ML17229A253

Requests Approval to Incorporate Code Case N-524, Alternative Exam Requirements for Longitudinal Welds in Class 1 & 2 Piping Section Xi,Div 1.

ML17229A253
Person / Time
Site:	Saint Lucie
Issue date:	03/05/1997
From:	Stall J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-97-58, NUDOCS 9703120440
Download: ML17229A253 (5)

Text

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REGULATO INFORMATION DISTRIBUTION TEM (RIDS)

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ACCESSION NBR:9703120440 DOC.DATE: 97/03/05 NOTARIZED: NO DOCKET FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power 6 Light Co. 05000335 AUTH. NAME AUTHOR AFFILIATION STALL,J.,A. Florida Power 6 Light Co.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Requests approval to incorporate Code Case Exam Requirements for Longitudinal N-524,'Alternative Welds in Class 1 6 2 Piping Section XI,Div 1."

DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-3 LA 1 1 PD2-3 PD 1 1 WIENS,L. 1 1 INTERNAL: ACRS 1 1 AEOD/SPD/RAB 1 1

~Z5WEUM. 1 1 NRR/DE/EMEB 1 1 NUDOCS-ABSTRACT 1 1 OGC/HDS3 1 0 RES/DET/EIB 1 1 RES/DET/EMMEB 1 1 EXTERNAL: LITCO ANDERSON 1 1 NOAC 1 1 NRC PDR 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN 5D-S(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 14 ENCL 13

Florida Power & Light Company, 6501 South Ocean Drive, Jensen Beach, FL34957

) March 5, 1997 L-97-58 10 CFR 50.4 10 CFR 50.55a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 RE: St. Lucie Unit 1 Docket No. 50-335 Inservice Inspection Plan Second Ten- Year Interval ASME Code Case N-524 - Re uest for Use Pursuant to 10 CFR 50.55a, (Footnote 6) and 10 CFR 50.55a(a)(3), Florida Power and Light Company (FPL) requests approval to incorporate Code Case N-524, Alternative Examination Requirements for Longitudinal Welds in Class I and 2 Piping,Section XI, Division I, for use in the St. Lucie Unit 1 Inservice Inspection Program for the second ten-year interval. Code Case N-524 was approved for use by ASME on August 9, 1993.

This Code Case is an alternative to the requirements for surface and volumetric examination of longitudinal piping welds presently required by ASME Section XI for Class 1 and 2 piping. The specific requirements are specified in Table IWB-2500-1, Examination Category B-J, Table IWC-2500-1, Examination Categories C-F-1 and C-F-2, and Table IWC-2520, Examination Category C-G. Use of this alternative will reduce the worker radiation exposure while preparing for the inspection and during the examination. In addition, it will reduce the scope for building scaffolding and removal of insulation for this inspection of the reactor coolant, safety injection, shutdown cooling, and other Class 1 and 2 system welds. A copy of the Code Case is attached for your information.

The St. Lucie Unit 1 Inservice Inspection Program for the second ten-year interval uses the 1983 Edition of ASME Section XI with addenda through the Summer 1983. In addition, FPL has adopted Code Case N-408, Alternative Rules for Examination of Class 2 Piping,Section XI, Division 1, which was approved by ASME on July 12, 1984, for use during this inservice inspection interval. Therefore, FPL uses the C-F-1 and C-F-2 requirements of Code Case N-408 for determining which longitudinal welds to examine. Code Case N-408 was endorsed by NRC Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability ASME Section Xl, Division 1, at the beginning of the second interval. Pursuant to RG 1.147, Revision 11, Position D.2, FPL plans to use this revision of Code Case N-408 for the remainder of the second interval.

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St. Lucie Unit 1 Docket No. 50-335 L-97-58 Page 2 The current requirement for Class 1 systems is to examine longitudinal welds for a distance of one pipe diameter but not more than 12 inches from the intersecting circumferential weld. Often, additional scaffolding must be built and additional insulation removed to accomplish this examination. Much of the reactor coolant system piping is carbon steel with cladding. This material requires increased weld cleaning and preparation time. The additional preparation increases the overall radiation exposure and the potential for personnel contaminations.

For Class 2 systems, the current requirement is to examine the longitudinal welds for a distance of two and one-half times the weld thickness from the intersecting circumferential weld.

Essentially the same preparation requirements and radiation concerns discussed above for Class 1 applications apply to Class 2 piping.

