Text

Third 10-Year Interval Inservice Inspection Program Submittal of Relief Requests (RR) RR-38, RR-39, and RR-40
	ML040910183
Person / Time
Site:	Hatch
Issue date:	03/29/2004
From:	Sumner H; Southern Nuclear Operating Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	GL-88-001, NL-04-0478, RR-38, RR-39, RR-40
	Download: ML040910183 (12)
	v • d • e

H. L Sumner. Jr. Southern Nuclear Vice President Operating Company, Inc.

Hatch Project Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.7279 March 29, 2004 SOUTHERNa Energy to Serve Your World Docket Nos.: 50-321 NL-04-0478 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin 1. Hatch Nuclear Plant Third 10-Year Interval Inservice Inspection Program Submittal of Relief Requests (RR) RR-38, RR-39. and RR-40 Ladies and Gentlemen:

The Hatch ISI program is undergoing a detailed review to ensure that the ASME Section XI Code requirements will be completed prior to the end of the ISI interval (December 31, 2005). This letter transmits two relief requests that were determined to be necessary for the February 2005 Hatch 2 outage (2R1 8). A third relief request which is considered beneficial due to potential dose and examination savings is also attached. A brief description of the three relief requests is given belowv.

Request for Relief No. RR-38 Approval of RR-38 would allow the deletion of the Section XI required RPV circumferential shell weld examinations (during the remainder of the 40 year initial license) based on NRC approved BWRVIP-05 (BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations). Approval has previously been granted to eliminate the Hatch Units I and 2 circumferential weld examinations during the Period of Extended Operation (as part of the License Renewal activities). Additionally, SNC has previously eliminated the Hatch Unit 1, 10 CFR 50.55a required augmented circumferential weld examinations as allowed by the NRC Safety Evaluation dated March II, 1999. Approval of RR-38 would obviate the need for SNC to perform costly and time consuming automated circumferential weld examinations during 2R18 (and I R22). Also, dose savings would be realized from not needing to set up the examinations.

Request for Relief No. RR-39 Approval of RR-39 would allow the use of BWRVIP-75 (Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules) for scheduling stainless steel and dissimilar metal piping weld examinations in lieu of Section XI requirements. NRC approved BWRVIP-75 is currently used at Hatch, and it provides the technical basis for reduction of examinations for the subject welds from the original Generic Letter 88-01 requirements. However, since the required examinations are less than those required by Section XI, relief must be obtained from the Section XI requirements. The NRC provided

U. S. Nuclear Regulatory Commission NL-04-0478 Page 2 a mechanism for this relief in the BWRVIP-75 Safety Evaluation which stated, "the revised BWRVIP-75 guidance is acceptable for licensee referencing as the technical basis for relief from, or as an alternative to, the ASME Code and 10 CFR 50.55a, in order to use the sample schedules and frequencies specified in the revised BWRVIP-75 report that are less than those required by the ASME Code." Approval of RR-39 would obviate the need for SNC to perform numerous high-dose examinations during 2R18 (and IR22).

Request for Relief No. RR-40 Approval of RR-40 would allow the elimination of unnecessary surface examinations based on the use of recently developed Code Case N-663 (Alternative Requirements for Classes I and 2 Surface Examinations,Section XI, Division 1) and the subsequent approval of the Entergy Pilot Plant application by the NRC. Approval of RR-40, which is based on Entergy's Safety Evaluation, would provide for a reduction in dose and examination time.

Approval of these Relief Requests is needed by January 2, 2005 to support Hatch outage 2R18, scheduled to begin February 5, 2005.

This letter contains no NRC commitments. If you have any questions, please advise.

Sincerely, H. L. Sumner, Jr.

HLS/IL/daj Attachments:

1. Request for ReliefNo. RR-38

2. Request for Relief No. RR-39

3. Request for Relief No. RR-40 cc: Southern Nuclear Operating Company Mr. J. B. Beasley, Jr., Executive Vice President Mr. G. R. Frederick, General Manager - Plant Hatch RTYPE: CHAO2.004 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. C. Gratton, NRR Project Manager - Hatch Mr. D. S. Simpkins, Senior Resident Inspector - Hatch

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38

1. System/Component for Which Relief is Requested: This Relief Request applies to the Reactor Pressure Vessel (RPV) circumferential shell weld examinations for Hatch Units I and 2.

