Text

One-Time Emergency Technical Specification Change for Emergency Diesel Generator (EDG) 1B-B Maintenance to Extend the Allowed Outage Time (AOT) - Technical Specification (TS) Change 05-05
	ML051810267
Person / Time
Site:	Sequoyah
Issue date:	06/17/2005
From:	Pace P; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	TVA-SQN-TS-05-05
	Download: ML051810267 (16)
	v • d • e

Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 June 17, 2005 TVA-SQN-TS-05-05 10 CFR 50.90 10 CFR 50.91(a)(5)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - ONE-TIME EMERGENCY TECHNICAL SPECIFICATION CHANGE FOR EMERGENCY DIESEL GENERATOR (EDG) lB-B MAINTENANCE TO EXTEND THE ALLOWED OUTAGE TIME (AOT) - TECHNICAL SPECIFICATION [TS] CHANGE 05-05 In accordance with the provisions of 10 CFR 50.90 and 10 CFR 50.91(a)(5), TVA is submitting a one-time emergency request for a license amendment to the SQN Licenses DPR-77 and DPR-79 to extend the allowed outage time (AOT) for the lB-B EDG for an additional three days. The basis for this request, information supporting the change, a no significant hazards consideration, and an environmental consideration are included. provides a "No Significant Hazards Evaluation" and the technical basis for the requested change. The emergency nature and why it could not have been avoided are also addressed in Enclosure 1 pursuant to 10 CFR 50.91(a)(5).

The need for the proposed change is based on needed repair of the generator flash circuit for the 1B-B EDG. As discussed with NRC staff on June 17, 2005, a one-time emergency TS change is needed to prevent a potential dual unit shutdown.

11_ 3'O P,.ted o rec paw

U.S. Nuclear Regulatory Commission Page 2 June 17, 2005 On June 13, 2005, EDG 1B-B was removed from service to begin the vendor recommended maintenance outage. The EDG outage was originally scheduled to be complete on June 18, 2005, at 0300 Eastern daylight time (EDT). On June 17, 2005, the EDG 1B-B first idle start tests were aborted because of maintenance problems. The first maintenance problem required repair of faulty valve lash adjusters. The second problem occurred during another idle EDG run and was the result of a generator brush fault that damaged the field flash circuitry.

Due to the nature of the circuitry damage and testing required to return the EDG to operable status, the full repair time for the EDG has the potential to exceed the limiting condition of operation AOT.

An additional three days is needed to allow for the orderly return to operability of the lB-B EDG. The emergency change request is a one-time change based on the potential that repairs and testing required to return the EDG to an operable status may not be completed prior to the expiration of the current AOT. The current AOT expires on June 20, 2005, at 0112 EDT.

There are no commitments in this letter. If you have any questions about this change, please telephone me at (423) 843-7170 or J. D. Smith at (423) 843-6672.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 1 7 th day of June, 2005.

P. L. Pace Manager, Site Licensing and Industry Affairs

Enclosures:

1.TVA Evaluation of the Proposed Changes 2.Proposed Technical Specifications Changes (mark-up)

U.S. Nuclear Regulatory Commission Page 3 June 17, 2005 JDS:DVG:PMB Enclosures cc (Enclosures):

Framatome ANP, Inc.

P. 0. Box 10935 Lynchburg, Virginia 24506-0935 ATTN: Mr. Frank Masseth Mr. Lawrence E. Nanney, Director Division of Radiological Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532 Mr. Douglas Pickett, Senior Project Manager U.S. Nuclear Regulatory Commission Mail Stop O-08G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739

ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 DOCKET NOS. 327 AND 328 PROPOSED ONE-TIME LICENSE AMENDMENT FOR EXTENDING ALLOWED OUTAGE TIME (AOT) FOR REPAIR OF EMERGENCY DIESEL GENERATOR (EDG) 1B-B 1.0. DESCRIPTION TVA is requesting an amendment to Operating Licenses DPR-77 and DPR-79 for SQN Units 1 and 2. TVA proposes to extend the AOT for SQN Technical Specification (TS) 3.8.1.1, Action (b) to include an additional three days beyond the current seven-day AOT.

