ML20207H332
| ML20207H332 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/17/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEB-88-009, IEB-88-9, NUDOCS 8808250264 | |
| Download: ML20207H332 (3) | |
Text
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot SH 157B Lookout Place AUB 171988 U.S. Nucicar Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAll NUCLEAR pbANT (SQN) - NRC BULLETIN 88-09 TillMBLE TUBE Til1NNING IN WESTINGil0USE REACTORS In response to the subject bulletin, TVA has identified oddy current test.ing of SQN's thimble tubes as the appropriate inspection methodology for detecting wear of the tubes.
Both SQN units 1 and 2 are considered to be in category 2.d of the Actions Requested section of the bulletin.
For unit 1, this determination has been made based upon insufficient timo to completo 'Fo inspections before restart. TVA does not havo the exportise in-houss 4a complete the cody current testing and evaluation, and no centract for the testing is in place. Additionally, as recommended in the bulletin, the Westinghouse owner's Group has received a proposal to develop an appropriate wear accept.ance critorion, but that critorion has not yet, been established.
The repositioning of tubes is an often recommended corrective action for tubes with excessive wear. Although SQN has not yet comploted f
inspections to identify tubos with excessive wear, all thimble tubos in unit I woro proventively withdrawn approximately one and one-half inchos in 1985. SQN also has adequate makeup carability for a postulated thimble tubo leak and has the capability to isolato leaking thimble tubes I
at the seal table. Those factors, along with SQN's core being the standard 12-foot, length, support the conclusion that thimble tube woar is l
a maintenance or economic issue at SQN.
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The eddy current, testing of the thimblo tubos will be performod during the cycle 4 refueling outage for unit 1 and the cycle 3 refueling outage for unit 2.
As required by the bulletin, reports will be submitted to NRC within 30 days of complet.Lon of the inspections for each unit. An appropriato inspection frequency will be established following evaluation of the initial eddi cueront, data.
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G808250264 esos37 DR ADOCK 05000327 PDC An Equal Opportunity Emp' oyer
r U.S. Nuclear Regulatory Comission g {]g Summary statements of commitments contained in this submittal are provided in the enclosure.
Please direct questions concerning this issue to Kathy S. Whitaker at (615) 870-7748.
Very truly yours, TENNES
.E V I
'Y AUTHORITY R. Celdley, Manager Nuclear Licensing and Regulatory Affairs Enclosure cc (Enclosure):
Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commiss'.on One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852, Mr. F. R. McCoy, Assistant Director for Inspection Prograns TVA Projects Division U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Coorgia 30323 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379
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ENCLOSURE LIST OF COMMITHENTS 1.
Eddy current testing of the unit i thimble tubes will be performed during the unit 1 cycle 4 refueling outage.
2.
Eddy current testing of the_ unit 2 thimble tubes will be performed during the unit 2 cycle 3 refueling outage.
3.
The report for unit i required in item 3 of the Reporting Requirements section of the bulletin will be submitted within 30 days of complation of the initial inspection for unit 1.
4.
The report for unit 2 required in item 3 of the Reporting Requirements section of the bulletin will be submitted within 30 days of completion of the initial inspection for unit 2.
5.
The appropriate inspection frequency for unit I will be established following evaluation of the initial unit 1 eddy current data.
6.
The appropriate inspection frequency for unit 2 will be established following evaluation of the initial unit 2 eddy current data.