05000247/LER-2012-002
| Docket Number | |
| Event date: | 02-17-2012 |
|---|---|
| Report date: | 19-11-2012 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2472012002R01 - NRC Website | |
Note: The Energy Industry Identification System Codes are identified within the brackets {}.
DESCRIPTION OF EVENT
On February 17, 2012, during evaluation of the effects of a previous forced maintenance outage on fuel characterization for storage, the Fuel Transfer Form preparer using Technical Specification (TS) 3.7.13 (Spent Fuel Plt Storage) as a reference, recognized an error in the Transfer Form (2-TF-2012-004) that had allowed 11 fresh fuel assemblies (FA) to be moved into the Spent Fuel Pool (SFP) {DB} on January 23 thru 24, 2012. The 11 fresh fuel assemblies were moved into Region 1-1 locations in a face-adjacent location to spent FAs. This configuration was not permitted by TS 3.7.13, which requires empty cells in between the Region 1-1 checkerboard locations of fresh fuel.
Subsequent to discovery of the error, a new Transfer Form was developed and 13 spent FAs in intermediate locations between the fresh FAs in Region 1-1 were relocated away from the locations between fresh FAs. The movement of spent FAs was complete on February 17, 2012 and the TS requirement met. The condition was recorded in the Indian Point Energy Center (IPEC) Corrective Action Program (CAP) as Condition Report CR-IP2- 2012-01019.
TS 3.7.13 provides guidance for loading fresh and spent fuel in the Unit 2 Spent Fuel Pool (SFP). The rules for fuel placement are based on the SFP criticality analysis NET-173-01 (Criticality Analysis for Soluble Boron and Burnup Credit in the Con Edison Indian Point Unit 2 Fuel Storage Racks). The TS for fuel placement are complex due to the assumption that the Boraflex neutron absorber built into the SFP racks degrades over time, which is consistent with industry experience. The Unit 2 SFP is divided into four irregularly shaped Regions (Region 1-1, Region 1-2, Region 2-1, and Region 2 2). In addition to the four regions there are six spe6ial locations known as peripheral locations in Region 2-2 which are treated as suitable for storage of fuel otherwise designated for Region 1-1 or 1-2. These regions are graphically depicted in TS Figure 3.7.13-5. Each one of these regions has its own rules for fuel placement which are identified in the TS.
Both fresh and spent fuel is moved in and out of the SFP, and within the SFP in accordance with Fuel Transfer Forms. The forms are generated using the Shuffleworks computer code and in accordance with the procedural controls of 0-NF-203 (Internal Transfer of Fuel Assemblies and Inserts). The procedure requires review of the applicable TS limitations for each SFP region designated to receive a FA. This procedure requirement appears on a checklist in procedure 0-NF-203 Attachment 3. This attachment is initialed by the preparer and verifier on the Transfer Form. Fresh fuel can only be placed in SFP Regions 1-1 and 1-2, or in the six peripheral locations of Region 2-2. No fresh fuel can be stored in the SFP unless it meets the minimum Integral Fuel Burnable Absorbers (IFBA) requirements identified in the TS Figure 3.7.13-4. Furthermore, for Region 1-1, all fresh fuel must be stored in a checkerboard pattern(i.e., alternating, non-face-adjacent locations) with interstitial locations vacant. The complexity of these differing requirements for fuel placement presents a possible human error trap. The barriers to preclude human error during the high risk activity of creating fuel movement sheets include procedure 0-NF-203, TS 3.7.13, the Shuffleworks program, and the establishment of a strategy for fuel movement. Reactor Engineering (RE) is responsible for identifying the need for a fuel movement campaign and establishes a strategy. RE prepares fuel movement sheets and notifies the Maintenance Fuels Group who schedules support and the plan to execute the moves. Work Orders (W0).are generated for each fuel movement sequence. Upon completion of the fuel moves, Maintenance Fuels Group returns the signed move sheets to RE for Configuration Database update. In the event Maintenance Fuels Group is unable to complete all the moves as planned, they return the fuel movement sheets with the completed moves signed.
