ML20198G374

Proposed TS Change Number 489 to Amend Applications 176 & 162 to Licenses NPF-10 & NPF-15,changing TS 5.5.2.11, SG Tube Surveillance Program

ML20198G374
Person / Time
Site:	San Onofre
Issue date:	12/22/1998
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20138M341	List: ML20198G341 ML20198G374 ML20198G400 ML20198G417 ML20198G434 ML20198G449
References
NUDOCS 9812290064
Download: ML20198G374 (12)

Text

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA EDISON 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. 176 Generating Station SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL. pursuant to 10 CFR 50.90, hereby sabmit Amendment Application No.176.

This amendment application consists of Proposed Change Number (PCN) 489 to Facility Operating License No. NPF-10.

PCN 489 requests changes to San Onofre Unit 2 Technical Specification (TS) 5.5.2.11, " Steam Generator (SG) Tube Surveillance Program," to allow steam generator tube repair using Westinghouse laser welded sleeving.

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day of _ O #J2 h, N [ 1998 Subscribed on this Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N C0 PANY E

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IEigifEE. Nu r Vice Preside State of California County of San Diego V

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'A bb personally appeared i NvN-O h ) 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 t h t 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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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERh CALIFORNIA

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EDIS0N COMPANY, EI AL. for a Class 103

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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. 162 Generating Station SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL. pursuant to 10 CFR 50.90, hereby submit Amendment Application No.162.

This amendment application consists of Proposed Change Number (PCN) 489 to Facility Operating License No. NPF-15.

PCN 489 requests changes to San Onofre Unit 3 Technical Specification (TS) 5.5.2.11, " Steam Generator (SG) Tube Surveillance Program," to allow steam generator tube repair using Westinghouse laser welded sleeving.

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day of O @ n b d 998 Respectfully submitted, j

4 SOUTHERN CALIFORNIA EDIS0N CQiPANY B

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Dwight E. Nun Vice President State of California County of San Diego N!k7 b lthe h

ND before me, On personally appeared 3 (4hN blLMhpersonally 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 hand and official seal.

MARIANE SANCHEZ Commission #1196482 I

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ENCLOSURE 2 WESTINGHOUSE TOPICAL REPORTS

" Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type and Westinghouse Preheater Steam Generators Generic Sleeving Report," Revision 2, Report No. WCAP-13698, Proprietary Version and Report No. WCAP-13699, Non-Proprietary Version, dated April, 1995.

" Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type and Westinghouse Preheater Steam Generators Generic Sleeving Report," Revision 2, Addendum 1, Report No. WCAP-13698, Proprietary Version and Report No. WCAP-13699, Non Proprietary Version, dated June, 1998.

" Specific Application of Laser Welded Sleeves for Southern California Edison San Onofre Units 2 and 3 Steam Generators," Revision 1, Report No. WCAP-15014, Proprietary Version and Report No. WCAP-15015, Non-Proprietary Version, dated July, 1998.

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1 ENCLOSURE 1 PCN-489 4

FOR SAN ONOFRE UNITS 2 AND 3 P

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• DESCRIPTION, NO SIGNIFICANT IIAZARDS CONSIDERATION, AND ENVIRONMENTAL CONSIDERATION FOR PROPOSED CIIANGE NPF-10/15-489 l

This is a request for a Technical Specification (TS) change to revise TS 5.5.2.11, Steam Generator (SG) Tube Surveillance Program.

EXISTING TECIINICAL SPECIFICATIONS I

Unit 2:

See Attachment A Unit 3:

See Attachment B PROPOSED TECIINICAL SPECIFICATIONS -(Strike out for deletions and highlight for additions.)

Unit 2:

See Attachment C Unit 3:

See Attachment D PROPOSED TECIINICAL SPECIFICATIONS - (Changes Incorporated)

Unit 2:

See Attachment E Unit 3:

See Attachment F PROPOSED BASES CIIANGES (for information only)(Strike out for deletions and highlight for additions.)

Unit 2:

See Attachment G Unit 3:

See Attachment H DESCRIPTION OF CII ANGE Technical Specification 5.5.2.11 " Steam Generator (SG) Tube Surveillance Program" is requested to be revised to describe the Westinghouse laser welde'd SG tube sleeve option. Additionally, i

some editorial errors are corrected.

