ML20034G813
| ML20034G813 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/09/1993 |
| From: | Hebdon F Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9303110341 | |
| Download: ML20034G813 (25) | |
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t UNITED STATES 5 -(. "
E NUCLEAR REGULATORY COMMISSION
- D WASHINGTON, D.C. 20555 o,,g~f March 9, 1993 Docket Nos. 50-259, 50-260, and 50-296 LICENSEE: Tennessee Valley Authority FACILITY: Browns Ferry Nuclear Plant, Units 1, 2, and 3
SUBJECT:
SUMMARY
OF A MEETING WITH THE LICENSEE REGARDING THE CONTROL ROOM EMERGENCY VENTILATION SYSTEM On February 3,1993, representatives of the Tennessee Valley Authority (TVA) met with the NRC staff in Rockville, Maryland, to discuss staff concerns previously described in a letter dated January 29, 1993.
In this letter the staff detailed its concerns regarding the adequacy of a fan pressurization test used by TVA to quantify the rate of unfiltered inleakage into the Control l
Building Habitability Zone (CBHZ) of the Browns Ferry Nuclear Plant (BFN).
Meeting attendees are listed in Enclosure 1.
Handouts provided by TVA at the meeting are contained in Enclosure 2.
The unfiltered inleakage rate is a critical assumption used by TVA's control room dose calculations for confirming compliance with General Design Criteria (GDC) 19 of Appendix A to 10 CFR 50.
Previous review efforts by the stzff identified some potential discrepancies with the special test (i.e., special test procedure 0-ST-91-07) TVA used to establish the rate of unfiltered inleakage into the CBHZ. By letter dated January 29, 1993, the staff expressed the following concerns:
1.
The testing methodology of special test procedure 0-ST-91-07 was inappropriate.
2.
The inleakage contribution from other ventilation systems that penetrate the control room was not accounted for.
3.
Affected systems (e.g., Control Room Emergency Ventilation System) were not properly configured during conduct of the special test procedure.
4.
Quantifying the control room inleakage on a routine basis should be incorporated as a Technical Specifications (TS) surveillance requirement, or justified otherwise.
In the context of their presentation, TVA discussed each of the aforementioned concerns in great detail. TVA provided its justification for using the fan pressurization method instead of the tracer gas dilution method. TVA also g[
explained how it quantified the unfiltered contribution of other ventilation systems and why the testing configuration was conservative.
Furthermore, TVA kl [J
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! l committed to develop a surveillance instruction (SI) for conducting regular tests of the coatrol room to determine the amount of unfiltered inleakage.
This SI would be a plant procedure only, not a TS surveillance requirement.
By the end of the meeting, TVA appeared to have adequately addressed each of the staff's concerns.
The staff's final conclusions regarding these concerns will be documented in a future safety evaluation.
It should be noted, that by letter dated March 1,1993, TVA has subsequently submitted a formal response to the staff's letter of January 29, 1993.
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Y Frederick J. Hebchn, Director Project Directorate 11-4 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosures:
- 1. Attendance List
- 2. Handouts cc w/ enclosures:
See next page i
I 1
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l committed to develop a surveillance instruction (SI) for conducting regular tests of the control room to determine the amount of unfiltered inleakage.
This SI would be a plant procedure only, not a TS surveillance requirement.
By the end of the meeting, TVA appeared to have adequately addressed each of the staff's concerns.
The staff's final conclusions regarding these concerns will be documented in a future safety evaluation.
It should be noted, that by letter dated March 1,1993, TVA h;s subsequently submitted a formal response to the staff's letter of January 29, 1993.
Original signed by Frederick J. Hebdon, Director Project Directorate 11-4 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosures:
- 1. Attendance List
- 2. Handouts l
cc w/ enclosures:
l See next page Distribution
- Docket.Filec(Enc 1osures 1 and 2)
NRC '&Tocal"PDRs (Enclosures 1 and 2)
BFN Reading (Enclosures 1 and 2)
T. Murley/F. Miraglia (Enclosure 1)
J. Partlow (Enclosure 1)
S. Varga (Enclosure 1)
G. Lainas (Enclosure 1)
F. Hebdon (Enclosure 1)
T. Ross (Enclosures 1 & 2)
J. Williams (Enclosures 1 & 2)
M. Sanders (Enclosure 1)
E. Jordan (Enclosure 1)
L. Cunningham (Enclosure 1)
J. Hayes (Enclosure 1)
- 1. Miller (Enclosure 1)
C. Patterson (Enclosures 1 and 2)
E. Merschoff (Enclosures 1 and 2)
P. Frederickson (Enclosures 1 and 2) l ACRS (10) (Enclosure 1)
L. Plisco, EDO (Enclosure 1) cc:
Licensee & Service List 0FC PDII-4/LA PDII-4/PM PDII-4/PM/f4 PDIIt4/D NAME MSanders flyd TRoss:asI JWillia [
FHNdon DATE
$/k /93 1/8 /93 3 /f' /93 2 / 9 /93 DOCUMENT NAME: CREWSMTG.SMY
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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 i
i Mr. J. R. Bynum, Vice President Regional Administrator
l 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.N.R.C.