I. Code Requirements: The following 1989 Edition of ASME Section XI Code requirements apply to this request.

IWB-2500 requires components to be examined as specified in Table IWB-2500-1.

Table IWB-2500-1, Category B-A, Item No. Bl.l 1 requires that all circumferential welds be essentially 100% examined.

Ill. Code Requirement from Which Relief is Requested: Southern Nuclear Operating Company (SNC) proposes to permanently (until the end of the current 40-year license) exclude the examination of RPV circumferential shell welds as required in Table IWB-2500-1, Category B-A, Item No. BI.I1.

IV. Background Information: By letter dated September 28, 1995 the Boiling Water Reactor Vessel and Internals Project (BWRVIP) submitted BWRVIP-05 (BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations) to the NRC. BWRVIP-05 initially proposed to reduce the inspection coverage of the BWR RPV shell welds from essentially 100% of all RPV shell welds to 50% of the longitudinal welds and 0% of the circumferential welds. By letter dated October 29, 1996 the BWRVIP modified the recommendation in BWRVIP-05 to examine essentially 100% of the longitudinal welds and 0% of the circumferential welds (except for that portion of a circumferential weld intersecting with the longitudinal weld being examined).

The NRC issued their final safety evaluation (SE) for BWRVIP-05 by letter dated July 28, 1998.

The SE stated that, "BWR licensees may request relief from the inservice inspection requirements of 10 CFR 50.55a(g) for volumetric examination of circumferential reactor pressure welds (ASME Code Section XI, Table IWB-2500-1, Examination Category B-A, Item 1.11, Circumferential Shell Welds) by demonstrating: (1) at the expiration of their license, the circumferential welds satisfy the limiting conditional failure probability for circumferential welds in this evaluation, and (2) they have implemented operator training and established procedures that limit the frequency of cold over pressure events to the amount specified in this report." The SE indicated that the NRC staff concluded that a near-term safety concern did not exist; however, the NRC staff identified a need to evaluate the high conditional failure probabilities for axial welds. In a request for additional information, the NRC requested the BWRVIP to provide a more realistic potential for axial weld failures due to cold over-pressure events and to provide the failure frequency of axial welds based on NRC recommendations.

On November 10, 1998 the NRC issued Generic Letter 98-05 ( Boiling Water Reactor Licensees Use of the BWRVIP-05 Report to Request Relief from Augmented Examination Requirements on Reactor Pressure Vessel Circumferential Shell Welds) to provide guidance for licensees to request relief from the augmented examination requirements for circumferential RPV shell welds.

[By letter dated December 2, 1998 SNC requested approval to permanently exclude the examination of the Hatch Unit I RPV circumferential shell welds, based on this guidance, and by letter dated March 11, 1999 the NRC issued an SE for Hatch Unit I granting this request pursuant to 10 CFR 50.55a(a)(3)(i).]

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN 1.HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38 (cont.)

By letters dated December 15, 1998 and November 12, 1999 the BWRVIP supplied additional information regarding axial weld failure probabilities. By letter dated March 7, 2000 the NRC issued a supplement to the July 28, 1998 SE concluding that, "the RPV failure frequency due to the failure of the limiting axial welds in the BWR fleet are below 5 x I O per reactor-year, consistent with RG 1.154, given the assumptions described in the attached SE." Therefore, the issue with axial welds was resolved.

By letter dated January 31, 2001, in response to a request for additional information (RAI) for the Hatch Units I and 2 License Renewal Application (LRA), SNC supplied Hatch Units I and 2 RPV weld conditional failure probabilities and information regarding cold over-pressure events to the NRC. The NRC subsequently approved the Hatch Units I and 2 LRA which included the deletion of the requirement for the volumetric examination of the RPV circumferential welds during the Period of Extended Operation (PEO). The information supplied to the NRC in response to the RAls is provided in Enclosure 1. Because of issues associated with the conditional failure probability of axial welds during the PEO, conditional failure probabilities for axial welds were also provided to the NRC and are included in this relief request (for information purposes) as Enclosure 2.

V. Technical Basis: Per the NRC SE dated July 28, 1998 and Generic Letter 98-05, BWR licensees may request relief from the inservice inspection requirements of 10 CFR 50.55a(g) for volumetric examination of circumferential reactor pressure welds (ASME Section XI Code, Table IWB-2500-1, Examination Category B-A, Item 1.11, Circumferential Shell Welds) by demonstrating:

1. At the expiration of their license, the circumferential welds satisfy the limiting conditional failure probability for circumferential welds in this evaluation.