DISCUSSION:

This proposed Technical Specification change is to revise the San Onofre Units 2 and 3 Technical Specifications (TS) to allow steam generator tube repair using Westinghouse laser welded sleeves in accordance with Westinghouse generic topical report WCAP-13698 Revision 2, " Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type and Westinghouse Preheater Steam )

v Generators Generic Sleeving Report" dated April,1995, Westinghouse topical report WCAP-13698 Revision 2 Addendum 1," Laser Welded Sleeves for 3/4 inch Diameter Tube Feedring-Type and Westinghouse Preheater Steam Generators Generic Sleeving Report" dated June,1998, and Westinghouse plant specific topical report WCAP-15014 Revision 1 " Specific Application of Ldser Welded Sleeves for Southern California Edison San Onofre Units 2 and 3 Steam Generators" dated July,1998.

Background:

Generic topical report WCAP-13698 Revision 2, topical report WCAP-13698 Revision 2 Addendum 1, and site-specific topical report WCAP-15014 Revision 1 provide information to support a Technical Specification change allowing installation of Westinghouse laser welded sleeves in San Onofre Units 2 and 3 3/4" outside diameter (OD) steam generator tubes. Reactor operation with sleeves installed in the steam generator tubes will not increase the probability or consequence of a potential accident condition previously evaluated, will not create the possibility of a new or difTerent kind of accident, and will not reduce any existing margin of safety, because they are designed and installed to meet the design requirements of the original steam generator tubes.

There are two distinct categories of sleeves: tube sheet sleeves and tube support sleeves'. Tube sheet sleeves are to be installed in the tube sheet zone of the steam generator tubes, attached at the top by laser welding, and hard rolled to provide mechanical attachment at the bottom. Tube support sleeves are to be installed at the tube support plate zone of steam generator tubes and attached to the tube at both ends by laser welding. Steam generator tubes with installed sleeves will meet the structural requirements of tubes which are not degraded.

San Onofre Units 2 and 3 each have two ABB/ Combustion Engineering (ABB/CE) steam generators with 3/4-inch OD tubing. The San Onofre Units 2 and 3 steam generator tubes have experienced tube wall degradation primarily near the tube expansion transitions and at the tube support locations. As a result of this degradation, steam generator tube plugging has been implemented at San Onofre Units 2 and 3.

l This proposed Technical Specification change will allow Westinghouse sleeving at San Onofre Units 2 and 3 as an alternative to either ABB/CE sleeving, recently approved by Amendments 140 and 132 for Units 2 and 3 respectively, or tube plugging. By Amendments 140 and 132 the allowed reactor coolant system primary to secondary leakage through any one steam generator, following installation of any sleeving in any steam generator, was reduced to 150 gallons per day.

Technical Specification Changes:

This amendment request is to revise San Onofre Units 2 and 3 Technical Specification 5.5.2.11

" Steam Generator (SG) Tube Surveillance Program" to allow SG tube repair with Westinghouse laser welded sleeves in accordance with Westinghouse generic topical repon WCAP-13698, Revision 2, topical report WCAP-13698 Revision 2 Addendum 1, and site-specific topical report 2

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WCAP-15014 Revision 1.. Additionally, as part of this amendment request a typographical error is corrected and editorial errors in Table 5.5.2.11-1 are corrected.

The basis for SG tube surveillance and plugging / repair is to ensure that the structural integrity of the reactor coolant pressure boundary is maintained. Sleeving technology was developed to span degraded regions of tubing with new tubing material such that the integrity of the tube is maintained. Removal of a tube from service by plugging results in a reduction of reactor coolant system flow. Repair of the tube by sleeving maintains the heat transfer area and results in a very small reduction in reactor coolant system flow. This minimizes loss of credit for reactor coolant flow through the SG in the Loss of Coolant Accident (LOCA) and various non-LOCA safety analyses.

These TS amendments are proposed to address tube degradation which is occurring within the tubesheet region, above the top of the tubesheet, and at the tube suppon plate intersections in areas accessible to the sleeving equipment, by using the sleeving process and equipment described in Westinghouse reports WCAP-13698 and WCAP-15014.

