Original scientific paper
Nuclear Fuel Modelling During Power Ramp
Federico Cantini,
; GRNSPG, San Piero a Grado Nuclear Research Group, University of Pisa Via Livornese 1291, San Piero a Grado (PI), Italyv
Martina Adorni,
; GRNSPG, San Piero a Grado Nuclear Research Group, University of Pisa Via Livornese 1291, San Piero a Grado (PI), Italy
Francesco D’Auria
; GRNSPG, San Piero a Grado Nuclear Research Group, University of Pisa Via Livornese 1291, San Piero a Grado (PI), Italy
Abstract
Fuel rods operating for several years in a LWR can experience fuel-cladding gap closure as a
result of the phenomena due to temperature and irradiation. Local power increase induces
circumferential stresses in the cladding as a result of the different expansion in the cladding and the
pellet. In presence of corrosive fission products (i.e. Iodine) and beyond specific stress threshold
and level of burnup, cracks may grow-up from the internal to the external cladding surface, causing
fuel rod failure. The phenomenon, known as pellet cladding interaction-stress corrosion cracking
PCI/SCC, or PCI, has been identified as a problem since the 70's.
The PWR Super-Ramp experiment (part of OECD/NEA “International Fuel Performance
Experiments (IFPE) database”) twenty eight fuel rods behaviour has been simulated using
TRANSURANUS code version “v1m1j11”. Two sets (“Reference” and “Improved”) of suitable
input decks modelling the fuel rods, based on the available literature are used to run the simulations.
Focus is given to the main phenomena which are involved or may influence the cladding failure.
Systematic comparison of the code results with the experimental data are performed for the
parameters relevant for the PCI phenomenon. Sensitivity calculations on fission gas release models
implemented in TRANSURANUS code are also performed in order to address the impact on the
results.
The results show the ability of TRANSURANUS version “v1m1j11” in conservatively
predicting the rods failure due to PCI in PWR fuel and Zircaloy-4 cladding. Increased availability of
experimental data would help to perform a deeper analysis.
Keywords
Hrčak ID:
199044
URI
Publication date:
31.7.2017.
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