ML20091K992

Responds to Generic Ltr 84-11 Re Insp of BWR Stainless Steel Piping.Util Currently Performing Insp Per IE Bulletins 82-03,Rev 1 & 83-02 During Refueling Outage 6 & Replacing Portions of IGSCC Type 304 Stainless Steel Pipe

ML20091K992
Person / Time
Site:	Pilgrim
Issue date:	06/04/1984
From:	Harrington W BOSTON EDISON CO.
To:	Vassallo D Office of Nuclear Reactor Regulation
References
BECO.-#84-074, BECO.-#84-74, GL-84-11, IEB-82-02, IEB-82-03, IEB-82-2, IEB-82-3, NUDOCS 8406070278
Download: ML20091K992 (3)

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BOSTON EDISON COMPANY 800 BOYLSTON STREET WOSTON, MA35ACHuarns 02199 wgLLIAM D. HARRINGTON messen vess pnessesset

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BECo. #84 074 June 4, 1984 Mr. Domenic B. Vassallo, Chief Operating Reactors Branch #2 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555 License No. DPR-35 Docket No. 50-293

Reference:

Generic Letter 84-11: Inspections of BWR Stainless Steel Piping

Dear Sir:

Backaround Generic Letter 84-11 directed licensees to respond to suggested actions for the reinspection of piping susceptible to intergranular stress corrosion cracking (IGSCC) in large-diameter recirculation and residual heat removal piping.

Action Item 1 A reinspection program of piping susceptible to IGSCC should be undertaken.

The reinspection should connence within about two calendar years, adjusted to coincide with the next scheduled outage, from the previous inspection performed under IE Bulletin 82-03, 83-02, or our August 26,1983 Order.

Response

Boston Edison is currently performing an inspection pursuant to IE Bulletins 82-03, Revision 1 and IE Bulletin 83 02 during Refueling Outage 6 (RF0 6). We-are also replacing a major portion of the IGSCC susceptible Type 304 stainless steel piping with Type 316 " nuclear grade" stainless, a type which has been demonstrated to be highly resistant to IGSCC. The inspection and replacement is being conducted in accordance with the above referenced Bulletins and a Confirmatory Order dated August 26, 1983.

If appropriate, an augmented inspection program of piping susceptible to IGSCC will be developed and submitted to the NRC for review prior to RF0 7.

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' BO3 TON CCON COMPANY Domenic~B. Vassalo June 4, 1984 Page 2 Action Item 2 These reinspections should include the following stainless steel welds, susceptible to IGSCC, in piping equal to or greater than 4" in diameter, in

systems' operating over 200*F, that are part of or connected to the reactor coolant pressure boundary, out to the second isolation valve as follows.

(a) Inspection of 20% of the welds in each pipe size of IGSCC sensitive welds not inspected previously (but no less than 4 welds) and reinspection of 20% of the welds in each pipe size inspected previously (but not less than 2 welds) and found not to be cracked. This sample should be selected primarily f rom weld locations shown by experience to have the highest propen:ity for caacking.

(b) All unrepaired cracked welds.

(c) Inspection of all weld overlays on welds where circumferential cracks longer than 10% of ' circumference were measured. Disposition of any findings will be reviewed on a case-by-case basis. Criteria for operation beyond one cycle with overlaid joints are under development.

(d) Inspection of any weld treated by induction heating stress improvement which has not been post treatment UT acceptance tested.

(e) In the event new cracks or significant growth of old cracks are found, the inspection scope should be expanded in accordance with IEB 83-02.

Response

As stated above, pipe inspection and replacement associated with IGSCC is currently in progress. The welds subject to augmented inspection may change because of replacement or repair based on the results of the ongoing effort.

Boston Edison shall provide the appropriate list prior to beginning the augmented inspections during RF0 7.

Action Item 3 All level 2 and level 3 UT examiners should demonstrate competence in accordanie with IEB 83-02 and level 1 examiners should demonstrate field performance capability.

Response

Boston Edison Company plans to continue the current practice of requiring that all Level 11 and Level III UT examiners demonstrate their ability to detect IGSCC in accordance with the IE Bulletin 83-02. In addition, all Level 1 UT examiners are and will be required to demonstrate field performance capability. To date, the inspection agency hired by BECo to perform IGSCC inspections has provided sufficient qualified examiners to perform the required' examinations.

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EOCTON CICCN COMPANY Domenic B. Vassalo June 4,.1984 Page 3 Action Item 4 Leak detection and leakage limits should be sufficiently restrictive to ensure timely investigation of unidentified leakage. See attachment 1.

Besponse The August 26, 1983 Confirinatory Order mandated interim leakage limits and operability requirements for the prirr.ary containment leak detection systems.

These requirements reflect Attachment I to Generic Letter 84,1.

Boston Edison shall use the Order's interim measures as guidelines in the preparation of a technical specification amendment which shall be submitted ir the near future.

Action Item 5 Respond to the crack evaluation and repair criteria in Attachment 2 of GL84-11.

Response

At present Boston Edison plans to use the crack evaluation and repair criteria contained in Attachment 2 of Generic Letter 84-11.

The Electric Power Research Institute (EPRI) and the Boiling Water Reactors Owners Group (BWROG) have been developing a guideline for flaw evaluation and remedial actions for IGSCC. A draft of this has recently been submitted for BWROG approval. After the BWROG position on the guideline is determined, we may decide to adopt all or part of it in response to this item.

Very truly yours, Connonwealth of Massachusetts) l County of Suffolk )

Then personally appeared before me W. D. Harrington, who, being duly sworn, did state that he is Senior Vice President - Nuclear of the Boston Edison Company, the applicant herein, and that he is duly authorized to execute and file the submittal contained herein in the name and on behalf of the Boston Edison Company and that the statements in said submittal are true to the best of his knowledge and belief.

My Co'. mission expires: 7/Pdf f wwu < "/>

Notary Public/

cc: Darrell G. Eisenhut, Director Division of Licensing PMK/dyb

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