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.
- 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)
- 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@exeloncorp.com)
by 7/1/2011. Responses will be collected and a summary will be sent
out to all respondents
Thanks for your help