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Proposed Tech Specs,Revising Normal Alignment to Automatic Tap Changing Common Station Svc Transformers
	ML20070Q946
Person / Time
Site:	Sequoyah
Issue date:	05/16/1994
From:	; TENNESSEE VALLEY AUTHORITY
To:	;
Shared Package
ML20070Q944	List: ML20070Q940; ML20070Q946;
References
	NUDOCS 9405190278
	Download: ML20070Q946 (9)
	v • d • e

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- l ENCLOSURE 1 1

i PROPOSED TECHNICAL' SPECIFICATION. CHANGE I SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 1

DOCKET NOS. 50-327 AND 50-328 j (TVA-SQN-TS-93-18) l I

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' t ELECTRICAL POWER SYSTEMS ACTION (Continued)

b. With one offsite circuit and one diesel generator set of the above l required A.C. electrical power sources inoperable, demonstrate the l OPERABILITY of the remaining A.C. sources by performing Surveillance Requirements 4.8.1.1.1.a within one hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter, and Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ; R104 restore at least one of the inoperable sources to OPiRABLE status within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . Restore at least two offsite circuits and four diesel generator sets to 0PERABLE status

! within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from the time of initial loss or be in at least HOT l STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following

!. 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

c. With two of the above required offsite A.C. circuits inoperable, ,

demonstrate the OPERABILITY of 4 diesel generator sets by performing Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , unless the R104 J diesel generator sets are already operating; restore-at least one of l the inoperable offsite sources to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months or l

be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . With only one l offsite source restored, restore at least two offsite circuits to i OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from time of initial loss or be in I at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

l l d. With either diesel generator sets 1A-A and/or 2A-A inoperable j simultaneous with 1B-B and/or 2B-B, demonstrate the OPERABILITY of two offsite A.C. circuits by performing Surveillance Requirement j 4.8.1.1.1.a within one hour and at.least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter; restore at least 1) 1A-A and 2A-A or 2) 1B-B and 2B-B to OPEPABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or be in at least H0T STANDBY within'the next

6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ; Restore j at least four diesel generator sets to OPERABLE status.within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from time of initial loss or be in least HOT STANDBY within l the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

SURVEILLANCE REOUIREMENTS 4.8.1.1.1 Each of the above required-independent circuits between the offsite transmission network and the onsite Class'1E distribution system shall be:

a. Determined OPERABLE at least once per 7 days by verifying correct breaker alignments, indicated' power availability, and

b. Demonstrated OPERABLE at least once per 18 months during shutdown by )

transferring (manually and automatically) unit power supply from the a nor= 1 circuit to the alt ^rnate circuit.

tha rr GEMERATOR. Suppoemp kE F ERRtb PoWR (GDC, fl)

R141 SEQUOYAH - UNIT 1 3/4 8-2 Amendment No. 100,137 April 27, 1990 I -- , ,. , , .-..w , , . , , , . .,r. , . , . . - - -.r-.--w-- < - - - . . - , - - - - - - - .m..~---

ELECTRICAL POWER SYSTEMS ACTION (Continued)

b. With one offsite circuit and one diesel generator set of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining A.C. sources by performing Surveillance Requirements 4.8.1.1.1.a within one hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months R89 thereafter, and Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ; restore at least one of the inoperable. sources to OPERABLE status within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . Restore at least two offsite circuits and four diesel generator sets to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .from the time of initial loss or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ,

c. With two of the above required offsite A.C. circuits inoperable, demonstrate the OPERABILITY of 4 diesel generator sets by performing Surveillance Requirement 4.8.1.1.2.'a.4 within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , unless th'e R89 diesel generator sets are already operating; restore at least one of the inoperable offsite sources to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months , With only one offsite source restored, restore at least two offsite circuits to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from time of initial loss or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

d. With either diesel generator sets 1A A and/or 2 A-A inoperable simultaneous with 1B-B and/or 28-B, demonstrate the OPERABILITY of two offsite A.C. circuits by performing Surveillance Requirement 4.8.1.1.1.a within one hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter; restore at least 1) 1 A-A and 2A-A or 2) 1B-B and 28-B to OPERABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . Restore at least four diesel generator sets to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from time of initial loss or be in least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

SURVEILLANCE REQUIREMENTS 4.8.1.1.1 Each of the above required independent circuits between the offsite transmission network and the onsite Class 1E distribution system shall be:

a. Determined OPERABLE at least once per 7 days by verifying correct

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D V' D D Demonstrated OPERABLE at least once per 18 months during shutdown by transferring (manually and automatically) unit power supply from the m normal circuit to the eltc mat circuit.

U NIT be,METMTOR buPPC,RTED

. --ERIFERRED iOuRlh hDC h

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SEQUOYAH - UNIT 2 3/4 8-2 Amendment No. 89 ,123 R123 April 27, 1990. ,

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ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR. PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-93-18)

DESCRIPTION AND JUSTIFICATION FOR I

NORMAL ALIGNMENT TO AUTOMATIC TAP CHANGING l

COMMON STATION SERVICE TRANSFORMERS i

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4 Description of Change TVA proposes to modify the Sequoyah Nucicar Plant (SQN) Units 1 and 2 technical specifications (TSs) to clarify the surveillance for verification of offsite to onsite circuits (TS 4.8.1.1.1.b). The present description of normal and alternate circuits is being replaced with unit generator supported and preferred power (GDC 17) circuits, respectively.

