ML20127N424
| ML20127N424 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 11/23/1992 |
| From: | Starkey R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20127N428 | List: |
| References | |
| NLS-92-306, TAC-M81880, NUDOCS 9212010255 | |
| Download: ML20127N424 (3) | |
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e CA&L Carolina Power & Ught Company P o aan i551. no..gn. N c mm (NOV 231992 A e ST AME Y, JR Vg e P'etadent Nxsea# servet a Depa1wil SERIAL: NLS 92 300 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO.1 DOCKET NO. 50-325/ LICENSE NO. DPR 71 EXAMINATION OF FEEDWATER NOZZLE N4D (NRC TAC NO. M81880)
Gentlemen:
The purpose of this letter is to provide to the Nuclear Regulatory Commission (NRC) staff information concerning recently completed ultrasonic examinations of feedwater nozzle joint number 1821N4D 5 SW12 for the Brunswick Steam Electric Plant, Unit No.1. This weld joint was previously reported as having an indication that was conservatively assumed to be intergranular stress corrosion cracking (IGSCC). provides a description of the inspection scope, a summary of the ultrasonic testing (UT) process used, and the UT results. Enclosure 2 provides a copy of the General Electric ultrasonic examination report (Report No. R 1). Based on these UT results, CP&L intends to:
(1) re categorize this weld as a NUREG 0313 Category D weld joint and (2) discontinue crack arrest verification system (CAVS) monitoring as previously described.
Please refer any questions regarding this submittal to Mr. D. B. Waters at (919) 546-4061.
Yours very truly,
/
[
44 -)
R. B. Starkey, Jr.
WRM/wrm (nts92306.wpf)
Enclosures cc:
Mr. S. D. Ebneter Mr. R. H. Lo Mr. R. L. Prevatte 30021u g
9212010255 921123 If PDR ADOCK 05000325
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a ENCLOSURE 1 BRUNSWICK STEAM ELECTRIC PLANT, UNIT 1 NRC DOCKET NO. 50-325 OPERATING LICENSE NO. OPR 71 EXAMINATION OF FEEDWATER NOZZLE N4D (NRC TAC NO. M81880)
The ultrasonic testing (UT) examination that is the subject of this report was performed during the period of July 13 through July 23,1992.
(1) OPERATIONAL HOURS EXPERIENCED Unit 1 had operated for approximately 6500 hours0.0752 days <br />1.806 hours <br />0.0107 weeks <br />0.00247 months <br /> sinco the previous ultrasonic examination.
(2)
SUMMARY
OF EXAMINATION TECHNIQUES The weld joint was examined with the General Electric Company ' Smart 2000" automated system using 45' and 60' refracted longitudinal wave and 458 shear wave units. Manual ultrasonic techniques (60 RL,45' shear wave and an inside diameter (ID) creeping wave search units) were used to confirm the size of the indication and to verify that there is no apparent connection between the mid wallindication and the inside diameter surface of the pipe.
(3) NONDESTRUCTIVE EXAMINATIONS RESULTS No indications with characteristics of intergranular stress corrosion cracking (IGSCC) were noted.
One mid wall non geometric type indication was recorded. This Indication had been previously recorded in 1990, was reported to the Nuclear Regulatory Commission by letter dated January 7, 1991 (Reference 1), and was conservatively assumed to be IGSCC at that time, t
This indication did not show any discernable difference in ligament dimension or length when compared to previous data collected in 1990. The indication does not have the characteristics of IGSCC. Additionally, a manual scan utilizing a ID creeping wave search unit confirmed that there is no apparent connection between the mid wallindication and the inside diameter surface of the pipe. This examination, which utilized a ID creeping wave search unit, was not performed in 1990.
(4) CONCLUSIONS This indication had previously been recorded in 1990 and was the subject of meeting in May 1991 (see Reference 4) to discuss a potential mid cycle inspection. Additionalinformation (References 5, 7, and 8) was submitted to the NRC to support the operation of BSEP Unit 1 without a mid cycle.
examination.
Since the indication did not show any discernible change and does not show a connection to the -
inside diameter of the safe end, this weld joint is no longer considered by CP&L to be a potential IGSCC indication, The Company considers the indication to be a mid-wall discontinuity associated with a weld repair made during the original fabrication process..There are documented repairs in the area of the indication. Recent NRC Region ll evaluations, as documented in inspection Report El-1
i No. 50 325/92 27 and 50 324/92 27 dated October 20,1992 (Reference 9), also support CP&L's conclusion that the indication is not IGSCC.
Therefore, CP&L believes there is no justification to continue monitoring tnis joint as a flawed weldment (NUERG 0313 Category F) as previously committed to in Reference 1. The Company believes this weld sho'>ld be re-categorized as a NUREG 0313 Category D weld joint (non-resistant material, no stress improvement). The Company also believes that monitoring of the Crack Arrest Verification System (CAVS) autoclave specifically for crack growth in this weld joint, as discussed in References 1, 5, 7, and 8, is no longer considered necessary.
Since this weld joint it, being lemoved as part of thu feedwater sparger replacement project scheduled in Refueling Outage Number 9 (currently scheduled for Spring 1995), nu additional examinations are scheduled t'n th!s weld joint before the feedwater sparger replacement project.
A total of appror.imately 0.75 person-rem has been accumulated performing UT examinations of this joint in the previous outage and in the outage currently underway, II f
(5) REFERENCES 1.
Letter from G. E. Vaughn (CP&L) to NRC Document Control Desk dsted January 7,1991,
" Examination / Evaluation Results For Wold No.1821N4D-5 SW12 Refueling Outage 7," Serial No. NLS-91-001.
2.
Letter from G. E. Vaughn (CP&L) to NRC Document Control Desk dated January 24,1991, "lGSCC Inspection Results Rafueling Outage 7," Serial No. NLS 91017.
3.
Letter from N. B. Le (USNRC) to L. W. Eury (CP&L) dated February 11,1991, " Evaluation of Feedwater Nozzle Wold Indicat:on Brunswick Steam Electric Plant, Unit 1 (TAC No. 79381)."
4.
Letter from N. D. Le (USNRC) dated May 31,1991, " Evaluation of UT Indication for Feodwater Safe End/ Pipe Extension."
5.
Letter from G. E. Vaughn (CP&L) to NRC Document Control Desk dated November 27,1991, "Feedwater Nozzle N4D Safe End UT Indication (NRC TAC No. 79381)," Serial No. NLS 91307.
t 6.
Letter from N. B. Le (USNRC) to L. W. Euiy (CP&L) dated December 11,1991, " Evaluation of Feedwater Nozzle Weld (No.1321N4D-5 SW12) Indication and Intergranular Stress Corrosion Cracking (IGSCC) Inspection During Refueling Outage 7 - Brunswick Steam Electric Plant, Unit 1 (TAC Nos. M79381 and 79508)."
7.
Letter from G. E. Vaughn (CP&t) to NRC Document Control Desk dated January _10,1992, "Feedwater Nozzle N4D Safe E...', L'T indication (NRC TAC No. M81880)," Serial No. NLS 91335.
8.
Letter from R. B. Starkey, Jr. (CP&L) to NRC Document Control Desk dated March 30,1992, "Feedwater Nozzle N40 Safe End UT fndication (NRC TAC No. M81880) " Serial i
No. NLS 92102, 9.
NRC Inspection Report No. 50-325/92 27 and 50-324/92-27 dated October 26,1992, Paragraph 2.
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