ML17229A240
| ML17229A240 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/21/1997 |
| From: | Stall J FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| L-97-48, NUDOCS 9703030008 | |
| Download: ML17229A240 (7) | |
Text
CATEGORY j.
REGOLATC INFORMATION DISTRIBUTION+STEM (RIDE)
ACCESSION NBR:9703030008 DOC.DATE: 97/02/21 NOTARIZED: NO FACIL".50 ~3'89 St. Lucie Plant, Unit 2, Florida Power s Light Co.
AUTH.NAME AUTHOR AFFILIATION STAI L,J.A.
Florida Power
& Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET 05000389
SUBJECT:
Requests approval of Interim Relief Request 21 for non-code repair of Class 3 intake cooling water pump piping,per ISI plan second 10-yr interval.
DISTRIBUTION CODE:
A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:
RECIPIENT ID CODE/NAME PD2-3 LA WIENS,L.
INTERNAL: ACRS P'
0 DOCS-ABSTRACT RES/DET/EIB EXTERNAL: LITCO ANDERSON NRC PDR COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 RECIPIENT ID CODE/NAME
'PD2-3 PD AEOD/SPD/RAB NRR/DE/EMEB OGC/HDS3 RES/DET/EMMEB NOAC COPIES LTTR ENCL 1
1 1
1 1
1 1
0 1
1 1
1 NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE!
CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN SD-5(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, FL 34957 PI@I February 21, 1997 L-97-48 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 2 Docket No. 50-389 In-Service-Inspection Plan Second Ten-Year Interval Interim Relief Request 21-Non-Code Re air of Class 3 ICW Pi in Pursuant to 10 CFR 50.55a(a)(3) and 50.55a(g)(5)(iii), Florida Power and Light Company (FPL) requests approval of Interim Relief Request 21 "Non-Code Repair of Class 3 ICW Piping." The piping is on the 2B intake cooling water (ICW) pump discharge header.
Attachment 1 is Interim Relief Request 21 ~ Attachment 2 is the engineering disposition of the non-Code repair of ASME Class 3, Intake Cooling Water (ICW) Piping I-30"-CW-11.
FPL determined that an ASME Section XI:Code repair is not practical within the Technical Specification allowed outage time of the ICW system.
As discussed in the relief request, the Technical Specification allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for the affected headers may be insufficient to accomplish a Code repair.
A plant shutdown and cooldown with unnecessary cycling of facility systems and components would be required to perform a Code repair of the piping. A Code repair/replacement willbe accomplished during the upcoming Unit 2 refueling outage (SL2-10) which is scheduled to start on April 14, 1997.
FPL has determined pursuant to 10 CFR 50.55a (a)(3) that the proposed alternatives would provide an acceptable level of quality and safety, and that compliance with the specified requirements would result in hardship or unusual difficultywithout a compensating increase in the level of quality and safety.
Please contact us ifthere are any questions about this submittal.
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 t
'.'> ~970303,0008 970221 Tl
~f /I an FPL Group company llllllllllllllKIGIIII[8PIIEIElllllllll
St. Lucie Unit 2
~ Doc)et No. 50-389 L-97-48 Attachment 1 Page 1
Relief Request No. 21
¹n-Code Repair on ICW Class 3 Piping A. Component Identification ASME Class 3, Intake Cooling Water (ICW) Piping I-30"-CW-11 B. Examination/Repair/Replacement Requirements The 1989 Edition,Section XI, IWA-4000 C. Relief Requested Relief is requested from performing a Code required repair or replacement on an ICW piping leak.
D. Basis for Relief See Attachment 2 the Final Engineering Disposition.
E. Alternatives FPL has installed a temporary non-Code repair on the ICWpiping leak. This repair meets the guidelines of NRC GL 90-05. It consists of a passive device installed for pressure boundary integrity only, using adequate and suitable materials acceptable for system temperature and pressure.
It is removable, and does not compromise the structural integrity of the piping system and its associated supports.
An augmented examination was performed in the area of the leak to look for additional flaws within 15 days of the initial discovery.
These identified two individual flaws. FPL then examined eleven additional points, in the most susceptible locations, based on the root cause analysis.
These augmented examinations did not reveal any additional flaws.
St. Lucie Unit 2
. Docket No. 50-389 L-97-48 Attachment 1 Page 2 F. Implementation Schedule The temporary non-Code repair has been installed as a stop-gap measure in accordance with the guidelines ofNRC GL 90-05. Itwillremain in place until the next St. Lucie Unit 2 refueling outage, currently scheduled to begin April 14, 1997.
During that outage, FPL willperform a Code repair.
The augmented examinations have been completed.
G. Attachments to the Relief Final Engineering Disposition
St. Lucie Unit 2
~ Docket No. 50-389 L-97-48 Attachment 2 Page 1
BACKGROUND:
FINALENGINEERING DISPOSITION While conducting blast cleaning of the 2B intake cooling water (ICW) Pump discharge line I-30"-
CW-11 for potential corrosive degradation, a through wall flaw was detected.
FPL examination personnel conducted an inspection and UT examination of the flawed area.
An additional wall thinning flaw was detected in close proximity to the through wall flaw noted in this evaluation.
These areas were examined and mapped such that an appropriate evaluation could be conducted by Engineering in accordance with the guidelines in NRC Generic Letter (GL) 90-05, "Guidance for Performing Temporary Non-Code Repair of ASME Code Class 1, 2 and 3 Piping."
