05000410/FIN-2014004-01
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Finding | |
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| Title | Loss of Secondary Containment due to Loss of Auxiliary Boiler System |
| Description | The inspectors identified a Green finding (FIN) of CNG-PR-1.01-1005, Control of Technical Procedure Format and Content, Revision 00500, because Exelon Generation Company, LLC (Exelon) provided Unit 2 operators with an inadequate auxiliary boiler system operating procedure. Specifically, N2-OP-48, Auxiliary Boiler System, Revision 01100.00, did not provide operators adequate detail to properly establish chemistry requirements for water conductivity of the auxiliary boiler system. On March 23, 2014, when Unit 2 experienced a trip of the auxiliary boiler system due to inadequate water conductivity, operators became challenged with system restoration which caused an unplanned loss of secondary containment and entry into Technical Specification (TS) 3.6.4.1, Secondary Containment. Exelon generated condition report (CR)-2014-002281 regarding this issue. Immediate corrective actions included updating chemistry requirements associated with auxiliary boiler procedures, implementing new preventive maintenance (PM) strategies for significant components associated with the auxiliary boilers, and implementing new performance monitoring plans. This finding is more than minor because it affected the procedure quality attribute of the Barrier Integrity cornerstone and affected the cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, over the past 2 years, the auxiliary boilers have experienced trips as a result of insufficient procedural guidance. On March 23, 2014, the inadequate procedural guidance resulted in a trip and subsequent loss of reactor building (RB) differential pressure (DP). This caused an unplanned entry into the secondary containment emergency operating procedure and an unplanned entry into TS 3.6.4.1, which presented unnecessary challenges and distractions to operators during a planned downpower. In accordance with IMC 0609.04, Initial Characterization of Findings, the inspectors used IMC 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power, because secondary containment was declared inoperable following a loss of building heating. Using Appendix A, Exhibit 3, Barrier Integrity Screening Questions, Section C, Control Room, Auxiliary, Reactor, or Spent Fuel Pool Building, the inspectors determined that this finding is of very low safety significance (Green) because although the performance deficiency resulted in a trip of the auxiliary boiler system and a loss of secondary containment, the RB DP was restored to greater than 0.25 inches of water, within the allowable limiting condition for operation time, and did not result in a failure of the ability for secondary containment to maintain isolation or impact the ability for standby gas treatment system to maintain secondary containment. This finding has a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not ensure personnel, equipment, procedures, and other resources were available and adequate to support nuclear safety. Specifically, the inadequate management oversight of the auxiliary boilers resulted in numerous failures of the auxiliary boilers due to inadequate knowledge transfer, inaccurate classifications of maintenance rule functional failures for the system, inadequate procedures for boiler operation, and inadequate procedures for the prompt restoration of secondary containment when the auxiliary boiler system is not available [H.1]. |
| Site: | Nine Mile Point  |
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| Report | IR 05000410/2014004 Section 4OA3 |
| Date counted | Sep 30, 2014 (2014Q3) |
| Type: | Finding: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | C Graves D Lawyer D Schroeder E Burket E Miller G Stock K Kolaczyk O Masnyk Bailey |
| CCA | H.1, Resources |
| INPO aspect | LA.1 |
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Finding - Nine Mile Point - IR 05000410/2014004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Nine Mile Point) @ 2014Q3
Self-Identified List (Nine Mile Point)
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