APR1400-F-C-EC-13008-NP
PLUS7 Fuel Design for the APR1400
1. Improvement of Topical Report
2. Contents of PLUS7 Fuel Design Report
3. Design Features
4. Fuel Assembly Design Evaluation
5. Fuel Rod Design Evaluation
6. Experience and Performance
7. Conclusion
Non-Proprietary
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1. Improvement of Topical Report (1/2)
a. Fuel Performance Codes
NRC approved codes and methodologies were used for fuel performance The applicability of the codes and methodologies were described in detail Used codes : FATES3B, CEPANFL, PAD
b. In-reactor Data
Additional Pool Side Examination(PSE) data for the four Lead Test Assemblies(LTAs) were added
PSE data for the four Commercial Surveillance Assemblies(CSAs) were added
Hot cell data for one LTA were added including cladding hydrogen content evaluation
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1. Improvement of Topical Report (2/2)
c. Test, Inspection and Surveillance Plan
PLUS7 TR describes that the test, inspection and surveillance plan are described in the DCD Tier 2 section 4.2 in detail
d. Seismic/LOCA Analysis
The separate technical report for the Seismic/LOCA events will be submitted with DCD
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2. Contents of PLUS7 Fuel Design Report
1. Introduction
2. Fuel Assembly and Components Design
3. Fuel Rod Design
4. PLUS7 Fuel Experience
5. Conclusion
6. References
Appendix
A. Summary of PLUS7 Fuel Assembly TestsB. Commercial Operating Experiences of KEPCO NF PWR FuelsC. PLUS7 Scram Data VerificationD. PLUS7 Wear Performance Analysis
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A. Overview B. Fuel RodC. Mid GridD. Top NozzleE. Bottom Nozzle
3. Design Features
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3.A Overview (1/4)
PLUS7 Developed for the APR1400 & OPR1000 PWRs
Joint program with Westinghouse Electric Co. (WEC) April 1999 ~ March 2002 Designed/tested at WEC-Columbia, SC
Design Goal
Improvement of fuel performance compared to CE-Guardian Batch average discharge burnup > 55 MWd/kgU Overpower margin > 10% increase Seismic resistance > 0.3g ground acceleration No foreign material-induced and fretting wear-induced rod failure
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3.A Overview (2/4)
More than 2,300 PLUS7 fuel assemblies were loaded as of 2012
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3.A Overview (3/4)
•Guide post, holddownspring, holddown plate and adapter plate remains one piece
•Mixing vanes Enhancing thermal
margin•Straight grid straps Improving Seismic
Resistance•Conformal spring/dimple Reducing GTRF
•Advanced cladding tube ZIRLO tube
•Optimized rod OD STD rod OD
•Axial blanket Improving neutron
economy
• Increasing debris filtering efficiency
•Small hole/slot bottom nozzle
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3.A Overview (4/4)
Item Guardian RFA PLUS7
Cladding Zry-4 ZIRLO ZIRLO
Rod diameter 0.382″ 0.374″ 0.374″
Axial blanket X O O
Mid grid
Spring Cantilever Diagonal Conformal
Dimple Arched Horizontal Conformal
Strap Wavy Straight Straight
Mixing vane X O O
Top nozzle Separated Assembled Assembled
Bottom nozzle Large hole Small hole Small hole & slot
PLUS7 incorporated the proven Guardian structure and the proven Westinghouse type fuel features to improve fuel performance
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3.B Fuel Rod
ZIRLO cladding : advanced material
Variable pitch spring : increase plenum volume
Top & bottom axial blankets : increase neutron economy
Long bottom end plug : protect foreign material induced failure
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3.C Mid Grid (1/2)
ZIRLO : advanced material
Mixing vanes : improve thermal performance
Straight strap : improve strength
Conformal spring & dimple : improve fretting wear resistance
Guide vane & tab : remove hang-up potential
Strap joint : laser welding
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3.C Mid Grid (2/2)
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3.D Top Nozzle
Components : adapter plate instrument housing
holddown springs holddown plate
outer guide posts
Removable top nozzle : possible to reconstruct easily
Top nozzle is jointed to guide thimble by inner extension
TS
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3.E Bottom Nozzle
Small hole bottom nozzle : improve foreign material filtering efficiency
Bottom nozzle is jointed to guide thimble by guide thimble screw
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A. Fuel AssemblyB. Bottom NozzleC. Top NozzleD. Holddown SpringE. Guide ThimbleF. GridG. Joint and Connection
4. Fuel Assembly Design Evaluation
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4.A Fuel Assembly
Item Design CriteriaEvaluation
ResultsRemarks
Rod-to-top nozzle axial clearance
Hydraulic stability
Shipping and handling loads
Mechanical compatibility
TS
The evaluation results for the Seismic/LOCA events are described in a separate technical report.
