ML110950640

Memorandum Regarding Sequoyah, Unit 2 - Spring 2011 RFO Steam Generator RFO Conference Call

ML110950640
Person / Time
Site:	Sequoyah
Issue date:	04/05/2011
From:	Siva Lingam Plant Licensing Branch II
To:	Cook R Tennessee Valley Authority
Lingam, S NRR/DORL 415-1564
References
TAC ME5977
Download: ML110950640 (1)

Text

ADAMS Accession No. ML110950640 From: Lingam, Siva Sent: Tuesday, April 05, 2011 12:10 PM To: 'Cook, Rodney Michael' Cc: Broaddus, Doug; Karwoski, Kenneth; Johnson, Andrew; Franke, Mark; Obodoako, Aloysius

Subject:

Sequoyah 2 - Spring 2011 Steam Generator RFO Call (TAC No. ME5977)

Inservice inspections of steam generator (SG) tubes play a vital role in assuring SG tube integrity. As discussed with you and agreed by you this morning, a telephone conference call will be arranged with members of your staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Sequoyah Nuclear Generating Station Unit 2 spring 2011 refueling outage. This call will occur after the majority of the tubes have been inspected, but before the SG inspection activities have been completed. Please note the following list of discussion points during this call.

1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.

3. Discuss any exceptions taken to the industry guidelines.

4. For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100% of dents/dings greater than 5 volts and a 20% sample between 2 and 5 volts), and the expansion criteria.

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide a summary of the number of indications identified to-date for each degradation mode (e.g.,

number of circumferential primary water stress corrosion cracking indications at the expansion transition). For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

6. Describe repair/plugging plans.

7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).

8. Discuss the following regarding loose parts:

$ what inspections are performed to detect loose parts

$ a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known)

$ if the loose parts were removed from the SG

$ indications of tube damage associated with the loose parts

9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessing deposit loading, etc).

10. Discuss any unexpected or unusual results.

11. Provide the schedule for steam generator-related activities during the remainder of the current outage.

The NRC staff will document a summary of the conference call, including any material that you provide to the NRC staff in support of the call.

Siva P. Lingam U.S. Nuclear Regulatory Commission Project Manager (NRR/DORL/LPL2-2)

Sequoyah Nuclear Plant Location: O8-D5; Mail Stop: O8-G9a Telephone: 301-415-1564; Fax: 301-415-1222 E-mail address: siva.lingam@nrc.gov