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August 9, 1995 MEMORANDUM T0:
David B. Matthews, Project Director Project Directorate II-2 Division of Reactor Projects I/II/III FROM:
Keith R. Wichman, Chief Material Integrity Section Materials and Chemical Engineering Branch Division of Engineering
SUBJECT:
FLORIDA POWER AND LIGHT COMPANY, FRACTURE MECHANICS EVALUATION OF ST. LUCIE PRESSURIZER INSTRUMENT N0ZZLES Plant Name:
St. Lucie 2 Licensee:
Florida Power and Light Company TAC No.:
M91704 Review Status:
Complete On March 2, 1995, Florida Power and Light Company (the licensee), submitted in a report, for NRC approval, its fracture mechanics evaluation of St. Lucie 2 l
pressurizer instrument nozzles. The licensee later responded to NRC's request 4
for additional information (RAI) by sending in its response on July 7, 1995 and Revision 1 of the report on August 2,1995. The evaluation documented in these reports is an update of a submittal dated March 28, 1994, which was approved by the NRC on April 1, 1994. The issue originated from boric acid leakage from the "C" instrument nozzle in the pressurizer upper head, which j
was detected during the 1994 refueling outage. Using IWB-3600 of Section XI i
of the American Society of Mechanical Engineers (ASME) Boiler and Pressure i
Vessel Code, the licensee's contractor made some very conservative assumptions in the 1994 flaw evaluation to gain approval without flaw removal or repair for one fuel cycle. The current submittal by the licensee was intended to gain approval for 30-year plant life using more realistic assumptions and employing finite element models in the analytical evaluation of the nozzles flaws. A proposed inservice examination plan in accordance with IWB-2420 (b) and (c) is also included in this report.
The Materials and Chemical Engineering Branch has completed the review and found the submittals acceptable. The staff concludes that the methodology and criteria used in the flaw evaluation for the pressurizer instrument nozzles of St. Lucie 2 plant are in accordance with IWB-3600 of Section XI of the ASME Code. Based on the information provided, the staff also determines that the i
fatigue crack growth methodology is adequate. Hence, the reported flaws CONTACT:
S. Sheng, NRR d
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415-2708 4
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David B. Matthews are acceptable without repair for an additional 30 years of plant life. The proposed inservice inspection plan and schedule in Attachment C, which addresses the inservice reexamination requirements of IWB-2420 of the ASME Code, calls for ultrasonic reexamination of the four repaired instrument nozzles during the next three inspection periods and is adequate.
This completes our work for Tac No. M91704.
Docket No.: 50-389 Attachments: As stated cc:
Jan Norris, PM DISTRIByllQfi:
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NAME SSheng:ss:adi KM DATE 8/09/95:jb 8/09/95 0FFICIAL COPY e