During an EDG outage to perform vendor recommended maintenance on SQN's lB-B EDG, delays were encountered to repair and test the generator field flash circuitry. TVA estimates that additional time may be required to complete the repairs and testing for returning the EDG to service.

Failure to return the EDG to an operable status within the current AOT would result in shutdown of both SQN units.

2.0 PROPOSED CHANGE

TVA's current SQN TS Limiting Condition for Operation (LCO) 3.8.1.1, Action (b) states:

b.# With diesel generator set(s) lA-A and/or 2A-A or 1B-B and/or 2B-B of the above required A.C. electrical power sources inoperable,* demonstrate the OPERABILITY of the remaining A.C. sources 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, and determining OPERABLE diesel generator sets are not inoperable due to common cause failure or performing Surveillance Requirement 4.8.1.1.2.a.4 within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; restore at least four diesel generator sets to OPERABLE status within 7 days 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 .

Required actions, to verify OPERABLE diesel generator sets are not inoperable due to common cause failure or perform SR 4.8.1.1.2.a.4, shall be completed if this action is entered.

El-l

No more than one diesel generator may be made simultaneously inoperable on apre-planned basis for maintenance, modifications, or surveillance testing.

TVA requests an emergency TS change to allow an additional three days beyond the current 7-days AOT. TVA's proposed change will state:

"b.# With diesel generator set(s) 1A-A and/or 2A-A or 1B-B and/or 2B-B of the above required A.C. electrical power sources inoperable,* demonstrate the OPERABILITY of the remaining A.C. sources 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, and determining OPERABLE diesel generator sets are not inoperable due to common cause failure or performing Surveillance Requirement 4.8.1.1.2.a.4 within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; restore at least fg' diesel generator sets to OPERABLE status within 7 days 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 .

II Required actions, to verify OPERABLE diesel generator sets are not inoperable due to common cause failure or perform SR 4.8.1.1.2.a.4, shall be completed if this action is entered.

No more than one diesel generator may be made simultaneously inoperable on a pre-planned basis for maintenance, modifications, or surveillance testing."

[** A temporary increase of an additional three days is allowed for the current 1B-B diesel generator maintenance outage. The temporary increase will expire on June 23, 2005, at 0112 Eastern daylight time.

3.0 BACKGROUND

AND BASIS FOR EMERGENCY AMENDMENT REQUEST The SQN electrical system design is described in Section 8.0, "Electrical Power," in the SQN Final Safety Analysis Report (FSAR). SQN is connected to a strong offsite transmission network. In the vicinity of SQN, the lines are on right of ways which are sufficiently wide enough to preclude the likelihood of a failure of one line causing failure of the other line. Electric power to SQN is supplied by two physically and electrically independent circuits from the SQN 161-kilovolt (kV) switchyard through three separate transformers to the onsite electrical distribution system. The 161-kV switchyard is designed E1-2

with two main bus sections and is arranged so that the supply to the onsite power system, as well as the connections to the generator and the 500-161-kV transformer bank, is maintained to one bus section for a failure of the other section. Four 161-kV lines terminate on one bus, and four other .161-kV lines terminate on the other bus. Two fuseless 84 Millivolt Amperes Reactive 161-kV capacitor banks are tied to the 161-kV switchyard through double bus-tie breakers.

Each bank is independently switched. These capacitors provide reactive voltage support for the 161-kV offsite system.

The SQN power supply system and operating practices provide high reliability of uninterrupted power.

Preferred power to SQN is supplied by either of the 161-kV buses to three common station service transformers (CSSTs). The CSSTs supply power to the four start buses (SBs), which supply power to the eight unit boards. There are four unit boards per unit and the unit boards supply power to the four shutdown boards, there are two shutdown boards per unit. Each of the shutdown boards supply a single train of safe shutdown equipment along with some common equipment.

