ML102980282

Email, Request for Additional Information Results of the Fall 2009 Steam Generator Tube Inspections

ML102980282
Person / Time
Site:	Diablo Canyon
Issue date:	09/27/2010
From:	Wang A Plant Licensing Branch IV
To:	Parker L, Wang A Pacific Gas & Electric Co, Plant Licensing Branch IV
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC ME3995
Download: ML102980282 (2)

Text

From: Wang, Alan Sent: Monday, September 27, 2010 10:54 AM To: Wang, Alan; 'Parker, Larry M' Cc: 'Baldwin, Thomas (DCPP)'; Lyon, Fred

Subject:

RE: Unit 2 SG Reort Tom and Larry, By letter dated May 5, 2010 (Accession Number ML101330269), Pacific Gas and Electric Company (the licensee), submitted information summarizing the results of the fall 2009 steam generator tube inspections performed at Diablo Canyon Power Plant. The US Nuclear Regulatory Commission (NRC) staff has determined that the following additional information is needed to complete its review of the subject report. This request was discussed with Larry Parker of your staff on September 23, 2010, and it was agreed that a response would be provided within 60 days of receipt of this email. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1445 or via e-mail at Alan.Wang@nrc.gov.

REQUEST FOR ADDITIONAL INFORMATION

1. Please provide the following information pertaining to your steam generators (SGs):

• Tubesheet map depicting the row and column numbers

• Sketch of the SG depicting the tube support naming convention

• The thickness of the tubesheet with and without cladding

• Tube support plate material and thickness

• U-bend support material and design

• Steam generator fabricator

• Tube manufacturer

• Tube pitch

• Method and extent of tube expansion within the tubesheet (e.g., hydraulic)

• Tube support plate hole configuration (e.g., quatrefoil shaped openings)

• Extent to which any tubes were stress relieved following bending

• Smallest U-bend radius and associated tube row

2. On page 4 of your May 5, 2010 letter, it states that 12 tubes were reported with proximity indication signals in the U-bend region. Please identify the tubes and discuss the cause of the indications.

3. Please clarify what the trough region is that is referenced in Section g.3.3 of your May 5, 2010 letter.

If you have any questions, please contact me at (301) 415-1445.

Alan Wang Project Manager (Diablo Canyon)

Nuclear Regulatory Commission

Division of Operating Reactor Licensing Alan.Wang@NRC.gov Tel: (301) 415-1445 Fax: (301) 415-1222 E-mail Properties Mail Envelope Properties (E40997F5463E5D4F997D8ECC42D100190AF14789EE)

Subject:

RE: Unit 2 SG Reort Sent Date: 9/27/2010 10:53:34 AM Received Date: 9/27/2010 10:53:00 AM From: Wang, Alan Created By: Alan.Wang@nrc.gov Recipients:

Alan.Wang@nrc.gov (Wang, Alan)

Tracking Status: None LMP1@pge.com ('Parker, Larry M')

Tracking Status: None TRB1@pge.com ('Baldwin, Thomas (DCPP)')

Tracking Status: None Fred.Lyon@nrc.gov (Lyon, Fred)

Tracking Status: None Post Office:

HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 16847 9/27/2010 Options Expiration Date:

Priority: olImportanceNormal ReplyRequested: False Return Notification: False Sensitivity: olNormal Recipients received: