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The thermal conductivity of technetium
JOURNAL
OF THE LESS-COMMON
METALS
435
Short communication The thermal
conductivity
Technetium
of technetium
has been recovered
from fission product
pure metal for studies of the alloying behavior alloys. The thermal
diffusivity
and properties
from room temperature
wastes and reduced
to
of tungsten-technetium
to 575°C was measured
on a
small quantity of the technetium that had been electron-beam melted and fabricated to a 0.12 cm thick wafer. The thermal conductivity was calculated from the thermal diffusivity data. The isolation of 800 g of technetium from fission product wastes was carried out at the Hanford project in four stages that included two anion exchange cycles, preparation of pure ammonium
pertechnetate,
and reduction
ate to metal in a hydrogen furnace. The as-reduced of about
150
p.p.m.,
principally
of the ammonium
Al and l?e. After melting,
the oxygen
levels were z and 3 p.p.m. respectively. An eight gram button was melted
in an electron
as-cast
IOS to 134 (IZO average)
hardness
parameters
of the metal
were determined
was DPH
as uo =
2.7414
x,
pertechnet-
metal had total metallic impurities
CO
=
and nitrogen
beam evaporator
4.3997 A; c!a ratio
unit.The
and its lattice = 1.604. The
button was vacuum encapsulated in a heavy walled molybdenum container, heated to 1540°C by induction, and the assembly was press forged from 2.16 cm to 0.95 cm height
in one pass.
The
molybdenum
cladding
was removed
chemically
using a
0.16
Fig. I. The thermal diffusivitv and thermal conductivity of technetium. J. Less-Cammm
MefaZs, 8 (1965) 435-436
SHORT
436
COMMUNICATION
HN03, H&01, Hz0 mixture. The technetium, approximately 0.21 cm in thickness, was ground on both surfaces with metallographic equipment to produce a flat wafer 0.12 cm thick and about 2.3 cm in diameter for testing. The metal was only partially recrystallized after this working and those areas of recrystallization occurred primarily along the prior cast grain boundaries and occasionally along twin bands. The thermal diffusivity of the technetium wafer was measured by the flash method of W. J. PARKER et a1.1s2. A short pulse of radiant energy from a xenon-filled flash tube was applied to the front surface of the sample and the resulting temperature rise of the rear surface was observed with an oscilloscope. The temperature rise was typically 1.553%. A tube furnace with resistance wire heating elements maintained the sample at the desired measurement temperature in a helium atmosphere. The apparatus and procedure were the same as that previously used to measure the thermal conductivity of irradiated graphites. The results of the thermal diffusivity measurements for technetium from 25” to 575°C are shown in Fig. I. Thermal conductivity, K, may be calculated from the thermal diffusivity OL,density Q and specific heat, CP by the equation K = ol@C,. The density of a similar electron beam melted sample of the current material was measured and found to be 11.492 g/cma. MOONEY~ reported a value of 11.497 g/cm3 for the density of Tc-99. The heat capacity data of STULL AND SINKER were used for calculating the thermal conductivity of Tc-99 which also appears in Fig. I. ACKNOWLEDGEMENT
The author wishes to thank R. S. KEMPER, JR. for supplying the samples and physical-property data. This work was performed for the Office of Advanced Research and Technology, National Aeronautics and Space Administration under contract AT (45-1)1830 with the U.S. Atomic Energy Commission. Rattelle
Memorial
Institute,
D. E.
BAKER
Pacific Xorthwest Laboratory, Richland, Wash. (U.S.A.) I 2 3 4 5
J. PARKER, R. J. JENKINS, C. P. BUTLER AND G. L. ABBOTT, J. Apfil. Phys., 32 (1961) 1679. R. L. RUDKIN, R. J. JENKINS AND W. J. PARKER, Rev. Sci. Znstr., 33 (1962) 21. D. E. BAKER, J. Nucl. Mat., IZ (1964) 120. R. C. L. MOONEY, Acta Cryst., I (1948) 161. D. R. STULL AND G. C. SINKE, Thermodynamic Properties of the Elements, American Chemical Society, Washington, D. C., 1956, p. 198
W.
Received
March eznd, 1965.
