ML20151Y630

Summary of 880811 Meeting W/Util in Rockville,Md Re Control Room Ventilation Sys.List of Meeting Attendees & Viewgraphs Encl

ML20151Y630
Person / Time
Site:	Browns Ferry
Issue date:	08/19/1988
From:	Gears G NRC OFFICE OF SPECIAL PROJECTS
To:	NRC OFFICE OF SPECIAL PROJECTS
References
NUDOCS 8808260495
Download: ML20151Y630 (21)

Text

'o. UNITED STATES

!" b NUCLEAR REGULATORY COMMISSION

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WASMNGTON, D. C. 20666 August 19, 1988 k ..... /

Docket No. 50-260 LICENSEE: Tennessee Valley Authority FACILITY: Browns Ferry Nuclear Plant, Unit 2

SUMMARY

OF OSP/TVA MEETING ON CONTROL ROOM EMERGENCY VENTILATION SYSTEM On August 11, 1988, the staff met with the Tennessee Valley Authority (TVA or the licensee) at the White Flint Building to discuss the Browns Ferry Control Room Emergency Ventilation System (CREYS). Enclosure 1 lists the meeting participants.

The licensee made a presentation describing the as-configured design of the CREVS and the identification of a potential problem with unfiltered duct leakage bypassing the CREVS. Enclosure 2 contains the slides used in the licensee presentation.

TVA provided a technical presentation (Enclosure 2) on the short tam solution to the identified problem. TVA's presentation included calculated dose estimates to control room operators based upon specific unfiltered leakage cases during specific accident events. The staff raised several questions concerning the selection of the appropriate design basis accident since main steam ifne breaks were not specifically addressed in the TVA presentation. The staff also noted that the projected operater dose calculations using the  ;

exfiltration case would most certainly require identification of compensatory measures by the licensee. As a result of discussions, the staff and TVA ,

t identified specific commitments and schedules for the potential resolution of I this issue. These comitments are identified in Enclosure 3 and are susinarized below:

TVA will provide technical justification in tems of dose calculations from spesified design basis accidents cases. This technical justification will be in support of a proposed Unit 2 liconse amendment to pemit one cycle of operation without a fully functional CREVS. Due September 30, 1988.

As part of the above submittal, TVA will provide a discussion on potential compensatory actions and a comitment to employ specific ccepensatory l actions, when and where appropriate. -

TVA will provide its long tem resolution and implementation sched91e for l identified CREVS functional deficiency within 90 days after restart of Unit 2.

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• NRC will review TVA's proposed technical justification and compensatory actions within 60 days of the receipt of TVA's submittal.  ;

l.s l Gerald E. Gears, Project Manager TVA Projects Division Office of Special Projects

Enclosures:

1. Attendanco List

2. Control Room Emergency Ventilation System

3. TVA Commitments cc w/ enclosures:

See next page DISTRIBUTION i Docket File NRC PDR Local PDR Those on Attached List 1

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OF0 :0SP:TVA/LA :0SP:TVA/PM :TYA: app  :  :  :  :  ;

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NAME iMSimms /h bb :GG :SBla6  :  :  :  : 1 i .....:............:.... .......:............:.................................................

DATE !8//t7/88 :8//4/88 i

8/l9/88  :  :  :  : i i

Mr. S. A. White Browns Ferry Nuclear Plant cc:

General Counsel Regional Administrator, Region II Tennessee Valley Authority U.S. Nuclear Regulatory Comission 400 West Sumit Hill Drive 101 Marietta Street, N.W.

Eli B33 Atlanta, Georgia 30323 Knoxville, Tennessee 37902 Resident Inspector / Browns Ferry NP Mr. R. L. Gridley U.S. Nuclear Regulatory Comission Tennessee Valley Authority Route 12, Box 637 SN 157B Lookout Place Athens, Alabama 35611 Chattanooga, Tennessee 37402-2801 Mr. C. Mason Dr. Henry Myers, Science Advisor Tennessee Valley Authority Comittee on Interior Browns Ferry Nuclear Plant and Insu'iar Affairs P.O. Box 2000 U. S. House of Representatives Decatur, Alabama 35602 Washington, D.C. 20515 Tennessee Valley Authority Mr. M. J. May Rockville Office Tennessee Valley Authority 11921 Rockville Pike Browns Ferry Nuclear Plant Suite 402 P.O. Box 2000 Rockville, Maryland 20852 Decatur, Alabama 35602 Mr. D. L. Williams Tennessee Valley Authority 400 West Sumit Hill Drive W10 B85 Knoxville, Tennessee 37902 Chairman, Limestone County Comission P.O. Box 188 Athens, Alabara 35611 l Claude Earl Fox, M.D.

