ML20217A818
| ML20217A818 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/16/1997 |
| From: | Nunn D SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML20046D781 | List: |
| References | |
| NUDOCS 9709230003 | |
| Download: ML20217A818 (20) | |
Text
{{#Wiki_filter:-.. -.. - . ~. l UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA ) Docket No. 50-361 EDISON COMPANY, H R. for a Class 103 ) License to Acquire, Possess, and Use ) a Utilization Facility as Part of ) Amendr.ient Application Unit No. 2 of the San Onofre Nuclear ) No. IlQ Generating Station ) SOUTHERN CALIFORNIA EDISON COMPANY, G E, pursuant to 10 CFR 50.90, hereby submit Amendment Application No. JJLQ. This amendment application consists of Proposed Change Number (PCN)-487 to Facility Operating License No. NPF-10. PCN-4B7 is a request to revise Technical Specification (TS) 3.4.13 "RCS Operational Leakage" to reduce the allowable primary to secondary steam generator leakage with Steam Generator (SG) sleeving installed, to revise TS 5.5.2.11 " Steam Generator Tube Surveillance Program" to allow Steam Generator (SG) tube repair with ABB/CE leak tight sleeves, and to revise TS 5.7.2, "Special Reports" to include reporting of SG sleeve inservice inspections. Subscribed on this V day of 44h O W,1997 Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY . d By: wigfit E. Nunn y Vice President state of California n o / before me, lkiDD /Q]1 fM persoh illy hp edred b _O)Aldi-VrA NRh1 , personally known to me to be the person Mose n&m'e 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 ins'trument the person, or the entity upon behalf of' hich the person acted, executed the instrument. ^^^^^^^^^^^^ WITNESS my b and official seal. [ica$7[ A [. Notwy PtNe - Co:lfomic h ] / ) b( f / Q W Comm. Expires oci 14,1993 ( signature ORANGE COUN1Y ~ < l i 7 ....m., s 9709230003 970916 PDR ADOCK 05000361 p PDR
1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA ) Docket No. 50 362 EDISON COMPANY, U 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.1M Generating Station ) SOUTHERN CALIFORNIA EDISON COMPANY, U al. pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 1M. This amendment application consists of Proposed Change Number (PCN)-487 to Facility Operating License No. NPF-10. PCN-487 is a request to revise Technical Specification (TS) 3.4.13 "RCS Operational Leakage" to reduce the allowable primary to secondary steam generator leakage with Steam Generator (SG) sleeving installed, to revise TS 5.5.2.11 " Steam Generator Tube Surveillance Program" to allow Steam Generator (SG) tube repair with ABB/CE leak tight sleeves, and to revise TS 5.7.2, "Special Reports" to include I reporting of SG sleeve inservice inspections. Sebscribed on this day of Clyi3H'F,1997. V Respectfully submitted, SOUTHERNCALIFRNIAEDIq0NCOMPANY B l ' Uwig E. Niinn i Vice resident State of california T 5 /i ( - fore me ' Dijld/ M N' 4 perso'nally appea' red 0161 l; _ i ! (A_ n__A _), personally known to i me to be the person Whose n6me 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 o ch the person acted, executed the instrument. h WITNESS ho da. official seal. MAmANE SANCHEZ h f signatur L-{_.) L Notory on omio i c_ _.. _. _ r d
i t s 4 ENCLOSURE 5 ABB/CE PROPRIETARY INFORMATION AFFIDAVITS FOR i ENCLOSURES 3 AND 4 SAN ONOFRE UNITS 2 AND 3 I 4 4 k
AFFIDAVIT PURSUANT TO 10 CFR 2.790 I, Ian C. Rickard, depose and say that I am the Director, Operations Licensing, of Combustion Engineering, Inc., duly authorized to make this affidavit, and have reviewed or caused S hue reviewed the informatiun which is identified as proprietary and referenced in the paragraph immediately below. I am submitting this affidavit in conjunction with the application of Southern Califomia Edison Company and in conformance with the provisions of 10 CFR 2.790 of the Commission's regulations. J j The information for which proprietary treatment is sought is contained in the following document: CEN-630-P, Rev. 02, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," June 1997. This document has been appropriately designated as proprietary. I have personal knowledge of the criteria and procedures utilized by Combustion Engineering in designating information as a trade secret, privileged or as confidential commercial or financial information. Pursuant to the provisions of paragraph (b)(4) of Section 2.790 of the Commission's regulations, the following is fumished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure, included in the above i referenced document, should be withheld. 1. The information sought to be withheld from public disclosura, is owned and has been held in confidence by Combustion Engineering. It consists of the details conceming the fabrication process, material properties, and l l
