves, the RHR Shutdown Cooling suction piping, the Core Spray Loop I and II injection piping, which is downstream of the injection valves, and the HPCI injection piping.For the RHR Loop I and II injection piping, the RHR Shutdown Cooling suction piping, the Core Spray Loop I and II injection piping, and the HPCI injection piping, the walkdowns showed an acceptable pipe slope for horizontal sections for the RHR piping and Core Spray piping. Due to the configuration of the HPCI piping (as confirmed by walkdowns), it cannot contain avoid that exceeds acceptance criteria and no measurements were required.For the RHR Loop I and II injection piping, it was identified that both are elevated above the vent locations used in loop venting procedures, 1-SR-3.5.1.1(RHR.I) and (RHR II), with Loop I containing an inverted U. The Core Spray Loop I and II1'injection piping also contained an inverted U. The Core SprayLoop II slopes upward and then drops down before the Loop II Testable Check Valve, 1-CKV-075-0054, which creates an inverted U. Loop I of Core Spray contains an inverted Uin the same geometric location as Loop II, but the Loop I Testable Check valve, 1-CKV-075-0026, is in the line prior to the down slope which lessens the impact of a potential void.Furthermore, it was found that each Loop of iRHR i`and CoreSpray injectionipi ping has an existing vent line at the top of the inverted U. However, these vent lines were not identified in any of the procedures reviewed for venting the systems during return to service. Both of the RHR lines are vented dynamically when placed in service for Shutdown Cooling. Technical Specification (TS) Surveillance 3.5.1.1 verifies, for each Emergency Core Cooling System (ECCS) injection/spray subsystem, the piping is filled with water from the pump discharge valve to the injection valve. As 'stated in our October 11, 2008 response, an analysis of ECCS piping downstreamf'o
tIhe i ` .1.injection valves was completed and a determination was made that the existence of air voids in this piping would have no adverse consequences related to accident conditions..
Even if small voids did exist,-the pressure transientwould no te greater than the normal injection pressure.
As an enhancement, venting of.these portions of piping was added to the system operating instruction fill and ventprocedures..:
.No confirmatory ultrasonic test (UT) (nondestructive) examinations were performed on previously inaccessible piping.E-2 -- -
- 3. Vent Valves For the RHR Loop I and II injection piping, the RHR Shutdown Cooling suction piping, the Core Spray Loop I and II injection piping, and the HPCI injection piping, no new vent valve locations were identified and no modifications to existing vent valves were required.For the RHR Loop I and II and Core Spray Loop I and II injection piping downstream of the injection valves, system operating instructions were revised to add existing vent valves to the system fill and vent procedures as discussed in Section A.2.4. Procedures RHR and Core Spray System Operating Instructions, 1-01-74, and 1-01-75, respectively, were revised to address venting of piping downstream of the injection valves.B. DESCRIPTION OF NECESSARY ADDITIONAL CORRECTIVE ACTIONS 1. Additional Corrective Actions RHR and Core Spray System Operating Instru6tion-s, 1-0-o*74,,and respectively, were revised to address venting of piping downstream of the injection valves.2. Corrective Action Updates The following corrective actions, described in TVA's October 1,1, 2008 response, are repeated in Table 1 for clarity, changed where needed, and include a status as of the completion of the Unit 1 Cycle 7 Refueling Outage.a. Changed Corrective Actions 1. The Table 1, Item 3, corrective actioin 'revise- the for venting the low pressure coolant injection (LPCI) injectionliines usinrg the iven 'tvalve on the bonnet of the LPCI injection isolation valve. For BFN Unit 1, it was determined that use of the bonnet valves to vent the high point upstream of the injection valves was not practicable.
The venting procedures were revised to perform UT examinations at the system highpoint piping upstream of the injection valves instead.2. Prior to this review, the description of Table 1, Item 7, was not as intended and has been corrected.
This item was intended to be the same as the Watts Bar and Sequoyah action, also described in TVA's October 11, 2008 response, and is characterized as a review error.b. Additional Completed Corrective Actions ----As an enhancement, the RHR and Core Spray System Operating Instructions, 1-01-74, and 1-01-75, respectively, were revised to address venting of piping downstream of the injection valves. These actions were identified during the confirmatory walkdowns.
- c. Additional Planned Corrective Actions -No additional corrective actions are required as a result of the outage activities and evaluations.
E-3.
C. CONCLUSION TVA has evaluated the previously unevaluated portions of the applicable systems at BFN Unit 1 that perform the functions described in the GL and has concluded that these systems are operable as defined in the BFN TS and are in conformance to commitments to the applicable General Design Criteria, as stated in the Final Safety Analysis Report.E-4 TABLE 1 Status Status_ _ _ _ _ _ _ _ _ _ _ October 11, 2008 Unit 1 Cycle 7 Refueling Outage 1. TVA will evaluate adopting the revised Integrated Within 6 months of NRC Unchanged Standard Technical Specification (ISTS). approval of the Traveler 2. The design change review checklist is revised to Complete Unchanged include an explicit item to determine if the design change introduces or increases the potential gas accumulation beyond established acceptance criteria.3. The procedure for venting the LPCI injection lines is Complete For BFN Unit 1, procedures have revised to use the vent valve on the bonnet of the been revised to require that UT LPCI injection isolation valve, examinations be used in lieu of bonnet venting.4. The ECCS and DHR System operating procedures 11/26/2008 Complete are being revised to require UT inspection or dynamic venting of locations that could contain a significant void should this pipe be drained. _ _,,__ __.5. The venting. procedures for LPCI discharge pipe are, Complete Unchanged revised to include a time, requirement on water flow, , from the ventt.*..6. The Core Pump flow test procedures are Complete Unchanged revised to require the monthly vent procedures to be used for verifying the system is full of water prior to testing theapump.
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7., Periodic venting T-he procedures that ari used,feF to0" A4421 0 Prior to this review, it was SIR 3.5.1.1 are being r eoreque determined that this item (action)gaz- rc...... bo ti,, .nd rc..... trndd. Th. was not as intended.
Corrections ntngproodr will al 'qin' are as shown. The new date the event of'an extended gas release, a report'is supports this change.entered into the Corrective Action Program., _ _ _ _ _ __ _ _ _ _E-5