05000387/LER-2008-001
| Docket Numbersequential Revmonth Day Year Year Month Day Year Susquehanna Steam Electric Station Unit 2Number No. 05000388 | |
| Event date: | 2-5-2008 |
|---|---|
| Report date: | 8-29-2008 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material |
| 3872008001R01 - NRC Website | |
EVENT DESCRIPTION
Susquehanna Unit 1 and Unit 2 Reactor Buildings share a common Refuel Floor. To mitigate the consequences of a fuel handling accident, radiation monitors exist on both units to realign the Reactor Building ventilation system (EIIS Code:
VA) and initiate the Standby Gas Treatment (EllS Code: BH) & Control Room Emergency Outside Air Supply (EIIS Code: VI) Systems if elevated radiation levels are detected. On 1/31/2008, a work order was implemented to defeat the Unit 1 & Unit 2 High Exhaust Radiation Monitors in support of activities on the Refuel Floor. The Exhaust Radiation Monitors are required to be operable during irradiated fuel moves and are defeated during activities which could cause a spurious trip as a result of 'shine'. This information was documented on shift turnover sheets as a potential LCO. Fuel moves were subsequently scheduled to begin on 2/05/2008. Fuel moves were discussed at the Operations morning brief of 2/05/2008. A procedural checklist for fuel handling was completed which recognized the Technical Specification requirement for operability of the radiation monitors. The checklist was completed without confirmation that the Radiation Monitors were operable. At 1700 on 2/05/2008 permission to move fuel was documented in the control room log and then subsequently logged at 1804 that fuel moves were complete for the day. During the oncoming shift turnover that same day it was recognized that the High Exhaust Radiation Monitors were inoperable. The inability of these systems to respond to radiological conditions on the refuel floor constitutes a condition that could have prevented the fulfillment of safety functions needed to control the release of radioactive material and is reportable per 10 CFR 50.73(a)(2)(v)(C). The Control Room alarms and indications for all of these monitors remained operable and actual radiological conditions observed on the refuel floor during the fuel shuffles did not approach levels necessary for system actuation. There were no actual adverse consequences to the fuel, any plant equipment, or to the health and safety of the public as a result of this event.
CAUSE OF EVENT
The root cause for this event was determined to be less than adequate individual performance in the application of operator fundamentals. The on-shift Unit Supervisor (US) received turnover information from the off-going shift that the High Exhaust Radiation Monitors were potential LCOs but did not recognize this as conflicting with fuel moves. Another SRO assigned to fuel moves failed to review the turnover sheet for potential LCOs and perform a system status review as directed during the pre-job brief. The SRO also failed to communicate the desire to have his operability review peer checked.
This event was determined to be reportable under 10 CFR50.73(a)(2)(v)(C) in that the inability of these systems to respond to radiological conditions on the refuel floor constitutes a condition that could have prevented the fulfillment of safety functions needed to control the release of radioactive material.
ANALYSIS/SAFETY SIGNIFICANCE
Actual Safety Significance: Automatic isolation of the Refuel Floor would not have occurred in response to radiation conditions on the floor from the U1 or U2 high exhaust radiation monitors. Both Unit 1 and Unit 2 High Exhaust Radiation Monitors were inoperable during a plant evolution requiring their operability per Technical Specifications. No actual radiological challenge arose during the irradiated fuel movement that necessitated automatic system response. It should be noted that U1 and U2 Refuel Floor Wall Exhaust radiation monitors were operable and would have caused the same automatic initiations as the monitors that had their trip function disabled.
Potential Safety Significance: Defeating the auto initiation and isolation capability provided by the radiation monitors compromises the protection afforded to the general public in the event of an actual fuel handling accident. However, the Control Room alarms and indications for all of these monitors remained operable and would have enabled operators to respond to an actual event.
CORRECTIVE ACTIONS
The following corrective actions have been completed:
- Temporarily increased management oversight to re-enforce operator fundamentals.
- Individual performance deficiencies relative to this event were addressed.
- Revised the Fuel Handling procedure to include a system status file operability check, LCO/TRO & potential LCOTTRO log review, U1 & U2 Unit Supervisor verification, and Shift Manager Review.
The following corrective actions are planned:
- Develop methodology for scheduling risk significant equipment/systems out of service that span more than one week.
- Review and revise Work Management (WM) procedures. Provide training to WM personnel on guidance for risk identification, assessment and management to ensure consistency.
- Review the standards for procedure adherence with WM personnel and include this event in the discussion.
Update terminology in the revised Fuel Handling procedure relative to 'independent review' to coincide with established station standards.
ADDITIONAL INFORMATION
Failed Component Information:
None
Previous Similar Events:
found Racked-Out" Inadequate Maintenance and Inadequate Operability Testing"