ML101060328

Talking Points

ML101060328
Person / Time
Site:	Crystal River
Issue date:	04/09/2010
From:	- No Known Affiliation
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2010-0116
Download: ML101060328 (1)

Text

TALKING POINTS On October 2, during removal of the containment concrete in preparation for steam generator replacements, Progress Energy discovered a separation 'in the approximately 42-inch-thick concrete wall surrounding the reactor containment liner. The reactor was shut down at the time of discovery.

Region II inspectors are on site performing independent assessments of the overall condition of the containment structure. The inspection results will be discussed at a public meeting and documented in an NRC inspection report.

The NRC will conduct a Special Inspection with inspectors and experts from the Region II office in Atlanta and NRC headquarters in Rockville, Md. It is also likely the NRC will contract one or more independent experts to assist in the inspection.

" The NRC special inspection will continue for several weeks during the plant's outage and the plant will not restart until the agency is satisfied that the analyses and all work completed provide the required safety margin.

• The separation is about one-half inch wide and appears to be located in the concrete about nine inches from the outer surface. No problems have been noted with the steel liner.

" Progress Energy is investigating the extent of the separation or gap and has initiated assessment of the implications. The company is working with company resources as well as experts from independent organizations to analyze and assess the separation.

• The reactor building is designed to serve as one of three barriers protecting the public and environment from radiation exposure.

" The building has a carbon steel liner with a thickness of about three-eighths inch for the cylinder wall and dome, and about one-quarter inch for the base. The steel liner is the primary barrier to a release.

" The 3.5-foot-thick reinforced concrete wall includes a post-tensioning system with steel tendons in a horizontal and vertical lattice structure ensuring that the integrity of the liner is maintained. The separation was found near the horizontal tendons.

• There are 144 vertical tendons and 282 horizontal tendons.

• Each horizontal tendon extends 120 degrees around the cylinder.

• Following construction, the building was subjected to a one-time structural integrity test of 115% of the original design pressure. A containment pressure test that simulates accident pressure conditions was last performed in 2005 and was successful.

• In 1976, Crystal River repaired a concrete delamination, or separation, issue affecting the dome. A containment structural integrity test was successfully performed after the repair.