ML12088A213

Concrete Degradation - Alkali Silica Reaction

ML12088A213
Person / Time
Site:	Seabrook
Issue date:	07/20/2011
From:	- No Known Affiliation
To:	Office of Information Services
References
FOIA/PA-2012-0119
Download: ML12088A213 (3)

Text

Seabrook Concrete Degradation - Alkali Silica Reaction Status as of July 20, 2011 (essentially no new developments since June 30)

Agenda

• Refresh on Background

1. Licensee Current status

• Licensee Ongoing actions 0 NRC Ongoing Actions

• Summary Refresh on Background

• See attached salient details provided in staff brief to Chairman

• Chairman asked for final operability determination on that brief

• (Conte to Hipschman) Reported NextEra change in plans for final operability determination on or about June 29, 2011 Licensee Current Status

• In the evaluation of other buildings for the extent of conditions review, NextEra found degrade values for the modulus of elasticity; compressive strength numbers improved in comparison to the Control Building/Electrical Tunnel core sample results - NextEra reviewing results from different labs, more core samples are to be taken in the Fall 2011.

• Other Buildings for which concrete core samples taken: Containment Enclosure Building, ECCS Equipment Vault, EFW Building, EDG Building ("B" section);

Radiological Controlled Area Walkway (share walls with Control Building and Waste Process building) a Immediate and Prompt Operability Determination (POD) completed for the review of the results for the five other buildings.

a Currently two open PODs one for CB and one for the other five buildings - Licensing basis not exceeded based on licensee's current calculational methods.

1. Since the ASR has resulted in reduction of elastic modulus of concrete and, in some cases, compressive strength in portions of below grade walls, NextEra has hired contractors to evaluate effects and calculation method potentially producing an updated model for building analysis.

Licensee Ongoing Actions

• Extent of Conditions from Control Building and the Five other building with concrete core samples to date.

• Apparent cause review for the maintenance rule NCV issued by region 1

• Root cause evaluation related to ASR issue

• Periodic operability assessments as information is developed

• Developing a comprehensive test and evaluation plan to manage ASR in response to staff questions (DLR issue latest RAI on June 29, 2011)

" Biweekly status call with regional staff (headquarters tied in as necessary)

Information in this record was deleted in accordance with thP Freedom of I format' Act, exem t'ions_

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NRC Staff Ongoing Actions (Seabrook Specific)

Outside of Scope

• The staff is continuing to review and challenge the licensee's current operability determination - TIA being reviewed

Outside of Scope (3 pages)