The shutdown boards can also be supplied emergency power by seismic, environmentally qualified EDGs that supply backup power to the vital 6.9-kV, and 480-kV busses in the event of a loss of normal and alternate offsite power.

During power operation, the EDGs help to ensure that sufficient power will be available to the safety-related equipment, which is needed for the safe shutdown of the plant and for mitigation and control during accident conditions. During shutdown and refueling conditions, the EDGs help to ensure that the facility is able to maintain shutdown or refueling conditions for extended periods of time.

SQN EDGs have high availability and reliability ratings. TVA's performance indicator data clearly demonstrate the high confidence factor that can be assumed for EDG availability. The following is a tabulation of the latest reported data through December 2004.

Diesel Generator Planned unavailable hours Unplanned unavailable hours E1-3

Diesel Generator lA-A 1B-B 2A-A 2B-B Total unavailable 9.16 6.06 3.70 14.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months Unavailable hours last 280.75 145.02 364.55 235.57 36 months Required hours 2209.0 2209.0 2209.0 2209.0 Required hours last 36 26304.0 26304.0 26304.0 26304.0 months Train 1.1 0.6 1.4 0.9 unavailability (percent)

TVA's proposed change to add three days to the current seven day AOT is due to unanticipated problems encountered while performing vendor recommended maintenance and testing. TVA initiated the 2/4/6-year EDG outage on June 13, 2005, at 0112 EDT to begin maintenance as recommended by the EDG vendor. The maintenance activity was originally scheduled for completion on June 18, 2005, at 0300 EDT. During the first test runs on June 17, 2005, EDG 1B-B idle start tests were aborted because of maintenance problems. The first maintenance problem required repair and schedule delays from newly installed faulty valve lash adjustors that required replacement. The valve lash adjustors were installed as part of the vendor required maintenance. The problem was identified during the post-maintenance testing. The second problem that occurred during another EDG idle run was the result of a generator brush fault that damaged the field flash circuitry. Due to the nature of the circuitry damage and testing required to return the EDG to operable status, the full repair time and testing for the EDG has the potential to exceed the LCO AOT.

The generator brush failure is attributed to a maintenance-related activity from improper reinstallation of the brush wiring. This was found during post-maintenance testing. TVA considers the error to be an isolated condition associated with the lB-B EDG.

4.0 TECHNICAL ANALYSIS

The proposed extension of the AOT for the lB-B EDG is requested as a result of the potential challenges to plant safety systems associated with an unnecessary unit shutdown evolution. Such a shutdown involves a certain level of risk in itself and the small increase in risk involved in the AOT extension request is an acceptable alternative to the shutdown. The high reliability of the SQN offsite power supply system supports the unlikely need for the 1B-B EDG as well as the redundant capabilities of the remaining EDGs that E1-4

also have a good reliability history. Therefore, a shutdown of both.SQN units, in lieu of.a three day extension, is considered unnecessary and would result in an equivalent level of risk as the proposed AOT extension.

TVA has prepared a risk assessment of the proposed AOT using Revision 3 of the Sequoyah Probabilistic Safety Assessment (PSA). A brief discussion of the evolution of the Sequoyah PSA follows.

The original Sequoyah Individual Plant Examination (IPE) was prepared to satisfy the requirements of Generic Letter 88-20, "Individual Plant Examination for Severe Accident Vulnerabilities." The IPE was subsequently updated to arrive at the Revision 1 PSA.

The Revision 1 PSA was used in the risk assessment for SQN's TS change request to extend the AOT for the EDGs from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to the current 7 days. Response to NRC's Question 4(b) in TVA's letter dated August 27, 1999, "Sequoyah Nuclear Plant (SQN) - Units 1 and 2 -

Technical Specification (TS) Change No. 96-08, Revision 1, Section 3.8.1, 'A.C. Sources' and Response to Request for Additional Information," describes in more detail the Revision 1 PSA.

