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Industry SNM Operating Experience. Tom Morello and Nicole Walker Constellation Energy. Overview. Introduction SNM Operating Experience Cause Compliance Conclusion. Incore Detector Containing Special Nuclear Material Inappropriately Released From Storage (OE24386). February 12, 2007 - PowerPoint PPT Presentation
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Industry SNM Operating Experience
Tom Morello and Nicole WalkerConstellation Energy
Overview
Introduction SNM Operating Experience Cause Compliance Conclusion
2
Incore Detector Containing Special Nuclear Material Inappropriately
Released From Storage (OE24386)
February 12, 2007 Event:• Maintenance removed an incore detector from its
storage location without prior notification to Radiation Protection.
• The incore detector contained SNM, but there were no labels signifying this on the detector storage area.
• The area housing the detector was controlled with a Radiation Protection key.
3
Incore Detector Containing Special Nuclear Material Inappropriately
Released From Storage (OE24386)
Event Continued:• Assumed that detector was not under RWP control
(not labeled SNM) Causes:• SNM storage areas not labeled, but required by
procedure• The supervisor of storeroom maintained a key which
RP should have had instead
4
Incore Detector Containing Special Nuclear Material Inappropriately
Released From Storage (OE24386)
Ensuring Compliance:• Label SNM storage areas• Train personnel about SNM storage and
accountability (Radiation Protection, Security, etc)• Ensure SNM is stored separately from other
non-SNM materials
5
Inadequte Control of Special Nuclear Material Located Outside Protected
Area (OE29504)
December 6, 2008 Event:• An intermediate range nuclear instrument detector
was found in a storage area outside the plant’s Protected Area, but within the Owner Controlled Area.
• The detector contained about 7.12 g of U-235• The SNM custodian understood SNM requirements:
– Stored in a locked, radiologically-controlled area6
Inadequte Control of Special Nuclear Material Located Outside Protected
Area (OE29504)
Event Continued:• SNM custodian unaware SNM required by
procedure to be in Protected Area (PA)• Security review of procedures in 2009 led to
discovery of the source’s location• The SNM was relocated inside the PA and tamper-
indicating tape was placed on container Cause:• Procedure for SNM Control- inadequate
7
Inadequte Control of Special Nuclear Material Located Outside Protected
Area (OE29504)
Ensuring Compliance:• Correct procedure use• Procedure should only allow storage of SNM in
ICA’s in the protected area
8
Loss of Accountability of Less Than 1 Gram of SNM (OE24760)
April 4, 2007 Event:• In 1990, an assembly was disassembled for rod
inspections• One of the rods was confirmed failed, but bent and
snapped while in fuel inspection funnel.• A bucket placed under the broken fuel rod segments
contained small dark particles and a small piece of material
9
Loss of Accountability of Less Than 1 Gram of SNM (OE24760)
Event Continued:• The small piece of material was suspected to be less
than 10% of a single pellet’s worth (less than 1 gram).
• Greater than 400 Rad/hr on contact- most likely a piece of fuel pellet
• The bucket and its contents were hung on a wall in the Spent Fuel Pool
10
Loss of Accountability of Less Than 1 Gram of SNM (OE24760)
Event Continued:• The next refueling outage, the bucket was knocked
into the pool resulting in a loss of control of licensed material.
• This was reportable under 10CFR20.2201 Causes:• Not understanding the requirements for tracking less
than 1 gram of SNM
11
Loss of Accountability of Less Than 1 Gram of SNM (OE24760)
Ensuring Compliance:• Understand reporting requirements for all SNM• Do not use an open container, like a bucket, to store
SNM
12
Reportable Quantity of SNM Was Not Being Reported (OE29634)
August 4, 2009 Event:• Audit showed the Plutonium-Beryllium(PuBe)
source was not being reported on the annual NRC form 742.
• The source had material type 83 (Pu-238).• The source contained 0.33 g of Pu-238. Type 83
material should have been tracked to the nearest 0.1g (NuReg/BR-0007)
13
Reportable Quantity of SNM Was Not Being Reported (OE29634)
Event Continued:• There was no form 741 because there was less than
1.0 g of SNM. • Radiation Protection manuals processed the receipt
of the source; documentation is limited• The source was tracked and verified semiannually.• A form 741 will be generated, and the source will be
added to the yearly Material Balance Report.
14
Reportable Quantity of SNM Was Not Being Reported (OE29634)
Cause:• Lack of understanding of tracking and reporting of
requirements of material type 83. Ensuring Compliance:• Report type 83 material to nearest 0.1g.• Ensure understanding of material types in any
sources on site.
15
Special Nuclear Material Reporting Requirements Not Met on Reactor
Vessel Head (OE25343)
June 19, 2009 Event:• Comanche Peak agreed to notify NMMSS within 30
days of plant start up of it’s new Japanese reactor vessel head.
• Because part of the vessel head was made in Japan, CPNPP had new SNM tracking requirements.
• After 59 days of operation, there was still no report on the change in obligations.
16
Special Nuclear Material Reporting Requirements Not Met on Reactor
Vessel Head (OE25343)
Event Continued:• CPNPP also discovered errors in their obligation
codes for the fuel that was in the core.• Upon agreement between NMMSS, Reg Affairs, and
the NRC, CPNPP had to submit the corrections from the fuel receipt, and then submit the Japanese obligation.
Causes:• Errors in tracking and documenting SNM
17
Special Nuclear Material Reporting Requirements Not Met on Reactor
Vessel Head (OE25343)
Ensuring Compliance:• Report head obligation material in accordance with
the agreement with the NRC.
18
Plutonium and U234/U235 Sources Not Tracked by the SNM Program
(OE24419)
February 2, 2007 Event:• Radiation Protection asked to identify any non-fuel
SNM.– Discovered 14 electroplated Pu-239 disk sources and 6
U234/U235 sources• RP procedures require inventory every 3 months, so
the detectors were accounted for and controlled as licensed material
19
Plutonium and U234/U235 Sources Not Tracked by the SNM Program
(OE24419)
Event Continued:• The sources were never part of the SNM inventory
(already inventoried by RP procedures)• All non-fuel SNM are required to be included in the
SNM inventory Causes:• Lack of understanding of the SNM reporting
requirements for non-fuel SNM.
20
Plutonium and U234/U235 Sources Not Tracked by the SNM Program
(OE24419)
Ensuring Compliance:• Update procedures to include any sources (even
ones owned by RP) in the SNM physical inventory.• Incorporate RP so that they report SNM inventory to
the SNM custodian.• Track check sources (either SNM custodian or RP)
21
Special Nuclear Material Inventory Error (OE24314)
February 6, 2007 Event:• Failed source range monitors, intermediate range
monitors, and TIP detectors were stored in a designated location in Radwaste Building
• In November 2000, a non-irradiating traversing in-core probe (TIP) was documented as being in storage drum 471 with tamper proof seal.
22
Special Nuclear Material Inventory Error (OE24314)
Event continued:• A source range monitor (SRM) documented to be in
a drum numbered 742 with tamper proof seal.• Storage drum 742 was shipped off-site.• Reactor engineering was performing inventory and
noticed that the TIP detector was not in its specified location in the SNM Inventory Account.
• A radioactive material bag labeled “TIP cables” was found in drum 471, instead.
23
Special Nuclear Material Inventory Error (OE24314)
Event Continued:• The tamper proof seal on drum 741 was not
breached from 2000-2007.• A radioactive material bag labeled SRM cable had
an SRM. The SRM was not included in the annual inventory.
Cause:• Site personnel relied on the description and date of
the RAM tag to identify the contents.24
Special Nuclear Material Inventory Error (OE24314)
Ensuring Compliance:• Follow procedures and SNM inventory requirements• Update procedures to label/tag storage areas better.• Do not rely on tags/labels
25
Tamper Indicating Devices on Detector Storage Containers Inadequate
(OE25059)
June 14, 2007 Event:• An NRC Material Control and Accountability Audit
performed.• Locks on storage areas for fission chambers not
adequate.• A controlled key is not an acceptable substitute even
though site personnel argued the locks would have to be physically broken for an unapproved access.
26
Tamper Indicating Devices on Detector Storage Containers Inadequate
(OE25059)
Ensuring Compliance:• Install tamper evident devices on storage containers
used to store non-exempt detectors• Perform a piece count of the detectors.
27
Special Nuclear Material Movement Authorization Sheet did not Specify Correct
Location for Fuel Assembly in SFP During MPC Loading (OE29837)
June 25, 2009 Event:• After first ISFSI campaign, there were
supplemental moves that needed to be done before the 2nd loading.
• The supplemental moves were not completed until a week later, so only the first ISFSI loading move sheets were updated in the fuel accountability database.
28
Special Nuclear Material Movement Authorization Sheet did not Specify Correct
Location for Fuel Assembly in SFP During MPC Loading (OE29837)
Event continued:• The second cask loading move sheets were issued
without first completing the supplemental moves.• The supplemental moves were completed that same
day, as was the database.• During the 2nd cask loading, the fuel handling
supervisor noticed that there was not an assembly in the location specified by the move sheet.
• Work stopped until the issue was resolved.29
Special Nuclear Material Movement Authorization Sheet did not Specify Correct
Location for Fuel Assembly in SFP During MPC Loading (OE29837)
Event Continued:• The SFP map was accurate, not the move sheets for
the 2nd cask loading. Cause:• Move sheets were made before the previous set of
move sheets were retrieved and used to update the fuel accountability database.
30
Special Nuclear Material Movement Authorization Sheet did not Specify Correct
Location for Fuel Assembly in SFP During MPC Loading (OE29837)
Ensuring Compliance:• Procedures should allow only one set of move sheets
at a time (except for core alterations)• Update database before planning more moves.• Require that all move sheets be returned to the SNM
custodian at the end of shift for database updates (except for core alterations)
• Use a database or procedure that ensures plant configurations are up to date.
31
Special Nuclear Material Inventory Discrepancy (OE29563)
July 22, 2009 Event:• A SFP cleanup campaign held in February 2005. It
staged detectors into a shipping cask for disposal. No LPRM canisters were shipped offsite.
• An unirradiated local power range monitor detector was expected to be stored in a canister in a SFP drum.
• The detector continued to be on the SNM inventory32
Special Nuclear Material Inventory Discrepancy (OE29563)
Event continued:• The detector could not be located during an SNM
inventory. • SNM Tracking Sheet STS-1-14-21 showed the
detector being shipped to Barnwell, SC in February 2005.
Causes:• Assuming the detector was stored in the detector
canister. 33
Special Nuclear Material Inventory Discrepancy (OE29563)
Ensuring Compliance:• Adhere to procedure to properly store SNM in
identifiable containers.
34
35
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