ML20246P827
| ML20246P827 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 01/07/1987 |
| From: | Hood D Office of Nuclear Reactor Regulation |
| To: | Tucker H DUKE POWER CO. |
| Shared Package | |
| ML20246P833 | List: |
| References | |
| NUDOCS 8905220290 | |
| Download: ML20246P827 (5) | |
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'n NUCLEAR REGULATORY COMMISSION f9
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January 7, 1987 fccket Nos.: 50-369 and 50-370 e
i Mr. H. B. Tucker, Vice President Nuclear Production Department Duke Power Company 422 South Church Street Charlotte, North Carolina 28242
Dear Mr. Tucker:
SUBJECT:
REQUEST FOR PROPOSED CHANGE TO TECHNICAL SPECIFICATION 3/4.7.7, " AUXILIARY BUILDING FILTERED VENTILATION EXHAUST SYSTEM,"
McGUIRE NUCLEAR STATION, UNITS 1 AND 2 By letter dated September 16, 1985, you requested that the Action Statement to McGuire Technical Specification 3/4.7.7, " Auxiliary Building Ventilation -
Exhaust (VA) System" be modified to allow one system to be inoperable for 7 days, instead of the current 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time limit.
In support of this request, you noted that while there is only one VA system per McGuire unit, redundancy could be met through the VA systen in the other unit because:
(1)eachsysten, has its air intake in the same general open areas of the auxiliary building; (2) each VA system, while not of eaufvalent capacit the auxiliary building at a negative pressure; (3) y, is capable of maintaining following a LOCA on either reactor, both VA systems start automatically; and (4) both VA systems have a diversity of power sources.
You also indicated that these systems are not required to reduce the consequences of ECCS pump room leakage in order to meet
- 10 CFR Part 100 dose criteria following a design basis LOCA.
l The NRC's evaluation of the radiological consequences of a design basis LOCA included an assumption of leakage associated with a gross failure of a passive component pursuant to Standard Review Plan Section 15.6.5, Appendix B.
We, thus, found that the VA system was necessary to mitigate the consequences of a LOCA. In order to have some confidence that either VA system could fulfill the redundancy requirements, you were requested in our December 20, 1985 letter to provide additional data justifying that the VA system of lower flow capacity (43,400 cfm) could independently establish negative pressure for those areas normally serviced by the 54,282 cfm VA system.
We also requested that you provide additional data justifying that either VA system could provide sufficient cooling to the cubicles of the other unit's equipment even for the lower capacity rated VA system.
On September 2,1983, Duke Power Company first requested relief from the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO when the charcoal in the Unit 1 VA system failed the acceptance i
criteria. The requested relief was granted October 6,1983 by license amendment 24.
On September 20, 1985, you again requested emergency relief from the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LC0 of the technical specification on the VA system because the Unit 1 VA system had been declared inoperable due to the failure of a carbon sample to pass the acceptance criteria.
However, the system was subsequently retested and declared operable orior to the end of the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> limit.
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Mr. H.B. Tucker January 7, 1987 Discretionary enforcement was requested due to failure of the Unit 2 carbon filter saraples on Scpterr'ber 23, 1986.
This enforcement was granted based on certain information that was supplied by Duke Power Cerrpery and a ; stipulation that Duke Power Company make efforts to demonstrate that the VA systern for either unit be able to achieve a negative pressure of 0.25 inches of water gauge (P.G.) relative to the atnosphere.
Ycu agreed to provide a plan by October 7,1986 describing this performance gc61.
In addition, you coritaitted in your September 25, 1986 letter to address those items of additionai infor1aation requested by NRC letters dated Noven,ber 29, 1985 and Decer.ber P0,1985; NRC inspection reports 50-369/86-01 and 50-370/E6-01 and 50-369/85-39 and 50-370/85-40; concerns raised in the June 19,19FF SALP Ecard Report; and those itens raisec curing discussions of Septenber P3 and 24, 1986, on the terr.perary waiver request.
Your October 9,1986 letter transmitted some of the information requested by the staff.
In this transmitted you indicated:
(1) that while Duke Power Company will strive to meet the 0.25 inch W.G.
negative pressure in the euxiliary building when tested in 10 rocoth intervels, the licensing basis of the plant is that the VA system is designed to maintair the auxiliary building slightly negative. Any significant degradation would be evaluated by Duke but the 0.25 inch W.G.
limit would not be considered an acceptance criterion for system operability and any fGC attempt to impose such a limit wculd be considered a backfit subject to 10 CFR 50.109; (2) that the VA syster is not considered necessary to remove heat in order to mitigate the consequences of an accident and while the estirated building temperature is expected to reach 135 F and that temperature exceeds the t
torperature established for continuous operation of some essentiel equ4prent, a terrperary excursion to this level is considered acceptable; and (2) that the McGuire VA systern contains inherent features which will lir.it tFe influent relative humidity to approximately 70% under all postulated cer:ditions. Any desired hRC design changes (e.g., heaters) to impreve effective sustained operatico during humid conditions should be pursued through the backfit rule.