_ surveillance data used to develop an approach to ascertain the embrittlement of reactor vessels. 2. The information consists of test data or other similar data conceming a process, method or component, the application of which results in cubstantial competitive advantage to Combustion Engineenng. 3. The information is of a type customarily held in confidence by Combustion { Engineering a id not customarily disclosed to the public. Combend Engineeriru has a rational basis for determining the types of information customarily 1:ald in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP-537 from F. M. Stem to Frank Schroeder dated December 2,1974. This system was applied in determining that the subject document herein is proprietary. 4. The information is being transmitted to the Commission in confidence under the provisions of 10 CFR 2.790 with the understanding that it is to be received in confidence by the Commission. 5. The information, to the best of my knowledge and belief, is not available in public sources, and any disclosure to third parties has been made pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence. 6. Public disclosure of the information is likely to cause substantial harm to the competitive position of Combustion Engineering because: 1 a. A similar product is manufactured and sold by major pressurized water re-Mor competitors of Combustion Engineering. b. Development of this informat:on by Combustion Engineering required milUons of dollars and thousands of manhours of \\
l l effort. A competitor would have to undergo similar expense in - generating equivalent information. c. In order to acquire such information, a competitor would also require considerable time and inconvenience to develop the design, development, and installation process for a welded sleeve for repairing 3/4 inch O.D. steam generator tubes. d. The information consists of the design, development, and installation process for a welded sleeve for repairing 3/4 inch O.D. steam generator tubes, the application of which provides a competitive economic advantage. The availability of such information to competitors would enable them to modify their product to better compete with Combustion Enginaering, take marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus, e. In pricing Combustion Engineering's products and services, significant research, development, engineering, analytical, manufacturing, licensing, quality assurance and other costs and expenses must be included. The ability of Combustion l Engineering's competitors to utilize such information without similar expenditure of resources may enable them to sell at prices reflecting significantly lower costs. f. Use of the information by competitors in the internationc! marketplace would increase their ability to market nuclear steam supply systems by reducing the costs associated with their technology development. In addition, disclosure would have an adverse economic impact on Combustion 4
_ Engineering's potential for obtaining or maintaining foreign licensees. Further the deponent sayeth not. ~~ (s4;r w t r,' / lanb Director, Operations Licensing Sworn to before me i this / f l day of u6M .1997 d (Lili L ). L otcry Public My commission expires: 31 9 9
AFFIDAVIT PURSUANT TO 10 CFR 2.796 1, Ian C. Rickard depose and say that I am the Director, Operations Licensing, of Combustion Engineering, Inc., duly authorized to make this affidavit, and have reviewed or caused to havo reviewed the information which is identified as proprietary and referenced in the paragraph immediately below. I am submitting this affidavit in conjunction with the application of Southern California Edison Company, and in conformance with the provisions of 10 CFR 2.790 of the Commission's regulations. The information for which proprietary treatment is sought is contained in the following document: Report Number 96-OSW-003-P, Rev. 00, "EPRI Steam Generator Examination l Guidelines Appendix H Oualification for Eddy Current Plus-Point Probe Examination of ABB-CE Welded Sleeves," April 27,1996 This document has been appropriately designated as proprietary. I have personal knowledge of the criteria and procedures utilized by Combustion Engineering in designating information as a trade secret, privileged or as confidential commercial or financial information. Pursuant to the provisions of paragraph (b) (4) of Section 2.790 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure, included in the above referenced document, should be withheld. 1. The information sought to be withheld from public disclosure, is owned and has been held in confidence by Combustion Engineering. It consists of I
