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Abstract

Two different methods were used to measure the thermal conductivity of oxides of uranium, americium and neptunium: Diffusivities were determined in the temperature range from 1000 to 1800 K by a modulated electron beam technique and converted to conductivities whereas a direct electrical heating method was used to deduce mean conductivities between about 1600 K and the melting temperature of the oxides. The principal result of this investigation is the observation, that the thermal conductivity of uranium - americium dioxide exhibits an upswing above 1800 K as in the case of uranium and uranium - plutonium dioxide, whereas the conductivity of uranium - neptunium dioxide continues to decrease with temperature, like that of thoria, as one would expect for a pure phonon conductor. The high-temperature rise has been attributed to an electronic contribution which, apparently, is related to the ability of the oxide to accomodate the metals in question in another than the four-valent state.

Additional information

Authors: SCHMIDT H E, JRC KARLSRUHE ESTAB. (GERMANY);AGIP ENEA, ROMA (ITALY);SARI C, JRC KARLSRUHE ESTAB. (GERMANY);AGIP ENEA, ROMA (ITALY);RICHTER K, JRC KARLSRUHE ESTAB. (GERMANY);AGIP ENEA, ROMA (ITALY);GERONTOPOULOS P JRC KARLSRUHE ESTAB. (GERMANY), JRC KARLSRUHE ESTAB. (GERMANY);AGIP ENEA, ROMA (ITALY);AGIP ENEA, ROMA (ITALY), JRC KARLSRUHE ESTAB. (GERMANY);AGIP ENEA, ROMA (ITALY)
Bibliographic Reference: ACTINIDES '85, AIX-EN-PROVENCE (FRANCE), SEPT. 2-6, 1985 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 32140 ORA
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