05000346/FIN-2012005-02
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Finding | |
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| Title | Decay Heat Pump Cyclone Separators Incorrectly Installed |
| Description | On December 3, 2012, while servicing the No. 2 DH pump mechanical seal, the licensee identified that the cyclone separator had been installed upside down during a past maintenance activity dating back to May 12, 2012. Additionally, on December 6, 2012, while correcting the orientation of the cyclone separator, licensee mechanical maintenance personnel discovered that spacers were also missing from the inlet and dirty drain lines of the cyclone separator. The spacers are intended to fill unused space between the body of the separator and the tube fittings that connect the tubing. Empty spaces in these areas could collect debris under accident conditions and prevent cooling flow to the mechanical seal. An extent of condition inspection was performed on the No. 1 DH pump on December 14, 2012, which identified the spacers were also missing from the cyclone separators. The most recent maintenance activity on the No. 1 DH pump cyclone separators occurred during the last quarter of 2011, during a mid-cycle outage to replace the reactor vessel closure head. On December 14, 2012, the licensee made a voluntary report to the NRC via telephone regarding the potential impact to the past operability of both DH pumps. A subsequent investigation by the licensee determined the condition did not render the DH pumps inoperable. However, a considerable amount of engineering analysis/judgment was used to predict the consequences of running the DH pumps without seal cooling from the cyclone separators and achieve this conclusion. Based on the expected pump operating conditions during an accident, the licensees analyses concluded that breakage of the seal faces would not occur. As such, leakage out from the pump seals would remain below the allowable leakage rate determined by the licensees design basis calculations. An update was made to the voluntary report to the NRC reflecting this position. The cyclone separator condition was immediately corrected for each pump upon discovery. The licensee has entered the conditions into the CAP and assigned a root cause analysis to CR 2012-18831. Because the licensees root cause analysis was still in progress at the end of this inspection period, the issue is being treated as an unresolved item (URI) pending the inspectors review of the licensees root cause report and completion of the inspectors review of the licensees evaluation into the past operability of the DH pumps. (URI 05000346/2012005-02). |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2012005 Section 4OA7 |
| Date counted | Dec 31, 2012 (2012Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | A Dunlop A Wilson D Kimble D Reeser J Cameron J Laughlin L Jones M Phalen P Smagacz R Walton T Brileya Wilsond Kimble D Reeser E Sanchez J Cameron R Langstaff R Winter S Bell T Briley |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2012005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2012Q4
Self-Identified List (Davis Besse)
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