1. Adaptation of FRAPTRAN 2. 0 to VVER Fuel FRAP
Adaptation of FRAPTRAN 2.0 to VVER Fuel FRAP* Users’ Group Meeting, 10 September 2017, Jeju Katalin Kulacsy

2. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Institution
1950’s to 1990’s: KFKI (Central Physics Research Institute)
1990’s to 2012: (KFKI) AEKI (Atomic Energy Reserch Institute)
2012 to present: MTA EK
Hungarian Academy of Sciences (MTA)
Centre for Energy Research (EK)
Atomic Energy Research Institute (AEKI)
Fuel end Reactor Materials Department
Fuel Modelling Research Group
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

3. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
FRAP* usage
Codes
FRAPCON: tried, never really used (in-house code FUROM)
FRAPTRAN: since late 1990’s (FRAP-T6)
Used FRAPTRAN 1.3, 1.4, then 2.0 (1.5 omitted)
Purpose
VVER fuel (4 units with VVER-440 reactors at Paks NPP), adaptations since FRAP-T6
confirmatory code (licensing based on Russian anayses)
input from FUROM
FUROM+FRAPTRAN used for NPP (TRANSURANUS used for authority)
research, benchmarking
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

4. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Experiences with FRAPTRAN
VVER-specific models and other changes:
fitted plastic deformation model parameters + failure limits for FRAP-T6, valid for FRAPTRAN 1.3
implemented Halden thermal conductivity model for Gd-bearing fuel since FRAPTRAN 1.3
more detailed resolution in time and space
Code versions
major changes from 1.3 to 1.4  lost fitted model (RRC-KI model lost as well)
1.3 more stable than 1.4
2.0 quite stable (thousands of runs with only cladding), not sensitive to time step or model (FRACAS-1 or BALON2) choice
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

5. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
VVER cladding alloys
Russian alloys: Zr1%Nb
oxidation
kinetics significantly different from Zry-4 and from each other
E110 suffers breakaway oxidation between 800 and 1050 °C
mechanical behaviour
significantly different from Zry-4, similar to each other (G slightly stronger)
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

6. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Publications related to oxidation
IFPE AEKI database
Erzsébet Perez-Feró et al.: Experimental database of E110 claddings exposed to accident conditions, Journal of Nuclear Materials, 397 (2010) 48–54
E110G oxidation
Marton Király et al.: High-temperature steam oxidation kinetics of the E110G cladding alloy, Journal of Nuclear Materials 475 (2016) 27-36
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

7. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
New oxidation kinetics correlations
𝑞 𝑡 =𝑘 𝑡,𝑇 𝑡 𝛼(𝑡,𝑇)
where q is weight gain or oxide layer thickness
4 models:
E110 best-estimate
E110 conservative
E110G best-estimate
E110G conservative
To be made available to the community.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

8. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
New oxidation kinetics correlations: E110
Range of validity for best-est. :
Range of validity for cons. :
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

9. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
New oxidation kinetics correlations: E110G best-est.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

10. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
New oxidation kinetics correlations: E110G cons.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

11. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Results, E110 best estimate
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

12. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Results, E110 conservative
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

13. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Results, E110G best-estimate
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

14. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Results, E110G conservative
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

15. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Future plans and needs
Plans
continue developing VVER version
plastic deformation + failure (new experimental data on mechanical behaviour)
E110 breakaway oxidation model
Needs
possibility of using FUROM+FRAPTRAN combination after FRAPCON-FRAPTRAN merger =
possibility of external input to the FRAPTRAN part
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

16. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – VVER balloning and burst
changes in the code  fitted parameters not valid
ballooning and burst data from the AEKI database + FZK + RRC-KI
new failure limits (independent of the code)
new parameters (K, m, n) for plastic deformation (depend on failure limits and the code):
𝜎=𝐾 𝜀 10 −3 𝑚 𝜀 𝑛
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

17. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – VVER failure limits - true tang. stress
Only relevant stress states used (no axial or ring tensile tests).
No strong dependence on strain rate.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

18. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – VVER failure limits – eng. tang. strain
Strong dependence on strain rate.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

19. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – parameters of plastic deformation - K
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

20. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – parameters of plastic deformation - m
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

21. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Ongoing work – parameters of plastic deformation - n
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

22. FRAP* Users’ Group Meeting, 10 September 2017, Jeju
Conclusions
Satisfied with code, 2.0 significantly better than previous versions.
Planning to use it in the future.
Ongoing and future development for VVER fuel to be made available to the community.
FRAP* Users’ Group Meeting, 10 September 2017, Jeju

23. Thank you for your attention