05000285/FIN-2016004-02
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | Technical Specification 2.0.1 requires the unit to be shut down within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> in the event a limiting condition for operation and/or associated action requirement cannot be satisfied because of circumstances in excess of those addressed in the specification. Contrary to the above, the licensee failed to enter Technical Specification 2.0.1 and take the prescribed actions on several occasions when shutdown cooling heat exchanger valves were opened which impacted component cooling water (CCW) flow to the containment air cooling units under certain accident conditions. On May 10, 2016, an unanalyzed condition was discovered during scheduled maintenance on the shutdown cooling heat exchanger valves. As part of the maintenance, HCV-484, Shutdown Heat Exchanger AC-4A Component Cooling Water Outlet Valve, and HCV-481, Shutdown Cooling Heat Exchanger AC-4B Component Cooling Water Inlet Valve, were failed open which rendered both valves inoperable. Under these conditions, with the assumed single failure loss of DC control power during a loss of coolant accident (LOCA), CCW would be allowed to flow through both shutdown cooling heat exchangers, effectively reducing CCW system flow to the containment air cooling units. These conditions are not assumed under plant design basis calculations and placed the plant in an unanalyzed condition. It has not been demonstrated that the CCW system would adequately perform its design function of providing a cooling medium for the containment atmosphere under LOCA conditions with CCW flow diverted through the shutdown cooling heat exchangers. With two containment air cooling units inoperable, Technical Specification 2.4, does not provide an associated action; therefore, Technical Specification 2.0.1 applies. Upon completion of the maintenance activity, both valves were returned to service which eliminated the condition. The licensee conducted an extent of condition review and identified that they had created this unanalyzed condition six times within the last 3 years and had exceeded the Technical Specification 2.0.1 6-hour shutdown action statement on March 8, 2016; April 21, 2016; and May 10, 2016. In addition, the licensee determined this condition was first identified on February 3, 2015, in Condition Report 2015-01388. Procedure TDB-VIII, Equipment Applicability Guidance, Revision 64, incorrectly stated the valves had a required safety function in the open direction. The licensee initiated procedure change EC-68088 on September 26, 2015, to correct the procedure; however, the proposed change did not accurately reflect the safety function of the valves to remain closed for all LOCA conditions. This procedure change was still under review on May 10, 2016. The failure to promptly correct Procedure TDB-VIII was a contributing cause of the violation. The violation is more than minor because it is associated with the configuration control attribute of the Mitigating Systems Cornerstone. On March 8, 2016; April 21, 2016; and May 10, 2016, the plant was placed in a condition prohibited by technical specifications and exceeded the Technical Specification 2.0.1, 6-hour shutdown action statement. This adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. A senior reactor analyst qualitatively determined that this finding was of very low safety significance (Green) for increases in core damage frequency and large early release frequency because of the short exposure time of less than 3 days and because of the low frequency of events where a LOCA with an independent and coincidental loss of DC control power would occur. Therefore, this finding screens to Green. The licensee entered the issue into their corrective action program as Condition Reports 2016-05340 and 2016-04468. |
| Site: | Fort Calhoun  |
|---|---|
| Report | IR 05000285/2016004 Section 4OA7 |
| Date counted | Dec 31, 2016 (2016Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | G Miller J O'Donnell L Brandt P Elkman P Voss S Hedger S Schneider |
| Violation of: | Technical Specification |
| INPO aspect | |
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Finding - Fort Calhoun - IR 05000285/2016004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Fort Calhoun) @ 2016Q4
Self-Identified List (Fort Calhoun)
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