ML20077K091

Responds to NRC Bulletin 89-001,Suppl 2, Failure of Westinghouse Steam Generator Tube Mechanical Plugs

ML20077K091
Person / Time
Site:	Vogtle
Issue date:	07/31/1991
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-02981, ELV-2981, IEB-89-001, IEB-89-1, NUDOCS 9108060366
Download: ML20077K091 (3)

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Trn ? .m a eL3-i W. 6, ' ' '. .wn, lit Y, ji j' c ELV-02981 1054 Docket Nos. 50-424 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

V0 GILE ELECTRIC GENERATING PLANT RESPONSE TO NRC BULLETIN 89-01 SUPPLEMENT 2 FAILURE OF WESTINGHOUSE STEAM GENERATOR TUBE MECHANICAL PLUGS NRC Bulletin 89-01, " Failure of Westinghouse Steam Generator Tube Mechanical Plugs," requested that licensees determine whether certain mechanical plugs supplied- by Westinghouse were installed in their steam generators, and if so, implement an action plan to ensure these plugs will continue to provide adequate assurance of reactor coolant system (RCS) pressure integrity under normal operating, transient, and postulated accident conditions. Supplement 2 to this bulletin requested that actions similar to those noted above be extended to include all Westinghouse mechanical plugs fabricated from thermally treated Inconel 600 material.

Suoolement 2 Actions Reauested

1. " Addressees are requested'to verify that information contained in Table 2 of Reference 4 (Addressees have previously verified similar information for Group 1 plugs in response to the original bulletin) for their plants is correct for plugs fabricated from group 2 heats. The specific information to be verified is the number of Westinghouse mechanical plugs installed in the hot-leg and cold-leg side of each steam generator, categorized by heat number and date of installation. The plug operating temperature for each plant given in this table should also be verified. if information from this table is incorrect, addressees should-provide correct information.

Addressees are requested to so state if their plants have not installed Westinghouse mechanical plugs from group 2 heats."

The information in Table 2 of Reference 4 is correct for the Vogtle Electric Generating Plant - Units 1 and 2.

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U. S. Nuclear Regulatory Commission ELV-02981 Page 2

2. " Addressees are requested to take the following actions, to be implemented initially during any refueling outage or extended outage' (greater than four weeks) which ends 60 days or more following receipt of this bulletin and during all future refueling outages. For the period of time between receipt of the bulletin and 60 days, the actions requested in the original version of this bulletin continue to be applicable for plugs fabricated from group I heats.

a) Addressees should implement appropriate remedial actions (i.e., repair and/or replacement) for all plugs whose estimated lifetime in item 2b, below does not extend to the next refueling outage."

All estimated lifetimes for inconel 600 plugs installed at the Vogtle Electric Generating Plant - Units 1 and 2 extend substantially beyond the next refueling outages. The use of Inconel 600 plugs has been discontinued. At the next outage on each unit, the Inconel 600 plugs will be replaced with Inconel 690 mechanical plugs. This replacement program ensures the lifetime of the existing plugs is not exceeded and resolves the remainder of actions associated with item 2. Georgia Power Company will consider the ALARA principles when the plug replacement is performed.

In our previous s|letter dated June 16, 1989]] (ELV-00615), we indicated that Westinghouse plugs removed from the steam generators would be inspected for primary water stress corrosion cracking. At this time, we intend to drill out these plugs; thus no samples will be available for an examination.

Mr. W. G. Hairston, III states that he is a Senior Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company and that, to the best of his knowledge and belief, the facts set forth in this letter are true.

GEORGIA POWER COMPANY By: Lt. -

W. G. Hairston, 111 AT Sworn to and subscribed before me this 31" day of July,1991.

HIlu $ ~l 1 ii Notary Public W Corms 3t0N DFmES DEC.15.19o2 WGH,III/PAH/gmb xc: (See next page)

. Georgia Power A U. S. Nuclear Regulatory Commission CLV-02981  !

Page 3 xc: Georaia Power Company Mr, C. K. McCoy Mr. W. B. Shipman Mr. P..D. Rushton Mr. M. Sheibani NORMS U. S. Nuclear Reaulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr D. S. Hood, Licensing Project Maneger, NRR Mr. B. R. Bonser, Senior Resident inspector, Vogtle