2. Licensees have implemented operator training and established procedures that limit the frequency of cold over pressure events to the amount specified in this report.

Based on these two requirements the NRC has previously granted approval for:

o The deletion of the requirement for the volumetric examination of the Hatch Units I and 2 RPV circumferential welds during the PEO.

o Permanent deferral (during the initial 40-years of operation) of the Hatch Unit I augmented examination requirements for the circumferential welds pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5).

Hatch Units I and 2 are bounded by the NRC analysis for circumferential weld limiting conditional failure probabilities during at the end of the PEO, as shown in Enclosure 1.

Therefore, at the expiration of the initial 40-year license period, the Hatch Units I and 2 circumferential welds also will satisfy the limiting conditional failure probability for circumferential welds. (Note: Hatch Unit I is currently in its 29th year of commercial operation and Hatch Unit 2 is currently in its 25'h year of commercial operation).

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD I 0-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38 (cont.)

SNC has previously demonstrated that operator training and established procedures limit the frequency of cold over pressure events. This information was supplied to the NRC in the December 2, 1998 Hatch Unit I submittal (for the permanent deferral of the augmented examination requirements), which was subsequently approved by the NRC in the March I1, 1999 SE. This information was later referenced by SNC in the January 31, 2001 response to License Renewal RAls, where, it was also noted that the operator training and procedures for Hatch Units I and 2 are the same. Extracts of this information are shown in Enclosure 3.

VI. Alternative Examinations: Axial welds and intersecting portions of circumferential welds will be examined to the extent practical, dependent upon interference by another component or restrictions due to the geometrical configuration. For those cases where the reduction in coverage is greater than 10%, relief will be requested pursuant to 10 CFR 50.55a requirements.

VII. Justification for Approval: At the expiration of the PEO (60 years) and therefore the initial 40-year license period as well (which corresponds to the start of the PEO), the Hatch Units I and 2 circumferential welds will satisfy the limiting conditional failure probability for circumferential welds. Procedures and training used to limit cold over-pressure events are the same for both Hatch units (approved for Hatch Unit I by NRC letter dated March II, 1999). Approval has previously been granted by the NRC to eliminate the examination of the Hatch Units l and 2 RPV circumferential shell welds during the PEO and for permanent deferral of the augmented circumferential weld examination requirements for the Hatch 1. Therefore, approval should be granted to eliminate the examination of the Hatch Units I and 2 RPV circumferential shell welds (during the remainder of the initial 40-year license period) pursuant to 10 CFR 50.55a(a)(3)(i).

Vill. Implementation Schedule: Required for the Hatch 2 RPV weld examinations during the 18th Refueling Outage (currently scheduled to begin in February 2005).

IX. Relief Request Status: Awaiting NRC approval.

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN 1.HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38 (cont.)

ENCLOSURE I EVALUATION OF LIMITING CONDITIONAL FAILURE PROBABILITIES FOR HATCH CIRCUMFERENTIAL WELDS DURING THE PERIOD OF EXTENDED OPERATION By letter dated January 31, 2001, in response to a request for additional information (RAI) for the Hatch License Renewal Application (LRA), SNC supplied Hatch RPV weld conditional failure probabilities to the NRC. RAI 4.6-1 addressed the circumferential welds, and as shown below, the Hatch RPV conditional failure probability for circumferential welds is bounded by the NRC analysis.

"The Hatch limiting circumferential weld properties from Tables 3-1 and 3-2 of the LRA Appendix E are compared to the information in Table 2.6-4 and Table 2.6-5 from the staff SER on BWRVIP-05."

"The NRC staff used materials and fluence data in Tables 2.6-4 and 2.6-5 to evaluate failure probability of BWR circumferential welds at 32 and 64 EFPY. The NRC used Mean RTNDT for the comparison. Mean RTNDT is defined as: RTNDT +

ARTNDT. The Mean RTNDT used by the NRC have been compared to the Hatch values derived using Appendix E of the LRA. The Hatch I and Hatch 2 values at 54 EFPY are bounded by the 32 EFPY analysis by the'NRC by at least 40 OF, and almost 75 0F at 64 EFPY. Although a conditional failure probability has not been calculated, the fact that the Hatch 54 EFPY value is bounded by the 32 and 64 EFPY value the staff used leads to the conclusion that Hatch RPV conditional failure probability is bounded by the NRC analysis."

