ML20083D645
| ML20083D645 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/27/1991 |
| From: | Zeringue O TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9110010121 | |
| Download: ML20083D645 (6) | |
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SEP 2 71991 U.S. Nuclear Regulatory Commission NfTH: Document Control Desk Washington, D.C.
20555 Centlemtni In the Matter of
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Docket Non. 50-259 Tennessee Valley Authority
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50-296 11ROWNS FERRY NUCLEAR PLANT (liFN) - RESTART TEST PROGRAM (RTP) DESCRIPTION FOR UNITS 1 AND 3
Reference:
TVA letter dated July 10, 1991, liFN Regulatory Framework for the Rentart of Unita 1 and 3 In the referenced letter, TVA committed to provide submittals f or Unit I and 3 programs that vill depart from the Unit 2 implementation precedent. The RTP for Units 1 and 3 vill be similar to the Unit 2 RTP with the exception of eliminating the complete Lons of Of fsite l'ower/ Loss of Coolant Accident test. The restart tests for Unita 1 and 3 vill be based on the 'Jnit 2 Syntem Test Specifications, tent procedurea, and test results taking into consideration the differencea in the unitn. TVA requests the NRC review and approve changen in implementation precedento proposed for the Unit 1 and 3 RTPa as deneribed in Enclosure 1 by March 1992.
A nummary list of commitmenta contained in thin let cr is provided in.
If you have any questions, please telephone J. E. McCarthy, Restart Licensing Manager, at (205) 729-2703.
Very truly youro, TENNESSEE VALLEY AUTIIORITY
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Enclosures cc (Enclor'tres):
NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35609-2000 Mr. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, HW, Suite 2900 Atlanta, Georgia 30323
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Page 1 of 3 ENCLOSURE 1 BROWNS TERRY NUCLEAR PLANT - UNITS 1 AND 3 RESTART TEST PROGRAM of the January 9, 1991 letter identified the Restart Test Program as one of the programs that will take advantage of the lessons learned during the Unit 2 recovery.
TVA's Restart Test Program Plan for BFN Unit 2 was initially submitted to the NRC by TVA letter dated October 7, 1986 and supplemented by letter dated July 13, 1987.
The proposed program was also described in Volume III, Section 8.0 of the Nuclear Performance Plan. TVA presented the BFN Restart Test Program to the NRC Staff during meetings held on April 26, 1988, and June 21, 1988.
The NRC conducted several inspections of the implementation of the RTP as documented in Inspection Reports (irs) 50-260/87-11, 87-27, 87-30, 87-33, 87-37, 87-42, 87-46, 88-02, 88-04, 88-05, 88-10, 88-16, 88-18, and 88-21.
TVA's l
Restart Test Program was accepted by the NRC Staff as documented in Enclosure 2 to NRC letter dated August 12, 1988 and NUREG-1232, Volume 3, Supplement I dated October 24, 1989.
The following is a summary of the Restart Teat Program for Unit 2, lessons learned from the Unit 2 RTP, and a description of the differences in the Restart Test Programs planned for Units 1 and 3.
Unit 2 Restartj0est Procram The primary purpose of the Unit 2 Restart Teet Program (RTP) was to verify that systems were capable of meeting their safe she*.down requirements. The test scope consisted of test requirements necessary to verify system design functions utilized in satisfying the safe shutdown analysis and to ensure reliable system operation.
Baseline test requirements, generated by the Design Baselint Verification Program (DBVP), were used to generate System Test Specifications (STS).
The STS is a system specific document that specifies the m!nimum testing to be performed for the RTP.
From this document an RTP Tect Instruction was written to implement the test requirements. Test requirements were a result of the DBVP and RTP system reviews. A system review was performed to determine test requirements necessary for reliable system o7eration. This system review looked at past maintenance and operational history, vendor recommanued testing, the extent of modifications performed during the Unit 2 Cycla 5 outage, and licensing commitments.
As a result of the DBVP and these system reviews, TVA identified those systems requiring extensive testing and those requiring no specific or special testing.
The RTP required testing of systema necessary to support Unit 2 safe shutdown following an accident.
TVA provided an RTP system test list to the NRC by submittal dated July 13, 1987 for the systems to be tested as part of the RTP.
This list included systems required for BFN to achieve and maintain safe shutdown.during design basis events.
At the request of the NRC, TVA reviewed the BFN RTP against Regulatory Guide 1.68 guidelines (Initial Test Programs for Water-Cooled Nuclear Power Plants) regarding the criteria used for selection of plant systems to be preoperat.ionally tested. The RTP was determined to be consistent with the regulatory guide.
Test deviations or exceptions which occurred during testing were evaluated and dispositioned by TVA per procedure. Equipment associated with normal plant cooldown was
Page 2 of 3 excluded from the RTP since evaluations assured that a f&ilure of normal plant cooldown equipment would not prevent BFN from achieving safe shutdown.