P.O. Box 2000 Route 12, Box 637 Decatur, Alabama 35602 Athens, Alabama 35611 l
1 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 0. Medford, Vice President Nuclear Licensing and Regulatory Affairs Nuclear Assurance, Licensing and Fuels 5B Lookout Place Tennessee Valley Authority 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 llH 400 West Summit Hill Drive Knoxville, Tennessee 37902 l
Chairman, Limestone County Commission
-P.O. Box 188 Athens, Alabama 35611 1
Enclosure I ATTENDEES February 3. 1993 Hamt Oroanization Lemoine Cunnigham NRC/PRPB John Hayes NRC/PRPB Isabel Miller NRC/SPLB Frederick Hebdon NRC/PDII-4 Thierry Ross NRC/PDII-4 Joe Williams NRC/PDII-4 Charles Patterson NRC/RII Glenn Silver TVA/BFN Nuclear Engineering William Eberly TVA/BFN Nuclear Engineering Leo Klaes TVA/BFN Nuclear Engineering Howard Crisler TVA/BFN Nuclear Engineering Greg Pierce TVA/BFN Licensing Mike Morrison TVA/BFN Licensing Steve Kane TVA/BFN Licensing Roger Huston TVA/Rockville Office l
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ENCLOSURE 2 AGENDA FOR TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENTILATION SYSTEM (CREVS)
SPOKESMAN TOPIC BACKGROUND G. D. PIERCE ISSUES G. D. PIERCE TVA RESPONSE TO ISSUES G. A. SILVER CONCLUSION G. D. PIERCE OPEN DISCUSSION
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SPOKESNAN TVA RESPONSE TO ISSUES G. A. SILVER LOCATION OF CONTROL BUILDING WITH RESPECT TO OTHER PLANT BUILDINGS (FIGURE 1) o THE CONTROL BAY HABITABILITY ZONE IS LOCATED IN THE CONTROL BUILDING o THE FANS THAT PRESSURIZE THE DUCTWORK THAT SUPPLIES EQUIPNENT IN THE CONTROL BUILDING-ARE LOCATED IN THREE VENT TOWERS ON TOP OF THE CONTROL BUILDING a
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SPOKESMAN TVA RESPONSE TO ISSUES (CONTINUED)
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. LAYOUT AND EQUIPMENT LOCATED IN THE CONTROL BUILDING (FIGURE 2) o DESCRIPTION OF SUPPLY FANS IN EACH VENT TOWER o DIFFERENCES BETWEEN TOWERS i
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. DESCRIPTION OF DUCTWORK THAT PENETRATED THE HABITABILITY ZONE AND THE EQUIPNENT/ AREAS SERVED BY THAT DUCTWORK (FIGURE 4) o THE FANS IN THE THREE VENT TOWERS NAY OPERATE DURING AND AFTER AN ACCIDENT t
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. DESCRIPTION OF SPECIAL TEST CONFIGURATION (FIGURE 5)
. TESTING PERFORMED TO DETERMINE BOUNDARY OUTLEAKAGE AREA o HABITABILITY ZONE PRESSURIZED BY DOOR FAN o VENT TOWER FANS ISOLATED o HABITABILITY ZONE PRESSURE AND DOOR FAN FLOW MEASURED o HABITABILITY ZONE LEAKAGE AREA CALCULATED 12
TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENTILATION SYSTEM (CREVS)
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G. A. SILVER
. TESTING PERFORMED TO DETERMINE AMOUNT OF PRESSURIZATION AS A RESULT OF UNFILTERED INLEAKAGE o DOOR FAN DISCONNECTED o VENT TOWER FANS STARTED IN GROUPS o HABITABILITY ZONE PRESSURE MEASURED AFTER EACH FAN GROUP STARTED ~
. ANALYSIS PERFORNED TO CALCULATE UNFILTERED INLEAKAGE RATE IN ACCORDANCE WITH NFPA 12A 13
l TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENTILATION SYSTEM (CREVS) o,
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SPOKESMAN TVA RESPONSE TO ISSUES (CONTINUED)
G. A. SILVER
. THE CALCULATION OF THE UNFILTERED INLEAKAGE IS CONSERVATIVE o PRESSURIZATION OF THE HABITABILITY ZONE FROM THE CREVS UNITS WOULD INCREASE THE HABITABILITY ZONE PRESSURE o RESULTING IN A DECREASE IN THE DIFFERENTIAL PRESSURE BETWEEN THE SUPPLY DUCTWORK AND THE HABITABILITY ZONE o LESS DRIVING FORCE WOULD DECREASE THE RATE OF UNFILTERED INLEAKAGE SINCE THE HABITABILITY ZONE WOULD'BE AT A RELATIVELY HIGH PRESSURE COMPARED TO THE OUTSIDE, ALL OTHER LEAKAGE WOULD BE OUTLEAKAGE 14 i
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TOPIC r
SPOKESMAN TVA RESPONSE TO ISSUES (CONTINUED)
G. A. SILVER
. TVA DETERMINED TOTAL AMOUNT OF UNFILTERED INLEAKAGE
. THE IDENTIFICATION OF INDIVIDUAL INLEAKAGE CONTRIBUTORS IS NOT NECESSARY TO SHOW COMPLIANCE WITH GDC 19
. TVA'S ESTIMATE OF UNFILTERED INLEAKAGE INTO THE CONTROL BAY HABITABILITY ZONE INCLUDED:
o THE LEAKAGE PAST DAMPERS FC0 150B AND 150D o
THE DUCTWORK THAT PENETRATES-THE CONTROL ROOM ENVELOPE o
THE FLOOR, CEILING, AND SIDE WALLS OF THE I
CONTROL ROOM ENVELOPE TVA'S-ANALYSIS ENVELOPED THE OPERATING ALIGNMENT THAT WOULD EXIST IN THE EVENT OF AN ACCIDENT
. TVA'S DETERNINATION OF UNFILTERED INLEAKAGE INTO THE CONTROL BAY HABITABILITY ZONE IS CONSERVATIVE
. ~. _ _...
b TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENTIL.ATION SYSTEM (CREVS)
TOPIC r
SPOKESNAN TVA RESPONSE TO ISSUES (CONTINUED)
G. A. SILVER
. TVA WILL DEVELOP A SURVEIL..dCE INSTRUCTION TO REQUIRE PERIODIC TESTING TO QUANTIFY UNFILTERED INLEAKAGE
. THE FOLLOWING PARANETERS WILL BE ADDRESSED:
o CREVS FLOW RATE o
HABITABILITY ZONE BOUNDARY OUTLEAKAGE o
THE HABITABILITY ZONE BOUNDARY PRESSURE o
A BASELINE TEST WILL BE ESTABLISHED AS PART OF THE CREVS POST-NODIFICATION TESTING
. A SUBSTANTIAL CHANGE IN THE FLOW RATES REQUIRED TO NAINTAIN THE BOUNDARY PRESSURE WOULD INDICATE BOUNDARY DEGRADATION
. THE UNFILTERED INLEAKAGE WILL BE DETERNINED BASED ON TEST RESULTS 17 m
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TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENTILATION SYSTEM (CREVS)
TOPIC t
SPOKESMAN TVA RESPONSE TO ISSUES (CONTINUED)
G. A. SILVER
= THE WORDING OF THE CURRENT BFN TECHNICAL SPECIFICATION SURVEILLANCE REQUIREMENT 4.7.E.3 IS SIMILAR TO THE IMPROVED STANDARD TECHNICAL SPECIFICATION SURVEILLANCE REQUIREMENT
. NO CHANGE TO THE BFN TECHNICAL SPECIFICATIONS IS REQUIRED
. TVA HAS A PROGRAM IN PLACE TO CONTROL PENETRATIONS 0F THE HABITABILITY ZONE AND A MAINTENANCE PROGRAM FOR DOOR SEALS j
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TVA/NRC MEETING ON FEBRUARY 3, 1993 CONTROL ROOM EMERGENCY VENT 7.LATION SYSTEM (CREVS)
TOPIC r
SP0KESMAN CONCLUSION G. D. PIERCE
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. TVA'S ESTIMATE OF UNFILTERED INLEAKAGE INTO THE CONTROL BAY HABITABILITY ZONE IS CONSERVATIVE
. TVA WILL PERFORM A PERIODIC SURVEILLANCE TO QUANTIFY UNFILTERED INLEAKAGE 19
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