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On December 15, 2009, Callaway Plant reported a condition in which valve FBV0146, an isolation valve on an auxiliary steam line in the Auxiliary Building, was found to be kept normally open. With FBV0146 open, the auxiliary steam line downstream of FBV0146 must be considered a high energy line. This configuration was not consistent with the analysis of record for High Energy Line Break (HELB) events. Valve FBV0146 was closed upon discovery of the condition. This condition was reported under EN # 45571 as an unanalyzed condition that significantly degrades plant safety. EN #45571 was then retracted on January 21, 2010 when analysis showed that no safety-related components would be rendered inoperable in a postulated HELB event due to the condition. Based on this analysis, FBV0146 was reopened. Subsequent review of this condition now shows that, with FCV0146 open, a harsh environment from a postulated HELB downstream of FBV0146 could be transmitted to other areas of the Auxiliary Building. This would occur via a flow path through door gaps and an Auxiliary Building elevator shaft. This flow path had not been considered by the previous analysis. The areas that could be affected by a postulated line break contain safe shutdown equipment (such as equipment for the Component Cooling Water system) that is not assumed to experience harsh conditions. Because of the potential impact on this equipment, this condition is considered to have met the criteria for reporting under 10 CFR 50.72(b)(3)(ii)(B). FBV0146 is now closed. This review was performed as part of the ongoing evaluation of HELB Program deficiencies described in Callaway Plant License Event Report (LER) 2010-009-00. The NRC Resident Inspector has been notified. The auxiliary steam line in the Auxiliary Building feeds non-safety related components.

• * * UPDATE AT 1519 EDT ON 4/8/11 FROM KEITH DUNCAN TO S. SANDIN * * *

The licensee is retracting this report based on the following: On 02/07/2011, EN #46597 documented that a harsh environment from a postulated High Energy Line Break (HELB) could be transmitted to areas of the Auxiliary Building not qualified for harsh environments. This break was postulated to occur on an Auxiliary Steam line downstream of valve FBV0146 when FBV0146 is open. This condition was initially reported as an unanalyzed condition that significantly degraded plant safety. When EN #46597 was reported, the analysis of the Auxiliary Steam line included postulated break locations at any intermediate fitting, welded attachment, or valve. Subsequent analysis shows that this section of Auxiliary Steam piping is able to withstand safe shutdown earthquake (SSE) loadings and rupture loadings. For piping of this qualification, line breaks are only assumed to occur at terminal ends and at the locations specified for ASME Class 2 and 3 piping. Breaks at intermediate fittings, welded attachments, and valves are not required to be assumed. Postulated breaks of this Auxiliary Steam line at the locations described above have been analyzed. This analysis demonstrates reasonable assurance that safety-related equipment would have performed their safety functions following a postulated break of this Auxiliary Steam line. Therefore, this condition is not an unanalyzed condition that significantly degrades plant safety and does not meet the reporting requirements of 10 CFR 50.72(b)(3)(ii)(B). Event notification #46597, made on 02/07/2011, is hereby retracted. The NRC Resident Inspectors have been notified. Notified R4DO (O'Keefe).