SIMULATION WITH THE DIONISIO 1.0 CODE OF THE OPERATION BEHAVIOR

SOBA, ALEJANDRO; DAJCZGEWAND, JULIAN; DENIS, ALICIA

Buenos Aires

Congreso; TECHNICAL MEETING ON PRESSURISED HEAVY WATER REACTOR (PHWR) FUEL DESIGN, FABRICATION AND PERFORMANCE; 2009

CNEA

The code DIONISIO 1.0 describes most of the main phenomena that take place in a nuclear fuel rod throughout its life under normal operation conditions. Starting from the power history, the code predicts the temperature distribution in the domain, the elastic and plastic stress and strain, creep, swelling and densification, release of fission products like noble gases, cesium and iodine to the internal free volume of the rod, gas mixing, pressure increase, irradiation growth of the Zircaloy cladding, development of an oxide layer on its surface and hydrogen uptake, restructuring and grain growth in the pellet. The combined effect of an internal or external corrosive atmosphere and the stress state of the cladding on crack propagation as well as the possibility of pellet-cladding mechanical interaction are also considered. The code is two-dimensional, assumes cylindrical symmetry for the rod and uses the finite element method to integrate the differential equations, some of which are non-linear. The diverse models are interconnected and mutually dependent. In the present occasion, the code results are compared with experimental data corresponding to PHWR fuels, compiled in the IFPE Database. Experiments like the AECL-BUNDLE, performed in the NRU experimental reactor at the Chalk River Laboratories, the irradiation tests EFE N51 and EFE N89 performed in the Nuclear Research Institute Pitesti, Romania, the CANDU/IRDMR experiments conducted in a loop of the NRX reactor, the CNEA-MOXRAMP tests of argentine prototypes irradiated in the reactor HFR-Petten, Holland, and the EXP-BDL-406 tests performed in the NRU reactor at the Chalk River Laboratories are simulated. Good results are obtained in the different cases.