ML20126K011
| ML20126K011 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/30/1992 |
| From: | Williams J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9301060368 | |
| Download: ML20126K011 (14) | |
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UNITED STATES NUCLE AR REGULATORY COMMISSION
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December 30, 1992 Docket Nos. 50-259, 50-260 and 50-296 LICENSEE:
Tennessee Valley Authority FACILITY:
Browns Ferry Nuclear Plant, Units 1, 2, and 3 SUBJE'CT:
SUMMARY
OF THE DECEMBER 16, 1992 MEETING REGARDING DESIGN AND OPERATION OF THE BROWNS FERRY HARDENED WETWELL VENT On December 16, 1992, representatives of the Tennessee Valley Authority (TVA) and the NRC staff met in Rockville, Maryland,to discuss the design and operation of the Browns Ferry Nuclear Plant (BFN) hardened wetwell vent.
Meeting attendees are listed in Enclosure 1.
Handouts distributed by TVA are provided in Enclosure 2.
This meeting was held to follow ur on a finding from a team inspection conducted at BFN which examined engineering design change packages. This finding noted that the hardened wetwell vent design included three drain valves which required local manual action when the vent is operated. The inspection team was concerned that these local actions may be prevented by high radiation fields in the event of core damage, and, therefore, plant operators would be unable to perform actions called for in the Browns Ferry emergency operating procedures.
TVA provided an outline of the vent design and plant layout. TVA plans to install the BFN Unit 2 vent during the refueling outage scheduled to begin on January 29, 1993.
The BFN Units 1 and 3 vents will be installed prior to the restart of each reactor. TVA stated that the Browns Ferry vent is designed in accordance with the BWR Owners Group guidelines approved by the NRC. The team inspection findings are consistent with this statement.
In response to the concern raised by the team inspection, TVA stated that they will install float valves on two of the three drain lines.
These float valves will operate passively, eliminating the need for local operator action on these lines. The third drain valve is located within the plant stack.
TVA is evaluating whether or not this valve can be opened during an accident and left g* t y, m m 5 9 p rocq e
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9301060368 921230 1 h l, l PDR ADOCK 05000259
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DISTRIBUTIQH Docket File i
NRC & Local PDRss BfN Rdg. File T. Murley\\f. Miraglia 12-G-18 J. Partlow 12-G-18 S. Varga 14-E-4 G. Lainas 14 H-3 F. Hebdon J. Williams T. Ross M. Sanders OGC 15-B-18 E. Jordan MNBB-3701 L. Pilsco 17-G-21 ACRS (10)
L. Lambrois R. Frahm 8-E-23 E. Herschoff Ril B. Wilson Ril
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. i open without increasing round-level radiation source terms and associated doses beyond regulatory imits for design basis events, if this valve can be 1 eft open, the team's concern regarding local operator action will be i
resolved.
TVA will inform the staff of the results of its evaluation.
Original signed by Joseph F. Williams, Project Manager Project Directorate 11-4 Division of Reactor Projects - I/II
Enclosures:
1.
List of Attendees 2.
TVA llandouts cc w\\ enclosures:
See next page DISTR'9Uil0N
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Browns Ferry Nuclear Plant CC:
Mr. John B. Waters, Chairman State Health Officer Tennessee Valley Authority Alabama Dept. of Public Health ET 12A 434 Monroe Street 400 West Sunnit Hill Drive Montgomery, Alabama 36130-1701 i
Knovville, Tennessee 37902 Mr. J. R. Bynum, Vice President Regional Administrator Nuclear Operations U.S.N.R.C. Region 11 3B Lookout Place 101 Marietta Street, N.W.
1101 Market Street Suite 2900 Chattanooga, Tennessee 37402-2801 Atlanta, Georgia 30323 Mr. Charles Patterson Site Licensing Manager Senior Resident Inspector Browns Ferry Nuclear Plant Browns Ferry Nuclear Plant Tennessee Valley Authority U.S.N.R.C.
P.O. Box 2000 Route 12, Box 637 Decatur, Alabama 35602 Athens, Alabama 35611 Mr. O. J. Zeringue, Vice President Site Quality Manager Browns Ferry Nuclear Plant Browns Ferry Nuclear Plant Tennessee Valley Authority Tennessee Valley Authority P.O. Box 2000 P. O. Box 2000 Decatur, Alabama 35602 Decatur, Alabama 35602 Mr. M. J. Burzynski, Manager Dr. Mark O. Medford, Vice President Nuclear Licensing and Regulatory Affairs Tennessee Valley Authority 5B Lookout Place Nuclear Assurance, licensing and Fuels Chattanooga, Tennessee 37402-2B01 3B Lookout Place 1101 Market Street TVA Representative Chattanooga, Tennessee 37402-2801 Tennessee Valley Authority 11921 Rockville Pike Suite 402 Rockville, Maryland 20852 General Counsel-Tennessee Valley Authority ET llH 400 West Summit Hill Drive Knoxville, Tennessee 37902 Chairman, Limestone County Commission P.O. Box 188 Athens, Alabama 35611 l,
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4 Ef1 CLOSURE 1 ATTENDEES DECEMBER 16, 1992 TVA/f4RC MEEllfiG BROWNS FERRY HARDEf4ED WETWELL VElil DESIGft AND OPERAlloti llAfi[
ORGAf{lZ AT10t1 Joe Williams liRR/DRPE/PD 11-4 Joe McCarthy TVA Recovery Mechanical /tluclear Engineering Manager Greg Pierce TVA Browns Ferry Licensing Manager Ron frahm l4RR/DSSA/PSAB Lambros lois tiRR/DSSA/SRXB Jim Maddox TVA Browns ferry Engineering Manager Max Herrell TVA Browns Ferry Operations Manager Fred Hebdon liRR/ Director, PD 11-4 Jack Kudrick llRR/DSSA/SCSB Cheryl Beardslee f4RR/DRPE/PD 11-4 Mohan Thadani i1RR/DRPE/PD 11-4 Thierry Ross llRR/DRPE/PD 11-4 Matt Mueller TVA Mechanical /fluclear Engineering Sam Malur MRR/DRil/RSIB
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I AGENDA l
DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN BACKGROUND G. D. PIERCE VENT PATH J. E. McCARTHY DESIGN GUIDELINES / CRITERIA J. E. McCARTHY l
ISSUES J. E. McCARTHY CURRENT ACTIVITIES J. E. McCARTHY CONCLUSION J. E. MADDOX i.
