ML20216B999

Application for Amends 175 & 161 to Licenses NPF-10 & Proposed Change 490,eliminating Ref to Inverters in TS 3.4.12.1

ML20216B999
Person / Time
Site:	San Onofre
Issue date:	03/06/1998
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:	NRC
Shared Package
ML20216B974	List: ML20216B969 ML20216B999 ML20216C005
References
NUDOCS 9803130238
Download: ML20216B999 (9)

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UNITED STATES OF AMERICA l NUCLEAR REGULATORY COMISSION 1

l Application of SOUTHERN CALIFORNIA .

EDIS0N COMPANY, El AL. for a Class 103 Docket No. 50-361 License to Acquire, Possess, and Use a Utilization Facility as Part of Amendment Application Unit No. 2 of the San Onofre Nuclear No. 175 Generating Station

, SOUTHERN CALIFORNIA EDISON COMPANY, EI AL. pursuant to 10 CFR 50.90, hereby submit Amendment Application No.175. This amendment application' consists of Proposed Change Number NPF-10-490 to Facility Operating License No. NPF-10.

Proposed Change Number NPF-10-490 is a request to revise Technical Specification (TS) 3.4.12.1 " Low Temperature Overpressure Protection (LTOP)

System" to not mention the inverter since it is being eliminated.

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Subscribed on this h. day of MA4LCd , 1998.

Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY 1\

By: N .

D t E. Nu n Vice President State of California County of San Diego on E Y before me) lLl1k) Nf ,

personally appeared If)h PG MitutJ personaiiy 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 behaif of which the person acted, executed the instrument.

WITNESS and and official seai. . - . .. MARANE $ANCHE7

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jj i MyComm.Ex;*eeOCT14.1998 h' Signature wn - - - - - - - > >

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4 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMISSION Application of SOUTHERN CALIFORNIA EDISON COMPANY, EI R . for a Class 103 Docket No. 50-362 License to Acquire, Possess, and Use a Utilization Facility as Part of Amendment Application Unit No. 3 of the San Onofre Nuclear No. 161 Generating Station SOUTHERN CALIFORNIA EDIS0N COMPANY, EI R. pursuant to 10 CFR 50.90, hereby l submit Amendment Application No. 161. This amendment application consists of j Proposed Change Number NPF-15-490 to Facility Operating License No. NPF-15.

Proposed Change Number NPF-15-490 is a request to revise Technical Specification (TS)3.4.12.1"LowTemperatureOverpressureProtection(LTOP)

System" to not mention the inverter since it is being eliminated.

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4 Subscribed on this b day of MASN , 1998.

l Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY t

l By: 1 -

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DwightE.Nijnn  !

l Vice President l

State of California l County f Sa Die )n on )\ 0 before me,) } k Y{%1t ' 1 kW personally appeared l IL hit /Ll( personally known to me to be the person whose name is subscribed to the within instrument I and acknowledged to me that he executed the same in his authorized capacity, l

and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

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WITNESS hand and official seal. MAPIANE sANCHEZ g CoMM.p tc337g,3 iA g

z Notay pwgc - Cotfornia ouNos COUNTY f

Signature [ c ULfLR) L '

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DESCRIPTION AND SAFETY ANALYSIS t 0F PROPOSED CHANGE NPF-10/15-490 This is a request to revise the San Onofre Units 2 and 3 Technical l Specification (TS) 3.4.12.1, " Low Temperature Overpressure Protection (LTOP)

System."

Existino Specifications Unit 2: See Attachment "A" Unit 3: See Attachment "B" j l

Proposed Specifications  !

Unit 2: See Attachment "C" .

Unit 3: See Attachment "D" j 1

Proposed Bases Chanaes Units 2 & 3: See Attachment "E" Units 2 and 3 Plant Modification Design Change

Description:

See Attachment "F."

l DESCRIPTION OF PROPOSED CHANGES i

Technical Specification Surveillance Requirement, SR 3.4.12.1.4 Note 2, is i being revised as follows: 1 The power-lock open requirement is satisfied either with the AC breakers open for_ valve pair 2HV9337 and 2HV9339 or the-invertcr input and regulating? transformer output breakers open for valve pair 2HV9377 and 2HV9378'" whichever^ialve pair is OPERABLE.

For your information, upon approval of this change, paragraph 2 of Technical Specification Bases, B 3.4.12.1 will be revised as follows (Attachment E): i This surveillance requirement, SR 3.4.12.1.4, is modified by two notes.