g 2-information concerning the steam generator tube repair process of sleeving, including qualification program results and analyses. 2. The information consists of test data or other similar data concerning a process, method or component, the application of which results in substantial competitive advantage to Combustion Engineering. 3. The information is of a type customarily held in confidence by Combustion Engineering and not customarily disclosed to the public. Combustion Engineering has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP-537 from F. M. Stem to l Frank Schroeder dated December 2,1974. This system was applied in determining that the subject document herein is proprietary. -4. The information is being transmitted to the Commission in confidence under the provisions of 10 CFR 2.790 with the understanding that it is to be received in confidence by the Commission. 5. The information, to the best of my knowledge and belief, is not available in public sources, and any disclosure to third parties has been made pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence. 6. Public disclosure of the information is likely to cause substantial harm to the competitive position of Combustion Engineering because: A similar product is manufactured and sold by major a. pressurized water reactor competitors of Combustion Engineering. b. Development of this information by Combustion Engineering required millions of dollars and thousands of manhours of
effort. A competitor would have to undergo similar expense in generating equivalent information. c. In order to acquire such information, a competitor would also require considerable time and inconvenience to develop an understanding of welded steam generator tube sleeve installation problems and evaluate specific examples based on test or pulled steam generator tube data and develop and qualify a steam generator tube sleeving program, d. The information consists of a description of the steam generator tube repair process of sleeving, including qualification program results and analyses, the application of which provides a competitive economic advantcge. The availability of such informatiori to competitors would enable them to modify their product to better compete with Combustion Engineering, take marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus, e, in pricing Combustion Engineering's products and services, significant research, development, engineering, analytical, manufacturing, licensing, quality assurance and other costs l and expenses must be included. The ability of Combustion Engineering's competitors to utilize such information without similar expenditure of resources may enable them to sell at prices reflecting significantly lower costs. f. Use of the information by competitors in the intemational marketplace would increase their ability to market nuclear steam supply systems by reducing the costs associated with
11 their technology development. In addition, disclosure would have an adverse economic impact on Combustion Engineering's potential for obtaining or maintaining foreign licensees. Further the deponent sayeth not. f fY/ 1 /* lan Director Operations Licensing Sworn to before me this A N bd day of _,1997 0 QuA L) Notkry Public [ My commission expires: 3/ 97 e
1 ENCL.OSURE1 PCN-487 FOR SAN ONOFRE UNITS 2 AND 3 4
DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CIIANGE NPF-10/I5-487 This is a request for a Technical Specification (TS) change to revise TS 5.5.2.11," Steam - Generator (SG) Tube Surveillance Progiam", TS 5.7.2 "Special keports", and TS 3.4.13 "RCS Operational Leakage" for San Onofre Units 2 and 3. j i Existine Technical Specificalinnn Unit 2: See Attachment A Unit 3: See Attachment B 1 Proposed Technical Specifications: Unit 2: See Attachment C Unit 3: See Attachment D DESCRIPTION OF CII ANGE - Technical Specification LCO 3.4.13 "RCS operational LEAKAGE shall be limited to:" item "f'is added as follows: "With steam generator sleeving installed in any SG,150 gallons per day primary to secor.dary LEAKAGE through any one SG." Technical Specification 5.5.2.11 " Steam Generator (SG) Tube Surveillance Program" is being revised throughout to allow sleeving as an alternative SG tube repair to plugging, including addition of a new table 5.5.2.11-2 " Steam Generator Sleeved Tube Inspection." Additionally, an editorial correction is made to TS 5.5.2.11.e.2 by referencing 5.5.2.11.e.1 instead of 5.5.2. ll.f. Technical Specification 5.7.2, "Special Reports," is revised to include the number and extent of sleeves inspected in the special report submitted following each insersice inspection of steam generator tubes. DISCUSSION: This proposed Technical Specification change is to revise the San Onofre Nuclear Generating Station (SONGS) Technical Specifications (TG) to allow steam generator tube repair using ASEA Brown Boveri/ Combustion Engineering (ABB/CE) leak tight sleeves in accordance with ABB/CE generic tcpical report CEN-630-P Revision 02, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," dated June,1997.