Longitudinal welds are not produced in the field or fabrication shops as is the case of a circumferential weld. Longitudinal piping welds for Class 1 and 2 applications were made by the piping manufacturer under controlled conditions that produce higher quality welds and more uniform residual stress patterns. These welds were examined by the appropriate ASTM or ASME specifications. The manufacturing controls specified by the appropriate ASTM or ASME specifications provide assurance of the structural integrity of the longitudinal welds at the time the piping is manufactured.

The preservice examination and initial inservice examinations have provided assurance of the structural integrity of the longitudinal welds during the service life of the plant to date. Based on results of these inservice inspections, St. Lucie Unit 1 has not experienced degradation that would warrant continued examination beyond the intersection area or volume bounded by this Code Case. In addition, experience in the United States has been that ASME Code longitudinal welds have not experienced degradation that would warrant continued examination beyond the boundaries required to meet the circumferential weld examination requirements. No significant loading conditions or known material degradation mechanisms have become evident to date which specifically relate to longitudinal seam welds in nuclear plant piping.

By using this Code Case, FPL will meet the intent of Section XI. FPL will examine those areas of the longitudinal welds within the boundaries of the intersecting circumferential welds. If the longitudinal weld cannot be seen, then FPL will perform the examination around the entire length of the circumferential weld according to the Code Case. If any degradation associated with a longitudinal weld were to occur, it is expected that it would be found at the intersection with a circumferential weld. This intersection will be inspected according to the provisions of Code Case N-524. Since longitudinal welds will be examined within the boundaries of the intersecting circumferential welds, the total costs, examination time, and radiation exposure will be reduced.

When this Code Case is applied to the volumetric examination of ferritic welds, the volumetric

St. Lucie Unit 1 Docket No. 50-335 L-97-58 Page 3 examination of the circumferential welds will include scanning for reflectors transverse to the weld.

In addition to the above, there is significant accumulation of personnel radiation exposure associated with the examination of longitudinal welds. The radiation exposure associated with the examination of longitudinal welds is dependent on the time it would take to remove and reinstall the insulation and interferences, prepare the weld for examination, and perform the examinations.

Based on the current examination scope for the upcoming Unitl refueling outage, exposure savings of approximately 1.5 to 2 man-REM could result from the approval to use Code Case N-524. Therefore, the continued imposition of the ASME Code,Section XI examination requirements for longitudinal welds constitutes a hardship to St. Lucie Plant with no compensating increase in the level of quality or safety, Code Case approval is requested by July 2, 1997, to support its use during the upcoming Unit 1 refueling/steam generator replacement outage (SL1-15). The outage is currently scheduled to begin in October 1997. If are any questions about this submittal, please contact us.

Very truly yours, J. A. Stall Vice President St. Lucie Plant JAS/GRM cc: Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant

CASE N-524 CASES OF ASME BOILER AND PRESSURE VESSEL CODE Approval Date: August 9, 1993 See Numerical Index for expiration and any reaffirmation dates.

Case N-524 Alternative Examination Requirements for Longitudinal Welds ln Class I and 2 Piping Section XI, Division 1 Inquiry: What alternative requirements may be ap-plied to the surface and volumetric examination of longitudinal piping welds specified in Table IWB-2500-1, Examination Category B-J, Table IWC-2500-1, Examination Categories C-F-1 and C-F-2 (Exam-ination Category C-F prior to Winter 1983 Adden-da), and Table IWC-2520, Examination Category C-G (1974 Edition, Summer 1975 Addenda)?

Reply: It is the opinion of the Committee that the following shall apply:

(a) When only a surface examination is required, examination of longitudinal piping welds is not re-quired beyond those portions of the welds within the examination boundaries of intersecting circumfer-ential welds.

(b) When both surface and volumetric examina-tions are required, examination of longitudinal piping welds is not required beyond those portions of the welds within the examination boundaries of inter-secting circumferential welds provided the following requirements are met.

(1) Where longitudinal welds are specified and locations are known, examination requirements shall be met for both transverse and,parallel flaws at the intersection of the welds and for that length of lon-gitudinal weld within the circumferential weld ex-amination volume; (2) Where longitudinal welds are specified but locations are unknown, or the existence of longitu-dinal welds is uncertain, the examination require-ments shall be met for both transverse and parallel flaws within the entire examination volume of inter-secting circumferential welds.

903 SUPP. 6 NC