State Health Officer State Departrient of Public Health State Office Buildir.g Montgomery, Alabama 36130 l

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ENCLOSURE 1 LIST OF ATTENDEES AUGUST 11, 1988 TVA/NRC MEETING l CONTROL ROOM HABITABILITY Name Organization Steven kane TVA/BFN/ Licensing Gerry Gears NRC/OSP Janet Kelly NRC/OSP Rex Wescott NRC/OSP Irwin Spickler NRC/NRR Phil Polk TVA William A. Eberly TVA Charlie Anderson TVA ,

Charles A. Chandley TVA Robert Pierson NRC/OSP i Charles R. Nichols NRC/NRR Mike May TVA/BFN/ Licensing  ;

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CONTROL ROOM EMERGENCY VnNTILATION-SYSTEM .

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BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM DEFINITION OF PROBLEM o CAQR BFP 870531 OBSERVED POTENTIAL PROBLEM VITH UNFILTERED DUCT LEAKAGE BYPASSING THE CREV SYSTEM o EMERGENCY SUPPLY AIR DUCT TRAVERSES CONTROL ROOM AND SE AMS LE AK e, NORMAL HVAC ISOLATION DAMPERS LEAX o LEAKAGE IS SIGNIFICANT (1800-3000 cfm) COMPARED WITH CREV FLOW OF 500 cfm o LEAKAGE NOT CONSIDERED IN CONTROL ROOM DOSE CALCULATIONS o CREV FLOW IS SUPPLEMENTED BY THE LEAKAGE TO MEET THE CONTROL ROOM PRESSURIZATION DESIGN OBJECTIVE 4

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BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM BACXGROUND o BROWNS FERRY FS AR J l

- SECTION 10.12 DESCRIBES THE CREV SYSTEM 1

- SECTION 14.10.5 DESCRIBES CONTROL ROOM SHIELDING AND DOSE CALCULATIONS

- ORIGINAL FS AR QUESTION 10.2 RESPONSE DESCRIBED CONTROL ROOM DOSE VITH CREVS AND EXFILTRATION FROM REACTOR BUILDING

- NO CREV PERFORMANCE ANALYSIS IN UPL ATED FS AR o TMI ITEM III.D.3.4 (NUREG-0737)

- TVA RESPONDED MARCH 17,1981

- REFERRED TO FSAR SECTION 14.10.5 FOR SHIELDING AND DOSE CALCULATIONS

- REFERRED TO QUESTION 10.2 RESPONSE FOR CREVS DESIGN DETAILS

- SUMMARIZED UPDATED HAZARDOUS CHEMICAL EVALUATION

- PROVIDED LIST OF ADDITIONAL DESIGN DETAILS

- STATED THAT PRESENT TECH SPECS ENSURE HABITABILITY l

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BROWNS FERRY

- CONTROL ROOM EMERGENCY VENTILATION SYSTEM BACKGROUND o NRC SAFETY EVALUATION (ITEM III.D.3.4)

- ISSUED AUGUST 30, 1982

- FOUND TVA RESPONSE ACCEPT)7LE FOR NORMAL AND ACCIDENT RADI ATION AND T0XIC GAS CONDITIONS

- OBSERVED WHOLE BODY EXPOSURE LIMITED TO LESS THAN 5 REM

- DID NOT ADDRESS GDC-19 THYROID LIMIT OF 30 REM o TECHNICAL SPECIFICATIONS

- CREVS ADDRESSED IN SECTION 3.7.E/4.7.E

- LCO REQUIRES BOTH TRAINS OPERABLE WITH FUEL IN REACTOR VESSEL

- ALLOWS ONE TRAIN INOPERABLE FOR UP TO 7 DAYS

- REQUIRE COLD SHUTDOWN IN 24 HRS AND TERMINATION OF REFUELING OPERATIONS IF MORE THAN 7 DAYS

- BASES CALL FOR LESS THAN 1 PERCENT BYPASS OF CHARCOAL FILTERS AND " ALL LEAKAGE SHOULD BE OUTLEAXAGE" FROM CONTROL ROCH l

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. TABLE 1

- CONTROL ROOM OPERATOR DOSES FOR LOCA AND FUEL H ANDLING ACCIDENT (FHA)

CONSIDERING CREVS BYPASS LEAKAGE WITHOUT EXFILTRATION FROM SECONDARY CONTAINMENT CASE PARAMETERS 30 DAY OPERATOR DOSE (rem)

Unfiltered Filtered Whole Body Whole Body Accident Bypass, CREV Flow, Gamma Beta Thyroid cfm cfm t

LOCA 2750 500 1.77 0.24 10.5 e

LOCA 726 500 1.77 0.23 7.3 FHA 2750 500 0.27 0.24 12.3 FHA 726 500 0.27 0.24 8.6 NOTES:

• Includes 1.75 rem contribution from direct shine from the secondary containment and core spray piping.

