ML20149M730
| ML20149M730 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/20/1997 |
| From: | Boulette E BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BECO-2.97-003, BECO-2.97-3, NUDOCS 9701270127 | |
| Download: ML20149M730 (2) | |
Text
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10CFR50.55::(c)(3)
G Boston Edison Pilgnm Nuclear Power Station Rocky Hdi Road Plymouth, Massachusetts 02360 E. T. Boulette, PhD Senior Vice President-Nuclear January 20,1997 1
BECo Ltr. #2.97-003 i
U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Docket No. 50-293 j
License No. DPR-35 SUPPLEMENTARY INFORMATION 1
RELATED TO PILGRIM REFUELING OUTAGE #11 ISI RELIEF j
(BECo Letter No.96-105. Dated December 12.1996)
Boston Edison Company (BECo) requested relief from Refueling Outage (RFO) #11 inservice inspection (ISI) requirements by BECo Letter No.96-105, dated December 12, 1996, to avoid unnecessary exposure due to elevated radiation levels in the drywell. The letter stated BECo planned to implement chemical decontamination of the recirculation system during RFO#12, and the deferred ISI examinations would be completed during RFO#12 after the decontamination and dose reduction strategies have been implemented.
We have since decided to perform a chemical decontamination of the recirculation system piping during RFO#11. The decontamination process involves extensive planning and coordination of refueling activities within the outage schedule. It is not practical to conduct the subject ISI examinations within that portion of the outage window remaining after completion of the RFO#11 chemical decontamination process. Accordingly, we are still requesting the subject ISI examinations be deferred to RFO #12 to obtain full benefit of the reduced dose rates from the chemical decontamination effort as presented in BECo Letter No.96-105.
We provide the following information regarding N1A welds in response to a NRC request in a telephone call on January 8,1997.
Relief Requests #1 and #3 (BECo Letter No.96-105) make reference to reactor vessel penetration nozzle N1A. The ASME Section XI code requires non-destructive examinations of the (i) nozzle-to-vessel weld, (ii) nozzle inner radius area, and (iii) safe-end weld for each vessel penetration nozzle. The N1A safe-end weld is also a Category A weld within the scope of Generic Letter (GL) 88-01 and is made of IGSCC resistant material. The NRC position on GL 88-01 inspection schedules requires Category A welds "as a minimum" must h
9701270127 970120 PDR ADOCK 05000293 h(0 0
PDR 270028 D
be examined in extent and frequency comparable to that specified in applicable provisions of Section XI of the ASME code. We selected the N1A safe-end weld examination frequency to be consistent with the examination frequency as specified by ASME Section XI.
Even though the inner radius and noza.le-to vessel weld examination for nozzles N1 A, N2A, and N2B were conducted during RFO#6, and the N1A safe-end weld was conducted in RFO#7 (following its replacement in RFO#6), all these examinations were conducted in the first period of the second ISI interval. Therefore, they were required by code to be re-examined during the first period of the third ISI interval (i.e., RFO #11) which is the only outage during the first period of the third ISI interval. Because the N1A safe-end weld is Category A material, the same justification applies to it as presented for deferring the inner radius and vessel-to-nozzle weld examinations from RFO#11 to RFO#12. Accordingly, the GL 88-01 Category D weld examination frequency does not apply to the N1A safe-end weld.
The N1A safe-end weld is the first weld attaching the 316 SS (nuclear grade) recirculation inlet pipe to the carbon steel nozzle. Inconel (Ni-Cr) 82 weld wire was used to weld the 316 i
SS (NG) pipe to the carbon steel nozzle. The non-resistant material was completely shaved and replaced with resistant inconel (Ni-Cr) 82 followed by post-weld heat treatment.
Should you wish further information on this request, please contact Walter Lobo at (508) 830-7940.
h E. T. Boulctte, PhD WGUdmc/rfoisir4 cc:
Project Manager Division of Reactor Projects - 1/II Mail Stop: 14D1 U. S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region 1 475 Allendale Road King of Prussia, PA 19406 Senior Resident inspector Pilgrim Nuclear Power Station 2
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