Technical Considerations:

Provided below is a summary discussion of the sleeve designs, installation process, tube' plugging equivalency, installation examination, in-service examination, corrosion test qualification, mechanical test qualification, stmetural analysis qualification, leakage assessment, and sleeving of previously plugged tubes.

Sleeve Designs Topical report WCAP-13698 describes Westinghouse laser welded sleeves that are generically applicable to ABB/CE SGs. The two categories of sleeves are tube sheet sleeves and tube support sleeves:

1. Tube Sheet Sleeves

a. Full Length Tube Sheet (FLTS) Sleeve The sleeve extends the full length of the tube within the tube sheet and is mechanically (hard rolled) joined to the tube in the vicinity of the tube sheet bottom. The upper end of the sleeve is laser welded to the steam generator tube inside diameter.

b. Elevated Tube Sheet (ETS) Sleeve The sleeve extends over approximately one-third of the tube length within the tube sheet and is mechanically (hard rolled) joined to the tube approximately 14 inches above the tube sheet bottom. The upper end of the sleeve is laser welded to the steam generator tube inside diameter.

2. Tube Support Sleeves (TSS)

The sleeve is to be installed at the tube support plate zone of steam generator tubes and attached to the tube at both ends by laser welding.

The standard tube sheet sleeves (FLTS and ETS) are up to 36 inches in total length, and the tube 1

support sleeves (TSS) may be up to 15 inches long.

Installation Process The installation process for laser welded sleeves is de' scribed in WCAP-13698 and its Addenda 1.

First, the tubes are sized (if required) to remove weld roll-over. Second, the tubes are cleaned, and then the sleeves are inserted. Next, the sleeves are expanded hydraulically to secure them in place at the upperjoint. Welding of the upperjoint is performed at this point, followed by heat treatment of the upperjoint. Subsequently, the lowerjoint is rolled. Installation examination is discussed below.

Tube Plugging Equivalency The hydraulic equivalency of the laser welded sleeves installed in the tubes is calculated using the -

relationship and nomagraph that are in WCAP-13698. The position of the sleeve or sleeves is accounted for and the equivalency relationship demonstrated by calculation for both normal operation and LOCA flow conditions. Programs are in place to ensure that plugging equivalency from the combination of plugs and sleeves does r xceed the assumptions for plugging in the Updated Final Safety Analysis Report (UFSAR) thapter 15 accident analysis for San Onofre Units 2 and 3.

Installation Examination Visual inspection of the welds is performed following welding. Ultrasonic inspection is performed for acceptance of all welds. Following acceptance by Ultrasonic testing, all welds are heat treated for stress relief. Southern California Edison (SCE) requires stress relief of all welds. Eddy current testing using qualified procedures completes the installation process.

In-Service Examination in-service examination is to be conducted using Eddy Current Testing (ECT) techniques qualified in accordance with the requirements of Electric Power Research Institute (EPRI) Pressurized Water Reactor (PWR) Steam Generator Examination Guidelines. The inspection scope will be in accordance with TS table 5.5.2.11-2.

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l Corrosion Test Qualification The W stinghouse Laser welded sleeve is fabricated from Alloy 690TT (thermally treated) and has been demonstrated to be highly resistant to intergranular stress corrosion cracking under steam generator conditions. Westinghouse has performed qualification testing as a means to demonstrate the suitability of the sleeve for the intended service, and the test included evaluation of the effect of th'e sleeve on the parent tube and the tube-to-tubesheet weld. The qualification tests are described in WCAP-13698 and WCAP-15014.

Leakage and Mechanical Test Qualification Westinghouse has performed mechanical testing to demonstrate the mechanical and pressure integrity of the laser welded sleeve. These tests include the types of sleeves that SCE intends to employ for tube repairs at San Onofre. The qualification tests are described in WCAP-13698 and WCAP-15014.

Structural Analysis Qualification Structural analysis has been performed for the Westinghouse laser welded sleeve. Applicable criteria for evaluating the sleeve is defined in the ASME code,Section III Subsection NB,1989 edition, with no addenda. The analysis considered plant-specific design loading conditions for San Onofre Units 2 and 3. The analysis is described in WCAP-13698 and WCAP-15014.

