ML20081D082

Proposed Tech Specs,Changing Allowable Value for Diesel Generator Start & Load Shed Timer.Significant Hazards Determination Consideration Encl

ML20081D082
Person / Time
Site:	Sequoyah
Issue date:	10/24/1983
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20081D065	List: ML20081D063 ML20081D082
References
NUDOCS 8310310438
Download: ML20081D082 (5)

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ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 f

TVA-SQN-TS-50 F

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8310310438 831024 DR ADOCM 05000327 PDR I------- -,_- _.-._._. ._., _ _ , . _ _ . _ , _ _ .

TABLE 3.3-4 (Continued)

ENGINEERED SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION TRIP SETP0INTS .

a E FUNCTIONAL UNIT TRIP SETPOINT ALLOWABLE VALUES g *b. 6.9 kv Shutdown Board-Degraded q Voltage

1. Voltage Sensors 6560 volts 6560 volts 1 33 volts

2. Diesel Generator Start and Load Shed Timer 300 seconds 300 seconds 160 seconds

3. SI/ Degraded Voltage Logic Enable Timer 10 seconds 10 seconds 1 0.5 seconds

8. ENGINEERED SAFETY FEATURE ,

y ACTUATION SYSTEM INTERLOCKS 4

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• NOTE: This technical specification is to be implemented at the startup following the 2nd refueling outage or following completion of the modification, whichever is earlier.

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• TABLE 3.3-4 (Continued) .

ENGINEERED SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION TRIP SETPOINTS .,

S E FUNCTIONAL UNIT TRIP SETPOINT

. ALLOWABLE VALUES g *b. 6.9 kv Shutdown Board-Degraded q Voltage

1. Voltage Sensors 6560 volts 6560 volts 1 33 volts

2. Diesel Generator Start and Load Shed Timer 300 seconds 300 seconds 160 seconds

3. SI/ Degraded Voltage Logic Enable Timer 10 seconds 10 seconds 1 0.5 seconds

8. ENGINEERED SAFETY FEATURE ,,

ACTUATION SYSTEM INTERLOCKS ..

w a.  !!

Pressurizer Pressure li" h

w Manual Block of Safety Injection P-11 5 1970 psig 5 1980 psig l

• NOTE: This technical specification is to be implemented during the startup following the 1st refueling outage. i l

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ENCLOSURE 2 JUSTIFICATION FOR PROPOSED TECHNICAL SPECIFICATION CHANGE TVA-SQN-TS-50 SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 The NRC recently approved our proposed changes (TVA-SQN-TS-36, Enclosure No. 5) to the Sequoyah unit 1 and unit 2 technical specifications (T/S) to reflect the forthcoming installation of undervoltage protection for Class 1E buses. This approval was received on May 5,1983 by Amendment 29 to Facility Operating License DPR-77 for unit 1 and by Amendment 18 to Facility Operating License DPR-79 for unit 2.

The purpose of this T/S change is to increase the tolerance in the allowable value, specified in Table 3.3-4, for the diesel generator start -

and load shet timer. As stated in the additional information provided to the NRC by my December 1,1982 letter, the " error associated with the timers is + 10 percent for timers with settings greater than or equal to 200 seconds. . . ." The manufacturer can only certify a setting of +

10 percent. This was the basis for the NRC approval of the T/S for the undervoltage modification. Attachment 1 provides the significant hazards consideration determination. The proposed change was evaluated pursuant to 10 CFR Part 50 92 and no significant hazards considerations are involved.

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ATTACHMENT ,

SIGNIFICANT HAZARDS CONSIDERATIONS DETERMINATION

1. Is the probability of an occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report increased?

The proposed change has been analyzed and reviewed for the degraded voltage T/S change submitted to the NRC as TVA-SQN-TS-36. This is an administrative change in the tolerance for. the allowable value to be consistent with the basis for the allowable value previously submitted to the NRC.

2. Is the possibility for an accident or malfunction of a different type than evaluated previously in the safety analysis report created?

No new accident possibility is created, only a change in the tolerance for allowable value is changed.

3. Is the margin of safety as defined in the basis of any technical specification significantly reduced?

Changing the technical specifications to agree with underlying analysis will not decrease the margin of safety.

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