Background:
Generic report CEN 630 P provides information to support a Technical Specification change allowing installation of two types ofleak tight sleeves in SONGS 3/4" O.D. steam generator (SG) tubes. The report demonstrates that reactor operation with sleeves installed in the steam generator tubes will not increase the probability or consequence of a potential accident condition previously evaluated. Also, it will not create the possibility of a new or difTerent kind of accident and will not reduce the existing margin of safety. The first type of sleeve spans the steam generator tube at the top of the tube sheet, is welded at the upper end, and is hard rolled into the tube within the steam generator tube sheet. The second type of sleeve spans degraded tube areas at a tube support. Steam generator tubes with installed sleeves meet the structural requirements of tubes which are not degraded. SONGS Units 2 and 3 each have two ABB/CE steam generators with 3/4-inch OD tubing. SONGS has been experiencing tube wall degradation primarily near the tube expansion transiticas and at the tube support locations. As a result of this degradation, tube plugging has been implemented at SONGS. l This proposed Technical Specification change will allow sleeving at SONGS as an alternative to tube plugging. Technical Specification Changas: This amendment request is to revise SONGS Technical Specification 3 A.13 "RCS Operational LEAKAGE" so that if SG sleeving is used, then the allowable primary to secondary leakage through any one SG is reduced from 720 to 150 gpd, Technical Specification 5.5.2.11 " Steam Generator (SG) Tube Surveillance Program" to allow SG tube repair with ABB/CE leak tight sleeven in accordance with generic topical report CEN-630-P Revision 2, and Technical Specification 5.7.2 "Special Reports" to include the number and extent of sleeves inspected in the special report submitted following each inservice inspection of steam generator tubes. Additionally, an editorial correction is made to TS 5.5.2.11.e.2 by referencing 5.5.2.11.e.1 instead of 5.5.2.11.f The basis for SG tube surveillance and plugging / repair is to ensure that the structural integrity of the tube is maintained. Sleeving technology was developed to span degraded regions of tubing with new tut;ng material such that the integrity of the tube is maintained. Removal of a tube from sersice by plugging results in a redudion 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 margin for reactor coolant flow through the SG in the loss-of-coolant accident (LOCA) and non-LOCA safety analysis, and maintains the heat transfer area of the SGs. I 1
These TS amendments are being proposed to address tube degradation which is occurring within the tubesheet region, above the top of the tubesheet, and at the tube support plate intersections in areas accessible to the sleeving equipment by using the sleeving process and equipment described in report CEM-630-P. Technical Considerations: Provided below is a summary discussion of the sleeve designs, installation process, tube plugging aquivalency, installation examination, in service examination, corrosion test qualitication, mechanical test qualification, structural analysis quali0 cation, leakage assessment, and sleeving of previously plugged tubes. Sleeve Designs Report CEN-630-P describes two types of ABB/CE leak tight sleeves that are generically applicable to ABB/CE SGs. These two types of sleeves are: 1. A sleeve which spans the expansion or roll transition at the top of the tubesheet. This Expansion / Roil Transition Zone (ETZ) sleeve is attached to the parent tube with a welded upperjoint and hardrolled lowerjoint, and 2. A sleeve which spans a tube support or egg crate support plate elevation and is welded in both the upper and lowerjoint. The standard ETZ sleeve covered by CEN-630-P is up to 26 inches in total length. The second type of sleeve described above is 9 inches in total length. Installation Process The basic installation process for each type of sleeve involves cleaning the inside diameter of the tube in the joint region, visual examination (VT) of the tube ID surface in the weld region, installation of the sleeve, hydraulic expansion of the sleeves in the weld joint region to provide sleeve-to-parent tube contact, welding of thejoint, ultresonic examination (UT) of the weld, a VT of the weld, a post-weld-heat-treatment, completion of the lowerjoint (welded or rolled), and eddy current examination (ECT) of the sleeve. Heat treatment of the sleeve welds will be performed in accordance with proposed Technical Speci0 cation Bases B3.4.13.f). Tube Plugging Equivalency Reactor coolant Cow reduction from sleeving is addressed in the ABB/CE topical report CEN-630-P Table 10.1 by a ratio of number of tubes sleeved to equal a plugged tube. -3
Installation Examination During the installation process, a combination of VT, UT, and ECT are used at difTerent stages to ensure an acceptable installation (
Reference:
Topical Report 95-OSW-003 P "EPRI Steam Generator Examination Guidelines Appendix H Qualification for Eddy Current Plus-Point Probe Examination of ABB/CE Welded Sleeves"). These inspection techniques and equipment use state-of-the-art practices and may change as new techniques become available. The first inspection is an optional VT of the inner diameter of the tubing aller the tube brushing (cleaning) has been completed. This VT confirms the adequacy of the bruahing step to prevent weld failures due to oxide inclusions, if adequate cleanliness is not confirmed, the tube brushing is repeated until acceptable cleanliness is observed. Relaxation of this requirement during future outages depends on initially demonstrating a high degree of cleanliness acceptance in the field. Afler the weld is made the weld is inspected with UT to confirm a leak tight bond has been achieved by the welding process. Upon completion of the sleeve installation piocess an ECT is done (currently using the + point probe) over the entire length of the sleeve pressure boundaiy, l including the parent tube in the pressure boundary behind the sleeve. The acceptance criteria for the ECT is covered in the following section, "in Senice Examination." An optional VT examination of the sleeve welds is available to help resolve uncertainties in the surface conditions detected by either the UT or ECT inspections. Southern California Edison (SCE) intends to perform post weld VT examination on 100% of new sleeve installations. Relaxation of this requirement during future outages depends on initially demonstrating a high degree of acceptable welds. Sleeve weld ECT inspection and acceptance criteria are described in section 5.2.2 of the ABB/CE Topical Report CEN-630-P. The acceptance criteria will be based on the logic presented in Section 5 of CEN-630-P. ECT indications in the weld zone are separated into the two categories of surface and subsurface. Surface indications can be caused by weld sag or local irregularities in the weld surface. Additional VT reviews are used to evaluate surface relat;d indications prior to acceptance. If no surface condition is observed, then the ECT signal is considered as a subsurface weld zone indication and is evaluated consistent with the guidance in Section 6.5 of Generic Topical Report 96-OSW-003-P "EPRI Steam Generator Examination Guidelines, Appendix H Qualification for Eddy Current Plus-Point Probe Examination of ABB/CE Welded Sleeves." In-Senice Examination in-senice examination is to be conducted using ECT techniques qualified in accordance with the EPRI PWR Steam Generator Examination guidelines. The + point probe, or equivalent probe, will be used to exar ine the sleeve full length. Inspection scope will be in accordance with TS 5.5.2.1! which requires that a minimum of 20% of repaired tubes be inspected at each in-senice inspection outage. Scope expansion is in accordance with new Table TS 5.5.2.11.-2.,
Corrosion Test Quali6 cation ABB/CE sleeves are fabricated from Alloy 690 which is procured to ASN1E Boiler and Pressure Vessel Code Case N 20 and ash 1E Speci6 cation SB 163. In addition, a thermal treatment process is applied to impart greater corrosion resistance and lower residual stress level in the sleeve. The primary selection criterion for Alloy 690 as the sleeve material is its high corrosion resistance to pure water cracking in primary water and caustic corrosion cracking in normal and faulted secondary water pressurized water reactor (PWR) environments. ABB/CE conducted tests to evaluate the corrosion resistance of the welded sleevejoint. Of panicular interest is the effect of the mechanical expansion and weld residual stresses and the condition of the weld and the weld heat affected zcne. Tests conducted demons: rate that the welcid sleeve-tubejoint performs well in corrosion tests designed to simulate typical fault and normal conditions on an accelerated basis. General corrosion unc'er anticipated service conditica l is expected only for the SG tube and not for the sleeve or weld material. None of the ABB/CE l sleeves installed to date have exhibited any indication or corrosion using state-of-the-art ECT. Actual pulled tubes from another plant in 1996 showed no in service degradation of the weld, or of the parent tube in the vicinity of the weld joint. Niechanical Test Quali6cuion hicchanical tests were performed using allowable ASN1E code stresses on sleeve assemblies to determine axial load, collapse, burst, and thermal cycling capability. The load capacity of the upper and lower sleevejoints is sullicient to withstand the thermally induced stresses in the weld resultirg from the temperature ditTerential between the sleeve and tube and the pressure induced stresses resulting from normal operating and postulated accident conditions. The burst and collapse pressure of the sleeve proviies a large safety flictor over the limiting pressure ditTerentials. Mechanical testing revealed that the installed sleeve will withstand the cyclical loading from power changes in the plant and plant transients. Load cycle testing was performed on the lower hardrolliohit for a 3/4-inch tube sleeve. Hydrostatic and helium leak testing con 6rmed joint elTectiveness. All of the hardrolled joints were leak tight. Structural Analysis Qualification The ABB/CE welded and welded-hardrolled sleeves were designed to conform to the stress limits and margins of safety in the ASNIE Boiler and Pressure Vessel Code. The methodology used is in accordance with Section 111 of the 1989 Edition of the AShiE Code. Safety factors of 3 for normal operating conditions and 1.5 for accident conditions, vere applied. In performing the analytical evaluation of the sleeves, the operating and design conditions for ABB/CE plants operating with 3/4-inch inconel tubing were considered. Stress evaluations were done for the above the tubesheet weld at the nominal weld height and at the minimum weld height. The stress intensity values are less than the ASME Code allowable values, and fatigue usage factort nre less than 1. Evaluations of the tube support plate sleeve upper and lower welds show that the stresses and loads calculated for the expansion transition zone (ETZ) sleeve upper weld are bounding. The