The assessment of operability for the above flaws demonstrated that:
~
the through wall flaw has been evaluated using the guidelines delineated within GL 90-05 and was found acceptable.
The wall thinning flaw is bounded by this evaluation.
~
potential inventory losses based on the as-found size of the through wall flaw are bounded by the existing evaluations assumming a 3/4 inch instrument line rupture.
ROOT CAUSE/ANALYSISOF PROBLEM:
In response to concerns ofcorrosive degradation to an inaccessible portion of the 2B ICW Pump discharge line I-30"-CW-11, the piping configuration and material condition was evaluated.
The configuration of support CW-3000-7003 prohibited access to the underside of the pipe for inspection, maintenance, or. repair.
This condition, coincident with the salt-laden environment of the ICWvalve pit, had accelerated corrosion effects to the piping. The support was removed to facilitate the appropriate non-destructive examinations of the degraded pipe wall ~ It was during the cleaning evolution of this task that the subject flaws were found. The apparent cause of the flaws is advanced external corrosion as a result of coating breakdown.
Line I-30"-CW-11 is associated with the intake cooling water system which is classified as safety related, Quality Group C. NRC Generic Letter 90-05 and follow up NRC correspondence to GL 90-05 (Letter From J. Strosnider to F. J. Hebdon, dated February 16, 1993, "Structural Integrity Reporting Requirements for ASME Code Class 3 Components" ) state that with respect to the timing and execution of the GL 90-05 relief request process for moderate energy Class 3 pipes, the following has been adopted:
1.
Prompt flaw and structural evaluation (Operability Assessment).
St. Lucie Unit 2
. Docket No. 50-389 L-97-48 Attachment 2 Page 2 2.
3.
Ifthe provisions of the GL are met, a reversible leak mitigating measure may be applied.
The licensee must provide a thorough safety evaluation and structural analysis of the proposed temporary actions.
Augmented inspection completed within 15 days of discovery of the initial leak.
4.
Relief Request submittal to NRC in a timely manner.
Flaw and Structural Evaluation Item 1 above includes the flaw characterization, determination of acceptable spacing criteria for multiple flaw determination, area (or size) of flaw acceptance, and the linear fracture mechanics evaluation.
These attributes have been evaluated within calculation PSL-2FSC-97-005, Revision 0 and found acceptable.
Accordingly, the provisions of the GL were met using "through wall" criteria, and an appropriate leak mitigating device could then be applied to the flaw as a stopgap leak limiting measure.
Installation of Sto a
Leak Limitin Measure Item 2 above was achieved by an engineering evaluation.
The evaluation established that the, affected system was an ASME Class 3 system of moderate energy, the location of the leak was unisolable, demonstrated that the leak mitigating device installed as a stopgap measure, was a passive device installed for pressure boundary integrity only, used adequate and suitable materials acceptable for system temperature and pressure, was removable, and did not compromise the structural integrity of the piping system and its associated supports.
In addition, provisions were included in the safety evaluation to qualitatively assess the integrity of the leak limiting device by visual inspection on a weekly basis, which satisfies GL 90-05 Enclosure I, Paragraph B3, Specific Considerations.
The provision in this paragraph for NDE assessment by UT or RT of the non-Code repair is not required since the Unit 2 Cycle 10 outage willoccur before the specified 3 month interval has elapsed, at which time the appropriate Code repair willbe made.
Based on the above, the appropriate safety evaluation and structural analysis of the temporary repair have been completed.
Au mented Ins ections Item 3 above reflects the requirements of 90-05 Enclosure I, Paragraph C4, Augmented Inspection, These requirements stipulate the most susceptible locations, based on root cause determination, should be identified and examined to assess the overall degradation of the affected system.
The augmented inspection should be performed within 15 days of initial flaw detection and include at least 5 susceptible locations for Class 3 moderate energy systems.
The GL also discusses sample expansion should additional flaws be found.
Note that the inspections and subsequent flaw spacing criteria evaluation determined that two individual flaws were identified.
Accordingly, a minimum of 10 additional susceptible locations should be specified in the augmented inspection plan. The original inspection plan called for gridding the suspect area using
St. Lucie Unit 2 Dorket No. 50-389 L-97-48 Attachment 2 Page 3 the 2 inch square grid method as described in Standard MN-3.9, Revision 1, "Evaluation of Erosion/Corrosion in Power Plant Piping." The grid extent encompassed the entire underside of the pipe where support CW-3000-7003 was installed (approximately 2 ft x 12 ft) and an area within the well that exhibited gross coating holidays.
In addition, several suspect areas showing evidence of heavy scaley corrosion within the intake well were also identified, cleaned, and inspected.
In all, eleven additional points were inspected, along with the gridded area below the pipe support.
Therefore, it is concluded that the appropriate augmented inspections have been conducted and no additional flaws were identified.
Code Re air Method The necessary Code repair shall be made during the upcoming Unit 2 refueling outage (SL2-10) using the repair guidelines of Appendix B to Specification SPEC-M-023, "ICWSystem Inspection and Repairs for St. Lucie Units 1 and 2," Revision 1.
This repair procedure will ensure compliance with the ASME Code.
NODE RESTRICTIONS:
There are no mode restrictions associated at this time.
The Code repair to the affected ICW piping will b'e conducted while the affected portion of the 'B'eader of ICW is declared out of service.
This repair will be made prior to reaching Mode 1 in the upcoming Unit 2 refueling outage (SL2-10).