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4.B Bottom Nozzle
Item Design CriteriaEvaluation
ResultsRemarks
Structural integrity
Prevent rod ejection
Compatibility with the lower support structure
Compatibility with the instrument
TS
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4.C Top Nozzle
Item Design CriteriaEvaluation
ResultsRemarks
Structural integrity
Prevent rod ejection
Compatibility with the upper guide structure
Remote reconstitutability
Compatibility with handling equipment
TS
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4.D Holddown Spring
Item Design CriteriaEvaluation
ResultsRemarks
Holddown force in normal operation
maximum deflection
and solid condition
Holddown spring shear stress
TS
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4.E Guide Thimble
Item Design CriteriaEvaluation
ResultsRemarks
Structural integrity
CEA drop time
TS
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4.F Grid
Item Design CriteriaEvaluation
ResultsRemarks
Fuel rod support
Shipping and handling
Fuel rod fretting wear
Fuel rod bow
Mid grid buckling strength
Grid width
TS
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4.G Joint and Connection
Item Design Criteria Evaluation Results Remarks
Top nozzle / guide thimble
Bottom nozzle / guide thimble
Grid / guide thimble and instrument tube
TS
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A. Fuel Rod Design Codes and Methodology
B. Applicability of Design Codes and Methodology
C. Fuel Rod Design Criteria and Evaluation
5. Fuel Rod Design Evaluation
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NRC-approved codes are used for fuel rod design criteria evaluation
5.A Fuel Rod Design Codes and Methodology (1/3)
Code Design Criteria
FATES3B
Cladding strain/stress
Cladding fatigue
Rod internal pressure
Fuel temperature
CEPANFL Cladding collapse
PADCladding external
oxidation & hydriding
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5.A Fuel Rod Design Codes and Methodology (2/3)
Codes and methodology are described in NRC- approved topical reports FATES3B Code CENPD-139-P-A, C-E Fuel Evaluation Model Topical Report, Combustion
Engineering Inc., July 1974
CEN-161(B)-P-A, Improvements to Fuel Evaluation Model, August 1989
CEN-161(B)-P Supplement 1-P-A, Improvements to Fuel Evaluation Model, January 1992
CEPANFL Code CENPD-187-P-A, CEPAN Method of Analyzing Creep Collapse of Oval Cladding,
Combustion Engineering, Inc., April 1976; Supplement 1-P-A, June 1977
PAD Code WCAP-15063-P-A, Rev. 1, with Errata, Westinghouse Improved performance
Analysis and Design Model(PAD4.0), July 2000
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5.A Fuel Rod Design Codes and Methodology (3/3)
Fuel Rod Burnup of 60 MWD/kgU Application CEN-386-P-A, Verification of the Acceptability of a 1-Pin Burnup Limit of 60
MWD/kgU for Combustion Engineering 16x16 PWR Fuel, August 1992
Rod Internal Pressure Analysis Methodology CEN-372-P-A, Fuel Rod Maximum Allowable Gas Pressure, May 1990
Gadolinia Absorber Application Methodology CENPD-275-P, Revision 1-P-A, C-E Methodology for Core Designs Containing
Gadolinia-Urania Absorbers, May 1998
ZIRLO Cladding Application Methodology CENPD-404-P-A, Rev. 0, Implementation of ZIRLOTM Cladding Material in CE
Nuclear Power Fuel Assembly Designs, November 2001
Collapse Analysis Methodology EPRI NP-3966-CCM, CEPAN Method of Analyzing Creep Collapse of Oval Cladding
Volume 5 : Evaluation of Inter-pellet Gap Formation and Cladding Collapse in Modern PWR Fuel Rods, Combustion Engineering, Inc., April 1985
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5.B Applicability of Design Codes and Methodology (1/12)
NRC SER(Safety Evaluation Report) Compliance
Item Limitations, Restrictions and Conditions(LRC) Compliance
CENPD-275-P Revision 1-P-A “C-E Methodology for Core Designs Containing
Gadolinia-Urania Burnable Absorbers”
1 The gadolinia fuel properties are acceptable for up to 8 weight percent gadolinia concentration
CEN-386-P-A “ Verification of the Acceptability of a 1-Pin Burnup Limit of 60
MWD/kgU for Combustion Engineering 16x16 PWR Fuel”