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l BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM i

l DESIGN BASIS FOR CONTROL ROOM HAEITAEILITY l

o CONTROL ROOM IN-LEAKAGE

- NOT RECOGNIZED IN ORIGINAL CREV DESIGN l

- MINIMAL (10 cfm) CONSIDERED IN DOSE CALCULATIONS i PRIOR TO THIS CONCERN o DOSE CALCULATIONS

- QUESTION 10.2 RESPONSE

• SHINE DOSE FROM SECONDARY CONTAINMENT

• STACK RELEASES

• SECONDARY CONTAINMENT EXFILTRATION l

• NO CREV BYPASS LEAKAGE i

• RESULTS:

TOTAL WHOLE BODY DOSE LESS THAN 2 REM TOTAL THYROID DOSE LESS THAN 24 REM I

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BROWNS FERRY CONTROL ROOH EMERGENCY VENTILATION SYSTEM DESIGN BASIS FOR CONTROL ROOM HABITABILITY o DOSE CALCULATIONS (CONT'D) )

CURRENT CALCULATION

• TID 14844 SOURCE TERM

• CONSIDERED LOCA, FUEL HANDLING, ROD DROP AND STEAM LINE BREAX ACCIDENTS

• INCLUDES: SHINE DOSE  !

l S5ACK RELEASES 2750 CFM CREV BYPASS  !

RECENT METEOROLOGY

• RESULTS:

LOCA IS CONTROLLING CASE l TOTAL WHOLE BODY DOSE LESS THAN 2 REM TOTAL THYROID DOSE = 10.5 REM

- EXFILTRATION CASE

• INCLUDES EXFILTRATION RELEASE PATH (GROUND LEVEL)

• LOCA RESULTS:

TOTAL WHOLE BODY DOSE LESS THAN 1 REM TOTAL THYROID DOSE = 295 REM 1

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l TABLE 2 QpNTROL qqqd,0PERATOR DOSES FOR LOCA CONSIDERING C ;V5 BYPASS LE AK AGE WITH EXFILTRATION FROM SECOND ARY _ CONTAINMENT l

se l 30 DAY OPERATOR DOSE (rem)

LOCA CASE P ARAMETERS ,

SC Whole Body Whole Body  !

Unfiltered Filtered Thyroid CREV Flow, Pressure, Gamma Beta Bypass, cfm cfm in. WG

-0.25 0.09 0.93 295. f 2750 500 i

" 0.09 0.90 280. ]

2200 500

" 0.06 0.67 107.

300 500

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100 1000 I 2750 500 -0.50 0.05 0.50 91.

l 500 -0.60 0.03 0.33 13. l 2750

., i NOTES:

• • These results include stack release contribution based on a J refined dispersion factor for fumigation conditions.

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CONTROL ROOM EMERGENCY VENTILATION SYSTEM l I

l PROPOSED SOLUTION DESIGN CONSIDERATIONS l i

o DUCT SEALING IS LESS THAN PERFECT

- RESIDUAL LEAXAGE ESTIMATED AT 10%

- SEALS MAY DEGRADE WITH TIME

- NOT ALL SEAMS ACCESSIBLE o POTENTI AL NEED FOR ADDITIONAL CREV CAPACITY IS HIGH o LONG LEAD TIME ON NEW CREV UNITS (MORE THAN 6 MONTHS) o DISRUPTIVE TO THE CONTROL ROOM o ASBESTOS FIBERS FOUND IN SOME DUCT INSULATION CEMENT j

o POSITIVE PRESSURE ENVELOPE DESIGN OBJECTIVE MORE IMPORTANT THAN CREV BYPASS CONCERN o DESIRE AN OPTIMUM SOLUTION CONSIDERING ALL CONTROL ROOM DESIGN OBJECTIVES ,

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BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM PROPOSED SOLUTION SCHEDULE  !

