SNM Industry Peers,
Please review the SNM Inventory event summarized below and respond with
answers to the short Benchmark Survey that follows.
Event Summary
During the Triennial NRC MC&A Inspection, the inspector identified an
error in the Byron 2010 Annual SNM Inventory. The inventory report
misidentified the position of two normally inaccessible storage
locations in the SFP V rack. Inaccessible locations VA05 & VB05 were
mismarked as containing fuel, while VA04 & VB04 which contained fuel
were identified as empty. The error did not impact the inventory result
(ie total piece count).
Error Precursors
Repetitive Actions / Monotony
* The SFP inventory consists of documenting fuel locations in
thousands of pool storage cells. The SFP at Byron is nearly full, and
the monotonous task requires repeated counting of rows and columns in
the racks. A loss of focus resulted in mismarking two locations.
Failed Defenses
Self Check / STAR
* The error originated with the performer in the field. The error
was not detected during the Review step of STAR or during comparison of
the field result with the expected TracWorks configuration. The large
number of assemblies (>2400) made the task susceptible to recording
errors and also made errors difficult to detect.
Peer Check
* The peer check in the field failed to detect the error for
likely the same reason as STAR. A peer check of the comparison with
TracWorks was not performed because it was procedurally not required,
and the peer was not available following the field activity.
1. How does your site document Location/Piece Count
inventories of the SFP?
* Do you markup blank maps or printouts from an
Inventory Control program?
* If using blank maps, do you mark every SFP
location, or just the exceptions? (e.g. Only marking empty cell
locations in a mostly full SFP)
2. What Human Performance tools do you use to ensure an
error free inventory?
* Are both a Performer and Reviewer (Peer Checker)
required for the field activity?
* Do they perform the task Concurrently or
Independently?
* Or is a review only conducted outside of the
RCA?
* Is a copy of the expected configuration
available to the Performer/Reviewer during the field activity?
* Or is the inventoried reconciled with
the expected configuration only after the field activity?
* Is the reconciliation also reviewed
(peer checked)?
Please respond to Jeff Dunlap (jeffrey.dunlap(a)exeloncorp.com) by
7/1/2011. Responses will be collected and a summary will be sent out
to all respondents
Thanks for your help
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