ML20080G836

Application to Amend Licenses NPF-9 & NPF-17,requesting Emergency Change to Allow Maintaining Hot Standby on Unit 1 W/Auxiliary Bldg Filtered Ventilation Exhaust Sys Inoperable While Carbon in Filter Unit Is Replaced

ML20080G836
Person / Time
Site:	McGuire, Mcguire
Issue date:	09/02/1983
From:	Owen W DUKE POWER CO.
To:	Adensam E, Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20080G843	List: ML20080G836 ML20080H051
References
NUDOCS 8309200367
Download: ML20080G836 (5)

Text

b * .

+

DUKE POWER GOMPANY Powan BurLntwo. Box 00109, CHARLOTTE,N. G. coa 4a W.**.OWEN gaECWM WuC4 POES4 DENT

- - **=' - September 2, 1983 - m-o Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: McGuire Nuclear Station Docket Nos. 50-369, 50-370

Dear Mr. Denton:

Attached is a proposed license amendment to the Technical Specifications for Facility Operating Licenses NPF-9 and NPF-17. This amendment concerns the Auxiliary Building Filtered Ventilation Exhaust System. The attached safety analysis and analysis of significant hazards considerations conclude that the proposed change does not involve a significant hazards consideration and does not adversely affect the health and safety of the public.

It is requested that this change be handled as an emergency change pursuant to 10 CFR 50.91. The situation described in the attachment could not have been avoided since the sample results were received on September 2,1983. This carbon sample was being analyzed to comply with Technical Specification 4.7.7.b.2) which requires a sample every 18 months. There was no reason to expect the sample results to be above the 1 percent limit since no flow goes through the carbon bed during normal operation. Consequently, Duke Power Company does not create the situation to take advantage of the emergency provision of 10 CfR 50.91.

Failure to grant the requested change will involve the derating of McGuira Unit 1 by forcing the unit to remain in a shutdown condition for an additional 3f, Murs.

With the requested change, Unit I will be maintained in a hot standby condition while the carbon in the filter unit is changed (approximately a three-day process).

Without the requested change, Unit I will be required to go to cold shutdown while the carbon in the filter unit is changed. With the unit in hot standby, plant start-up can commence virtually immediately once the work on the filter unit is completed. With the unit in cold shutdown, the plant must be heated up to full pressure and temperature before plant start-up can commence. Under optimum conditions with no ' problems occurring, this heat-up requires approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Thus, without the requested change, McGuire Unit I will be forced to remain shutdown for an additional 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. An equally importar.t reason for granting the proposed change is that one thermal cycle would be avoided. This has real benefits in terms of availability, component lifetime and safety.

Bobl l[I 8309200367 830902 N 00,00 PDR ADOCK 05000369 P PDR kl 2

T Mr. Ha'r old R. Denton, Director September 2, 1983 Page 2 Pursuant to 10 CFR 170.22, we propose that this request involves a Class III license amendment for McGuire Unit 1 and a Class I amendment for McGuire Unit 2. Accordingly, a check for $4,400 is enclosed. This acendment has been reviewed and determined to have no adverse safety or environmental impact.

Very truly yours, g4J -

Warren H. Owen GAC/php Attachments cc: Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Mr. Dayne Brown, Chief Radiation Protection Branch Division of Facility Services Department of Human Resources P. 0. Box 12200 Raleigh, North Carolina 27605

-Mr. W. T. Orders NRC Resident Inspector McGuire Nuclear Station l

l l

l

s Mr. Harold R. Denton, Director September 2, 1983

- Page 3 WARREN H. OWEN, being duly sworn, states that he is Executive Vice President of Duke Power Company; that he is authorized on the part of said Company to sign and file with the Nuclear Regulatory Commission this revision to the McGuire

' Nuclear: Station Technical Specifications, Appendix A to License Nos. NPF-9 and NPF-17; and that all statements and matters set forth therein are true and

- correct to the best of his knowledge.

Yl))tib) W Warren H. Owen, Executive Vice President Subscribed and sworn to before me this 2nd day of September, 1983.

o 0' If6tary Public '

i My Commissiori Expires:

September 20, 1984 L. _

HRD/CAC Attachment Septdabsr 2, 1983 Justification and Safety Analysis The proposed amendment would allow maintaining HOT STANDBY on Unit 1 until 11:59 p.m. September 7, 1983, with the Auxiliary Building Filtered Ventilation-Exhaust System (VA) inoperable. A sample of the charcoal filters for the VA System failed to pass surveillance requirements. Thus, the existing Technical Specification 3.7.7 requires shutdown ultimately to COLD SHUTDOWN. Replacing the charcoal and retesting is expected to require at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Maintain-ing HOT STANDBY during this period would reduce the time required to restart the unit and would prevent an unnecessary thermal cycle on plant equipment.

The function of the Auxiliary Building Filtered Ventilation Exhaust System (VA) is to filter radioactive materials associated with coolant leakage from ECCS equipment in the auxiliary building following a LOCA which may involve release from the fuel as a result of heatup. With the reactor at shutdown, the stored energy of the reactor system and core decay heat is relatively small.

Consequently, the core heatup and any accompanying release are expected to be much milder than the design basis conditions. Furthermore, the duration of standby mode requested by this Technical Specification change embodies only an insignificant exposure time for a LOCA (greater than 6 inches) with potential for core heatup. For example, considering a large break (> 6 inches) LOCA frequency of 4.7 x 10-5 per reactor year (see Sequyoh RSSMAP - NUREG/CR-1659) the probability of a large break LOCA during a six-day period is 7.7 x 10-7 There-fore, the proposed Technical Specification change does not involve any undue risk tu the health and safety of the public.

Furthermore, during the period of VA System inoperability while replacing the charcoal, the Unit 1 Ventilation System will be isolated to prevent unfiltered leakage from the ECCS pump areas. Because the ECCS pump areas are open to the Auxiliary Building which is shared for both units. ECCS leakage would be substantially filtered by the Unit 2 VA System filters before release off-site. During this period, operators will be instructed to manually start the Unit 2 VA System fans in the event of a LOCA on Unit 1.

l i

l l

f l

. .. HRD/CAC S:ptd:bar 2, 1983 Analysis of Significant Hazards Consideration Because the VA System serves only to mitigate the consequences of a LOCA, the l probability of an accident is unaffected by the proposed amendment. The con-sequences of an accident are not significantly increased by the proposed amend-ments because (1) the Unit 2 VA System would provide substantial filtration of postulated ECCS leakage, (2) the core heatup and any accompanying release would be milder at HOT STANDBY conditions than for the design basis at full power, and (3) the probability of a LOCA during a six-day period is small (7.7 x 10-7).

No new or different accident is created by the proposed change because the VA System only serves to mitigate accidents.

The safety margins contained in the LOCA analyses described in the FSAR are unaffected. Also, the dose consequences of a postulated LOCA are not signifi-cantly affected with the Unit 1 filter out of service. Accordingly, the proposed amendment would not involve a significant decrease in a safety margin.

Therefore, according to the standards of 10 CFR 50.92, the proposed amendment does not involve a significant hazards consideration.

. . , , _ . , . _ . . _ .