details are in CEN-630-P. Using the guidance of drafl Regulatory Guide 1.121, " Bases for Plugging Degraded PWR Steam Generator Tubes," and the ASME Code, the % allowable degradation for SONGS is 64% tube wall thickness. Making allowances for non-destniction examination (NDE) uncertainty and degradation growth, a tube repair criteria of 44% thru wall degradation has been established. Sleeve degradation, such as stress corrosion cracking located in the pressure boundary, would be plugged on detection. Leakage Qualification The ABB/CE welded sleevejoint is inherently a leak tight joint. UT examination of the weld is usea to confirm that no leak path exists. Load cycle testing was performed on the lower rolled joint for both 3/4 inch and 7/8-inch tube sleeves. Hydrostatic and helium leak testing was conduc'ed to confirm the joint effectiveness All of the hardrolled joints were leak tight. Sleeving of Previously Plugged Tubes The sleeve installation requirements described are applicable to the tube support plate sleeve and the 26-inch ETZ 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. SAFETY ANALYSIS The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive fmding in any one of the following areas: 1. Will operation of the facility in accordance with this proposed change involve a 5 significant increase in the probability or consequences of an accident previously evalurJ.ed? Response: No The supporting technical evaluation and safety evaluation for the Asea Brown Boven/Combustic,n Engineering (ABB/CE) leak tight sleeves demonstrate that the sleeve configuration will provice steam generator (SG) tube structural and leakage integrity under normal operating and accident conditions. The sleeve configurations have been designed and analyzed in accordance with the requirements of the ASME Code. Mechanical testing has shown that the sleeve and sleevejoints provide margin above acceptance limits. Ultrasonic Testing (UT)is used to verify the leak tightness of the weld above the tubesheet. Testing has demonstrated the leak tightness of the hardrolljoint due to the reinforcing effect of the tubed.eet. Tests have demonstrated that tube collapse will not occur due to postulated Loss of Coolant Accident (LOCA) loadings. A new, more conservative, TechrJeal Specification (TS) SG tube leakage rate requirement is introduced by this change. Accident analysis assumptions remain U*
unchanged in the event that significant leakage does occur from the sleevejoint or that the sleeve assembly mptures. Any leakage through the sleeve assembly is fully bounded by the existing SG tube rupture analysis included in the San Onofre Nuclear Generating Station (SONGS) Updated Final Safety Analysis Report. Reactor coolant flow reduction from sleeving is addressed by a ratio of number of tubes sleeved to equal a plugged tube. The proposed sleeving repair process does not adversely impact any other previously evah'ated design basis accidents. Therefore, proposed changes do not involve a significant incicase in the probability or consequences of an accident. 2. Will operation of the facility in accordance with this proposed changs create the possibility of a new or different kind of accident from any accident previously evaluated? Resoonse: No Installation of the sleeves does not introduce any significant changes to the plant design basis. The use of a sleeve to span the area of degradation of the SG tube restores the structural and leakage integrity of the tubing to meet the original design bases. Stress and fatigue analysis of the sleeve assembly shows that the requirements of the AShiE Code are met, hicchanical testing has demonstrated that margin exists above the design criteria. Any hypothetical accident as a result of any degradation in the sleeved tube would be bounded by the existing 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? Resoonse: No The use of sleeves to repair degraded SG tubing has been demonstrated to maintain the integrity of the tube bundle commensurate with the requirements of the ash 1E Code and drafl Regulatory Guide (RG) 1.121 and to maintain the primary to secondary pressure boundary under normal and postulated accident conditions. The safety factors used in the verification of the strength of the sleeve assembly are consistent with the safety liictors in the ash 1E Boiler and Pressure Vessel Code used in SG design. The operational and faulted condition stresses and cumulative usage factors are bounded by the ASN1E Code requirements. The sleeve assembly has been verified by testing to prevent both tube pullout and significant leakage during normal and postulated accident conditions. A test,
program was conducted to ensure the lower hardrolled joint design was leak tight and capable of withstanding the design loads. The primary coolant pressure boundary of the sleeve assembly will be periodically inspected by Non-Destructive Examination to identify sleeve degradation due to operation. Installation of the sleeves will decrease the number of tubes which must be taken out of service due to plugging. There is a small amount of primary coolant flow reduction due to the sleeve for which the eqitivalent sleeve to plug ratio is assigned based on sleeve length. The ratio is used to assess the final equivalent plugging percentage as an input to other safety analyses. The sleeve maintains the design basis requirements for the SG tubing. Therefore, operation c.f the facility with the proposed changes will not involve a significant reduction in a margin of safety. Safety and Sienificant 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. .g.}}