The Cause of Event The direct cause was RE move sheets issued in January 2012 were incorrect. The root cause was weak/ineffective use of Human Performance (HP) tools during preparation and verification of the move sheets. Both the preparer and verifier did not review TS 3.7.13 in its entirety. The error was a result of poor self and peer check/review, overconfidence during performance of the task and weak supervisory oversight due to failure to perform a pre-job brief.
Corrective Actions
The following corrective actions have been or will be performed under the Corrective Action Program (CAP) to address the cause of this event.
- A new Transfer Form was developed to move 13 spent fuel assemblies (FAs) away from the locations between fresh FAs to restore the SFP Region 1-1 compliance with TS 3.7.13. Action completed on February 17, 2012.
- Disciplinary action was taken in accordance with plant processes for both the preparer and verifier.
- The qualifications for fuel move development of the preparer and verifier were suspended.
- Performed a HP Engineering department Clock reset and a meeting with Engineering discussing lessons learned and expectations on use of HP tools and compliance with
TS
- Performed a Level 1 HP error review and stand-down to reinforce expectations for TS compliance.
- A training plan was developed for Reactor Engineering (RE) to reinforce expectations of TS compliance and independent verification and self checking.
Event Analysis
The event is reportable under 10CFR50.73(a)(2)(i)(B). The licensee shall report any operation or condition which was prohibited by the plant's TS. This events meets the reporting criteria because on February 17, 2012, RE recognized an error in the Transfer Form (2-TF-2012-004) that had allowed 11 fresh fuel assemblies (FA) to be moved into the Spent Fuel Pool (SFP) on January 23 thru 24, 2012, in Region 1-1 locations in a face-adjacent location to spent FAs. This configuration was not permitted by TS 3.7.13, which requires empty cells in between the Region 1-1 checkerboard locations of fresh fuel. A new Transfer Form was developed to move 13 spent FAs away from the locations between fresh FAs which was completed on February 17, 2012. The SFP was then compliant with the TS requirements as all fresh fuel in Region 1-1 was stored in a checkerboard pattern with vacant cells in the interstitial locations. There was no safety system functional failure as boron concentrations in the SFP were well above the limit to prevent criticality and sufficient water cooling capability was available for the SFP to limit SFP temperature to design.
Past Similar Events
A review was performed of the past three years of Licensee Event Reports (LERs) for events reporting a TS violation due to weak/ineffective use of Human Performance tools. No LERs were identified for actions associated with the SFP or new fuel movements. The following LERs were identified with causes due to inadequate use of Human performance tools: LER-2010-005, and LER-2012-001. LER-2010-005 reported a TS prohibited condition due to discovery of a normally open Control Room Ventilation System inlet damper closed. The apparent cause was Human Performance tools were not applied to ensure work activities did not affect other equipment in the area.
Corrective action was coaching and a brief on lessons learned and management expectations on use of human performance tools. LER-2012-001 reported a TS prohibited condition as a result of a Fuel Oil Storage Tank below the TS required level due to a lack of questioning attitude and understanding by the operations watch station field personnel. Corrective action included coaching on management's expectations on use of Human Performance tools and lessons learned. The coaching actions on use of human performance tools would not have prevented this event as the personnel were different (RE)
Safety Significance
This event had no significant effect on the health and safety of the public. The mis position of FAs did not create a criticality risk due to the minimum TS required boron concentration of the SFP. The SFP criticality analysis (NET-173-01) took credit for a limited amount of boron in the SFP water (786 ppm for limiting region) and allowed for the effects of fuel mis-positioning. The limiting boron concentration in this case (1495 ppm for limiting region) was exceeded by the minimum TS required boron concentration (2000 ppm) and was far exceeded by the actual boron concentration (2300 ppm). A radiation monitor is located in the Fuel Storage Building. The monitor provides continuous indication of the radiation level with high radiation alarm given both locally and in the Control Room.
A vendor analysis of the actual FA configuration for this event was performed. The engineering judgment used above concluding that there was no criticality risk was validated by the vendor analysis. The analysis verified Keff remained less than 0.95 with the TS required boron concentration as required by 10CFR50.68(b)(4).