ML20116L461
| ML20116L461 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/06/1996 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-94-03, GL-94-3, IEB-80-13, NUDOCS 9608190027 | |
| Download: ML20116L461 (2) | |
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2tation Support Department A
lEB 80-13 GL 9403 y
PECO NUCLEAR reco caerov comneov Nuclear Group Headquarters A UNir or PECO ENtucy 965 Chesterbrook Boulevard Wayne, PA 19087-5691 August 6,1996 Docket Nos. 50-277 50-278 License Nos. DPR 44 DPR-56 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
Subject:
Peach Bottom Atomic Power Station, Units 2 and 3 Reactor Vessel Internals Examination Plans for the Core Shroud and Core Spray Piping Dear Sir l
The purpose of this letter is to highlight our current plans for the inspection of the Peach Bottom Atomic Power Station (PBAPS), Unit 2 core shroud during the upcoming eleventh refueling outage (2R11) scheduled to begin September,1996. Additionally, this letter discusses an adjustment to the inspection scope and techniques of the core spray piping and spargers for the PBAPS, Units 2 and 3. The core spray piping anci spargers are also planned to be inspected during the upcoming eleventh refueling outage (2R11).
CORE SHROUD Baseline Ultrasonic Testing (UT) examinations were performed on the PBAPS, Unit 2 shroud during the tenth refueling outage (2R10) in 1994. These examinations were conducted in accordance with the recommendations of Genenc Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors," dated July 25, 1994, and were performed utilizing the guidance of the Boiling Water Reactor Vessel and internals Project (BWRVIP) for shroud examinations and evaluation of results ("BWR Core Shroud Inspection and Flaw Evaluation Guidelines," GENE-523-113-0894, Revision 0, September,1994).
As discussed in the Summary Report attached to our Supplemental Response to Generic Letter 94-03, dated November 7,1994, four of the seven shroud circumferential welds were comprehensively UT examined (H-2, H-3, H-4 and H-5). The evaluation of the examination results, which included two operating cycles of crack growth, indicated substantial safety margins will remain in these welds at the end of the fcur year evaluation period. Welds H-1, H4 and H-7 were only partially examined due to access restrictions. The evaluation of the data indicated that the condition of these welds would support continued operation for one cycle. Accordingly, welds H-1, H4 and H-7 have been scheduled for reexamination during the next refueling outage (2R11). These examinations will be performed using the General Electric Nuclear Energy (GENE) updated O.D. Tracker examination delivery system and the Smart 2000 data acquisition system. Comprehensive examination coverage is expected due to updated delivery systems.
Results of the examinations will be evaluated in j]D6 9608190027 960906 PDR ADOCK 05000277 g
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August 6,1996
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i secsdence with the BWRVIP ("BWR Core Shroud Inspection and Flaw Evaluation Guidelines," GENE-523-113-0894, Rev.1, March,1995).
This approach follows the j
current guidance provided by the BWRVIP for core shroud examination results. The examinations will be conducted in accordance with the PBAPS Augmented Inspection Program 9 (AUG-09).
CORE SPRAY PIPING AND SPARGERS Augmented visual examinations of the Core Spray System piping and spargers inside the reactor vessel have been conducted each refueling outage since 1980, as requested by IE Bulletin No. 80-13, " Cracking in Core Spray Spargers," dated May 12, 1980. These examinations have been implemented in accordance with the PBAPS Augmented Inspection Program 3 (AUG-03). Implementation of this program will be modified for 2R11, to incorporate industry experience, and to more closely follow the current guidance being developed by the BWRVIP ("BWR Core Spray Internals inspection and Flaw Evaluation Guidelines," BWRVIP-18, dated July,1996). The modifications will affect scope and examint%n technique. The adjustments to the examinations will focus more attention on j
the wel@ and their heat affected zones, utilizing an enhanced visual examination of the areas where degradation is more likely to occur, and will eliminate the detailed examination of the piping case metal between the welds. It is expected that portions of the piping base metal will be observed as cameras move past the core spray welds. This examination approach revision will be used for all future inspections at PBAPS, Units 2 and 3.
Core Spray downcomer welds at the spigot / sleeve joint connecting the downcomer to the sparger inlet elbow (welds P6 and P7, and the Heat Affected Zone of weld PS) will be examined per the above criteria. If indications are identified, PBAPS is prepared to install repairs similar to those installed during the past PBAPS, Unit 3 outage (3R10). There are no plans for volumetric characterization of the indications in this joint based on the availability of a repair.
If you have any questions, please contact us.
Very truly yours, IA/4 guA.
I G. A. Hunger, Jr.
Director-Licensing cc-T. T. Martin, Administrator, Region I, USNRC W. L. Schmidt, USNRC Senior Resident inspector, PBAPS 1
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