J. Less-Common
Metals,
8 (1965)
435-436
OF THE LESS-COMMON
METALS
435
Short communication The thermal
conductivity
Technetium
of technetium
has been recovered
from fission product
pure metal for studies of the alloying behavior alloys. The thermal
diffusivity
and properties
from room temperature
wastes and reduced
to
of tungsten-technetium
to 575°C was measured
on a
small quantity of the technetium that had been electron-beam melted and fabricated to a 0.12 cm thick wafer. The thermal conductivity was calculated from the thermal diffusivity data. The isolation of 800 g of technetium from fission product wastes was carried out at the Hanford project in four stages that included two anion exchange cycles, preparation of pure ammonium
pertechnetate,
and reduction
ate to metal in a hydrogen furnace. The as-reduced of about
150
p.p.m.,
principally
of the ammonium
Al and l?e. After melting,
the oxygen
levels were z and 3 p.p.m. respectively. An eight gram button was melted
in an electron
as-cast
IOS to 134 (IZO average)
hardness
parameters
of the metal
were determined
was DPH
as uo =
2.7414
x,
pertechnet-
metal had total metallic impurities
CO
=
and nitrogen
beam evaporator
4.3997 A; c!a ratio
unit.The
and its lattice = 1.604. The
button was vacuum encapsulated in a heavy walled molybdenum container, heated to 1540°C by induction, and the assembly was press forged from 2.16 cm to 0.95 cm height
in one pass.
The
molybdenum
cladding
was removed
chemically
using a
0.16
Fig. I. The thermal diffusivitv and thermal conductivity of technetium. J. Less-Cammm
MefaZs, 8 (1965) 435-436
SHORT
436
COMMUNICATION
HN03, H&01, Hz0 mixture. The technetium, approximately 0.21 cm in thickness, was ground on both surfaces with metallographic equipment to produce a flat wafer 0.12 cm thick and about 2.3 cm in diameter for testing. The metal was only partially recrystallized after this working and those areas of recrystallization occurred primarily along the prior cast grain boundaries and occasionally along twin bands. The thermal diffusivity of the technetium wafer was measured by the flash method of W. J. PARKER et a1.1s2. A short pulse of radiant energy from a xenon-filled flash tube was applied to the front surface of the sample and the resulting temperature rise of the rear surface was observed with an oscilloscope. The temperature rise was typically 1.553%. A tube furnace with resistance wire heating elements maintained the sample at the desired measurement temperature in a helium atmosphere. The apparatus and procedure were the same as that previously used to measure the thermal conductivity of irradiated graphites. The results of the thermal diffusivity measurements for technetium from 25” to 575°C are shown in Fig. I. Thermal conductivity, K, may be calculated from the thermal diffusivity OL,density Q and specific heat, CP by the equation K = ol@C,. The density of a similar electron beam melted sample of the current material was measured and found to be 11.492 g/cma. MOONEY~ reported a value of 11.497 g/cm3 for the density of Tc-99. The heat capacity data of STULL AND SINKER were used for calculating the thermal conductivity of Tc-99 which also appears in Fig. I. ACKNOWLEDGEMENT
The author wishes to thank R. S. KEMPER, JR. for supplying the samples and physical-property data. This work was performed for the Office of Advanced Research and Technology, National Aeronautics and Space Administration under contract AT (45-1)1830 with the U.S. Atomic Energy Commission. Rattelle
Memorial
Institute,
D. E.
BAKER
Pacific Xorthwest Laboratory, Richland, Wash. (U.S.A.) I 2 3 4 5
J. PARKER, R. J. JENKINS, C. P. BUTLER AND G. L. ABBOTT, J. Apfil. Phys., 32 (1961) 1679. R. L. RUDKIN, R. J. JENKINS AND W. J. PARKER, Rev. Sci. Znstr., 33 (1962) 21. D. E. BAKER, J. Nucl. Mat., IZ (1964) 120. R. C. L. MOONEY, Acta Cryst., I (1948) 161. D. R. STULL AND G. C. SINKE, Thermodynamic Properties of the Elements, American Chemical Society, Washington, D. C., 1956, p. 198
W.
Received
March eznd, 1965.
J. Less-Common
Metals,
8 (1965)
435-436