A subsequent update of the SQN PSA was made and is referred to as the draft-Revision 2 PSA. The draft-Revision 2 PSA received a peer review by the Westinghouse Owner's Group (WOG). Incorporation of significant WOG Peer Review findings resulted in the Revision 2 PSA. A more detailed description of changes made to the Revision 1 PSA to arrive at the Revision 2 model and significant peer review comments and their disposition were submitted in response to NRC's Question 14(2) in TVA's letter dated August 31, 2001, "Sequoyah Nuclear Plant (SQN) - Request to Request for Additional Information (RAI) Regarding Risk-Informed Inservice Inspection(RI-ISI) Program."

A recent update of the SQN PSA was made and is referred to as the Revision 3 PSA. This revision of the PSA was primarily a periodic update to incorporate plant operating experience since the last revision and correct previously identified deficiencies.

As previously stated, the risk assessment of the proposed AOT was prepared using the Revision 3 PSA and was prepared in accordance with the guidance provided by Regulatory Guide (RG) 1.177, "Risk Informed Changes to Technical Specifications." For a 10-day AOT on EDG 1B-B, the increase in the incremental conditional core damage probability (ICCDP) is 6.9E-08 (as compared to E1-5

5.OE-08) and the increase in the incremental conditional large early release probability (ICLERP) is 5.2E-09 (as compared to 5.OE-08). These increases in ICCDP and ICLERP are based'on going from the current 7-day AOT to a 10-day AOT on EDG lA-A. EDG 1A-A has the highest risk achievement worth (RAW) of any of the EDGs.

The accident sequences that dominate plant risk when an EDG is unavailable are those that involve a loss of offsite power followed by a failure of the redundant EDG. However, Sequoyah has additional capability to mitigate these station blackout (SBO) scenarios that has not been credited in the PSA. This additional capability for mitigating a SBO is described in TVA's letter dated April 28, 2005, "Sequoyah Nuclear Plant Units 1 and 2 - Safeguards Advisory for Operating Power Reactors (SA-05-02)." When the additional capability is factored into the risk evaluation, the only SBO scenarios that result in core damage are those that also contain a failure of the turbine driven auxiliary feedwater pump (TDAFWP). These SBO scenarios that contain a failure of the TDAFWP do not end in a large early release unless they also contain containment isolation failures. The TDAFWP is being maintained available for the EDG outages.

Note that an approved plant procedure provides checklists for determining the operability of components and systems required to satisfy TSs, such as the TDAFWP, when a diesel generator or shutdown board off-site power source is inoperable.

In conclusion, an additional three days of EDG unavailability is non-risk-significant.

5.0 REGULATORY SAFETY ANALYSIS TVA is requesting an amendment to Operating Licenses DPR-77 and DPR-79 for Sequoyah Nuclear Plant (SQN) Units 1 and 2.

TVA proposes to extend the allowed outage time (AOT) for SQN Technical Specification (TS) 3.8.1.1, Action (b) to include an additional three days beyond the current seven-day AOT.

During an emergency diesel generator (EDG) outage to perform vendor recommended maintenance on SQN's 1B-B EDG, problems were encountered with the generator flash circuitry.

Failure to return the EDG to an operable status within the current AOT would result in shutdown of both SQN units.

TVA has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment," as discussed E1-6

below:

5.1 No Significant Hazards Consideration

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The EDGs supply backup power to the essential safety systems in the event of a loss-of-offsite (normal) power. The EDGs cannot initiate an accident. The requested extension will not impact the plant design or operation.

The increased out of service time does not invalidate assumptions used in evaluating the radiological consequences of an accident and does not provide a new or altered release path.

Therefore, this proposed change does not involve an increase in the probability of any accident previously evaluated.

