ML20035F609

Responds to Util Request to Delete Requirement to Perform Suppl Insps of Reactor Vessel Nozzles Required by TS 4.4.10.b.Technique Satisfactory for Insp of Unit 1 Subj Nozzles for Cold Underclad Cracking During Outage

ML20035F609
Person / Time
Site:	Sequoyah
Issue date:	04/16/1993
From:	Labarge D Office of Nuclear Reactor Regulation
To:	Medford M Tennessee Valley Authority
References
TAC-M85308, TAC-M85309 NUDOCS 9304220083
Download: ML20035F609 (3)

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April 16, 1993 Doc e and 50-328 Tennessee Valley Authority ATTN: Dr. Mark O. Medford, Vice President Nuclear Assurance, Licensing & Fuels 38 Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

REACTOR VESSEL N0ZZLE SUPPLEMENTAL INSPECTIONS -

SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 (TAC NOS. M85308 AND M85309)

By letter dated January 8,1993, the Tennessee Valley Authority (TVA),

licensee for the Sequoyah Nuclear Plant Units 1 and 2, submitted a request to delete the requirement to perform supplemental inspections of the reactor vessel nozzles that are required by Technical Specification 4.4.10.b.

These inspections are unique to Sequoyah and were added to the technical specification prior to initial startup in 1980 due to concerns related to reactor vessel nozzle underclad crack indications.

Initial staff evaluation of the request found that insufficient data existed to justify deletion of the inspection requirement, and that TVA would be required to submit additional information before further action on the submittal was possible. Therefore, by letter dated April 1, 1993, TVA submitted additional information, along with a description of the nozzle testing that would be performed during the Unit 1 Cycle 6 refueling outage and a request for confirmation that the scope t.nd technique that would be used to perform the nozzle examinations would be acceptable.

This submittal was followed by a conference call on April 8,1993.

A research trip to Southwest Research Institute on March 23, 1993, compared the ultrasonic techniques used in 1980 and 1993 in order to show that the detection and sizing techniques used for the proposed nozzle examinations would satisfy the technical specification requirement.

The demonstration was attended by Mr. D. Naujock of the NRC and Mr. John Gieske, a technical consultant from Sandia National Laboratories under contract to the NRC, Based on these communications, TVA committed to satisfy the Technical Specification requirements by performing the following:

1.

An examination of the volume of all eight RPV nozzles as defined for the 10-year inservice inspection by the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME),Section XI; 2.

An examination of the clad-to-basemetal interface region of the nozzle

! Q as defined by ASME Section XI, Figure IWB-2500-7 (can coincide with item

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An examination of all reportable indications (reheat cracks, cold cracks, inclusions, etc.) identified in the supplemental examination that was submitted to the NRC by letter dated February 28, 1980 (some indications may coincide with Item 2 above) that described the results of the. original examination.

This technique would be used to detect and characterize (type, depth, length and orientation) any indications found. The staff has determined that this technique is satisfactory for inspection of the Unit I reactor vessel nozzles for cold underclad cracking during the Cycle 6 refueling outage.

Further review of the requested amendment and its application for the Unit 2 Cycle 6 refueling outage awaits NRC review of the results of the Unit I examination.

Since David E. LaBarge, Senior Project Manager Project Directorate 11-4 Division of Reacter Projects - I/II Office of Nuclear Reactor Regulation cc: See next page e

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An examination of all reportable indications (reheat cracks, cold cracks, inclusions, etc.) identified in the supplemental examination l

that was submitted to the NRC by letter dated February 28, 1980 (some indications may coincide with Item 2 above) that described the results of the original examination.

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This technique would be used to detect and characterize (type, depth, length i

and orientation) any indications found. The staff has determined that this technique is satisfactory for inspection of the Unit 1 reactor vessel nozzles for cold underclad cracking during the Cycle 6 refueling outage.

i Further review of the requested amendment and its application for the Unit 2 Cycle 6 refueling outage awaits NRC review of the results of the Unit 1 examination.

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Sincerely, Original signed by David E. LaBarge, Senior Project Manager i

Project Directorate 11-4 i

Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation-i

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