설계연구실 한전원자력연료. KEPCO NF Proprietary Information 0

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1 설계연구실 한전원자력연료 KEPCO NF Proprietary Information 0

2 노심설계및안전해석코드개요 노심설계 / 안전해석코드현황및계획 제 1 세대기술도입기 (80 s~90 s) 해외사코드도입 - KWU -CE -WH 제 2 세대기술개량화 ( 99~ 04) 대체코드개발 - 미국정부제한코드 - WH 와공동개발 제 3 세대원천기술확보 ( 05~ 15) 국가전략과제 고유설계코드개발 - 핵설계 - 열수력설계 - 연료봉설계 - 집합체설계 -LOCA 해석 - Non-LOCA 해석 제 4 세대기술고도화 ( 13~ ) 고유코드개선 미자립코드개발 3D 해석을위한코드융복합화 KEPCO NF Proprietary Information 1

3 Part 1. ROPER 연료봉설계코드 KEPCO NF Proprietary Information 2-2-

4 ROPER code As a fuel rod design code, ROPER has been developed by KNF: to perform reliable and efficient fuel rod design for PWR plants Fuel centerline temperature, rod internal pressure Cladding corrosion/hydriding, cladding stress/strain/fatigue to generate burnup-dependent fuel rod initial conditions for safety analysis Max/min fuel average temperature, gap conductance, rod geometry etc. to assist in-pile performance testing of fuel rod in research and commercial reactors KEPCO NF Proprietary Information 3

5 ROPER major features Single closed-channel enthalpy rise model Fuel temperature with finite differential method Fuel thermal conductivity degradation (TCD) by burnup Semi-mechanistic steady-state fission gas release Clad stress/strain analysis under generalized plain strain condition Clad corrosion and hydriding model Clad fatigue model Clad plasticity model KEPCO NF Proprietary Information 4

6 ROPER validation database Parameter Database Max BU (GWD/MTU) Fuel Centerline Temperature Halden 87 Steady-state Fission Gas Release Transient Fission Gas Release Cladding Corrosion Rod Diameter Change IFPE, HBEP, Korean PWR plants HBEP, Super-ramp, Over-ramp, Petten ramp Korean PWR plants (Imp. Zr-4, ZIRLO TM, M5 TM ) Korean PWR plants (Imp. Zr-4, ZIRLO TM, M5 TM ) KEPCO NF Proprietary Information 5

7 Fuel centerline temperature IFA432 Rod 1 IFA Rods KEPCO NF Proprietary Information 6

8 Fission gas release Steady-State FGR Transient FGR KEPCO NF Proprietary Information 7

9 Cladding corrosion 피복관산화막두께측정치 & 예측치 KEPCO NF Proprietary Information 8

10 Fuel thermal conductivity issue UO 2 fuel thermal conductivity degradation (TCD) model Un-irradiated Irradiated KEPCO NF Proprietary Information 9

11 Fuel temperature vs. TCD UO 2 핵연료온도 : q /(4 ) = 핵연료열전도도저하 (TCD) 현안 기존코드의 UO 2 열전도도는온도의함수로만적용함 연소도증가로조사결함및핵분열생성물축적에의하여열전도도저하 (Thermal Conductivity Degradation) TCD에의한핵연료온도증가발생 동일출력에서핵연료온도상승 핵연료중심선용융선출력감소 초기저장에너지증가 핵연료 중심선 핵연료 표면 핵분열기체방출률증가 연료봉내압증가 KEPCO NF Proprietary Information 10

12 Fuel rod design methodology A statistical methodology such as SRSS (Square Root of the Sum of the Squares) has been used for evaluation of fuel rod design criteria. P design P B. E. n Pi PB. E. i 1 2 where, P design = conservative design value P B.E. P i = best estimate design value = design value which is obtained by setting i-th performance model or dimensional uncertainty to be upper or lower bound value from the best estimate case (e.g.: fuel densification/swelling, clad corrosion, clad creep, pellet OD, clad OD/ID, etc.) KEPCO NF Proprietary Information 11

13 Fuel CL temperature uncertainty IFA 핵연료중심선온도 (M-P) vs. BU T T KEPCO NF Proprietary Information 12

14 Fuel thermal model adj. factor 95% 신뢰도및 95% 확률의핵연료중심선온도상한예측치 열적모델조정인자 (Thermal Model Adjustment Factor) 고려 KEPCO NF Proprietary Information 13

15 Power-to-melt evaluation RFA 및 PLUS7 핵연료용융선출력 핵연료용융선출력 (kw/ft) 연소도 (GWD/MTU) 코드 PAD FATES ROPER (0.875) ROPER (TMAF) ROPER(TCD) RFA(PAD) ROPER(0.875) PLUS7(FATES) KEPCO NF Proprietary Information 14

16 ROPER code application range Fuel type Rod avg. burnup : OPR1000/APR1400/WEC fuel rods : < 60 GWD/MTU Fuel pellet : UO 2, UO 2 -Gd 2 O 3 Pellet density : 92.5 ~ 96.5 %TD Pellet enrichment : 0.75 ~ 5.0% UO 2, 8 wt% UO 2 -Gd 2 O 3 Cladding : Zircaloy-4, ZIRLO TM, M5 TM KEPCO NF Proprietary Information 15

17 Part 2. THALES 노심열수력설계코드 KEPCO NF Proprietary Information

18 Licensing History THALES code Submit TR : Approval : Thermal design methodology Submit TR : Licensing : ~ (on-going) KEPCO NF Proprietary Information 17