An increase in the AOT would not change the conditions, operating configuration, or minimum amount of operable equipment assumed in the plant Final Safety Analysis Report (FSAR) for accident mitigation. The longer AOT would provide a longer time window for maintenance and testing to return the EDG to operable status. Based on an incremental conditional core damage frequency of less than 1.OE-07 and an incremental conditional large early release probability of less than 1.0 E-08 for the proposed three-day AOT duration, this change will not result in a significant increase in the consequences of an accident.

2. Does the proposed change create the possibility of a new or different kind of accident from any previously analyzed?

Response: No The proposed change to extend the AOT for the EDG three days does not alter the physical design or configuration of the plant. The EDG operation remains unchanged, therefore, this change does not create the possibility of a new or different kind of accident from any previously analyzed.

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3. Does the proposed change involve a significant reduction in a margin of safety" Response: No The proposed increase in the AOT for one EDG out of service is insignificant with respect to the predicted core damage frequency. This evaluation did not include credit for the additional plant capabilities to mitigate a station blackout (SBO) and compensatory measures imposed by TVA. When considered together, TVA concludes that the overall safety impact has not been significantly affected. In addition, the plant parameters that protect against postulated accidents are not changed by the proposed extension and will continue to perform their required safety functions.

Therefore, the proposed extension does not significantly reduce the margin of safety.

Based on the above, TVA concludes that the proposed amendments present no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and accordingly, a finding of "no significant hazards consideration" is justified.

Applicable Regulatory Requirements/Criteria General Design Criterion (GDC) 17, "Electric Power Systems," of Appendix A, "General Design Criteria for Nuclear Power Plants," to Title 10 of the Code of Federal Regulations (10 CFR) Part 50 requires, in part, that offsite electric power be supplied by two physically independent circuits designed and located so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions.

GDC-17 also requires that onsite electric power supplies have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure. In addition, this criterion requires provisions to minimize the probability of losing electric power from the remaining electric power supplies as the result of loss of power from the unit, the offsite transmission network, or the onsite power supplies. The proposed change to extend the AOT for the 1B-B EDG will not alter attributes of the electric power system such that the GDC 17 recommendations would not be satisfied.

E1-8

"i GDC-18, "Inspection and Testing of Electric Power Systems," requires that electric power systems that are important to safety be designed to permit appropriate periodic inspection and testing. The EDG design will not be altered by this change and the testing capabilities of the EDGs are not impacted. Therefore, the proposed change to extend the AOT for the lB-B EDG will not alter attributes of the electric power system such that the GDC-18 recommendations would not be satisfied.

Section 50.36 of 10 CFR, "Technical Specifications,"

requires the TS in a license to include LCOs, which include AOTs for equipment required for safe operation of the facility. Section 50.65 of the 10 CFR is entitled "Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," and identifies the objective of minimizing unavailability of systems, structures and components, due to monitoring or preventive maintenance. Regulatory Guide (RG) 1.93, "Availability of Electric Power Sources," gives guidance about operating restrictions (i.e., AOTs) if the number of available alternating current sources is less than the TS LCO requires. The proposed change increases the EDG AOT in response to an unforeseen condition and with the intent to prevent the unnecessary shutdown of a nuclear unit. Such a shutdown involves a certain level of risk in itself and the small increase in risk involved in the AOT extension request is an acceptable alternative to the shutdown. Therefore, the proposed change slightly alters TVA's manner in complying with regulatory provisions but within acceptable limits to continue to maintain an appropriate level of nuclear safety.

In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

6.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant E1-9

increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Therefore, pursuant to 10 CFR 50.22(b), no environmental impact statement or environmental assessment needs to be prepared in connection with the proposed amendment.

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ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 DOCKET NOS. 327 AND 328 TS MARKUP PAGES E2-1

3/4.8 ELECTRICAL POWER SYSTEMS 314.8.1 A.C. SOURCES OPERATING LIMITING CONDITION FOR OPERATION 3.8.1.1 As a minimum, the following A.C. electrical power sources shall be OPERABLE:

a. Two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and

b. Four separate and independent diesel generator sets each with:

1. Two diesels driving a common generator

2. Two engine-mounted fuel tanks containing a minimum volume of 250 gallons of fuel, per tank

3. A separate fuel storage system containing a minimum volume of 62,000 gallons of fuel,

4. A separate fuel transfer pump, and

5. A separate 125-volt D.C. distribution panel, 125-volt D.C.

battery bank and associated charger.

