ML20094E654

Application for Amends 150 & 134 to Licenses NPF-10 & NPF-15 Consisting of Change Request 453,proposing to Modify post- TS 3.8.1 to Extend Offsite Circuit AOT from 72 H & 6 Days from Discovery of Failure to Meet LCO

ML20094E654
Person / Time
Site:	San Onofre
Issue date:	11/02/1995
From:	Rosenblaum R SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20094E645	List: ML20094E641 ML20094E654 ML20094E663
References
NUDOCS 9511070344
Download: ML20094E654 (10)

Text

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1 UNITED STATES OF AMERICA l

NUCLEAR REGULATORY COMMISSION 1

l Application of SOUTHERN CALIFORNIA

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Docket No. 50-361 EDISON COMPANY, ET AL.

for a Class 103

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License to Acquire, Possess, and Use

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a utilization Facility as Part of

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Amendment Application Unit No. 2 of the San Onofre Nuclear

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No. 150 l

Generating Station

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SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL. pursuant to 10 CFR 50.90, hereby l

submit Amendment Application No. 150.

This amendment application consists of Proposed Change Number (PCN)-453 to Facility Operating License No. NPF-10.

PCN-453 is a request to revise Unit 2 l

post PCN-299 (Technical Specification Improvement Program) Technical Specification (TS) 3.8.1, "AC Sources - Operating," to 1) extend the Offsite Circuit Allowed Outage Time (A0T) from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" to "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 10 days from discovery of failure to meet LC0" and 2) extend the Emergency Diesel Generator (EDG) A0T from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" to "7 days AND 10 days from discovery of failure to meet LCO."

Additionally, PCN-453 proposes to further extend the EDG A0T to "10 days AND 10 days from discovery of failure to meet LC0" on a once-per-refueling cycle frequency.

1 951107o344 9s11o2 PDR ADOCK 05000361 P

PDR

Subscribed on this 2nd day of November

,1995 l

Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY b

By:

K,*

/tf

~ Richard M.' Rosenblum Vice President l

State of California

]

County of San Diego 1

on Nov. 2, 1995 before me, Linda L. Rulon/ Notary Public I

personally appeared Richard M. Rosenblum

. personally known to me to be the person whose name is subscribed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

WITNESS my hand and official seal.

Signature b bh

^ ^ ^ ^ ^ - - - - -

e UND,A L,RtA04 l

cc, mm

.l Notwy Pubilocalsforth 3

ORANGE COUNTY My comm. expres IMA W,H06 1

4

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION l

Application of SOUTHERN CALIFORNIA

)

Docket No. 50-362 EDISON COMPANY, ET AL.

for a Class 103

)

License to Acquire, Possess, and Use

)

a Utilization Facility as Part of

)

Amendment Application Unit No. 3 of the San Onofre Nuclear

)

No. 134 Generating Station

)

SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL. pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 134.

This amendment application consists of Proposed Change Number (PCN)-453 to Facility Operating License No. NPF-15.

PCN-453 is a request to revise Unit 3 post PCN-299 (Technical Specification Improvement Program) Technical Specification (TS) 3.8.1, "AC Sources-0perating," to 1) extend the Offsite Circuit Allowed Outage Time (A0T) from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" to "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 10 days from discovery of failure to meet LC0" and 2) extend the Emergency Diesel Generator (EDG) A0T from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" to "7 days AND 10 days from discovery of failure to meet LCO."

Additionally, PCN-453 proposes to further extend the EDG A0T to "10 days AND 10 days from discovery of failure to meet LC0" on a once-per-refueling cycle frequency.

l Subscribed on this 2nd day of November

,1995.

Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY By:

p e

l Richard M! Rosenblum Vice President l

State of California County of San Diego on Nov. 2, 1995 before me, Linda L. Rulon/ Notary Public personally appeared Richard M. Rosenblum

, personally known to i

l me to be the person whose name is subscribed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

WITNESS my hand and official seal.

