ML23075A332
| ML23075A332 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/16/2023 |
| From: | Jack Giessner, Kenneth Kolaczyk NRC/RGN-III, NRC/NRR/DRO/IRAB |
| To: | |
| References | |
| Download: ML23075A332 (15) | |
Text
Palisades Nuclear Plant Trapped in Containment August 6, 2008 Jack Giessner, RIII
Agenda
- The Event
- Special Inspection Team - Insights and Findings
- Lessons Learned - Inspector Safety
- Questions
Anatomy of an Accident
- Accidents are almost always the cumulative result of a chain of apparently minor deviations from known standards, practices, and procedures.
Hop Howlett II, Industrial Operators Guide
- This was an Event, not an Accident, that had many of the accident precursors present
The Event (Background)
- Plant shutdown for maintenance
- Containment entry for visual inspection
- Second entry of the evening to finish inspection
- NRC IP 71111.20 for inspection
The Event (Timeline)
August 5, 2008: 2000 - Reactor shutdown for control rod drive work 2100 First Containment entry for visual inspection, WBGT between 92-98 F
- heat stress index 115 F August 6: 0025 Second entry of the evening to finish inspection (Stay time 30 minutes) 0030 Phone system goes down (unknown to team) 0040 Scaffold team exits, leaves outer door partially open (unknown to team) 0053 Airlock exit not successful 0100 Attempt at phone failed 0115 Escape hatch attempt fails 0130 Partial removal of Anti Cs; water bottle use 0145 Cycle shield cooling pump discharge valve in attempt to notify CR 0155 Another team of scaffolders enters containment and team exits
Personnel Airlock Inner Door
Personnel Airlock Outer Door
Escape Hatch
The Event - Barriers Broken
- Failure to close outer hatch of Personnel Air Lock - lack of procedures; operator aid control
- Phone system down - no backup plan
- Escape hatch failed to operate - material condition; acceptance of deficient issues
- Heat stress control monitor - overall access control
The Event - Barriers Remaining
- Actions to mitigate heat stress - bottled water; removal of Anti-Cs
- Low Dose Area = Cool Area = Area near hatch
- Attempts to signal Control Room
- Timing/Luck - Another Group enters containment Accident does not occur
Special Inspection Team - Insights and Findings
- Containment Access Control - inadequate procedures
- Emergency Escape hatch not being maintained IAW design
- No procedure for operating the hatches +
Training and operator aids ineffective for airlocks
Lessons Learned - Inspector Safety
- High industrial safety risk evolutions
- You CAN ensure your own safety
- Spend time needed to understand the program (even if there is no direct tie to nuclear safety)
- High industrial safety risk programs
- Confined space
- Heat Stress
- Fall Protection
- Electrical Safety
- Heavy Loads
Lessons Learned - Inspector Safety
- Must be able to do your job - and you must be safe
- Think about surrounding and think about worse case contingencies
Next Week:
Callaway Disputed Violation