05000321/FIN-2012002-01
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Failure to Assess and Manage the Increase in Risk When Removing Residual Heat Removal and Core Spray from Service |
| Description | A self-revealing non-cited violation (NCV) of 10 CFR 50.65(a)(4) became apparent during the Unit 1 refueling outage when the residual heat removal shutdown cooling discharge valve, 1E11-F017B, failed to open electrically from the control room. The inspectors subsequently determined, on February 17, 2012, the licensee had failed to assess the increase in risk to the plant prior to hanging a tag-out which removed reactor coolant system injection capability from all four residual heat removal pumps and both core spray pumps. This resulted in an unplanned Orange risk condition for Unit 1 versus the previously assessed Green risk condition. The licensee removed the tag-out and restored operation of residual heat removal pump and core spray pump discharge valves to electrically open and restore compliance. This violation has been entered into the licensees corrective action program as condition report (CR) 410382. Failure to perform an adequate risk assessment prior to hanging tagout 1-DT-11- 1E11-00310 and removing residual heat removal and core spray equipment from service is a performance deficiency. The performance deficiency affects the Mitigating Systems Cornerstone and was determined to be more-than-minor because this issue is similar to IMC 0612, Appendix E, example 7e, not minor if the overall elevated risk would put the plant in a higher licensee-established risk category. Because this issue involves the licensees assessment and management of risk associated with performing maintenance activities under shutdown conditions, the inspectors utilized IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, and IMC 0609, Appendix G, Shutdown Operations Significance Determination Process. The Phase 1 screening required a Senior Reactor Analyst (SRA) to perform an independent risk assessment because the licensees shutdown risk assessment involved only qualitative analysis of the plant configuration. A Phase 3 analysis was performed by the regional SRA to characterize the risk associated with the performance deficiency. IMC0609, Appendix K requires performance of a risk analysis for Maintenance Rule issues. The SRA used IMC0609, Appendix G, which is a tool to estimate shutdown risk, to bound the risk of the deficiency. With the water level at the level for fuel transfer, and an exposure time of less than 3 days, the SRA used Worksheet 3 of IMC0609, Appendix G, Attachment 3. The dominant sequence was a loss of inventory, with a failure to line up an alternate source of water. Recovery credit was given for manually opening the valves or using alternate water sources due to the length of time available before fuel damage. The finding was subsequently determined to be Green. This performance deficiency has a cross-cutting aspect in the Decision-Making component of the Human Performance area, because the licensee failed to validate the underlying assumptions and identify possible unintended consequences when hanging tag out 1-DT-11-1E11-00310 and removing residual heat removal and core spray equipment from service. |
| Site: | Hatch  |
|---|---|
| Report | IR 05000321/2012002 Section 1R13 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | E Morris M Coursey C Dykes D Hardage F Ehrhardt |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
| ' | |
Finding - Hatch - IR 05000321/2012002 | |||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Hatch) @ 2012Q1
Self-Identified List (Hatch)
| |||||||||||||||||||||||||||||||||||||