Signature 1

- uuu=

t

• f

[

Notary PutbCaslande ORANGE COUNTY M comm. expres MAR 04,1998 lf l

l

l DESCRIPTION AND SAFETY ANALYSIS l

0F PROPOSED CHANGE NPF-10/15-453 This is a request to revise the San Onofre Units 2 and 3 post PCN-299 (Technical Specification Improvement Program) Technical Specification (TS) 3.8.1, "AC Sources - Operating,"

Post PCN-299 (Technical Specification Improvement Proaram) Specifications Unit 2:

See Attachment "A" Unit 3:

See Attachment "B" l

Proposed Specifications Unit 2:

See Attachment "C" i

Unit 3:

See Attachment "D" DESCRIPTION OF PROPOSED CHANGES In post PCN-299 TS 3.8.1, "AC Sources-Operating:"

o Extend the Second Completion Time in Required Action A.2 for an inoperable Offsite Circuit from "6 days from discovery of failure to meet LC0" to "10 days from discovery of failure to meet LCO."

o Extend the Allowed Outage Time (A0T) in Required Action B.4 for a single inoperable Emergency Diesel Generator (EDG) from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" to "7 days AND 10 days from discovery of failure to meet LCO."

o Add a Note in Condition B to further extend the EDG A0T in Required i

Action B.4 to "10 days AND 10 days from discovery of failure to r,1eet l

LC0" on a "once-per-refueling cycle" frequency.

Included in Attachment "C" for Unit 2 and Attachment "D" for Unit 3, respectively, are revised post PCN-299 LC0 pages 3.8-1 and 3.8-2, and revised Bases pages B3.8-6, B3.8-9, and B3.8-29.

Due to text overflow, Bases pages B3.8-10 through B3.8-21 are included for completeness.

BACKGROUND San Onofre Units 2 and 3 are each equipped with two seismically qualified, i

Class 1E, diesel engine driven generators which supply backup electrical power to the 4160 volt vital AC busses.

Each EDG is connected to the 4160 volt bus of a load group.

Each EDG is designed to automatically start in the event of l

a bus undervoltage condition on the 4160 volt Class 1E bus to which it is connected (loss of voltage signal-LOVS) or upon receipt of a Safety Injection Actuation Signal (SIAS).

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Each EDG is designed to start automatically so that within 10 seconds following receipt of a start signal it is operating at rated speed and ready to begin load sequencing.

The EDG is sized to supply reliable power to all safety-related loads in its respective load group, as well as specific nonsafety related loads. Loads supplied by each EDG are determined on the basis of nameplate or service factor rating, pump pressure and flow conditions, or pump runout conditions.

Each EDG has a continuous load rating of 4700 KW.

For emergency standby duty, the manufacturer allows specific overload values up to 116.1% of continuous duty rating based on the total hours the EDG is operated per year.

The EDGs may be contro: led or placed within their specific operating modes from the mimic bus panel in the control room or from a local panel within each EDG room.

These prov'sions allow EDG operation for surveillance testing and manual start and load operations, as well as l aal operations.

The EDGs are described in Section 8.3.1 of the _s, Onofre Units 2 and 3 Updated Final Safety Analysis Report (UFSAR).

DISCUSSION OF CHANGE The San Onofre Units 2 and 3 post PCN-299 (Technical Specification Improvement Program) Technical Specification (TS) 3.8.1 requires if an EDG is declared inoperable for any reason, the EDG must be restored to operable status within "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LC0" or place the plant in Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Cold Shutdown within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The proposed amendment would allow up to "7 days AND 10 days from discovery of failure to meet LC0" to restore EDG operability. The proposed change also makes provisions for "10 days AND 10 days from discovery of failure to meet LC0" A0T for a single inoperable EDG based on a "once-per-refueling cycle" frequency for the purpose of performing corrective or preventive maintenance necessary to restore EDG operability or improve its reliability.

The proposed amendment also extends the Second Completion Time for an inoperable Offsite Circuit from "6 days from discovery of failure to meet LC0" to "10 days from discovery of failure to meet LC0" to be consistent with the change in the EDG A0T.

The Second Completion Time in the A0Ts for the EDG and Offsite Circuit provides a limit on the maximum time allowed for any combination of required alternating current power sources to be inoperable during any single contiguous occurrence of failing to meet the Limiting Condition for Operation.

Implementation of this proposed A0T extension will:

o Allow increased flexibility in the scheduling and performance of preventive maintenance o

Reduce the number of individual entries into LCO action statements by providing sufficient time to perform related maintenance tasks with a single entry o

Allow better control of resource allocation.

During outage maintenance windows, plant personnel and resources are spread across a large number 2

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i and wide variety of maintenance tasks. Allowing on-line preventive maintenance (including overhauls) gives the flexibility to focus more quality resources on any required or elected EDG maintenance.

l Avert unplanned plant shutdowns and minimize the potential for requests o

for Notice of Enforcement Discretions (N0EDs).