See the table below for the comparison of values.

Group CE(VIP) CE(CEOG) CE(VIP) CE(CEOG) Hatch 1 Hatch 2 32 EFPY 32EFPY 64 EFPY 64 EFPY 54 EFPY 54 EFPY Cu% 0.13 0.183 0.13 0.183 0.197 0.047 Ni% 0.71 0.704 0.71 0.704 0.060 0.049 CF 151.7 172.2 151.7 172.2 91.0 31.0 Fluence 0.20 0.20 0.40 0.40 0.236 0.244 (10'9 n/cm2 )

ARTNDT 86.4 98.1 113.2 128.5 55.5 19.2 RTNDT(U) 0 0 0 0 -10 -50 Mean RTNDT 86.4 98.1 113.2 128.5 45.5 -30.8 P(F/E) 2.81 E-5 6.34E-5 1.99E-4 4.38E-4 ---

NRC P(F/E) No ---

BWVRVIP Failure I I I I

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN 1. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38 (cont.)

ENCLOSURE I (Continued)

EVALUATION OF LIMITING CONDITIONAL FAILURE PROBABILITIES FOR HATCH CIRCUMFERENTIAL WELDS DURING THE PERIOD OF EXTENDED OPERATION

References:

1. Hatch License Renewal Application, Appendix E, Tables 3-1 and 3-2.

2. Final SER of the BWR Vessel and Internals Project BWRVIP-05 Report (TAC No. M93925),

dated July 28, 1998.

3. GE-NE-AOO-05389-08, July 1995 Power Uprate Evaluation Task Report for Edwin 1. Hatch Plant Units I and 2, 110% Power Uprate Revised Impact on Vessel Fracture Toughness.

4. GE-NE-A13-00402-9, March 1998 Extended Power Uprate Evaluation Task Report for Edwin 1.

Hatch Plant Units 1 and 2 Revised Impact on Vessel Fracture Toughness.

5. BWVRVIP BWR Vessel and Internals Project BWR Reactor Pressure Vessel Inspection and Flaw Evaluation Guidelines, TR-1 13596.

6. Structural Integrity Associates Letter, SIR-00-160, Rev. 0, December 18, 2000.

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-38 (cont.)

ENCLOSURE 2 EVALUATION OF LIMITING CONDITIONAL FAILURE PROBABILITIES FOR HATCH AXIAL WELDS DURING THE PERIOD OF EXTENDED OPERATION In a response to RAI 4.6-1, SNC supplied Hatch RPV axial weld conditional failure probabilities to the NRC. As shown below, the Hatch RPV conditional failure probability for axial welds is bounded by the NRC analysis. RAI-4.6-2 states (in part):

"The SER in the May 7, 2000 letter supercedes the analysis in the July 28, 1998 letter. Therefore, the applicant should revise its analysis to compare the mean RTNDT for the Plant Hatch axial welds to the mean RTNDT for Pilgrim Mod 2."

In response, SNC stated:

"The Hatch limiting axial weld properties from Table 3-1 and 3-2 of Appendix E are compared to the information in Table 2.6-4 and Table 2.6-5 from the staff SER on BWRVIP-05. The NRC noted that it issued a revised SER on BWRVIP-05 on March 7, 2000 and that the limiting axial welds should be compared with data in Table 3 of that document (Mod 2 in Table below). Mean RTNDT is defined as: Mean RTNDT = RTNDT + ARTNDT. The Mean RTNDT used by the NRC have been compared to the Hatch values derived using Appendix E of the LRA. A comparison of the Mean RTNDT values from the NRC report with the Hatch data shows that the NRC analysis bounds the Hatch welds. Although a conditional failure probability has not been calculated, the fact that the Hatch 54 EFPY value is less than the 64 EFPY value the staff used leads to the conclusion that Hatch is bounded by the NRC analysis."

Group Mod 2 Hatch 1 Hatch 2 54 EFPY 54 EFPY Cu% 0.316 0.216 Ni% 0.724 0.043 CF 219 98.0 Fluence 0.347 0.244 (109 n/cm 2)

ARTNDT 155.1 60.6 RTNDT(u) -2 -50 -50 Mean RTNmT 114 105.1 10.6 P(F/E) 5.02E-6 ---

NRC _

P(F/E)

BWRVIP

References:

See circumferential weld references.

