ML20024D588

Proposed Tech Specs,Changing Surveillance Requirement for Diesel Generator.Justification Encl

ML20024D588
Person / Time
Site:	Sequoyah
Issue date:	07/29/1983
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20024D584	List: ML20024D583 ML20024D588
References
TVA-SQN-TS-44, NUDOCS 8308050289
Download: ML20024D588 (4)

Text

'

I ENCLOSURE 1 f

REVISED I PROPOSED TECHNICAL SPECIFICATION .

SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 TVA-SQN-TS-44 I.

CHANGE IN THE SURVEILLANCE REQUIREMENT, 4.8.1.1.2.d.11, FOR THE DIESEL GENERATOR h

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ELECTRICAL POWER SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)

8. Verifying the diesel generator operates for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.'

During the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of this test, the diesel generator.,

shall be loaded to greater than or equal to 4400 kw and duri'ng the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of this test, the diesel generator shall be loaded to greater than or equal to 4000 kw. The generator voltage and frequency shall be 6900 690 volts and 60 1.2 Hz within 10 seconds after the start signal; the steady state generator voltage and frequency shall be maintained within these limits during this test. Within 5 minutes after completing this 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test, perform Specification 4.8.1.1.2.d.4.b

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9. Verifying that the auto-connected loads to each diesel generator do not exceed the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of 4000 kw.

10. Verifying the diesel. generator's capability to:

a) Synchronize with the offsite power source while the generator is loaded with its emergency loads upon a simulated restoration of offsite power.

b) Transfer its loads to the offsite power source, and c) Be restored to its shutdown status.

11. Verifying that with the diesel generator operating in a test mode, that (1) simulated operation of the emergency feeder breaker instantaneous overcurrent relay trips the emergency feeder breaker , ,

(2) the diesel generator returns to standby operation, and (3) the emergency loads remained energized from the offsite power system.

l I 12. Verifying that the automatic load sequence timers are OPERABLE with the setpoint for each sequence timer within + 5 percent of its design setpoint.

13. Verifying that the following diesel generator lockout features prevent diesel generator starting only when required:

a) Engina overspeed j b) 86 GA lockout relay r

l e. At least once per 10 years or after any modifications which could

! affect diesel generator interdependence by starting the diesel generators simultaneously, during shutdown, and verifying that the diesel generaters accelerate to at least 900 rpm in 'less than or equal to 10 seconds. ,

SEQUOYAH - UNIT 2 3/4 8-5

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ELECTRfCAL POWER SYSTEMS

.. SURVEILLANCE REOUIREMENTS (Continued) _.

Within 5 minutes.after completing this 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test, perform Specification 4.8.1.1.2.c.4. The generator voltage and fre-quency shall be 6900 t 690 volts and 60 t 1.2 Hz within

- 10 seconds after the. start signal; the steady state generator voltage and-frequency shall be maintained within these limits during this test. <

9. Verifying that the auto-connected loads to each diesel geners, tor do not exceed the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of 4000 kw.

10. Verifying the diesel generator's capability to:

a) Synchronize with the offsite power source while the generator is loaded with its emergency loads upon a simulated restoration of offsite power'. -

b) ' Transfer its loads to the offsi.te power source, and c) Be restored to its shutdown status.

Il- Verifying that with the diesel generator operating in a test mode, that (1) simulated operation of the emergency feeder breaker instantaneous overcurrent relay trips the emergency feeder breaker, (2) the diesel generator returns to standby operation, and (3) the emergency. loads remained energized from the offsite power system.

12. Verifying that the automatic load sequence timers are OPERAELE with the setpoint for each sequence timer within + 5 percent of

. _ its design setpoint.

13. Verifying that the following diesel generator lockout features prevent diesel generator starting only When required:

a) Engine overspeed ,

b) 86 GA lockout relay

. e. At least once per 10 years or' after any modifications which could affect diesel generator interdependence by starting the diesel generators simultaneously, during shutdown, and verifying that the diesel generators accelerate to at least 900 rpm in less than or equal to 10 seconds.

f. At least once per 10 years

• by: .- ,

l

1. Draining each fuel oil storage tank, removing the accumulated sediment and cleaning the tank using a sodium hypoclorite i

solution, and l

2. Performing a pressure test of those portions of the diesel fuel oil system design to Section III, subsection ND of the

- ASME Code at a test pressure equal tc 110 percent of the l system design pressure. -

• These requirements are waived for the initial surveillance.

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SEQUOYAH - UNIT 1 3/4 8-5

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ENCLOSURE 2 JUSTIFICATION FOR PROPOSED TECHNICAL SPECIFICATION CHANGE TVA-SQN-TS-44 (R1)

SEQUOYAH NUCLEAR PLANT The probability of equipment important to safety failing is not increased.

Neither is an accident that has previously not been evaluated been introduced, nor the margin of safety decreased. Presently, the surveillance requirement in the technical specifications requires Sequoyah to verify that the diesel generator (D/G), while in the test mode, can be returned automatically to standby operation upon the Lat'roduction of a safety injection signal (SIS). Also, verifying that the emergency loads are connected to the offsite power source. The new revision introduces a simulated overcurrent condition on the D/G bus to place the D/G in standby.

This is a valid method of unloading the D/Gs when they are in this test mode. For testing, the D/G is connected to the 6900 volt shutdown board in parellel with the offsite power source. When either the normal or alternate feeder breaker is closed, the instantaneous overcurrent relays are inserted into the D/G emergency breaker trip circuit. Should there be a loss of voltage to the shutdown board, there is a five (5) second delay before the normal or alternate feeder breaker opens. During the five (5) second delay, the D/G bus will see an overcurrent and the D/G emergency feeder breaker will open, and the D/G will change to standby operation.

After the five seconds, the shutdown board will shed its load and the emergency equipment will sequentially load back onto the board through the blackout logic. If a real SIS is received while the D/G is being tested, the emergency equipment will start simultaneously, and the equipment will continue to run. Should there be a loss of offsite power, the D/G over-current relays will open the D/G emergency feeder breaker and load shedding will follow as described above. The new technical specification will demonstrate the effects of the simulated overcurrent (blackout) condition.

This overcurrent situation is also defined in Chapter 8 of the FSAR titled

" Diesel Generator Operational Testing."

Based on the above justification, we believe that the possibility of an unanalyzed accident or malfunction has not been created, nor has the margin of safety defined in the basis of the technical specification been reduced.

The instantaneous overcurrent relays are verified to be calibrated by TVA procedure AI-19. This calibration of the instantaneous overcurrent relays, in addition to the remainder of the testing required by the technical specifications, ensures that the circuit is tested. For the above reasons, the proposed technical specifications will not impair the diesel generator operability or availability.

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