ML14314A878

(VEGP) - Request for Additional Information on Spring 2013 Steam Generator Tube Inspections

ML14314A878
Person / Time
Site:	Vogtle
Issue date:	11/13/2014
From:	Martin R Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Martin R
References
TAC MF4288
Download: ML14314A878 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 13, 2014 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.

Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNIT 2- REQUEST FOR ADDITIONAL INFORMATION ON SPRING 2013 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MF4288)

Dear Mr. Pierce:

By letters dated July 2, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13184A269) and September 26, 2013 (ADAMS Accession No. ML14170A021 ), Southern Nuclear Operating Company, Inc. (the licensee) submitted information summarizing the results of the spring 2013 steam generator (SG) tube inspections performed at Vogtle Electric Generating Plant, Unit 2. These inspections were performed during refueling outage 16 (RFO 16). In a letter dated April 25, 2013 (ADAMS Accession No. ML13112A225), the U.S. Nuclear Regulatory Commission (NRC) staff summarized two conference calls that were held with the licensee during RFO 16. In order to complete the review, the NRC staff requests responses to the follow questions:

1. Please discuss the results of the tube plug visual inspections. Were all plugs confirmed to be present and free of degradation?

2. Please discuss the results of the SG channel head visual inspections.

3. Please clarify what is meant by "legacy items" in reference to the foreign object search and retrieval inspection. Does this mean that visual inspections were performed at locations where loose parts were known to be present fror:n prior inspections?

4. Possible loose part indications and wear attributed to loose parts were identified on the hot-leg side of the SG. Is wear attributed to loose parts a potential degradation mechanism at Vogtle, Unit 2, on the cold-leg side of the SG? If so, please discuss whether the bobbin coil is qualified to detect such degradation near the top of the tubesheet on the cold-leg side of the SG. If the bobbin coil is not qualified, please discuss why a probe capable of detecting such degradation and that may satisfy the applicable tube repair criteria was not employed at those locations where the potential for this degradation mechanism exists (e.g.,

peripheral tubes).

C. R. Pierce :2-

5. A "historical" tube wear indication in SG 4 was reported. In reviewing the prior

• inspection report submitted to the NRC, no reference was made to this indication.

Please confirm that this indication was detected in the prior inspection and that all indications are being reported .

. 6. With respect to the accident induced leakage performance criteria it was indicated that:

• There was no SG primary to secondary leakage present during Cycle 16. The calculated accident induced leakage rate is zero; therefore, the performance criteria for Cycle 16 with respect to the H* permanent alternate repair criteria have been satisfied.

No operational leakage was reported during the previous cycle; therefore, the calculated accident induced leakage rate is zero.

Please clarify these statements. The NRC staff notes the following: (1) there is no separate accident induced leakage rate limit for the H* permanent alternate repair criteria (rather the accident induced leakage rate limit applies tb leakage from all possible sources) and (2) the absence of operational leakage does not necessarily mean that the calculated accident induced leakage rate is zero (since there could be other sources of leakage such as from tube plugs and from degradation mechanisms other than those that may be permitted to remain in service under the H* criteria).

Sincerely,

.'~ IJ/J~~

~~~~artin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-425 cc : Distribution via Listserv

• .. ML14314A878 OFFICE DORULPL2-1 /PM DORL/LPL2-1 /LA DE/ESGB/BC DORL/LPL2-1 /BC DORULPL2-1 /PM NAME RMartin SFigueroa GKulesa RPascarelli RMartin DATE 11/12/14 ,11/12/14 10/15/14 11/13/14 11/13/14