Volatile fission product behaviour during thermal annealing of irradiated UO2 fuel oxidised up to U3O8

Fission product release and microstructure changes during laboratory annealing of a very high burn-up fuel specimen

“…The ultimate pores are found in the highest burn up regions, where the fissions are essentially originating from plutonium, but the Mo production should be smaller in that case. This result is also in contradiction with the evolution of the DG O 2 and the fact that this oxidation affects more Mo than the other metals of the precipitate as shown in a previous paper [28]. The only explanation could be the presence of a very stable phase around these pores (observed up to T > 1800 K), which could reduce locally on a microscopic scale the DG O 2 .…”

Research Program for the Evaluation of Fission Product and Actinide Release Behaviour, Focusing on their Chemical Forms

“…The oxidative atmosphere and high burn-up of fuel promote the release kinetics of Cs and I at lower temperatures. The main chemical forms of Cs compounds have been predicted to be CsI and CsOH, while those of other chemical forms such as Cs 2 MoO 4 and Cs 2 Te were suggested [23,36]. Besides, as it was suggested that higher volatility Cs compounds would be formed by reaction with sea water [37], the analysis of Cs release from the 1F core should pay attention to this point since large amount of sea water was injected into the 1F core [1].…”

“…Sb, Te, Mo, Sr and Pu are of intermediate importance [45]. Although Te, Mo and Pu have a small impact from the viewpoint of external exposure [27], they are important because Te and Mo are reported to form compounds with Cs, such as Cs 2 Te and Cs 2 MoO 4 [23,36], and Pu results in significant internal exposure [48]. Table 2.…”

A mass spectrometry method for quantitative and kinetic analysis of gas release from nuclear materials and its application to helium desorption from UO2and fission gas release from irradiated fuel

“…A calibrated volume (19) and the gas line are then filled with a certain pressure of spike gas from a chosen storage bottle (18) with the microvalve (M) and the valve (I and S). The calibrated volume (19) is then closed with the valve (S). At this point, the gas can be expanded into the expansion tank (20) by opening and closing the valve (E).…”

“…The Q-GAMES (Quantitative GAs MEasurement System) facility presented in this paper is originally designed to work in combination with two other devices: the first one is a high-temperature Knudsen effusion mass spectrometer (KEMS) [14][15][16] suited for thermodynamic (vapour pressure) [17,18] and kinetic (release behaviour) [4,15,16,[19][20][21] measurements on irradiated nuclear fuel. The second one is a laser heated Knudsen cell mass spectrometer (LKC-MS) [22] which is used to study the thermal release of gas from infused materials.…”