ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
of the six types of B,C are presented in Table
4.2.2, and the results of examinations of 20 irradi-
ated samples of the six types are given in Table
4.2.3.
The four types of B,C irradiated during this
quarter are described below:
1. The Norton Company supplied low-density,
high-purity samples that had been hot-pressed from
325 mesh, and finer, powder and fired at above
2000%. The boron content of this material was
62.4 f 0.4 wt %. These bodies were hard, strong,
and impervious.
2. The Norton Company also supplied low-
density, technical-grade samples that had been
hot-pressed from a-mesh, and finer, material and
fired at above 2oooOC. These bodies were hard,
strong, and nearly impervious, and they contained
62.4 f 0.4 wt % boron.
3. The Carborundum Company supplied tiles
(No. 1) cast from a basic mixture of 90% B,C
grains and 10% 200-mesh silicon metal. The cast
bodies were fired at 13500C and refired at 200OOC.
They were porous and friable, and they contained
64.7 f 0.5 wt 7% boron.
4. The Carborundum Company also supplied
tiles (No. 2) cast from a basic mixture of 80%
B,C, 10% 200-mesh, and finer, boron-metal powder,
and 10% 200-mesh, and finer, silicon-metal powder.
The cast bodies were fired at 1350°C and refired
at 2oooOC. They were porous and friable, and they
contained 67.8 f 0.4 wt 94 boron.
The samples were exposed for 800 hr in the
LlTR in a thermal flux of 2 x 1013 nv. The sample
temperature was less than 200OC, and the total
dose received by each sample was 6 x 1019 nvt
(thermal). These conditions are to be compared
with those expected in the ART in which the
temperature of the B,C layer will be 14500F and
the integrated neutron flux dosage for 500 hr of
operation will be 1.2 x lot9 nvt (exposure behind
a 0.030-in. gap in the cermet layer). The average
burnup of these samples was 2.9%, and most of
the burnup occurred in the first few thousandths
of an inch of the surface layer.
A much greater exposure will be required to
simulate the ART operating conditions for the
copper-B4C cermet layer and the boron steel, and
therefore these materials will be irradiated at the
MTR at a temperature of 16oOOF. Calculations
indicate that these samples should receive total
doses of 1.5 x lo2' nvt for the cermet and 8 x 1019
nvt for the boron steel, which are equivalent to
TABLE 4.2.2. RESULTS OF SPECTROGRAPHIC ANALYSES OF B4C SAMPLES
~~
Composition (%)
Norton Norton Norton Carborundum Corborundum Carborundum
Element* High-Density Low-Density Low-Density Sample Cast Tile No. 1 Tile No. 2
Refired at
Hot-Pressed Technical-Grade High-Purity and Bonded Refired at
Sample Sample Sample with Sic 20000c 20oooc
AI 0.01 -0.1 1-10 0.1-1 0.1 -1 0.1-1 0.1 -1
Ca 0.001 -0.01 0.001 -0.01 0.001 -0.01 0.001-0.01 0.001-0.01 0.001-0.01
Cr ** ** ** 0.01-0.1 0.01 -0.1 0.01 -0.1
cu ** 0.01 -0.1
** ** ** **
Fe 0.01-0.1 0.1-1 0.1-1 1-10 0.1-1 1-10
Mg 0.0001-0.001 0.001 -0.01 0.0001 -0.001 0.001 -0.01 0.001-0.01 0.001 -0.01
Mn ** 0.01 -0.1 ** 0.0 1-0.1 0.01 -0.1 0.01 -0.1
Ni ** ** ** 0.1-1 0.01 -0.1 0.01-0.1
Ti ** 0.1-1 0.1-1 0.1-1 0.1-1 0.1-1
Zr ** 0.1-1 0.1-1 1-10 1-10 1-10
*Limit of detection: Cr, 0.004%; Cu, O.&Ol%; Mn, 0.001%; Ni, 0.02%; Ti, 0.04%; a, 0.03%.
**Sought but not found.
I
f
G
.