19 Function of THALES code As a thermal hydraulic design code, THALES has been developed by KNF: to analyze the reactor coolant flow and energy fields in reactor core to generate the DNBR SAFDL for each fuel and plant to perform DNBR analysis for PWR plants KEPCO NF Proprietary Information 18

20 Definition of DNBR Surface Heat Flux, q" Single-Phase Forced Convection Local DNBR " " (Subcooled) Boiling Bulk Boiling Transition Boiling Film Boiling LHF = Limiting Heat Flux core average heat flux to approach the minimum DNBR to the target DNBR CHF CHF DNBR = 1 Target DNBR = limit DNBR ", Large margin Small margin and DNBR > 1 Low DNBR Bad for safety ", High DNBR Good for safety T CHF Surface Temperature, T W KEPCO NF Proprietary Information 19

21 History of COBRA family codes KEPCO NF Proprietary Information 20

22 THALES major features Simplified governing equations based on Navier-Stokes equation Use of matrix solver PBCGM Single phase wall friction pressure drop model Two phase friction multiplier Form drag pressure loss model Quality model Void fraction model Single phase forced convection model KCE-1 CHF correlation for PLUS7 fuel KEPCO NF Proprietary Information 21

23 Models in THALES Code Single phase pressure drop Two phase friction multiplier Thermal Hydraulic Model Quality Void fraction Single phase forced convection Heat Transfer Model Sub cooled nucleate boiling Saturated nucleate boiling Blasius correlation Homogeneous model Equilibrium model Homogeneous and slip ratio model Dittus Boelter correlation Jens Lottes correlation Chen correlation Sher Green and modified Martinelli Nelson correlation Levy Model Modified Armand model Thom correlation Armand correlation Modified Martinelli Nelson model Maier Coddington model Chexal Lellouche model KEPCO NF Proprietary Information 22

24 Mass flux at CNEN 4x4 flow test Non-heated 4x4 fuel rods for flow mixing p: 14.7 psia, T in : 68 o F, G avg : 0.48,0.98,1.93,2.82,3.81 Mlbm/hr-ft 2, TDC: 0.02 KEPCO NF Proprietary Information 23

25 Exit quality at ISPRA 4x4 mixing test Two phase flow & Enthalpy and flow at sub-channel exit (inner) p: 2305~2340 psia, T in : 550~594 o F, G avg : 1.6~2.37 Mlbm/hr-ft 2, q: 0.22~0.34 MBtu/ft 2 -hr KEPCO NF Proprietary Information 24

26 CHF prediction performance (THALES/KCE-1) Results of THALES/KCE-1 and TORC/KCE-1 are similar to each other KCE-1 CHF Prediction Performance and Correlation's DNBR 95/95 Limit Total Number of Data = 321, DNBR 95/95 Limit = Measured CHF, MBtu/hr-ft 변수 적용범위 계통압력, psia 1395 ~ 2415 국부건도 ~ 국부질량유속, 0.84 ~ 3.15 Mlbm / hr-ft Predicted CHF, MBtu/hr-ft 2 KEPCO NF Proprietary Information 25

27 Thermal design methodology Methodology for selection of the limiting assembly candidates is the same to the original one. SADL and TMV methodologies were modified. Selection methodology of the Limiting Assembly Candidates Safety Analysis Design Limit methodology (DNBR SAFDL generation) Thermal Margin Verification methodology (Conservatism verification of the Generic Thermal Margin model) KEPCO NF Proprietary Information 26

28 KEPCO NF Proprietary Information 27 Single stage core analysis model 138 (151) 139 (152) 137 (150) 122 (135) 121 (134) 124 (137) 125 (138) 123 (136) 136 (149) 126 (139) 149 (162) 135 (148) 127 (140) 148 (161) 160 (173) 134 (147) 128 (141) 147 (160) 159 (172) 132 (145) 133 (146) 130 (143) 129 (142) 131 (144) 146 (159) 158 (171) 163 (176) 143 (156) 144 (157) 141 (154) 140 (153) 142 (155) 145 (158) 157 (170) 162 (175) 161 (174) 156 (169) 155 (168) 154 (167) 153 (166) 152 (165) 151 (164) 150 (163) 106 (119) 107 (120) 101 (114) 102 (115) 104 (117) 100 (113) 105 (118) 103 (116) 115 (128) 114 (127) 113 (126) 112 (125) 111 (124) 110 (123) 109 (122) 117 (130) 119 (132) 120 (133) 108 (121) 116 (129) 118 (131) Channel # (Rod #) C/L

29 Single/Multi stages core model For single stage model, more detailed analysis at the boundary of hot assembly is possible. KEPCO NF Proprietary Information 28

30 SADL methodology Main features of SADL methodology : don t use the %DNBR and response surface model use the Monte-Carlo method (statistical approach) KEPCO NF Proprietary Information 29

31 Generic thermal margin model Changes in generic thermal margin model : use THALES code instead of CETOP-D code use full model of ¼ core instead of simplified two channel model KEPCO NF Proprietary Information 30

32 Summary ROPER code and design methodology have been developed by KNF and licensed for PWR fuel rod design. Validated for application to 60 GWD/MTU with various in-pile fuel performance DB Fuel TCD issue has been addressed for safety analysis. THALES code has been developed by KNF and licensed for PWR fuel rod design. Validated with experimental data and CHF test data Thermal design methodology is now under licensing. KEPCO NF Proprietary Information 31

33 감사합니다. - Q & A - KEPCO NF Proprietary Information 32