1 PHASE I o DEFINE THE PROBLEM 8/11/88 o EVALUATE HABITABILITY CONSEQUENCES 8/11/88 o IMPLEMENT DAMPER REFURBISHMENT 8/11/88 o DEVELOP TECHNICAL JUSTIFICATION FOR U2C5 8/11/88 AND FOR PHASE II PLAN

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• BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM PROPOSED SOLUTION SCHEDULE PHASE II o IDENTIFY OPTIONAL SOLUTIONS (SEE EXAMPLE) 9/30/88 o DEFINE SELECTION CRITERIA (SEE EXAMPLE) 9/30/88 o DEVELOP INPUT AND EVALUATE OPTIONS 10/15/88 (TECH. DATA, COST, SCHEDULE, ETC.)

o PERFORM DECISION ANALYSIS (KT) TO SELECT 11/01/88 2 OPTIONS (PRIMARY & ALTERNATE) o DEVELOP DETAILS ON SELECTdD OPTIONS 1/01/89 o CHECK / CONFIRM DECISION ANALYSIS 1/15/89 o PRESENT TO NRC FOR CONCURRENCE 1/31/89 o DEVELOP DESIGN CHANGE PACKAGE (S) o IMPLEMENT NODIFICATIONS o REVISE LICENSING DOCUMENTS o REVI.9E PROCEDURES & TRAINING o POST-MOD TEST o DESIGN CLOSURE 6/30/90 a

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BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM CREVS PLAN - PHASE II EXAMPLE SELECTION CRITERIA PROBLEM: HVAC DUCTWORK LEAXS, COMPROMISING THE CREVS DESIGN CONCEPT AND CREVS PRESSURIZATION CAPACITY IS LIMITED SOLUTION: HUST CRITERIA

1. YIELD CONTROL ROOM DOSES WITHIN ODC-19 LIMITS

2. MINIMIZE CREV FILTER BYPASS TO RESTORE CREV CONCEPT

3. BE IMPLEMENTED BEFORE U2C6, ASSUME BY 6/30/90

4. NOT CREATE OTHER PROBLEMS (DIESEL LOAD, EQ, SEISMIC, FIRE PROTECTION, ETC.)

5. MUST SUPPORT POSITIVE PRESSURE DESIGN REQUIREMENT WANT CRITERIA

1. MINIMIZE IMPACT ON OJERATIONS

2. IMPLEMENT WITH FUEL IN REACTOR VESSEL

3. MINIMIZE LICENSING / TECH SPEC CHANGES

4. MINIMIZE DISRUPTION TO CONTROL ROOM

5. MAXIMIZE COMPLI ANCE WITH LATEST STANDARDS

6. MINIMIZE COST i

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• I BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM i

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ggEVS PL AN - P H ASE II l I

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l IXAMPLE SOLUTION OPTIONS 1

1. SEAL DUCTWORK AND INSTALL LARGER CAPACITY CREV UNITS j 1

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2. REPLP.CE DUCTWORK WITH ALL WELDED AND REPLACE CREVS

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3. REROUTE DUCTWORK OUTSIDE CONTROL ROOM AND REPLACE CREVS l 4. REDUCE HABITABILITY ZONE ENVELOPE TO EXCLUDE DUCTWORK j (NEMBRANE) AND REPLACE CREVS l

5. PROVIDE ADDITIONAL CREY UNIT (S) WITH DEDICATED OUTSIDE I AIR SOURCE AND ISOLATE MAIN SUPPLY FOR SHORT PERIOD OF HIGH WIND $0LLOWING LOCA l i

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6. UPGRADE THE EMERGENCY SUPPLY AIR SYSTEM TO INCLUDE 1 CHARCOAL FILTERS AT THE INTAXES l i

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4 BROWNS FERRY CONTROL ROOM EMERGENCY VENTILATION SYSTEM PROPOSED SOLUTION JUSTIFICATION o POSSIBLE RESOLUTIONS 4

INVOLVE EXTENSIVE HARDWARE AND LICENSING CHANGES

- DIFFICULT TO IMPLEMENT IN SHORT TERM

- INTRUSIVE / DISRUPTIVE TO CONTROL ROOM

- HAVE POTENTIAL TO CREATE OTHER CONCERNS IF IMPLEMENTED HASTILY o DOSE RESULTS WITH EXISTING LEAKAGE CONDITION ARE WELL BELOW GDC-19 LIMITS (EXFILTRATION IS BEYOND DESIGN BASIS) l i

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, ' O!STRIBUTION FOR MEETING

SUMMARY

DATE0*ugust 19,1988 Facility: Brewis Ferry Nuclear Plant, Unit 2*

OISTRIBUTION

,.Doctet m e

• NRC POR Local POR Projects Reading OSP Reading J. Partlow S. Richardson S. Black B. D. Liaw i G. Gears

• D. Moran J. Kelly M. Sims F. McCoy J. Rutberg R. Wescott I. Spickler R. Pierson C. Nichols ACRS(10)

GPA/PA ,

GPA/CA (M. Callahan) (5) i F. Miraglia E. Jordan B. Grimes P. Gwynn J. Scarborough T. Elsasser C. Ader BFN Rdg. File f

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