Study on the in-core-instrumentation tube ejection failure at APR1400 lower reactor vessel

Transcription

1 1 Study n the in-cre-instrumentatin tube ejectin failure at APR1400 lwer reactr vessel Subhead Hwan r Yel Secnd Kim Line Severe Accident & PHWR Safety Research Divisin

2 ICI Penetratin fr APR1400 Severe Accident & PHWR Safety Research Divisin 2

3 ICI Penetratin Failure Penetratin tube ejectin & rupture Cmpare Pi and V Penetratin tube heat-up & rupture Severe Accident & PHWR Safety Research Divisin 3

4 Welding Ersin Test (1) VESTA-S Test Facility Melting 75 mm Specimen f Welding Material (ENiCrFe-7) 50 mm Reactin Severe Accident & PHWR Safety Research Divisin 4

5 Welding Ersin Test (2) Cmpsitin: Fe 46%, U 31%, Zr 16%, Cr 7%) Mass: kg Cmpsitin: SUS304 (Cr 19%, Ni 11%, Fe 70%) Mass: kg Severe Accident & PHWR Safety Research Divisin 5

6 ICI Penetratin Failure Test (1) Furnace vessel (VESTA ) Melt crucible Plug & Puncher Intermediate melt catcher Melt delivery channel Ar r Air Melt delivery channel Funnel Interactin vessel Pressure bundary Melt crucible Test specimen Severe Accident & PHWR Safety Research Divisin 6

7 ICI Penetratin Failure Test (2) Penetratin test specimen K-type T/C: 33 ea. C-type T/C: 1 ea. Penetratin test specimen (DOOSAN Heavy Industries and Cnstructin. C., Ltd.) C11, K11 : Melt temperature P1-P11 : Penetratin tube temperature PW1-PW4 : Penetratin weld temperature RVH1-RVH7 : Reactr vessel hle temperature RV1-RV10 : Reactr vessel temperature Severe Accident & PHWR Safety Research Divisin 7

8 ICI Penetratin Failure Test (3) Melt Material Charging Severe Accident & PHWR Safety Research Divisin 8

9 Temperature ( C) Pwer (kw) Temperature ( C) Pwer (kw) ICI Penetratin Failure Test (4) Melt Temp Pyrmter C-type TC Pwer Penetratin tube Temp Time (sec) P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 Pwer Time (sec) Severe Accident & PHWR Safety Research Divisin 9

10 Failure Mdels & Calculatins (1) Tube Ejectin (Weld failure) c=0.73 fr Mlten pl debris bed f PWR Ejectin criteria Fp V T where, V T F p : Ttal thermal binding shear frce : Ejecting pressure frce Severe Accident & PHWR Safety Research Divisin 10

11 Failure Mdels & Calculatins (2) Tube Ejectin 1. Free thermal expansin f tube and hle Tube: Hle: Δ Δ r T r T h r α 2. Pressure expansin f tube i i t Tube: Δr P 2 2 E r ri Hle: P Δr h 0 - The pressure expansin f hle is negligibly small. 3. Ttal expansin f tube Tube: r α h 4. Tube-hle radial gap at temperature and pressure δ i Δr p Δr + gap interface t h T T T, T 294 K t ref ref T T, T 294 K r h r Δr ref 2 ν P r Δr r Δr h h ref δ δ i i 5. Tube-hle interface pressure 0 : P th 0 : Pth lesser f r 2 r δ i E r r 2 1 2ν r 1 ν 2 σ 3 6. Ttal thermal binding shear V f T n n1 0 f P 2πr Δl : nt a f (temp.), but a f (rughness) 7. Ejecting pressure frce 8. Ejectin criteria F u t 2 r ln ri fr high-temperature, xidized cnditins 2 F p πr p i p V T th i 2 i Required interfacial pressure t frce the uter diameter f the tube t cnfrm t the diameter f the hle after free expansin Required pressure t cause cmpressin failure f the tube material t t Severe Accident & PHWR Safety Research Divisin 11

12 Failure Mdels & Calculatins (3) Experimental results Temperature distributin Mlten Crium Reactr vessel wall Penetratin tube Thermcuple Severe Accident & PHWR Safety Research Divisin 12

13 Failure Mdels & Calculatins (4) Tube Ejectin Pi=10 bar Input data Obtained temperature prfile Lt=180.6 Assumptin Pi=10 bar Clearance gap size: same as nrmal perating cnditin Tp surface temp. up t 2600 C while maintaining similar temp. prfile Severe Accident & PHWR Safety Research Divisin 13

14 Failure Mdels & Calculatins (5) Tube Ejectin (Weld failure) Simplified Flw Diagram Pi=10 bar Iteratin start Lt=180.6 V T Weld fail? Y f P 2r l th 2 F p πr p i t Update temperature prfile Lt=Lt-Lt F P >V T Y N t = t + t Ejectin criteria V T F p Tube ejectin : Ttal thermal binding shear frce, Fp V T where, 2 : Ejecting pressure frce, p i r f P 2r l Severe Accident & PHWR Safety Research Divisin 14 th t

15 Frce(kN) Failure Mdels & Calculatins (6) Tube Ejectin 100 Ejecting pressure Ttal binding shear frce Ejectin Tp surface temperature(c) Severe Accident & PHWR Safety Research Divisin 15

16 Frce(kN) Thickness(mm) Failure Mdels & Calculatins (7) Tube Ejectin Tp surface temperature = 1950 C Ttal tbinding shear frce Thickness Time(s) Severe Accident & PHWR Safety Research Divisin 16 0

17 ANSYS Analysis Detail A Displacement B.C. Melting Zne Nzzle RV RV Bttm Head Resultant Frictin Frce A Partial Mdel Line Gap= in ( mm) Gap Elements with Frictin Capability ICI Nzzle Defrmatin f reactr vessel affects the gap. Clamping r nn-clamping ICI nzzle depends n the lcatin. Clearance gap size may change. Severe Accident & PHWR Safety Research Divisin 17

18 Cncluding Remarks APR1400 ICI penetratin tube failure study Welding material ersin test at VESTA-S facility ICI penetratin tube failure test at VESTA facility ICI penetratin tube failure calculatin with suggested mdel Future wrk Test with high heat flux and elevated pressure Test under the external reactr vessel cling cnditin Analysis in case f clearance gap change Severe Accident & PHWR Safety Research Divisin 18