05000259/FIN-2011002-01
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Finding | |
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| Title | Loss of Reactor Water Level during Unit 2 Reactor Reassembly due to a Mispositioned Valve |
| Description | A self-revealing non-cited violation of Technical Specifications (TS) 5.4.1.a was identified for the licensees failure to adequately implement operations instruction 2-OI- 74, Residual Heat Removal System, to ensure the reactor cavity draindown flow path was isolated prior to suppression pool draindown. On March 25, 2011, Operations personnel inadvertently left a Residual Heat Removal (RHR) system drain valve in the open position which led to an uncontrolled draindown of the reactor pressure vessel (RPV) coolant to the suppression pool. Operators immediately identified the RPV level decrease and restored the valve lineup and water level. The licensees immediate corrective actions re-emphasized adherence to log keeping and turnover requirements; instituted shift manager challenges on activities that impact key safety functions including assessments of procedures, plant configuration, turnover information, and prejob briefs of personnel roles and responsibilities; and, for those same activities, instituted peer checks, marked up drawings, and supervisory review of completed field copies of procedures. This issue was entered into the licensees corrective action program as problem evaluation report (PER) 344533. This finding was considered more than minor because it was associated with the Human Performance attribute of the Initiating Events Cornerstone and adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown. Specifically, a mispositioned RHR drain valve resulted in a loss of control of the RPV water level. This finding was determined to be of very low safety significance (Green) according to Inspection Manual Chapter (IMC) 0609, Appendix G, Shutdown Operations, because the inadvertent loss in excess of 2 feet (approximately 40 inches) of reactor coolant inventory represented a loss of inventory control. Using IMC 0609, Appendix G, Attachment 3, Phase 2 Significance Determination Process Template for BWR During Shutdown, a Senior Reactor Analyst performed an analysis and determined the loss of inventory event was of very low risk significance (Green) due in part to automatic functions being available to isolate and mitigate the leak had it continued and remained undetected/uncorrected by the operators. The cause of this finding was directly related to the cross-cutting aspect of Work Activity Coordination in the Work Control component of the Human Performance area, because inadequate documentation and communication of plant system configuration by the control room operators resulted in a mispositioned valve and loss of RPV water level [H.3.(b)]. |
| Site: | Browns Ferry  |
|---|---|
| Report | IR 05000259/2011002 Section 1R20 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | A Nielsen C Dykes C Fletcher C Stancil E Guthrie L Pressley M Coursey P Higgins P Niebaum R Hamilton R Patterson S Walker T Ross |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Browns Ferry - IR 05000259/2011002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2011Q1
Self-Identified List (Browns Ferry)
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