ML091690432

Key Messages for Oyster Creek

ML091690432
Person / Time
Site:	Oyster Creek
Issue date:	06/05/2008
From:	- No Known Affiliation
To:	NRC Region 1
References
FOIA/PA-2009-0070
Download: ML091690432 (1)

Text

.*'Key Messages for Oyster Creek Overall, the station continues to demonstrate performance improvement. Areas of interest by

.Tesidents include equipment reliability and technical human performance. Licence renewal and tho AL=SB hoarings are Gignificant 4t9M.6 of oxtonal stakoholdorý ine it.'s Exelon

,I,.considering whether any license renewal commitment changes Sf6 needed, regarding Drywell Sand Bed Inspections, based on outage operating experience?

Oyster Creek Performance Highlights Page.

-5; For two outages in a row (2006 & 2008), there have been issues & difficulties with Leakage Monitoring (sand bed and/or cavity drain).

> Program's first level of defense is to prevent water intrusion into the sand bed region, versus mitigating the consequences of water in the sand bed bays. There is very little history to demonstrate the strippable coating has, been successful to prevent water intrusion, based on inconsistent leakage monitoring prior to 2006.ý

> The 2008 sand bed coatings inspection identified a number of deficiencies, such as blisters, seal cracks, rust stains from seal defects and coating blisters, and an area where the coating appeared to not have the 3rd layer of epoxy applied. The 2006 coatings inspection did not identify any coating or seal deficiencies. However, the blister with rust stain did exist in 2006.

> Based on these observations, sand bed coating inspections (visual & UT) once every 4 years for may not provide the confidence level that was initially intended.

> Number of identified issues in 2008 versus 2006

> Leakage monitoring issues

> Sand bed inspections scheduled to finish and be physically closed out, prior to cavity drain down A potential for un-identified water intrusion, after a sand bed is closed out, ma\,

>exist OUTSIDE OF THE SCOPE