ML102070044

Comment (6) of Scott Boggs, on Behalf of Nextera Energy, on Proposed Rule PR-50, Regarding American Society of Mechanical Engineers (ASME) Codes and New and Revised ASME Code Cases

ML102070044
Person / Time
Site:	Saint Lucie, Point Beach, Seabrook, Turkey Point
Issue date:	07/22/2010
From:	Boggs S Florida Power & Light Co, Nextera Energy
To:	NRC/SECY/RAS
SECY RAS
References
75FR24323 00006, PR-50
Download: ML102070044 (4)

Text

DOCKETED USNRC PR 50 J ,  :

(75FR24323) July 23,2010 (9:10am)

OFFICE OF SECRETARY Comments to 10CFR5055a RULEMAKINGS AND ADJUDICATIONS STAFF

Subject:

Docket ID NRC-2008-0554, Comments to conditions on ASME Code Case N-770

1) Condition §50.55a(g)(6)(ii)(F)(4) proposes to require essentially 100 percent coverage for axial flaws. Both Code Case N-770 and MRP-139 (Section 5.1.5) permit examination of axial flaws with inspection coverage limitations provided essentially 100 percent coverage for circumferential flaws is achieved and the maximum coverage practical is achieved for axial flaws. Does this condition negate taking credit for "baseline inspections" of butt welds as stated in the proposed condition in §50.55a(g)(6)(ii)(F)(3) that met the requirements of MRP-139 and N-770?

2) Condition §50.55a(g)(6)(ii)(F)(1 3) proposes to modify the last sentence in note 10 but does not specifically state how. The wording suggests that the condition will also include the 25% sample to be examined prior to the end of the mitigation evaluation period but omits the words from note 10 of "ifthe plant is to be operatedbeyond that time. " Would the last sentence in Note 10 be modified similar to the following? "100 % of the those welds not included in the 25%

sample shall be examined prior to the end of the mitigation evaluation period if the plant is to be operated beyond that time."

3) Code Case N-770, Table 1, Inspection Item "D", Uncracked butt welds mitigated by stress improvement, has a requirement in the second sentence of "Extent and Frequency of Examination" to spread out the population of mitigated welds in years 3 through 10 following applications of the mitigation. This provision creates an unintended penalty when compared to other mitigation categories which allows all of the population to be performed at once. A change was brought to the attention of the ASME Alloy 600 Task Group preparing revisions to the N-770-1 and accepted for incorporation into its next revision. The proposed change is being documented in ASME Codes & Standards Tracking number BC-09-1145. The change was to replace the 1st two sentences under the in the "Extent and Frequency of Examination" column of inspection Item "D" with the following sentence: "Examine all welds no sooner than the third refueling outage and no laterthan 10 yearsfollowing stress improvement application."

The basis for this proposed change is as follows: The proposed change was made because the current wording in Table 1, "Category D, Uncracked butt weld mitigated with stress improvement, Extent and Frequency of Examination,"

creates an unnecessary penalty (compared to other mitigation categories) for dissimilar metal piping welds that are mitigated by stress improvement by spreading the examination population for the I" examination through years 3 T poe= ey6&7 Ds

through 10. This provision was originally considered as consistent with the ASME Code Section XI, Table IWB-2412-1 and provisions in Table IWB-2500-1 for deferral to end of interval, which are only applicable for RV Nozzle to safe end welds, Category B-F welds item B5.10 and B5.20. However, when the population is applied to small quantity of mitigated welds other than the RV nozzles, it results in multiple mobilizations with possibly 1 weld per inspection period. The multiple mobilizations for these uncracked welds that are mitigated by stress improvement, creates an unrecognized inequity in N-770 and N-770-1 when compared to uncracked welds that are not mitigated (and remain in a larger population) as well as cracked welds that are mitigated by the same stress improvement method (Category E). This inequity is clear when recognizing that all other categories of mitigated welds, Categories E-K, do not require the spreading of the mitigated population for the 1 st exam after mitigation. The spreading out of the population of mitigated welds in Category D as currently written is considered punitive in the first interval when compared to inspection without mitigation and could result in an impediment to performing mitigation.

Comments submitted by:

Scott Boggs Nextera Energy (Formerly Florida Power & Light Co) 700 Universe Blvd Juno Beach FL 33408 561-694-4207

Rulemaking Comments From: Boggs, Scott [Scott.Boggs@fpl.com]

Sent: Thursday, July 22, 2010 3:07 PM To: Rulemaking Comments

Subject:

Docket ID NRC-2008-0554; Comments on the NRC "Proposed Rule Changes to 10 CFR 50, Relating to Code Case N-770 and Nonmandatory Appendix E, Evaluation of Unanticipated Operating Events" Attachments: Comments to 10CFR5055a.doc Attached are comments from Nextera Energy (Formerly Florida Power & Light Company) comments on the NRC "Proposed Rule Changes to 10 CFR 50, Relating to Code Case N-770

Thanks, Scott Boggs Nextera Energy/Florida Power & Light Co 700 Universe Blvd Juno Beach FL 33408 (W) 561-694-4207 I

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Date: Thu, 22 Jul 2010 15:06:57 -0400

Subject:

Docket ID NRC-2008-0554; Comments on the NRC "Proposed Rule Changes to 10 CFR 50, Relating to Code Case N-770 and Nonmandatory Appendix E, Evaluation of Unanticipated Operating Events" Thread-Topic: Docket ID NRC-2008-0554; Comments on the NRC "Proposed Rule Changes to 10 CFR 50, Relating to Code Case N-770 and Nonmandatory Appendix E, Evaluation of Unanticipated Operating Events" Thread-Index: AcsngSTxCWcF9UIESIajMobOeWF6jwAtMpIQAGZVKDA=

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