In-pile measurements of the fission gas pressure and comparison with ROFEM code results

Abstract Two experimental fuel elements with different UO 2 grain size were irradiated in the C2 capsule in the TRIGA MT reactor of INR Pitesti to a burn-up of 178.9 MWh kg −1 U and linear powers between 45 to 60 kW m −1 . Both elements were instrumented to measure internal gas pressure during irradiation. Experimental results presented in this paper represent data relative to two fuel elements with different UO 2 grain size. The predictions of fuel performance code ROFEM in terms of internal gas pressure were compared with the experimental data. Experimental programs are in progress at INR Pitesti. New instrumented tests are planed to be performed in the C2 capsule in order to establish the pellet microstructure influence on fission gas release. This paper describes measuring techniques used at INR Pitesti and present experimental results of the in-pile tests comparatively with the ROFEM code predictions.