05000318/FIN-2004008-01: Difference between revisions
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{{finding | {{finding | ||
| title = Failure | | title = Failure to Adequately Implement Modification Design Review of the Reactor Regulating System Quick Open Circuit | ||
| docket = 05000318 | | docket = 05000318 | ||
| inspection report = IR 05000318/2004008 | | inspection report = IR 05000318/2004008 | ||
| Line 12: | Line 12: | ||
| identified by = NRC | | identified by = NRC | ||
| Inspection procedure = IP 93812 | | Inspection procedure = IP 93812 | ||
| Inspector = A Blamey, E Cobey, J Richmond, J Schmidt, M Giles, S Barrn, Securit | | Inspector = A Blamey, E Cobey, J Richmond, J Schmidt, M Giles, S Barrn, Securit | ||
| CCA = N/A for ROP | | CCA = N/A for ROP | ||
| INPO aspect = | | INPO aspect = | ||
| description = A self-revealing event identified a finding of low to moderate safety significance, because Calvert Cliffs Nuclear Power Plant (CCNPP) did not perform a modification design review, as required by station procedures. Following a Unit 2 reactor trip on January 23, 2004, the atmospheric dump valves and turbine bypass valves automatically Quick Opened, as designed. However, the Quick Open signal did not clear when the reactor coolant temperature dropped below the Quick Open setpoint, because of a reactor regulating system relay failure. As a result, an uncontrolled cooldown of the reactor coolant system occurred, which in turn caused a loss of the normal heat removal system. This finding was more than minor because it was considered to be a precursor to a more significant event. A Significance Determination Process Phase-3 risk analysis determined that this finding was of low to moderate safety significance, based on the change in core damage frequency. | | description = A self-revealing event identified a finding of low to moderate safety significance, because Calvert Cliffs Nuclear Power Plant (CCNPP) did not perform a modification design review, as required by station procedures. Following a Unit 2 reactor trip on January 23, 2004, the atmospheric dump valves and turbine bypass valves automatically Quick Opened, as designed. However, the Quick Open signal did not clear when the reactor coolant temperature dropped below the Quick Open setpoint, because of a reactor regulating system relay failure. As a result, an uncontrolled cooldown of the reactor coolant system occurred, which in turn caused a loss of the normal heat removal system. This finding was more than minor because it was considered to be a precursor to a more significant event. A Significance Determination Process Phase-3 risk analysis determined that this finding was of low to moderate safety significance, based on the change in core damage frequency. | ||
}} | }} | ||
Latest revision as of 19:31, 20 February 2018
| Site: | Calvert Cliffs  |
|---|---|
| Report | IR 05000318/2004008 Section 4OA5 |
| Date counted | Jun 30, 2004 (2004Q2) |
| Type: | Finding: White |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 93812 |
| Inspectors (proximate) | A Blamey E Cobey J Richmond J Schmidt M Giles S Barrn Securit |
| INPO aspect | |
| ' | |