Sleeving of Previously Plugged Tubes The sleeve installation requirements described are applicable to the laser welded tube suppoa plate sleeves and the laser welded tubesheet sleeves for tubes which may or may not have been previously plugged. The existing requirements for tube integrity in the region outside of the sleeve pressure boundary must be met.

NO SIGNIFICANT IIAZARDS CONSIDERATION The Commission has provided standards for determining whether a significant hazards consideration exists as stated in 10 CFR 50.92. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with a proposed amendment would not: (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety. A discussion of these standards as they relate to this amendment request follows:.

I (1)

Will operation of the facility in accordance with this proposed change involve a significant f

increase in the probability or consequences of any accident previously evaluated?

l Resoonse: No Steam generator tubes, tube plugging, and tube failures are considered in the analysis of l

accidents in the Updated Final Safety Analysis Repon (UFSAR). The steam generator l

tube rupture accident analysis considered the failure of a steam generator tube. Also, inadvertent opening of a steam generator dump valve (IOSGDV), loss of condenser j

vacuum (LOCV), loss of coolant accidents (LOCAs), and feed water line break (FWLB) l accident analyses cany assumptions regarding steam generator tube plugging. In each

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case, the addition of steam generator tube sleeves to repair defective tubes will not change l

the probability or consequences of any accident previously evaluated.

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i The sleeve configurations have been designed, analyzed, and tested in accordance with the American Society of Mechanical Engineers (ASME) code requirements, and mechanical i

testing has shown that the sleeve and sleeve joints provide margin above acceptance limits.

l Ultrasonic testing (UT) and eddy current testing (ECT) are used to verify the adequacy of l

welds. Tests have demonstrated that tube collapse will not occur due to postulated LOCA l

loadings.

i The probability or consequence of any accident previously evaluated is not increased i

because any leakage through the sleeve assembly is fully bounded by the existing steam j

generator tube rupture analysis included in the San Onofre Unit 2 and 3 Updated Final l

Safety Analysis Repon. Additionally, any reactor coolant flow restriction from sleeving is addressed by a ratio of number of sleeved tubes to be equal to a plugged tube.

Therefore, the proposed sleeving repair process will not involve an increase in the probability or consequences of any previously evaluated accident.

4 (2)

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

f Response: No 1

l The sleeves are captured within the steam generator tubes by hard rolling and welding and i

as such are not able to physically affect other parts of the system. The failure of a sleeve is identical to the failure of the parent tube which has been previously analyzed.

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The use of a sleeve to span the area of degradation of the steam generator tube restores the structural and leakage integrity of the tubing to meet the original design requirements.

j Structural analysis of the sleeve assembly shows that the requirements of the ASNE Code are met. Mechanical testing has demonstrated that margin exists above the original tube

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design criteria. Any hypothetical accident as a result of any degradation in a sleeved tube l

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would be bounded by the existing steam generator tube rupture accident analysis.

Therefore, the operation of the facility in accordance with proposed changes does not create the possibility of a new or different kind of accident from any accident 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 The use of sleeves to repair degraded steam generator tubing wnl maintain the integrity of the tube bundle commensurate with the ASME Code and draft Regulatory Guide (RG) 1.121 margin requirements for original tubing. Sleeves are components which are part of the reactor coolant pressure boundary and meet the requirements for C! ass I components in Section III of the ASME Boiler and Pressure Vessel Code. The primary to secondary pressure boundary will be maintained to the same margins as the original tubes under normal and postulated accident conditions. The safety margins used in the verification of the strength of the sleeve assembly are consistent with the safety factors in the ASME Boiler and Pressure Vessel Code used in steam generator design. Further, a test program has been conducted by Westinghouse which demonstrated the integrity of the lower hard.

rolled joint design and its capability to withstand the design loads.

Therefore, operation of the facility with the proposed changes will not involve a significant reduction in a margin of safety.

Based on the responses to these three criteria, Southern California Edison (SCE) has concluded that the proposed amendment involves no significant hazards consideration.

ENVIRONM ENTAL CONSIDERATION SCE has determined that the proposed amendment involves no changes in the amount or type of effluent that may be released offsite, and results in no increase in individual or cumulative occupational radiation exposure. As described above, the proposed amendment involves no significant hazards consideration and, as such, meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

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PCN-489 i

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4 ATTACHMENT A EXISTING TECHNICAL SPECIFICATIONS

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