Note 1 requires to perform this SR when the SDCS Relief Valve isolation valve pair is inoperable. Note 2 saecifies that the power-lock open requirement is satisfied either wit 1 the AC breakers open fotvalye pair output breakers open for valve pair 2HV9377 and 2HV9378,htransformer,2HV93 v

pair is OPERABLE.

BACKGROUND l

During the weeks of October 16 and October 23, 1995, the NRC's Office of Nuclear Reactor Regulation completed the second phase of an Integrated f Performance Assessment of the San Onofre Nuclear Generating Station, Units 2 and 3. This phase of the assessment consisted of on-site observations by a teamofeightindividualsintheareasofsafetyassessment/correctiveaction,

4 operations, engineering, maintenance, and plant support. The results of the on-site assessment were integrated with tho . obtained during the team's preliminary in-office documentation review and were summarized in NRC In:,pection Report IR 95-201, dated December 21, 1995. A weakness identified in the Inspection Report was the licensee had not adequately resolved an issue associated with the capacity of the inverters for the shutdown cooling bypass valves. On July 12, 1996, The NRC issued a Safety Evaluation Report (SER),

" Inverter Design for Shutdown Cooling System Isolation Bypass Valves." For the reasons detailed in the SER, the staff concluded that the current design of the inverters does not comply with ap)licable industry guidance, and the licensee's modifications are not accepta)le as a 3ermanent solution. The staff further concluded that the steps taken by t1e licensee to improve the reliability of these inverters, primarily the installation of two additional selectable fuses per inverter, pron des an acceptable level of safety in the interim until a permanent solution can be implemented.

Southern California Edison (SCE) responded to the SER by letter dated August 26, 1996, and committed to implement a permanent solution by the end of the Cycle 10 refueling outage for each Unit.

SCE will be removing the inverters and replacing them with Selectable AC Power to HV-9377 and HV-9378 directly from A and B Train Motor Control Centers (MCC's) via Transfer Switches (see Attachment F).

DISCUSSION OF CHANGE Eronosed Chanae to the Technical Soecifications The proposed change to Technical Specification Surveillance Requirement, SR 3.4.12.1.4 Note 2, is required to facilitate removal of the ir.verters in the upcoming Cycle 10 refueling outages.

The change to the note removes the requirement to open both input and output breakers of the inverters which feed valve HV9377 and HV9378. There is no technical basis for both the input and output breakers to be open to achieve 30wer lock-out for these valves. Opening either the input or the output areakers would achieve power lockout. Replacing the reference to the input and output breakers of the inverter with the requirement to open the Regulating Transformer output breakers for valve pair HV9377 and HV9378 will still achieve power lock-out.

Proposed Plant Modification Attachment F provides a descri) tion of the design change to replace the shutdown cooling inverters wit 1 transfer switches. This description discusses the reason for the change, the functional objective of the change, the design alternatives that were considered, and provides the one-line electrical diagrams. Attachment F is included to show the NRC that the design change resolves the concerns associated with the inverters. The preliminary 10 CFR 50.59 safety evaluation shows that the proposed design change to operate with transfer switches instead of inverters does not involve an unreviewed safety c uestion. This 10 CFR 50.59 safety evaluation will be revised and updatet until is it completed at, part of the Design Change Package process.

l SAFETY ANALYSIS l

The proposed design change will be shown not to involve an unreviewed safety question as documented in SCE Design Change Package process. The preliminary evaluation does not indicate the proposed design change involves an unreviewed safety question. However, if in the final analysis SCE determines this design change will not pass the 10CFR50.59 safety evaluation, SCE will submit the design for NRC approval.

The proposed Technical Specification 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 significent increase in the probability or consequences of an accident previously evaluated?

Response: No There will be no change in the probability or consequences of any accident previously evaluated in the Updated Final Safety Analysis Report (UFSAR) because the required >ower lockout to valves HV9377 and HV9378 will be achieved by opening tie AC feeder breakers to these valves.

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

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 There will not be the possibility of a new or different kind of accident from any previously evaluated in the UFSAR because the required power lockout to valves HV9377 and HV9378 will be achieved by opening the AC breakers to these valves.

Therefore, this change does not create the possibility of a new or different kind of accident from any previously evaluated.

3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No Because power is being locked out by opening the breakers which serve these valves, as required by the Technical Specifications, this change does not involve any reduction in a margin of safety.

i Therefore, this change does nD1 involve a significant reduction in a margin of safety.

i Safety and Sianificant 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 l will also not result in a condition which significantly alters the impact of i the station on the environment as described in the NRC Final Environmental Statement.

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ATTACHMENT "A" EXISTING SPECIFICATIONS UNIT 2

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