1 Impacts of cladding changes should be included in these additional evaluations.
2 The stress analyses should include the effects of cladding thinning due to cladding oxidation.
TS
TS
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5.B Applicability of Design Codes and Methodology (2/12)
Item Limitations, Restrictions and Conditions(LRC) Compliance
CEN-161(B)-P Supplement 1-P-A “Improvements to Fuel Evaluation Model”
1
The approval of the fission gas release and fuel thermal expansion model is based on verification of FATES3B predictions against fission gas release data and thermal data that has operated in the ranges of the code’s intended applications andverification that the code inputs are adequatelyconservative for its intended applications
CEN-372-P-A “Fuel Rod Maximum Allowable Gas Pressure”
1
Those licensees referencing this high pressure topical report are required to 1) provide plant-specific LOCA analyses to determine the impact of maximum calculated rod pressures on cladding rupture timing and peak cladding temperatures and 2) provide analyses for DNB propagation in postulated accidents
TS
TS
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5.B Applicability of Design Codes and Methodology (3/12)
Item Limitations, Restrictions and Conditions(LRC) Compliance
CENPD-404-P-A “Implementation of ZIRLOTM Cladding Material in CE Nuclear Power Fuel Assembly Designs”
1 The corrosion limit will remain below 100 microns.
2The fuel duty will be limited for each CENP designed plant
3 The burnup limit for this approval is 60 MWD/kgU.
TS
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5.B Applicability of Design Codes and Methodology (4/12)
Applicability of FATES3B to PLUS7 Fuel Rod Design The FATES3B code applicability extends to all ZIRLO clad and UO2 fuel
pellets currently used in PWRs The main changes of PLUS7 fuel rod compared with GUARDIAN fuel rod
are fuel rod diameter and pellet diameter. The verification data base of FATES3B bounds the PLUS7 fuel rod
diameter.
