ML12200A246

Email from R. Auluck, NRR to s Cuadradodejesus, NRR Et Al., on DB Containment Crack RAI Abdul-RA

ML12200A246
Person / Time
Site:	Davis Besse
Issue date:	12/14/2011
From:	Rajender Auluck Division of License Renewal
To:	Cuadradodejesus S, Dennis Morey Division of License Renewal
References
FOIA/PA-2012-0121
Download: ML12200A246 (2)

Text

CuadradoDeJesus, Samuel From: Auluck, Rajender '61M 7

Sent: Wednesday, December 14, 2011 10:27 AM To: CuadradoDeJesus, Samuel; Morey, Dennis Cc: Sheikh, Abdul; Lehman, Bryce; Li, Rui

Subject:

DB Containment Crack RAI-abdul-RA.docx Attachments: DB Containment Crack RAI-abdul-RA.docx

Sam, This is a new RAI regarding shied building cracks at Davis Besse.

Thanks, Raj I

"" q

RAI B.2.39-X

Background:

In order to perform a scheduled reactor head replacement, a construction opening was made in the concrete shield building. During hydro-demolition of the concrete shield building, cracks were identified in the 'architectural shoulders' of the shield building. While investigating the extent of the cracking, additional cracks were identified around the shield building. These additional cracks were identified using an Impulse Response (IR) technique and core bores were used to verify the IR results.

Issue:

Extensive cracking in the shield building could affect the of the shield building and may impact its ability to perform its intended functior of extended operation.

Request:

1. Summarize the shield building degradationAhe n expected corrective actions.

2. Explain how the recent plant-specific operating. e: thf',h5ield Building's ability to perform its intended'functions during I*h'e a list of any additional aging *ff #s that may req on this operating experience. 'f",

3. Explain how the recent pla ,xperiEncehwill be incorporated into the Structures Monitoring P-rq lthe curnpnt program will be adequate to manage aging'of thefzhi enperiodiof extended operation, based on this operating.experience;> the f6*l* ing:

rdo Details of testr.pl deterr"i'" he long term effect of the concrete cracks on-tPiotnbl~ityof the. :to car X'*!design flos.

It.

• i~f. tny,o trpair the crackbr_ ie orce the shield building concrete.

Detailed'plans to mp tor the extentvand thickness of cracks, and corrosion of the r6bars over the long ,termi. \ ;.

iv. ýPlans,

, if any, to: rm~de6taIled structural analysis, with explicit modeling of rebar Iracks, and cor" nete, to demonstrate that the shield building will perform its intended 'design function,,Over the long term. This analysis should also consider the effect of shrinkape and environment on the concrete and rebar during the period of extended operation.

4. Identify and explain ' changes to the license renewal application based on the recent plant specific operating experience.