ML20044B175

Responds to NRC Request for Addl Info Re Util 890726 Proposed Amend to Tech Specs to Allow Continued Operation for Period of 12 H W/Main Steam Tunnel High Ambient Temp & High Ventilation Sys Differential Trips Bypassed

ML20044B175
Person / Time
Site:	LaSalle
Issue date:	07/09/1990
From:	Morgan W COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9007180035
Download: ML20044B175 (4)

Text

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'N Commonwealth Edison i ) 1400 Opus Ptee 4-*' *

(C J Downers Cr:ve, lHinois 60515

. v July'9, 1990 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Hashington, D.C. 20555 u

Subject:

LASalle County Station Units 1 and 2 Supplement to the Proposed A*cr.oment to the Technical Specifications for Facility Operating License NPF-il and NPF-18  ;

MRC_Dortet_HolmSD-323_Attd_50-314

Reference:

W.E. Morgan letter to U.S. NRC dated l July 26, 1989.

i

Dear Sirs:

Reference (a) transmitted Commonwealth Edison's proposed Technical Specification Amendment to allow continued plant operation for a period of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with the Main Steam Tunnel High Ambient Temperature and High Ventilation System Differential Temperature Trips Bypassed.

In review of this Amendment request the following information was requested by the NRC to support their review;

- The basis for the requested 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> time period, l i

- The time requirements for performance of preventive maintenance activities, surveillance tests; and

- The compensatory measures to be taken during the period of time the temperature trips are inoperable.

The following attachment provides this information.

Please direct any questions you may have regarding this matter to this office.

Very truly yours.

@y)

H. Morgan y f@@71$$$$

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$O000$73 PDC Huclear Lice ing Administrator '

Attachment ,

cc: R. Pulsife - Project Manager, NRR Senior Res- Inspector - LSCS 0[I

/Imw/ID71

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'O o AUACW H I In July, 1989 Commonwealth Edison submitted a Technical Specification amendment request reference (a) to allow bypassing the Main Steam Tunnel Ambient Temperature and High Ventilation Differential Temperature Trips for a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period. This amendment will allow the needed time to perform required maintenance activities and surveillances, such as the reactor building ventilation system (VR) filter changes, damper cycling and secondary containment leak rate tests, while reducing the risk of causing unnecessary challenges to reactor safety systems. Following the review of this submittal, the NRC has requested additional information concerning:

- The basis for the requested 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period.

- The time requirements for performance of preventive maintenance activities, survelliance tests and;

- The compensatory measures to be taken during the period of time the temperature trips are inoperable.

1 The basis for the requested twelve hour time period is to allow for completion of the secondary containment leak rate test as required by Technical Specification 4.6.5.1.c. while one or both reactors are operating. This item is the limit for which the bypassing of the isolations is required. All other activities are expected to be completed within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. At LaSalle County Station the secondary containment buildings for Units 1 and 2 are joined, making 't necessary to perform the leak rate test on both units simultaneously. During the performance of the test the reactor building ventilation systems (VR) for both units must be shutdown to that it can be demonstrated that the standby gas treatment system (VG) alone is capable of maintaining a negative pressure in the secondary containment.

Operation of the units'is limited during this test by the main steam tunnel (MST) temperatures. HIth either unit operating and the ventilation system shutdown the MST temperatures will rapidly increase and cause a Group 1 isolation (main steam isolation valve closure) on each operating unit. As a :

result, this test is normally scheduled during two unit outages.

Two unit outages are difficult to schedule and usually result in a severe drain on station and company resources, it would be desirable to be able to complete this test with one or both units operating. previously the

. secondary containment leak rate test could be completed in approximately ,

four hours. Per a NRC commitment, it is now necessary for the station to demonstrate that both.the inner and outer doors of the reactor boliding trackway are leak tight. Thus the test is performed twice requiring a time period of approximately 6 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (once to tert the Inner door and once again to test the outer door). A 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period will provide enough time to complete the test and allow time for unanticipated difficulties, floure 1 lists the tasks which must be completed during this test and indicates the t approximate time which is required to complete each task.

2-Preventive maintenance activities take less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to

" complete, however these activities also require the bypassing of both the HST temperature and differential trips to preclude unnecessary challenges to the reactor safety systems. For the purpose of Technical Specification requirement consistancy, LaSalle Station is requesting that the 12-hour time period also apply to the preventive maintenance activities referenced above. The compensatory measures outlined below will also be taken when preventive maintenance is being performed and the temperature trips are defeated.

The compensatory seasures that will be taken during the period of time that the temperature trips are defeated are as follows:

The station procedures will be revised to require that iuring the period of time that the temperature trips are defeated:

1. Where appropriate, special logs will be established and the following parameters will be monitored for indications of MST leakage. These logs will be initiated 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> prior to the test and require readings to be taken at half hour intervals:

a. Main condenser normal makeup flow rate.

b. The floor drain sump which collects the leakage of systems in the main steam tunnel.

c. HST ambient temperatures

2. The shift operating and maintenance personnel will be briefed prior to commencing the test. The briefing will include a discussion of the test procedures, the trips which will be disabled and the special logs to be initiated.

/Imw/ID71 l

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FIGURE 1 SECONDARY CONTAINMENT LEAK RATE TEST - TASKS VS TIME e iTIKE(Hrs.) 1 2 3 4 5 6 7 8 9 10 11 121  ;

ITASKSI I I i 1 1 I i 1 1 1 1 1 1 1 1--> (30) 1 I 2 1, -> (20) I i 3 1 -> (20) l I 4 1 > (10) l I 5 l -> (20) + + + + + + + + + l 1 6 1 -------> (80) 1 I 7 1 > (10) 1 ,

I 8 l > (10) 1 J l 9 1 --->-(40) I i 10 1 + + --> (30) + + + + + + + l- j l 11 1 ---> (40) 1 1 1 12 1 -> (20) l i i 13 1 -> (20) I  :

I 14 1 > (10) I )

I 15 1 + + + + -------> (80) + + + + + 1 l 1 16 'l > (10) I  !

l 17 1 > (10) l l l 18 1 --> (30) I i

i 19 l --> (30) l I 20 1 + + + + + + -> (20) + + + + l l l 21 1 ---> (40) l .

I 22 1 --> (30) I e Numbers in parenthesis indicate time in minutes required to complete the task. I TASKS

1. Install auspers and move bypass switches to prevent leak detection trips.

2. Ad]ust sanometers on four valls of RR floor. Connect to VR dp control.

3. Shut off VR and close isolation dampers on both unite.

4. Take RR floor vet and dry bulb temperatures. '

5. Take initial dp readings from the manometers. "

6. Start one of the SBGT trains and watch manometers.

7. Take dp readings at five minutes into the run.

8. Take dp readings at 60 minutes into the run. ,

9. Review the dp readings and the SBGT flow chart.

j 10. A11ov access into the Reactor Building.

11. Svap open close position of Reactor Building trackway doors. ,

12. Shut down running SBGT. train. '

.. 13. Take initial dp readings from the manometers.

l' 14. Take RR floor vet and dry bulb temperatures.

L 15. Start one of the SBGT trains and watch manometers.

L 16. Take dp readings at five minutes into the run. }

l 17. Take dp readings at 60 minutes into the run.

18. Review the dp readings and the SBGT flow chart.

! 19. Shut down running SBGT train and close Reactor Building trackway door.

L 20. Start up VR and open isolation dtspers on both units.

l- 21. Allow steam tunnels to cool off.

22. Remove Jumpers and move bypass switches to allow isolations.

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