Renon_fsr Change TVA has installed new common station service transformers (CSST) with auto tap changers to accommodate voltage variations in the 161-kilovolt (kV) system. The 161-kV system provides the preferred power supply for SQN to support normal and accident conditions (see Updated Final Safety Analysis Report Gections 8.1 and 8.2). These CSSTs replace existing transformers with only manual off-line tap changing capabilities. The new CSSTs will be able to adjust secondary voltage to plus or minus 10 percent by using 16 taps that provide 1.25 percent adjustment per tap. The changer is capable of changing taps at the rate of approximately one tap each second after a two-second delay that prevents unnecessary operation for momentary voltage changes.

The revision to the descriptions of the circuits in TS 4.8.1.1.1.b is required as a result of implementing normal alignment to the CSSTs.

Presently the normal circuit is connected to the unit station service transformers (USSTs) and transfers to the alternate circuit (CSST supplied) for accident conditions. The normal circuit will be changed to the CSST supply during the Unit 2 Cycle 6 refueling outage. This will result in these circuit descriptions in TS 4.8.1.1.1.b being reversed. l Since SQN may occasionally use the USSTs to supply unit power during maintenance, this transfer capability will still need to be verified to ensure alignment to the preferred power circuit (CSST supply) under accident conditions. Tbe revised descriptions will provide a more accurate indication of the transfer requiremente when normal alignment is implemented to the CSSTs.

Justification for Changs The revised descriptions for circuits in TS 4.8.1.1.1.b only provide clarifications of the required transfer to be verified. This is necessary to reflect the alignment of the alternating current distribution system after implementation of normal alignment to the CSSTs. There is no change to the intent or compliance with this surveillance requirement as a result of this clarification. This change will continue to require the same verifications and will not impact nuclear safety, i

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Environmental IIDEact Evaluation The proposed change request does not involve an unroviewed environmental question because operation of SQN Units 1 and 2 in accordance with this change would nott

1. Result in a significant increase in any adverse environmental impact previously evaluated in the Final Environmental Statement (FES) as modified by the staff's testimony to the Atomic Safety and Licensing Board, supplements to the FES, environmental impact appraisals, or decisions of the Atomic Safety and Licensing Board.

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2. Result in a significant change in effluents or power levels.

3. Result in matters not previously reviewed in the licensing basis for j SQ" that may have a significant environmental impact.

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- - PROPOSED TECHNICAL SPECIFICATION-CHANGE' -l 1-j l SEQUOYAH NUCLEAR. PLANT UNITS'1 AND'2s I

i DOCKET NOS. 50-327 AND 50-328

(TVA-SQN-TS-9'3-18)

DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION r ;

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Significant Hazards. Evaluation TVA has evaluated the proposed technical specification (TS) change and has determined that it does not represent a significant hazards-consideration based on criteria established-in 10 CFR 50.92(c).

Operation of Sequoyah Nuclear Plant (SQN) in accordance with the proposed amendment will not:

1. Involve a significant increase.in the probability or consequences of an accident previously evaluated.

The description ~ clarification for the circuits in TS 4.8.1.1.1.b does-not change any TS requirement and will not alter plant functions or components as a result of normal alignment to the common station service transformers (CSSTs).- By implementing normal CSST alignment.

to unit power, SQN has reduced the required. transfers to obtain alignment to the preferred power circuit under accident conditions.

The verifications provided by TS Surveillance 4.8.1.1.1.b'w111-continue to ensure the capability of this transfer during occasional-use of the unit station service transformer (USST) for maintenance or repair activities. The accidents described in Chapter.15 of the SQN Updated Final Safety Analysis Report assume the unit power supply to be from the USST circuit that requires transfer to the CSST after turbine trip. This analysis is bounding for normal' alignment'to the CSST that does not require a transfer.- These changes minimize the impact of malfunctions because transfers.will'not be. required as often. The consequences of an accident are therefore not. increased by this change. The proposed unit power alignment _.to the CSSTs has )

always been used for unit start-up; and since no plant functions are changed as a result of norma 1' alignment to the CSSTs,.other than a lower potential for transfers, the probability of an-accident is not increased.

2. Create the possibility of a new or different kind of accident from any previously analyzed.

The TS 4.8.1.1.1.b clarification does not change plant functions and only provides a more appropriate description of the circuits involved in the transfer function. The transfer from the USST circuit to the CSST circuit will still be available whe' SQN is using the USST circuit, but the need for these transfers will be reduced by normal alignment of unit power to the preferred CSST circuit. These changes will not create a new or different kind of accident because the plant functions remain unchanged and only the CSST alignment for normal unit power and circuit descriptions is altered. This CSST alignment has always been used for unit start-up and is being expanded to apply to normal power operation in addition to start-up and accident conditions.

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3. Involve a.significant reduction in a margin of safety.

j The clarification for the unit power circuit descriptions does not

- alter the intent or requirements for this surveillance. Plant functions and setpoints remain unchanged for automatic transfers from l l

the USST circuit to.the CSST. circuit.- This circuit description change provides a clearer explanation of how the transfer functions. )

j The margin of safety has not been altered for unit power alignment to l the USST or CSST, and this change will support JQN's use of the CSST 3 for'the normal unit power circuit. Therefore, these changes do not l' involve a significant reduction ~in a margin of safety.

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ML20070Q946

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