Development of Microwave Heating Method for Co-Conversion of Plutonium-Uranium Nitrate to MOX Powder

Oshima, Hirofumi

doi:10.1080/18811248.1989.9734282

Cited by 23 publications

(2 citation statements)

References 7 publications

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“…The whole view of microwave oven installed inside the GB is shown in Figure 2. Details of the MH method have been presented in the previous papers [7][8] [9]. Obtained material by the de-nitration was calcined at 750 °C for two hours in the air, and then the oxide (U 3 O 8 -PuO 2 or U 3 O 8 ) was reduced to mixed dioxide or uranium dioxide at the same temperature under the N 2 -H 2 mixture gas.…”

Section: Samplesmentioning

confidence: 99%

Wet granulation of mixed oxide powders de-nitrated by the microwave heating

Kato

2012

Journal of Nuclear Science and Technology

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A performance in a wet granulation of MOX powders prepared by the microwave heating de-nitration method was examined to fabricate MOX fuel pellets for FBR at an extremely simplified process. An agitating granulator equipped with three blades and a chopper was used and its performance was evaluated. Characteristics and physical properties of the raw powder and the granules were measured together with observations by SEM before/after granulation. We could obtain the granules of 120 to 140 μm in diameter within a narrow range of water addition ratio 12.5 to 13.5 wt% combined with a flow-ability > 73 and a product yield > 90 %. Specific surface area that corresponds to sintering performance was almost the same as that of raw powder. When the ratio was < 9 wt%, no granule was observed, and flow-ability did not change from that of raw powder < 30. It was estimated from an additional experiment that the reason was capillaries (or voids) in the raw powder. When the ratio was more than 14 wt%, the flow-ability saturated and the product yield decreased. This narrow range of water addition ratio and strong binding force were successfully understood based on the standard theory of granulation supposing the Pendular state and the Gorge method.

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Section: Samplesmentioning

confidence: 99%

Wet granulation of mixed oxide powders de-nitrated by the microwave heating

Kato

2012

Journal of Nuclear Science and Technology

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“…In Japan where the fundamental law on nuclear energy strictly confines it to peaceful use, the Microwave Heating (MH) method 4,5) was developed as a preparation route to prevent nuclear materials from being diverted to military use. In the process U/Pu nitrate solution is heated by microwaves and co-converted to (U,Pu)O 2 powder.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Properties of Uranium and Plutonium Nitrate Solution and the Oxide Compounds Formed in the De-nitration Process by the Microwave Heating Method

Kato¹,

Kurita²,

Abe³

2004

Journal of Nuclear Science and Technology

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In the microwave heating method, a liquid mixture of uranium nitrate and plutonium nitrate solution (U/Pu nitrate solution) is co-converted to MOX powder through four steps. Dielectric properties of U/Pu nitrate solution and denitrated MOX powder were measured. The reflection method was used for U/Pu nitrate solution and U 3 O 8 powder, while the perturbation method was used for 50%PuO 2 -UO 3 , -UO 3 , -UO 3 and U 3 O 8 powders.The measured dielectric loss product " 0 tan of U/Pu nitrate solution was strongly affected by the concentration of nitrate, but there was little dependence on the dielectric oscillation of uranium and plutonium ions. This behavior was explained by the Maxwell-Wagner effect. When U/Pu nitrate solution was continuously heated by microwaves, dielectric loss product increased until the boiling point and then it decreased rapidly, but temperature increased steadily at the same time due to the sharp decrease in heat capacity of the media.The temperature histories in the solution and compounds formed in the de-nitration process by the microwave heating method could be explained from the measured dielectric properties.

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