United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for May 2, 2001

                       Headquarters Daily Report

                         MAY 02, 2001

                    REPORT             NEGATIVE            NO INPUT
                    ATTACHED           INPUT RECEIVED      RECEIVED

REGION I                               X
REGION II                              X
REGION III                             X
REGION IV                              X

Licensee/Facility:                     Notification:

Union Electric Co.                     MR Number: H-01-0031
Callaway 1                             Date: 05/02/01
Dockets: 50-483

Subject: Callaway Inspection of Main Feedwater Piping Reveals
         Significant Pipe Wall Thinning


During a Callaway refueling outage that began on April 7, 2001, a
scheduled inspection to assess the effects of flow-accelerated corrosion
(FAC) on the main feedwater (MFW) system revealed numerous areas of
significant degradation. In 1999, following a steam line rupture event,
the licensee revised how MFW was modeled and upgraded their FAC software
to Checkworks, Rev. F.

The inspection of MFW during the current outage was driven by predictions
from the enhanced program. The licensee had anticipated finding
degradation, but not to the extent observed. In response to their
findings and additional industry information, the licensee further
expanded FAC inspections into additional system areas. The results of
these expanded inspections are not yet available.

With regard to MFW, numerous components, primarily 14-inch elbows, in
both the turbine building and reactor building were found to be degraded
to below minimum wall thickness or were expected to degrade below minimum
wall thickness prior to the next scheduled outage. These components were
scheduled for repair or replacement prior to restart. The licensee is
evaluating why a routine FAC program inspection identified high energy
piping degraded beyond expectations and in need of extensive unplanned

This issue is currently being followed by Region IV routine inspection.

Contacts:   William D. Johnson, R-IV/DRP/RPB
            (817) 860-8148
            Email: wdj@nrc.gov

            Ross Telson, NRR/DRIP/REXB
            (301) 415-1175
            Email: rdt@nrc.gov
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