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Parameters FATES3B D.B PLUS7
Clad OD, in
Clad ID, in
Initial pellet-clad gap, mils
Initial grain size, μm
Initial fuel density, %TD
Fill gas pressure at 70 ℉, psia
Enrichment, % U-235
FATES3B code is applicable to fuel rod design of PLUS7
5.B Applicability of Design Codes and Methodology (5/12)
Comparisons of design parameters between the verification data base and PLUS7 design
TS
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Applicability of FATES3B to the APR1400 Comparisons of irradiation parameters between the verification data base
and the APR1400
5.B Applicability of Design Codes and Methodology (6/12)
DataPeak Local
Power(kw/ft)Rod Average
Burnup(MWD/kgU)
Calvert cliffs
Over-ramp
Petten
IFA-418
RISO
Zorita
BR-3
Super-ramp
DOE ramp
APR1400
TS
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5.B Applicability of Design Codes and Methodology (7/12)
Data Coolant Pressure(psia)Coolant Inlet
Temperature(℉)
Calvert cliffs
Over-ramp
Petten
KWU
IFA-418
Zorita
BR-3
Super-ramp
DOE ramp
APR1400
Comparisons of thermal-hydraulic parameters between the verification data base and the APR1400
TS
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Applicability of CEPANFL to Collapse Analysis of PLUS7 fuel CEPANFL is a computer program to determine the minimum time to collapse
for fuel cladding under expected operating conditions
The CEPANFL is a program based on analytical shell theory, therefore, CEPANFL is independent on fuel rod dimension and pressure difference between rod internal pressure and external pressure
CEPANFL uses the same cladding creep model as that of FATES3B code
CEPANFL code is applicable to collapse analysis of PLUS7 fuel
5.B Applicability of Design Codes and Methodology (8/12)
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Applicability of PAD to Corrosion Analysis of PLUS7 Loaded in the APR1400 Adjustment of PAD corrosion model multiplier (input variable) based on the
measured oxide thickness of ZIRLO cladding at Yonggwang Unit 4 and UlchinUnit 3 (OPR1000)
Verification of PAD code with adjusted corrosion model multiplier using the CSA data of Yonggwang Unit 5 (OPR1000)
Operating conditions of OPR1000 are very similar to those of the APR1400
PAD code is applicable to cladding oxidation evaluation of PLUS7 fuel in the APR1400
5.B Applicability of Design Codes and Methodology (9/12)
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Comparisons of Operating Conditions between the OPR1000 and the APR1400
5.B Applicability of Design Codes and Methodology (10/12)
Parameter OPR1000 APR1400
Coolant inlet temperature(℉)
Coolant outlet temperature(℉)
Coolant mass flow rate (lbm/hr-ft2)
System pressure(psia)
TS
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TS
5.B Applicability of Design Codes and Methodology (11/12)
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TS
5.B Applicability of Design Codes and Methodology (12/12)
Verification of PAD Code with the adjusted corrosion multiplier based on the measured data from Yonggwang unit 5
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5.C Fuel Rod Design Criteria and Evaluation (1/2)
Item Design CriteriaEvaluation
ResultsCodes
Cladding stress
Cladding strain
Cladding fatigue damage
TS
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5.C Fuel Rod Design Criteria and Evaluation (2/2)
Item Design CriteriaEvaluation
ResultsCodes
Cladding oxidation and
hydriding
Rod internal pressure
Cladding collapse
Overheating of fuel pellet
(melting)
Pellet-to-cladding
interaction
TS
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A. Experience B. PSE ResultsC. PIE Results
6. Experience and Performance
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6.A Experience
Commercial Loading of PLUS7 as of 2012
Plant CycleNumber of FAs
Number of FRs
Max. Discharged Burnup
(MWD/MTU)
FA FR
TS
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Burnup Data of PLUS7 LTA and CSA
6.B PSE Results (1/10)
Items 1st Cycle 2nd Cycle 3rd Cycle
TS
LTA: Lead Test AssemblyCSA: Commercial Surveillance Assembly
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Configuration of Fuel Rods in PLUS7 LTAs and CSAs
6.B PSE Results (2/10)
TS
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Core Loading Pattern with PLUS7 LTAs
1st Cycle 2nd Cycle 3rd Cycle
6.B PSE Results (3/10)
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Core Loading Pattern with PLUS7 CSAs
1st Cycle 2nd Cycle 3rd Cycle
6.B PSE Results (4/10)
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Fuel Assembly Growth
FA growth has enough margin up to criteria of mm
Measured FA No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 2 2 2
CSA 4 2 2TS
6.B PSE Results (5/10)