DECEl'BER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN BACKGROUND G. D. PIERCE GENERIC LETTER 89-16 ENCOURAGED UTILITIES TO VOLUNTARILY INSTALL A HARDENED VENT TVA COMMITTED TO INSTALL THE HARDENED VENT ON UNIT 2 DURING THE FIRST REFUELING OUTAGE AFTER RESTART TO REDUCE RISK ASSOCIATED WITH THE LOSS OF DECAY HEAT REMOVAL SEQUENCE l
TVA ALSO COMMITTED TO INSTALL THE HARDENED VENT BEFORE THE RESTART OF UNITS 1 AND 3 THE HARDENED VENT WILL BE MODELED IN THE BFN PRA IN THE n_XT UPDATE AFTER INSTALLATION COMPLETED i
C' h DECEMBIR 16, 1992
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BROWNS TERRY HARDENED WETWELL VENT SP0KESMAN TOPIC J. E. McCARTHY VENT PATH PROPOSED VENT PAT l1 SHOWN ON THE ATTACHED FIGURE PROVIGES A DIRECT VENT PATH FROM THE TORUS TO AN EXHAUST POINT INSIDE THE PLANT STACK (ELEVATED RELEASE)
COMMON HEADER FOR UNITS 1, 2 AND 3 SIZED FOR ONE UNIT VENTING AT A TIME f
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DECEMBER 16, 1992 BROWNS-FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN DESIGN GUIDELINES / CRITERIA J. E. McCARTHY TVA'S DESIGN MEETS THE BWROG GUIDELINES -
DESIGNED TO REMOVE 1 PERCENT OF 105-PERCENT THERMAL POWER DESIGNED TO OPERATE UP TO A MAXIMUM TEMPERATURE OF 304*F-AND 56'PSIG THE BFN. HARDENED VENT VALVES ARE DC POWERED, PNEUMATICALLY OPERATED, AND ARE' DESIGNED TO GPERATE DURING AN STATION BLACKOUT EVENT
. THE BFN HARDENED VENT IS AN ACTIVE SYSTEMi IT WILL NOT OPERATE PASSIVELY, WITHOUT. OPERATOR ACTION
. INADVERTENT OPERATION OF THE BFN HARDENED VENT IS PREVENTED BY KEY LOCK SWITCHES IN THE CONTROL ROOM FOR THE ISOLATION VALVES 5
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DECEMBER 16, 1992 BROWNS FERRY HARDENED-WETWELL VENT TOPIC SPOKESMAN DESIGN GUIDELINES / CRITERIA (CONTINUED)
J. E. McCARTHY
. BFN VENT IS. CAPABLE OF WITHSTANDING EXPECTED CONDITIONS ASSOCIATED WITH THE "TW" SEQUENCE WITHOUT LOSS OF FUNCTIONAL' CAPABILITY
. BWROG AND TVA DID NOT ASSUME FAILED FUEL ASSOCIATED WITH THE "TW" SEQUENCE USES EXISTING RADIATION MONITORING NO IGNITION SOURCES IN THE PIPING 6
DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT
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SP0KESMAN TOPIC J. E. McCARTHY ISSUES l
CURRENT DESIGN REQUIRES MANUAL OPENING OF A DRAIN l
VALVE IN THE STACK PRIOR TO INITIATION OF VENTING CURRENT DESIGN REQUIRES MANUAL CYCLING OF LOW POINT DRAIN VALVES PRIOR TO RE-USING THE VENT EMERGENCY OPERATING INSTRUCTIONS ARE SYMPTOMATIC
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AND REQUIRE VENTING AT ELEVATED CONTAINMENT PRESSURES TO PRECLUDE CONTAINMENT FAILURE REGARDLESS OF RADIOLOGICAL CONDITIONS 1
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DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT j
SPOKESMAN TOPIC J. E. McCARTHY CURRENT ACTIVITIES-CALCULATIONS BEING PERFORMED TO DETERMINE IF STACK DRAIN VALVE CAN BE LEFT OPEN FOR DESIGN BASIS ACCIDENTS (GROUND LEVEL RELEASE)
STACK DRAIN VALVE ISSUE MUST BE RESOLVED CONCURRENT WITH NRC REVIEW OF-CONTROL ROOM EMERGENCY VENTILATION SYSTEM'S CONFORMANCE TO GDC 19 LOW POINT DRAINS VALVES TO BE REPLACED WITH FLOAT VALVES TO PRECLUDE MANUAL OPERATOR ACTION I
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~ BROWNS FERRY HARDENED WETWELL VENT TOPIC SP0KESMAN CONCLUSION J. E. MADD0X BFN HARDENED VENT MEETS OR EXCEEDS THE BWROG DESIGN CRITERIA
-BFN HAS BEEN PROACTIVE IN ADDRESSING NRC CONCERNS BFN WILL FULFILL ITS VOLUNTARY COMMITMENT TO INSTALL THE HARDENED VENT DURING THE UNIT 2 CYCLE 6 0UTAGE 9
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