ML20091Q163
| ML20091Q163 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 06/01/1984 |
| From: | Cutter A CAROLINA POWER & LIGHT CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0619, RTR-NUREG-619 NLS-84-228, NUDOCS 8406130283 | |
| Download: ML20091Q163 (2) | |
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Cp&L Carolina Power & Light Company SERIAL: NLS-84-228 JUN:
.1 1984 Director-of Nuclear. Reactor. Regulation Attention:
Mr. D. B. Vassallo, Chief
.. Operating Reactors Branch No. 2
-Division.of~ Licensing
-United States Nuclear Regulatory Commission
' Washington, DC.
20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO. 2-DOCKET No. 50-324/ LICENSE NO. DPR-62 DEFERRAL OF FEEDWATER SPARGER REPLACEMENT
Dear Mr. Vassallo:
INTRODUCTION By letter dated October 7,1981 (Serial:
No. 81-1652), Carolina Power & Light-Company (CP&L) committed to perform the feedwater sparger. replacement and nozzle cladding removal recommended by NUREG-0619 during the current Unit 2 refueling outage. ' Carolina Power & Light Company plans.to defer this work pending resolution of the feedwater sparger cracking issue at Northern States Power Company's'Monticello Nuclear Generating Plant.
DISCUSSION
'The replacement oflthe =feedwater spargers and removal of the feedwater nozzle
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cladding on. Unit 2 was scheduled to be completed during the current refueling outage; however, during recent inspections at Monticello, cracks' were discovered in the'feedwater.spargers. The replacement spargers intended.to be used at Brunswick are similar in designito those used at-Monticello and, therefore, may be susceptible to the. same cracking mechanism. An initial metallurgical ~ analysis,- performed by General Electric, indicates' the cracks in
- the:Monticello spargers are the result _of high cycle fatigue; however, the p
actual mechanism which causes'the cracking is still under. evaluation. The anticipated schedule for l completion of the analysis and identification of.
corrective actions does not support replacement of the Brunswick Unic 2 j
Tfeedwater spargers during the. current outage.. Carolina Power &' Light Company l
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' believes 'that replacement, of the Brunswick Unit 2 feedwater spargers prior to
- resolution of the new cracking
- phenomenon is premature.-and does not warrant the.
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radiation exposure.or the: resource. commitment required to complete the. work.
- A direct-visual examination of the existing. Brunswick Unit 2 feedwater -
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"spergers has been; completed. This examination' revealed some. flow. hole cracks rangingLfrom 0.200 inches to 0.500 inches in> length.. A propagation analysis
. performed by General: Electric. forf the cracks'in. the existing Brunswick Unit 2~
feedwater spargers. indicates the cracks could propagate'up-to a total of 1.3
- inches'in length during,the next cycle?of-operation. However,' cracks'in the-k 1
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DON 1 1984 Mr. D. B. Vassallo t
. range of 1.3 inches are acceptable since the feedwater sparger is not a safety-related item, and there is no effect on the vessel system pressure boundaries. The crack areas are small and will not affect feedwater flow i
distribution. The potential for loose parts is not a concern due to the orientation of the cracks.
i As a result of not replacing the feedwater spargers. the cladding removal from the feedwater nozzles will not be performed this outage. The following non-destructive examinations were performed on the feedwater nozzles with no adverse indications:
l 1)
' Liquid penetrant testing of the accessible portions (approximately 80%) of the feedwater nozzle internal blend radii. The accessible area includes the lower portion of the blend radius which has the highest susceptability to cracking.
[
2)
Ultrasonic testing _of the feedwater nozzle external blend radii.
3)
Litrasonic testing of the feedwater nozzle safe end forgings.
CONCLUSION Based on the results of the inspections, CP&L has determined that deferral of the feedwater sparger replacement and removal of the feedwater nozzle cladding does not represent :a safety concern. Hence, CP&L plans to defer this work until the next refueling outage for Unit 2 (currently scheduled to begin April 19, 1986) contingent upon a satisfactory and timely resolution of the sparger cracking issue at Monticello.
Carolina Power & Light Company's October 7,1981 submittal also provided a schedule for rerouting the reactor water cleanup piping to each feedwater line and evaluation of the :feedwater low-flow controller. Carolina Power & Light Company is still evaluating these two items and will provide their status and schedule in a separate submittal.
(Carolina' Power &LightCompanyErequestswrittenconcurrencewiththisaction by August 1, 1984. Should you have any questions concerning this submittal,.
"please contact Mr.~Sherwood R. Zimmerman at-(919) 836-6242.
.Yours very truly,'
/
A.
B.' Cutter - Vice President-I Nuclear Engineering & Licensing'
- MAT /cce.(121 MAT)
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cc:'
.Mr. D. O. Myers (NRC-BSEP)
Mr. J. P.10'Reilly - (NRC-RII)'
Mr. M. Grotenhuis E(NRC) 1 u
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