Risks incurred by unexpected plant shutdowns can be comparable to and often exceed those associated with continued power operation.

o Improve EDG availability during shutdown modes.

o Permit scheduling of EDG overhauls of up to 10 days on-line.

CE NPSD-996, CEOG " Joint Applications Report for Emergency Diesel Generators A0T Extension," provided detailed results of an integrated assessment of the overall risk associated with the adoption of the proposed EDG A0T extension.

This evaluation includes an assessment considering the risk associated with "at power," " transition," and " shutdown" operations and utilized Probabilistic Safety Analysis (PSA) methodology to fully evaluate the effect of the EDG A0T extension. The results of the evaluation are summarized below, l

Assessment of At Power Risk i

The evaluation of "at power risk" change resulting from the extended A0T was performed using plant specific information from each of the participating CE0G members.

The results for San Onofre Units 2 and 3 show that the proposed A0T changes could increase the average core damage frequency (CDF) by 4%.

Assessment of Transition Risk Transition risk represents the risk associated with reducing power and going to hot shutdown or cold shutdown modes.

This risk identifies the tradeoff between shutting the plant down and restoring EDG operability while the plant continues to operate.

The results of this risk assessment indicate that performing a 7-day A0T corrective maintenance at power, as compared to shutting down the plant to perform the work, would be risk beneficial.

Assessment of Shutdown Risk Shutdown risk is associated with removing an EDG from service while the plant is in a shutdown mode of operation.

The results of this risk assessment indicate that performing corrective or preventive maintenance at power would:

1) be risk neutral when compared with early outage maintenance, and 2) result in a slight increase in risk when compared with late outage maintenance.

However, performing EDG maintenance at power will provide greater EDG reliability upon entering shutdown modes than if maintenance had been performed at the end of a refueling outage.

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The CE NPSD-996 report evaluated the impact of the proposed A0T extension on large early release scenarios.

Large early release scenarios are releases arising from 1) containment bypass events (e.g., interfacing system LOCAs, steam generator tube ruptures with concomitant loss of steam generator isolation), 2) severe accidents accompanied by loss of containment isolation, and 3) containment failure associated with energetic events in containment.

The evaluation concluded that the increased unavailability of one EDG will result in a negligible impact on large early release probability.

The CE NPSD-996 report concludes that an EDG A0T extension from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days with a once-per-refueling cycle 10-day A0T may potentially result in a small increase in the "at power" risk.

However, when full scope of plant risk j

is considered, the risks incurred by extending the A0T for either corrective or preventive maintenance will be substantially offset by plant benefits associated with avoiding unnecessary plant transitions, reducing risks during plant shutdown operations and improved EDG reliability upon entering shutdown.

The data and risk results in CE NPSD-996 pertaining to the San Onofre units were supplied and endorsed by Southern California Edison.

SAFETY ANALYSIS The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any one of the following areas:

1.

Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response

No The Emergency Diesel Generators (EDGs) are backup alternating current power sources designed to power essential safety systems in the event of a loss of offsite power.

EDGs are not accident initiators in any accident previously evaluated.

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

The EDGs provide backup power to components that mitigate the consequences of accidents. The proposed changes to the Allowed Outage Times (A0Ts) do not affect any of the assumptions used in the deterministic safety analysis.

To fully evaluate the effect of the EDG A0T extension, Probabilistic Safety Analysis (PSA) methods were utilized.

The results of these analyses show no significant increase in the core damage frequency. As a result, there would be no significant increase in the consequences of accidents previously evaluated.

Therefore, this change does not involve a significant increase in the probability or consequences of any accident previously evaluated.

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2.

Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No This proposed change does not alter the design, configuration, or method of operation of the plant. Therefore, this change does not create the possibility of a new or different kind of eccident from any previously evaluated.

3.

Will operation of the facil!ty in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No The proposed changes do not affect the Limiting Conditions for Operation or their Bases that are used in the deterministic analyses to establish the margin of safety.

PSA evaluations were used to evaluate these changes, and these evaluations determined that the changes are either risk neutral or risk beneficial.

Therefore, this change does not involve a significant reduction in the margin of safety.

Safety and Sionificant Hazards Determination Based on the above Safety Analysis, it is concluded that: 1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92 and 2) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed change. Moreover, because this action does not involve a significant hazards consideration, it will also not result in a condition which significantly alters the impact of the station on the environment as described in the NRC Final Environmental Statement.

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ATTACHMENT "A" POST PCN-299 (TECHNICAL SPECIFICATION IMPROVEMENT PROGRAM) SPECIFICATIONS UNIT 2