ML14071A248

Email from G. Dentel, NRC to Debbie Grinnell, Explanation of IWE Requirements - Seabrook 2012

ML14071A248
Person / Time
Site:	Seabrook
Issue date:	02/26/2014
From:	Glenn Dentel Reactor Projects Branch 3
To:	Grinnell D - No Known Affiliation
DENTEL, GT
References
Download: ML14071A248 (1)

Text

From: Dentel, Glenn Sent: Wednesday, February 26, 2014 10:44 AM To: debbie@c-10.org

Subject:

Explanation of IWE requirements - Seabrook 2012 Ms. Grinnell, You left a voice mail with questions regarding the inspection of the containment liner and requirements of ASME IWE. I discussed this with Mel Gray and Tim OHara, the DRS inspector who conducted the inspection in 2012. The report described that during the fall 2012 Seabrook refueling outage, the licensee conducted an ultrasonic (UT) exam of a 1 by 1 area on the inside of the containment liner at elevation minus 26 foot and at approximate azimuth of 317.5 degrees. The UT identified this area to have a liner thickness of 0.375 and no indication of coating degradation, and no indication of exterior liner degradation. WO number 40185220-01 documented these results.

Mr. OHara noted the following:

1) This test was an augmented examination and was not part of the ASME baseline IWE inspection.

2) The required ASME IWE examinations are visual inspections of the coating on the interior of the containment liner. If degradation is observed on the coating during the visual inspection, the conditions are documented and the plant engineers will be required to disposition the observed conditions - UT examinations could be used to examine the liner for the necessary thickness.

3) ASME IWE requires inspection of the accessible surface area of the containment during every 10 year inspection interval. The 10 year interval is further broken down into three, 3 1/3 year periods to spread the inspections out over the life of the plant.

4) The Seabrook containment was fabricated from steel plates with 0.375 thickness. This thickness is sufficient to withstand internal containment pressures. Thus, the 0.375 UT thickness measurements demonstrates that there has been no observed deterioration due to corrosion of the containment liner since original plant construction.

Glenn Dentel Branch Chief responsible for oversight of Seabrook, Salem and Hope Creek 610-337-5233 (w)