International Atomic Energy Agency
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IAEA Safeguards at the Independent Spent Fuel IAEA Safeguards at the Independent Spent Fuel Storage Installation, Chinshan Nuclear Power PlantStorage Installation, Chinshan Nuclear Power Plant
SGOA3 & SGTS-TND SGOA3 & SGTS-TND 2012/01/242012/01/24
International Atomic Energy Agency2
• Background
• Spent Fuel Transfer & Storage Process
• Safeguards- By- Design
• Safeguards Measures
• Detection of Missing Pins with DCVD
• Summary
TopicsTopics
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• Cinshan nuclear power plants consist of two 636 MWe BWRs which have been in operation over 30 years.
• The spent fuel ponds (SFPs) are nearing the capacity of their storage capability.
• An independent spent fuel storage installation (ISFSI) is under construction with space for 1680 spent fuel assemblies (SFAs).
• The IAEA and TWN authorities are implementing safeguards by-design features and innovative technology which were adopted in the early design stage of ISFSI.
BackgroundBackground
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Spent Fuel Transfer & Storage ProcessSpent Fuel Transfer & Storage Process
Transportable Storage Canister -will be loaded with 56 spent fuel assemblies
TFROD 2.12 mID 1.72 mHt. 5.13 mWt. 46.18 t
TSCOD 1.70 mHt. 4.84 mWt. 16.65 t
Transfer Cask - to convey the TSC from the spent fuel ponds into the VCC.
56 SFAs
AOSSq. foot 4.5 x 4.5 mOD 4.20 mWall thk. 0.35 mHt. 6.03 mWt. 81.20 t
Add On Shield - to provide additional shielding for radiation protection.
Final installation
TSC/SFAs are loaded into
TFR
Vertical Concrete Cask-used for long storage of the spent fuel assemblies
VCCOD 3.45 mID 1.89 mHt. 5.70 mWt. 112.73 t
TSC/SFAs are loaded into
VCC
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Spent Fuel Transfer & Storage Process (cont’d)Spent Fuel Transfer & Storage Process (cont’d)
Tie DownDeconH2 MonitoringShield Lid WeldedPneumatic TestDrainVacuum DryHe PurgePort Cover WeldedHe Leak TestStructure Lid Welded
Shield LidLift upWashDrain
Fuel Loading
TFR/TSC Preparation
TFR ImmersingPositioning
VCC ReadyAdapter ReadyTFR LiftingTie DownTSC TransferVCC Closed
VCC Moving
ISFSI
Transfer
Day-11
Day-12 Day-13/14
Day-1/2/3
Day-3
Day-4/5/6Day-7 Day-
7/8/9/10
Storage monitoring
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• Two important features were incorporated in early design stage of the ISFSI;
1. Innovative Digital Cerenkov viewing device (DCVD) technology to perform SF verification for PD. 2. Unique dual sealing arrangement to address all credible diversion scenarios.
• Reduction of field efforts to a minimum level was an important factor in the design process.
• According to Agency requirements: LWR spent fuel assemblies considered as easily dismantle are due to partial defect (PD) verification when transferred to difficult to access conditions, in order to assure that at least half of the fuel rods are present.
• Continuity of knowledge (CoK) will be maintained by means of containment and surveillance during the SF transfer process.
Safeguards- By- DesignSafeguards- By- Design
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Safeguards MeasuresSafeguards Measures
Tie DownDeconH2 MonitoringShield Lid WeldedPneumatic TestDrainVacuum DryHe PurgePort Cover WeldedHe Leak TestStructure Lid Welded
Shield LidLift upWashDrain
Fuel Loading
TFR/TSC Preparation
TFR ImmersingPositioning
VCC ReadyAdapter ReadyTFR LiftingTie DownTSC TransferVCC Closed
VCC Moving ISFSI
Transfer
Day-11
Day-12Day-13/14
Day-1/2/3
Day-3
Day-4/5/6Day-7 Day-
7/8/9/10
Storage monitoring
UW cam
InspectorSeals on the VCC Dual seals
Surveillance in reactor hole (RH)
Surveillance in transfer hatch
Inspector
SDIS A (main)
SDIS B (back up)
Inputs From UW& reactor building cameras
Remote Monitoring (RM)
Spent fuel is verified by DCVD for PD prior to loading
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Safeguards Measures (cont’d)Safeguards Measures (cont’d)
•The VCC is the containment for the spent fuel - for safeguards purposes - on which the dual seals are applied.
•The top cover of the VCC in conjunction with AOS side walls are the components to be sealed and immobilized to the concrete pad.
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Detection of Missing Pins with DCVDDetection of Missing Pins with DCVD
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• The Cerenkov light emitted from SFA is recorded as a digitized image.
• PDT is performed in real time by quantitative analysis of the Cerenkov light pattern with custom software (DCView).
• Cerenkov light intensity emitted from SFA is a function of burn up (BU) and cooling time (CT). Pin substitution by un-irradiated dummies leads to a decrease of light intensity, pin removal to an increase.
International Atomic Energy Agency
Detection of Missing Pins with DCVD (cont’d)Detection of Missing Pins with DCVD (cont’d)
• Missing pins lead to high intensity spots on Cerenkov light image.
• Missing pins are detected and marked by an automated analysis in DCView based on local intensity comparison with fuel template.
• DCView software performs comparison between measured Cerenkov light intensity and expected intensity values calculated from declared BU and CT.
• Off-line re-evaluation is possible.
Missing pins
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SummarySummary Safeguards-by-design features and a process by which
they were successfully incorporated in the design phase, have been introduced.
Innovative DCVD technology for PD verification of SF, prior to its shipment to difficult to access conditions, has been presented.
Unique dual sealing arrangement to maintain CoK on SF which is stored in difficult to access conditions, has been presented.
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Thank you for your attentionThank you for your attention
Any questions?Any questions?
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