Exclusion of Technical Specification testing was justified sinco these test would be performed regardless of the scope of the RTP.
The RTP ocope also included demonstration of manual and automatic operation of equipment, and verification of operation following loss of normal power scpplies with the exception of testing in the degraded mode, which wap juatified by calculations.
The BFN RTP considered the incluelon of tests that demonstrate proper function of instrumentation and controls, permiosive and prohibit interlocks, equipment protective devices whose malfunction or premature actuation may shut down or defeat system or equipment operation, and eyotem vibration, expansion and restraint testing.
The BFN RTP included these test types with the exception of vibration, expansion, and restraint tecting, which had been previously performed.
In summary, various system specific test exceptions were taken for specific reasons provided by TVA that were found to be acceptable by the NRC.
During RTP implementation, individual systems to be testod were categorized for convenience and clarification into three groupe; 1) syatoms that were determined to be critical to safe shutdown, 2) systems that had few test requirements specified by the DDVP but provided direct support to plant operation, and 3) systema not directly supporting plant operation nor important to safety that, in general, required no testing.
The groupings provided a prioritization methodology for conducting the RTP system tente.
The primary difference between Groups 1 and 2 was the scope of the DUVP test requiremente for a particular system.
In addition to individual system testing, the ATP included integrated tests.
These testo were performed to provide added confidence it. integrated system performance, to provide additional verification of plant procedures and equipment, and for operator training.
The integrated teste performed were a Losc of Offeite Power / Lose of Coolant (LOP /LOCA) Test, a Backup Control Test and Integrated Cold Functional Tests.
s Leocone Lesrned from Unit & Reetart Trot Procram During the perta rmance of the Restart Test Program for Unit 2, there were several changes and adjustments to the program and methode as a result of lessons learned and experience gained.
Additionally, there were improvemento made based on input provided by the NRC Resident Inspectore during their monitoring of the program.
Lessons learned during the Unit 2 RTP implementation procews were considered in RTP program development for Unitu 1 and 3.
Key lessons learned were as follows:
o Test the system once, after the completion of modifications or maintenance, where possible.
o Conduct testa uning normal plant adminletrative procedures for teet control. This will minimize plant testing coordination problems.
o Use existing plant procedures (e.g.,
Surveillance Instructions) to obtain required test data where possible. This effectively eliminates duplication in test preparation and enhances toot performance, o
Schedule work and system completion dates to minimize required test exceptions.
Page 3 of 3 Peetert Teet.PrOQram Tiljittences fgr Units 1 LDA_1 Units 3 and 3 will use the experience gained in the Unit 2 1.TP to offect program improvements, to eliminate previous pr>blem areas and to realize program efficiencies.
For those systems that support safe chutdown, an assessment of tha Unit 2 System Test Specifications (STS), test procedures,
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and test resu5ts will be performed.
The results of that assessment in conjunction with the Unit 3 baseline test requirements will be the initiating basis for the Unit 3 STS.
The Unit 3 system modification and maintenance scope and other engineering specified test requirements will be reviewed to provide input into the restart test requirements.
The differences between the STS for Units 1 & 3 and the STS for Unit 2 will be the result of differences identified in baseline test requirements, other engineering specified test requirements, system modifications, and system maintenance.
The restart tests will be performed as an integrated part of the Startup Test Programs for Units 1 and 3, which will include post modification, post maintenant:e, restart, and surveillance tests.
TVA expects to improve Rcetart Test Program efficiency by performing system testing following the completion of major system modifications and maintenance. This wtli eliminate the repeat testing that occurred during the Unit 2 RTP when major work on a system was performed subsequent to testing.
Componer.ts that are not scheduled for modification or maintenance may be tested prior to completion of all system work.
The status of the operating unit (s) will be considered during the planning and scheduling of restart tests.
Similar integrated tests will be perf ormed on Units 1 and 3.
However, based on the previous testing completed on Unit 2, a complete Loss of offsite Power / Loss of Coolant Accident (LOP /LOCA) test will not be performed for Unit 3.
The LOP /LOCA tests performed during the Unit 2 RTP demonstrated the operation of the electrical system for all three unite down to the shutdown board level and the operation of all eight dienel generators.
TVA plans to take credit for the 18 month diesel generator Technical Specification surveillancs that demonstrates performance of Unit 3 systems by simuisting Loss of offsite Power to the shutdown boards and the loads they supply and simulation of the LOCA initiation signal for the Unit.
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-a Page 1 of 2 ENCLOSURE 2 BROWNB FERRY NUCLEAR PLANT
SUMMARY
OF COMMITMENTS l
For those systems that support safe shutdown, administrative controls for the l
Units 1 and 3 RTp will bo implemented to insure that an assessment of the Unit 2 System Test Specifications (STS), test procedures, and test results is performed. Adminstrative controls will be used to insure that the status of the operating unit (s) is considered during the planning and scheduling of restart tests.
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