TS
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Grid Width Growth
Upper 2 mid grid widths are shown in the graph Grid width growth has enough margin up to criteria of mm
Measured FA No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 1 1 2
CSA 0 2 2TS
6.B PSE Results (6/10)
TS
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Shoulder Gap
Every fuel rods on the 4 faces were measured Shoulder gap has enough margin up to criteria of zero gap
Measured FA No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 2 2 2
CSA 4 2 2TS
6.B PSE Results (7/10)
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Fuel Rod Channel Closure
Outer fuel rod to rod gaps were measured for every span Fuel rod channel closure has enough margin up to criteria of %
Measured FA No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 2 2 2
CSA 0 2 2TS
6.B PSE Results (8/10)
TS
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Cladding Oxide Thickness
Maximum ZIRLO oxide thickness is Cladding oxide thicknesses are within the limit of 100 μm
Measured FR No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 36 36 36
CSA 0 0 72
TS
6.B PSE Results (9/10)
TS
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Fuel Rod Diameter
Diameters range from Diameter increases are within the strain limit of
Measured FR No. 1st Cycle 2nd Cycle 3rd Cycle
LTA 0 0 8
CSA 0 0 8
TS
6.B PSE Results (10/10)
TS
TS
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Hot cell examinations on selected 6 fuel rods were performed after completing the 3rd cycle operation of PLUS7 LTA, HA03
Ass’y ID Rod IDRod Average
Burnup(MWD/MTU)
Cell Position
HA03
B14 Interior
D15 Interior
D16 Peripheral
A14 Peripheral
K07 Adjacent to IT
C03 Adjacent to GT
6.C PIE Results - Hot Cell Examination (1/9)
TS
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LTA HA03 PositionHot Cell Testing Fuel Rods Position
A B C D E F G H J K L M N P R
1
2
3
4
5
6
7
6 7 5 8
9
10
11
12
13
14
15
A B C D E F G H J K L M N P R
1
2
3
4
5
6
7
2 3 1 8
9
10
11
12
13
14
15
6.C PIE Results - Hot Cell Examination (2/9)
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Fuel Rod Fretting Wear
B14 rod (inner cell rod) shows darker color at contact area than others (A14, C03)
Slice section of dark color area was examinedTS
6.C PIE Results - Hot Cell Examination (3/9)
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Fuel Rod Fretting Wear (continued)
There is no measureable wear on the spring contact area
TS
6.C PIE Results - Hot Cell Examination (4/9)
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Cladding Oxide Thickness
6 fuel rods were measured using Eddy Current Test Maximum circumferential average oxide thickness is around
TS
TS
6.C PIE Results - Hot Cell Examination (5/9)
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Fuel Rod Diameter
6 fuel rods were measured using Linear Variable Differential Transformer Fuel rod diameters range from Very similar to the results of poolside examination
TS
TS
6.C PIE Results - Hot Cell Examination (6/9)
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Cladding Hydrogen Content
Hydrogen contents of 3 samples were measured Hydrogen contents of PLUS7 LTA fuel rods are bounded by the overall ZIRLO
cladding database
TS
6.C PIE Results - Hot Cell Examination (7/9)
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Cladding Hydrogen Content (continued)
Hydrogen contents averaged over the entire wall thickness were calculated based on the measured oxide thicknesses of PLUS7 LTA/CSA using the correlation of oxide thickness and hydrogen content
Calculated best estimated hydrogen concentrations are less than at discharge burnup of
TS
6.C PIE Results - Hot Cell Examination (8/9)
TS
TS
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Fission Gas Release
2 fuel rods were measured Gas release fractions are Internal pressures are Gas release fractions and internal pressures are well within PWR database
TS
TS
TS
6.C PIE Results - Hot Cell Examination (9/9)
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7. Conclusion
PLUS7 topical report was improved to reflect NRC comments Applicability of the fuel performance codes and methodologies are described in
detail Additional PSE and PIE data for LTAs and CSAs are provided Test, inspection and surveillance plan are described in DCD Tier 2 Section 4.2 The technical report of Seismic/LOCA analysis will be submitted with DCD
PLUS7 fuel assembly meet all of the design criteria up to the maximum fuel rod average burnup of 60,000 MWD/MTU
In-reactor performance of PLUS7 was verified through PSE and PIE
PLUS7 has a lot of in-reactor experience with satisfactory fuel performance
PLUS7 TR will be submitted by the end of September 2013