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN 1.HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-3 8 (cont.)

ENCLOSURE 3 EVALUATION OF OPERATOR TRAINING AND ESTABLISHED PROCEDURES Plant Hatch has procedures in place which monitor and control reactor pressure, temperature, and water inventory during all aspects of cold shutdown and refueling operations which minimizes the likelihood of a Low Temperature Over-Pressurization (LTOP) events from happening. In addition to procedural controls, periodic Licensed Operator Training further reduces the possibility of occurrence of LTOP events. Initial Licensed Operator Training and Simulator Training of plant heatup and cooldown events include performance of surveillance tests and monitoring which ensure pressure-temperature curve compliance. In addition, periodic operator training reinforces management's expectations for strict procedural compliance.

Finally, Southern Nuclear operating personnel continuously review industry operating experiences to ensure that Plant Hatch procedures consider the impact of actual events, including LTOP events. Appropriate changes to procedures and training are then implemented to preclude similar situations from occurring at Plant Hatch.

Based on the above, the probability of an LTOP event at Plant Hatch is considered to be less than or equal to that used in the NRC evaluation.

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-39

1. System/Component for Which Relief is Requested: This Relief Request applies to Hatch Nuclear Plant Units 1 and 2, Class I piping.

I. Code Requirements: The following 1989 Edition of ASME Section XI Code requirements apply to this request.

IWB-2412 requires that except for the examinations that may be deferred until the end of the inspection interval, examinations shall be completed in accordance with Table IWB-2412-1.

Table IWVB-2412-1 defines a minimum and maximum number of examinations to be performed each inspection period.

IIWB-2500 requires components to be examined as specified in Table IWB-2500-1. The Extent and Frequencyof Examination requires that all Category B-F welds be examined and that a minimum of 25% of Category B-J welds be examined over the ten-year ISI interval.

III. Code Requirement from Which Relief is Requested: Southern Nuclear Operating Company (SNC) proposes to use the schedules and frequencies specified in the BWRVIP-75 in lieu of the above listed Code requirements when examining high alloy steel welds and high nickel alloy welds. The Examination Method listed in Table IWB-2500-1 is not affected by this request.

IV. Basis for Relief: By letter dated May 14, 2002 the NRC issued their Final Safety Evaluation of BWRVIP-75 (Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules). In that Safety Evaluation, the NRC staff concluded that, "licensee implementation of the guidelines of BWRVIP-75 report, as modified, will provide an acceptable level of quality for inspection of the safety-related components." Additionally, the NRC concluded that, "the revised BWRVIP-75 guidance is acceptable for licensee referencing at the technical basis for relief from, or as an alternative to, the ASME Code and 10 CFR 50.55a, in order to use the sample schedules and frequencies specified in the revised BWRVIP-75 report that are less than those required by the ASME Code."

V. Alternative Examinations: The schedules and frequencies specified in the BWRVIP-75 for the examination of the subject welds will be used.

VI. Justification for Approval: The NRC staff determined that the BWRVIP-75 provides an acceptable level of quality and provides an acceptable alternative to the requirements of the ASME Code for inspection of these subject welds. SNC concludes that the use of BWRVIP-75 as defined by the NRC Final Safety Evaluation in lieu of the above specified IWB-2500 requirements, will provide an acceptable level of quality and safety. Therefore, approval should be granted pursuant to 10 CFR 50.55a(a)(3)(i).

VII Implementation Schedule: The first use of this request will be for the Hatch Unit 2 weld examinations during the 18'h Refueling Outage (currently scheduled to begin in February 2005).

VIII. Relief Request Status: Awaiting NRC approval.

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-40 I. System/Component for Which Relief is Requested: This Relief Request applies to Hatch Nuclear Plant Units I and 2, Class 1 and Class 2 piping and is similar to the Entergy request dated December 6, 2002 for ANO- 1, GGNS, RBS, and W3. The NRC subsequently approved Energy's request by letter dated August 26, 2003.

II. Code Requirement: INVB-2500 and IWC-2500 of the 1989 Edition of ASME Section XI, requires components to be examined as specified in Tables IWB-2500-1 and IWC-2500-1, respectively.

