ML20195F640

Withdraws Previous Request for long-term Use of Mechanical Nozzle Seal Assemblies (Mnsas) at Songs,Units 2 & 3.Licensee Now Requests Permission to Use Mnsas as Alternate ASME Section XI Code Repair for Interim Period

ML20195F640
Person / Time
Site:	San Onofre
Issue date:	11/18/1998
From:	Scherer A SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M99558, TAC-M99559, NUDOCS 9811200046
Download: ML20195F640 (4)

Text

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A. Edward Scherer V6{]QE EDISON sOUTHERNCAtllORMm =L, ,

An EDI5U!t iqlRNATIONAL* Company November 18,1998 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Docket Nos. 50-361 and 50-362 Use of the Mechanical Nozzle Seal Assembly San Onofre Nuclear Generating Station, Units 2 and 3 (TAC Nos.

M99558 and M99559)

References:

See Faclosure This letter withdraws the previous Southern California Edison Company (SCE) request for the long-term use of Mechanical Nozzle Seal Assemblies (MNSAs) at the San Onofre Nuclear Generating Station (SONGS), Units 2 and 3. Instead, this letter requests permission to use MNSAs as an alternate ASME Section XI Code repair for an interim period (until the end of the Unit 2 and Unit 3 Cycle 11 refueling outages), and provides a plan for obtaining cycle by cycle '

approval for the use of MNSAs at SONGS.

BACKGROUND In Reference 1, the U.S. NRC granted SCE permission to use MNSAs as an alternate ASME Section XI Code repair for an interim period (from the Unit 2 and Unit 3. Cycle 9 mid-cycle outages until the Cycle 10 refueling outages).

In an April 30, 1998, letter from J. (.. Rainsberry (SCE) to the Document Control Desk (U.S. NRC) (Reference 2), SCE provided additional information, as requested, to address long-term effects of degradation mechanisms. This was in response to issues also identified in the Safety Evaluation that was ,j enclosed in the U.S. NRC's February 17, 1998 letter (Reference 1). I 9811200046 981119 f DR ADOCK 050 31? .

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[ P. O. Box 128 l San Clemente, CA 92674-0128 949-368-750 t Fax 949-368-7575

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Document Control Desk ..

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-DISCUSSION -

l SCE is withdrawing our request for long-term approval of the MNSAs, as originally requested by Reference 3. Nevertheless, based on the information provided in Reference 3, SCE is requesting interim approval (until- the end of the Unit 2 and Unit 3 Cycle 11 refueling outages), based on the following plan:

1) SCE will request cycle by cycle approval from the U.S. NRC to operate with MNSAs installed.

• The current SCE request is for U.S. NRC approval to use the MNSAs in both Units 2 and 3 until the end of the Unit 2 and the Unit 3 Cycle 11 refueling outages (which are planned to be in the years 2000 and 2001).

• After the completion of the Cycle 10 refueling outages for Unit 2 and l

Unit 3, and prior to the Cycle 11 refueling outage for Unit 2, SCE will submit another request to use the MNSAs at both Units 2 and 3 l until the end of the Unit 2 and Unit 3 Cycle 12 refueling outages l (which are planned to be-in 2002).

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• After the completion of the Cycle 11 refueling outages for Unit 2 and Unit 3, and prior to the Cycle 12 refueling outage for Unit 2, SCE will submit a request to use the MNSAs at both Units 2 and 3 until the end of the Unit 2 and Unit 3 Cycle 13 refueling outages (which j are planned to be in 2004). l

• SCE will perform and document the visual inspections each refueling outage as specified in Reference 2.

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2) During the Cycle 12 refueling outages, SCE will remove all MNSAs and replace them.

• 1he MNSAs removed will be examined for any evidence of corrosion.

• The information gathered by this examination will be used to support l the request for permanent use of the MNSAs on the Pressurizer instrument nozzles and the Steam Generator channel head instrument nozzles.

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Document Control Desk < t CONCLUSION SCE requests permission to use MNSAs as an alternate ASME Section XI Code repair for the interim period through the end of the Unit 2 and Unit 3 Cycle 11 refueling outages. To support the Unit 2 Cycle 10 refueling outage, scheduled to begin in January, 1999, SCE requests this approval be granted by December 1, 1998.

SCE will remove all MNSAs and replace them during the Cycle 12 refueling outages. Evaluation of the condition of the original MNSAs will be used to i support permanent installation of the MNSAs as an alternative to the Code l repair. '

I Until permanent installation is approved, SCE will continue to request interim l approval on a cycle by cycle basis.

If you have any questions on this subject, please call me.

Sincerely,

-,, w- _

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Enclosure cc: E. W. Merschoff, Regional Administrator, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 & 3 J. W. Clifford, NRC Project Manager, San Onofre Units 2 and 3

.s Encl,osure i

References

1) Letter from William H. Bateman (U.S. NRC) to Dwight E. Nunn (SCE), dated February 17, 1998;

Subject:

Use of the Mechanical Nozzle Seal Assembly for the San Onofre Nuclear Generating Station, Units 2 and 3 (TAC Nos. M99558 andM99559)

2) Letter from J. L. Rainsberry (SCE) to Document Control Desk (U.S. NRC),

dated April 30, 1998;

Subject:

Docket Nos. 50-361 and 50-362, Use of the Mechanical Nozzle Seal Assembly, San Onofre Nuclear Generating Station, Units 2 and 3 (TAC Nos. M99558 and M99599)

3) Letter from J. L. Rainsberry (SCE) to Document Control Desk (U.S. NRC),

dated December 12, 1997;

Subject:

Docket Nos. 50-361 and 50-362,' Mechanical Nozzle Seal Assembly Code Replacement, Request for Relief from 10 CFR 50.55a, San Onofre Nuclear Generating Station, Units 2 and 3 4