APPLICABILITY: MODES 1, 2,3 and 4.

ACTION:

a. With one offsite A.C. circuit of the above required A.C. electrical power source inoperable, demonstrate the OPERABILITY of the remaining offsite A.C. circuit 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 two offsite circuits to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 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 .

b.# With diesel generator set(s) I A-A and/or 2A-A or I B-B and/or 2B-B of the above required A.

electrical power sources inoperable,* demonstrate the OPERABILITY of the remaining sources by performing Surveillance Requirement 4.8.1.1.1.a within one hour and ast once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter, and determining OPERABLE diesel generator sets are inoperable due to comon cause failure or performing Surveillance Requirement 4.8.1.1. .4 within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; restore at least four diesel generator sets to OPERABLE status within ays 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 .

Required actions, to verify OPERABLE diesel generator sets are not inoperable due to common cause failure or perform SR 4.8.1.1.2.aA, shall be completed if this action is entered.

No more than one diesel generator may be made simultaneously inoperable on a pre-planned basis for I maintenance, modifications, or surveillance testing.

A temporary increase of an additional three days is allowed for the current I B-B diesel generator maintenance outage.

The temporary increase will expire on June 23, 2005, at 0112 Eastern daylight time.

December 16,1998 SEQUOYAH - UNIT 1 3/4 8-1 Amendment No. 100, 132,137,205, 241 E2-2

3 t 314.8 ELECTRICAL POWER SYSTEMS 3/4.8.1 A.C. SOURCES OPERATING LIMITING CONDITION FOR OPERATION 3.8.1.1 As a minimum, the following A.C. electrical power sources shall be OPERABLE:

a. Two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and

b. Four separate and independent diesel generator sets each with:

1. Two diesels driving a common generator

2. Two engine-mounted fuel tanks containing a minimum volume of 250 gallons of fuel, per tank

3. A separate fuel storage system containing a minimum volume of 62,000 gallons of fuel,

4. A separate fuel transfer pump, and

5. A separate 125-volt D.C. distribution panel, 125-volt D.C. battery bank and associated charger.

APPLICABILITY: MODES 1, 2,3 and 4.

ACTION:

a. With one offsite A.C. circuit of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining offsite A.C. circuit 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 two offsite circuits to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 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 .

b.# With diesel generator set(s) 1A-A and/or 2A-A or 1B-B and/or 2B-B of the above required electrical power sources inoperable,* demonstrate the OPERABILITY of the remainin .C.

sources by performing Surveillance Requirement 4.8.1.1.1.a within one hour and east once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter, and determining OPERABLE diesel generator sets are n operable due to common cause failure or performing Surveillance Requirement 4.8.1.1.2 within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; restore at least four diesel generator sets to OPERABLE status within 7lays 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 .

Required actions, to verify OPERABLE diesel generator sets are not inoperable due to common cause failure or perform SR 4.8.1.1.2.a.4, shall be completed if this action is entered.

No more than one diesel generator may be made simultaneously inoperable on a pre-planned basis for maintenance, modifications, or surveillance testing.

I

*A temporary increase of an additional three days is allowed for the current 1B-B diesel generator maintenance outage.

The temporary increase Nwill expire on June 23, 2005, at 0112 Eastern daylight time.

December 16,1998 SEQUOYAH - UNIT 2 314 8-1 Amendment No. 89,119,123,195, 231 E2-3

v t e Letter Sequence Other
TAC:MC7340, (Withdrawn, Closed)
Initiation Acceptance... Administration Questions Answers Results Withdrawal Other: ML051810267, ML051860390
MONTHYEAR2005-06-21 [Table View]

ML051810267