These tables require inspection of a sampling of piping welds using volumetric, surface, or both examinations and inspection during pressure testing using visual examinations such as VT-2.

I11. Code Requirement from Which Relief is Requested: In lieu of the surface examination requirements for piping welds of Examination Category B-F (NPS 4 and larger), B-J (NPS 4 and larger), C-F-I, and C-F-2, Southern Nuclear Operating Company (SNC) proposes to use Code Case N-663 (Alternative Requirements for Classes I and 2 Surface Examinations,Section XI, Division 1) in its entirety.

IV. Basis for Relief:

Two risk-informed methodologies have been developed for the examination of piping welds and approved by the NRC:

1. EPRI TR-1 12657, Revision B-A, "Revised Risk-Informed Inservice Inspection Evaluation Procedure" (NRC SE dated 10/28/99).

2. WCAP- 14572, Revision I-NP- A, "Westinghouse Owners Group Application of Risk-Informed Methods to Piping Inservice Inspection Topical Report" (NRC SE dated 12/15/98).

Although the two methodologies use different approaches, they reach a similar conclusion that the only degradation mechanism that requires a surface examination is O.D. (outside diameter) chloride cracking, and consequently, surface examinations only need to be considered when 0. D.

chloride cracking is identified to be the degradation mechanism affecting the structural integrity of applicable welds.

This conclusion led the Code to investigate the value of requiring surface examination in the ASME Section XI Code. The ASME Section XI Task Group on ISI Optimization, Report No. 92-01-01, "Evaluation of Inservice Inspection Requirements for Class 1, Category B-J Pressure Retaining Welds in Piping", dated July 1995 concluded (with 50 units responding with a total of 9333 welds inspected) that only 2 welds (0.02%) were found to have flaws detected by Section XI surface examinations and these were fabrication-induced. Subsequently ASME Section XI developed Code Case N-663, which was approved by the ASME Boiler and Pressure Vessel Code Committee on September, 17, 2002, but is not yet included in the most recent listing of NRC approved code cases provided in Revision 13 of Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability - ASME Section XI Division 1."

Code Case N- 663 provides that "... in lieu of the surface examination requirements for piping welds of Examination Category B- F ( NPS 4 and larger), B- J ( NPS 4 and larger), C- F- 1, and C- F- 2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack." The susceptibility criteria are listed in Table I of Code Case N- 663 for two types of degradation mechanisms: 1)external (0. D.) chloride stress corrosion cracking and 2) other outside surface initiated mechanisms. These alternate requirements are acceptable

SOUTHERN NUCLEAR OPERATING COMPANY EDWIN 1.HATCH NUCLEAR PLANT, UNITS I AND 2 THIRD 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-40 (cont.)

because the inspection requirements defined in the Code Case are equivalent to the corresponding inspection requirements approved by the NRC and adopted by using risk- informed ISI programs.

Further, the Code Case requires that licensees conduct a plant- specific service history review to identify other mechanisms susceptible to outside surface attack, and to include plant- specific processes and programs that minimize chlorides and other contaminants. Hence, the alternative provides reasonable assurance that the proposed inspections will not lead to degraded piping performance when compared to the existing performance levels.

IV. Alternative Examinations: Surface examinations will be performed as required by Code Case N-663. Other ASME Section XI examination requirements for the subject piping welds, including volumetric examinations and pressure testing will continue to be performed.

Examination requirements for other components including Class I piping less than NPS 4 will continue to meet all Section XI requirements and are not subject to this relief request.

VI. Justification for Approval: Based upon the above information, SNC concludes that the use of Code Case N- 663 for Class 1 and 2 surface examinations, in lieu of the IWB- 2500 and IWC- 2500 requirements, will provide an acceptable level of quality and safety. This conclusion is based on the fact that inspection requirements defined in Code Case N- 663 are equivalent to the inspection requirements adopted by plants employing risk- informed ISI programs, and because SNC will be required to conduct a Plant Hatch Units I and 2 specific service history review to identify mechanisms that will cause outside surface attack upon subject plant components. Therefore, approval is requested pursuant to 10 CFR 50.55a(a)(3)(i).

VII. Implementation Schedule: This alternative will initially be used for the Hatch Unit 2 weld examinations during the 18'h Refueling Outage (currently scheduled to begin in February 2005).