ML20126K443

Summary of 921216 Meeting W/Util in Rockville,Md Re Discussions on Design & Operation of Plant Hardened Wetwell Vent.List of Attendees & Meeting Agenda Encl

ML20126K443
Person / Time
Site:	Browns Ferry
Issue date:	12/30/1992
From:	Williams J Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20126K433	List: ML20126K429 ML20126K443
References
TAC-M84161, TAC-M84162, TAC-M84163, NUDOCS 9301070125
Download: ML20126K443 (13)

Text

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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

SUMMARY

OF THE DECEMBER 16, 1992 MEETING REGARDING DESIGN AND OPERATION OF THE BRCWNS 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 < 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 up 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 valvor 41ch required local maw action when the vent is operated. The insp ,' n team was concerned 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 j 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 anuary 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 L a, .ordance 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 L will install float valves on two of the three drain lines. These float valves l will operate' passively, eliminating the need for local operator action on l these lines. The third drain valve is located within the plant stack. TVA is L evaluating whether or not this valve can be opened during an accident and left L

1 9301070125 921230 9 PDR ADOCK 0500 l P

open without increasing ground-level radiation source terms and associated doses beyond regulatory limits for design basis events. if this valve can be left open, the team's concern regarding local operator action will be resolved. TVA will inform the staff of the results of its evaluation.

Joseph F. Williams, Project Manager Project Directorate 11-4 Division of Reactor Projects - I/II

Enclosures:

1. List of Attendees

2. TVA Handouts cc w/ enclosures:

See next page

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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 Summit Hill Drive Montgomery, Alabama 36130-1701 Knoxville, Tennessee 37902 Mr. J. R. Bynum, Vice President Regional Administrator Nuclear Operations U.S.N.R.C. Region II 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.H.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 SB Lookout Place Nuclear Assurance, Licensing and Fuels Chattanooga, Tennessee 37402-2801 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 11H 400 West Summit Hill Drive Knoxville, Tennessee 37902 Chairman, Limestone County Commission P.O. Box 188 Athens, Alabama 35611 1

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,- C ENCLOSURE 1 ATTENDEES DECEMBER 16, 1992 TVA/NRC MEETING BROWNS-FERRY. HARDENED WETWELL VENT DESIGN AND OPERATION MAM{. ORGANIZATION .

Joe Williams NRR/DRPE/PD 11-4 Joe McCarthy TVA Recovery Mechanical / Nuclear <

Engineering Manager, _

Greg Pierce TVA Browns Ferry Licensing Manager Ron Frahm NRR/DSSA/PSAB Lambros Lois NRR/DSSA/SRXB Jim Maddox TVA Browns Ferry-Engineering Manager f

Max Herrell TVA Browns Ferry Operations Manager Fred Hebdon NRR/ Director, PD 11-4 Jack Kudrick NRR/DSSA/SCSB Cheryl Beardslee NRR/DRPE/PD 11-4 Mohan Thadani NRR/DRPE/PD 11-4 Thierry' Ross NRR/DRPE/PD II-4 Matt Mueller TVA Mechanical / Nuclear Engineering Sam Malur MRR/DRIL/RSIB n

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AGENDA -

DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SP0KESMAN ,

BACKGROUND G. D. PIERCE 4

VENT PATH J. E. McCARTHY DESIGN GUIDELINES / CRITERIA J. E. McCARTHY ISSUES J. E. McCARTHY CURRENT ACTIVITIES J. E. McCARTHY CONCLUSION J. E. MADD0X t

DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT ,

l TOPIC SP0KESMAN 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-

- 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'NEXT UPDATE AFTER INSTALLATION COMPLETED b

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DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN VENT PATH J. E. McCARTHY

. : PROPOSED VENT PATH SHOWN ON THE ATTACHED FIGURE

. PROVIDES 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 3

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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 OPERATE DURING AN STATION BLACKOUT EVENT

. THE BFN HARDENED VENT IS AN ACTIVE SYSTEM; IT WILL NOT OPERATE PASSIVELY, WITHOUT OPERATOR ACTION'

. INADVERTENT.0PERATION 0F THE BFN HARDENED VENT IS PREVENTED BY KEY LOCK SWITCHES IN THE CONTROL ROOM FOR THE' ISOLATION VALVES 5

L DECEMBER 16, 1992 3 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 i

TOPIC SPOKESMAN ISSUES -

J. E. McCARTHY

- CURRENT DESIGN REQUIRES MANUAL OPENING OF A DRAIN 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'0PERATING INSTRUCTI0I45 ARE SYHPT0MATIC AND REQUIRE VENTING AT ELEVATED CONTAINMENT PRESSURES T0' PRECLUDE CONTAINMENT FAILURE REGARDLESS OF RADIOLOGICAL-CONDITIONS b

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DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN CURRENT ACTIVITIES- - J. E. McCARTHY

. 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 0F CONTROL ROOM EMERGENCY VENTILATION SYSTEM'S CONFORMANCE TO GOC 19

. LOW POINT ORAINS VALVES TO BE REPLACED WITH FLOAT VALVES TO PRECLUDE MANUAL OPERATOR ACTION 8

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DECEMBER 16, 1992 BROWNS FERRY HARDENED WETWELL VENT TOPIC SPOKESMAN CONCLUSION -

J. E. MADDOX

. -BFN HARDENED VENT MEETS OR EXCEEDS THE BWR0G 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

.