Based on the staff's review of the inferration that you have provided, the technical specification change is denied.
Our denial is based on the following considerations:
(1) You tre erperently unwilling to cormit to a periodic surveillance test to deraonstrate that either VA systen will ensure releases to the auxilicry builpira ECCS areas will be processec by filters prior to release to the envi ronroent.
The staf f acceptance criterion for this is a demonstration throuch periodic testing, of meeting 0.25 inches W.G. negative pressure in these areas.
You state that any staf f atterapt to implement the 0.25 inch W.G. limit in the technical speci11 cation would be a backfit.
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-Mr. H.B. TuckerL
. January 7,=1987
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disagrees =that this denial constitutes a backfit.
imposed on the existing design or technical specificationFirst, no change'is-The issue ef a
-criterion is raised only in regard to. a request for change., Such chance involves considerations not previously reviewed by the fiRC staff.) Second.
you requested the change based on the claim that each of the VA systems could be considered redundant to the other.
The existing LC0/ Action
' Statements are based on a system design involving a single VA system forL each unit. The request to utilize a 7-day LC0/ Action Statement is e
~
request to utilize an LC0/ Action Statement appropriate to a VA syster
'. designed'with redundant trains for each unit. However, the configuration-of the ficGuire VA system does not support a finding of true redundancy because each VA system has only one train. NcGuire ventilation systen suctions for each of the VA systems are in the ECCS pump rooms of thet-unit, not.in the adjoining unit's ECCS pump rooms. Therefore, there ib doubt that adequate suction can be achieved in the adjacent purp room, Without e demonstration of. 0.25 inch W.G. negative pressure there is inadequate assurance that a single train will provide adeouete suction to collect leakage from the adjacent pump rcom.
Duke proposed no other pressure criterion (other than "any" negative pressure) end does not provide for uncertainty factors such as wind which can adversely affect system function with a single VA train.
(?) 'The systems must be able to provide sufficient cooling to the post-accident-equipment in the adjoining unit. Appropriate justification was not e
provided by Duke Power Company to support its claim that although the.
estimated building temperature could reach 135 F and that temperature
'i exceeds.the temperature established for continuous ' operation of some essential equipment, thet the excursion to this level is considered acceptable, nor was any demonstration provided.
(3)' Finally, you did not describe the inherent features which will limit the -
-influent relative humidity to'approximately 70% under all postulated conditions, nor any data which show that the charccal does not become saturated during high humidity conditions. Hence, we rerain concerned about the reliability of. a single VA train for the McGuire design (i.e.,
one filter pack per ficGuire unit) to accomplish its post-accident (iodine removal) function, especially after a period of prior operation.
Therefore, we believe that the period of dependency upon a sinole filter pack is appropriately limited by the present McGuire technical specification.
Accordingly, existing Technical Specification 3/a.7.7 remains in effect and no further review is plenned regarding your request for change.
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v Mr. H:B. Tuc,ker o j _ og. g '7 Enclosed. is a copy of a related notice which has been forwarded to the Office of the Federal Register for publication.
Sincerely, Darl Hood, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A
Enclosure:
As stated cc: See next page DISTRIBUTION:
Docket File BJYoungblood Reading EJordan NThompson Local PDR DHood JPartlow ACRS(10)
NRC PDR PWR#4 Reading BGrimes MDuncan
- SEE PREVI0lls CONCURRENCE pS6
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- PWRi4/DPWR-A
- PKRhDPWR-A rd u.rgP-A f
DHood/ rad PDubcan bJY n b ood 12/ /86 12/ /86
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Mr. H. B. Tucker Duke Power Company.
McGuire Nuclear Station cc:
i Mr. A.V. Carr, Esq.
Dr. John M. Barry,,
Duke Power Company Department of. Environmental Health l
P. O. Box 33189
'Mecklenburg County l.
422 South Church Street 1200 Blythe Boulevard Charlotte, North Carolina 28242 Charlotte, North Carolina 28203 County Manager of Mecklenburg County 720 East Fourth Street Charlotte, North Carolina 28202 Chairman, North Carolina Utilities Commission
-j Mr. Robert Gill Dobbs Building Duke Power Company 430 North Salisbury Street Nuc1 car Production Department Raleigh, North Carolina 27602 P. O. Box 33189 Charlotte, North Carolina - 28242 Kr. Dayne H. Brown, Chief Radiation Protection Branch J. Michael McGarry,. III, Esq.
Division of Facility Services Bishop, Liberman, Cook, Purcell Department of Human Resources and Reynolds 701 Barbour Drive 1200 Seventeenth Street, N.W.
Raleigh, North Carolina 27603-2008 Washington, D. C.
20036 Senior Resident Inspector c/o U.S. Nuclear Regulatory Connission Route 4, Box 529 Hunterville, North Carolina 28078 Regional Administrator, Region II U.S. Nuclear Regulatory Cocinission,
'.101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 L. L. Williams Area Manager, Mid-South Area ESSD Projects Westinghouse Electric Corporation MNC West Tower - Bay 239 P. O. Box 355 Pittsburgh, Pennsylvania 15230
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