ORNL-1771 - Oak Ridge National Laboratory

Similar remarks apply, in part, to the mass spec-
trographsc analysis. The samples taken are weighed
by the analysts on a microbalance to alleviate the
effect of small sample size. However, the handling
of the very small crucibles in the hot cells is not
so delicate an operation as might be desired. The
possibi?ities of contamination entering the sample
are high.
No highly useful conclusions have emerged from
much of the analytical work done in the past,
probably because of the difficulties described
above. Recently, however, mar ked improvement
has been made as a result of continued efforts to
improve sampling techniques, sample sizes, und
handling procedures, and uranium analyses have
been carried out in c1 satisfactory manner. Since
the analytical results obtained recently show that
no meosurable segregation of uranium takes place,
the procedure of taking more than one sample froin
each capsule will be abandoned. This will allow
very much larger samples to be obtained, will
make the analyses more sure, and will minimize the
effects of foreign additions to the salt.
NIGH-TEMPERATURE CHECK VALVE TESTS
W. R. Willis G. W. Keilholtr
Solid State Division
As part of the development program for a small
in-pile pump loop for operation in o beryljium
A-piece in the LITR, an attempt was made to
deve I op a h igh-temperature c Iiec k-va Ive pump.
Such a pump has the advantage of being a compact,
completely sealed unit.
A test rig was run with Inconel, stainless steel,
and Stellite25 check bolls. None of these materials
gave successful tests. Time of operation before
failure varied from 30 min for the Inconel to 2 hr
for the stainless steel. Except with the stainless
steel balls, operation of the valves was not con-
tinuous; they would occasionally stick in both
open and closed positrons. When failure occurred,
it was abrupt, and therefore sticking of he valves
was indicated rather than a gradual stoppage of the
system.
MINIATURE IN-PILE LOOP - BENCH TEST
An exploded
previously4 is
coil measures
J. C. Morqan G. W. Keilholtz
I
Solid State Division
view of the in-pile pump described
shown in Fig. 9.1. The RPM meter
the rotation of the shaft on which
PERlOD ENDING SEPTEMBER 10, 19.54
is mounted die motor armature, The Graphitar
bearing is mounted in the bearing casing above the
impeller housing. The assembled loop is shown
in Fig. 9.2. The pump contains an extra reservoir-
to enable metered vo/vmes of salt to be pumped
into the surge tank for calibrating the venturi. The
furnace for heating the pwmp and reservoir is also
shovvn. From performance tests with this setup,
pump speed vs head and pump speed YS flow have
been determined. At 5000 rpm the flaw was 4 Cps,
corresponding to a Reynolds number of 3000 in ea
200-mil tube. At the 540 w/cm3 generated in-pile,
die temperature differential is expected to be about
10PF.
LIFE TESTS ON AN RPM METER, BEA
AND A SMALL ELEtfRlC MOTOR UNDER
~ ~ ~ A ~ l ~ Y
ION
J. G., Morgan M. E. Robertson
G. W. Keilholtr
Solid State Division
Tests were conducted on an RPM meter, bearings,
and a small electric motor as a part of the de-
velopment of n loop fox insertion in an LdTR A-
piece, In order to drive the pumpr it is desirable
to USE a variable-speed electric motor and to align
the shah with lubricated bearings. Also, a record
of shaft speed would be desirable. The entire
motor assembly will be just above the upper grid
guide in the LBTR sand in an estimated thermal
flux of 5 fi lQ1 neutrons/cm2.sec. Hole 53 of the
ORNL Graphite Reactor provided a comparable flux
intensity and was used fur these tests.
The in-pile apparatus, with a single lower bearing
as in the second test, is shown in Fig. 9.3, A
motor was mounted in a horizontal position with
upper and lower armature shaft bearings. In the
first test two lower bearings were used. The motor
and RPM meter were canned and inserted into
the center line of the reactor. The variobles
measured were resistance of the motor winding,
resistance of the RPM coil, the voltage applied
to the motor, the current drawn by the motor, the
temperature of the lower Fafnir bearing, the temper-
ature of the motor field, and the speed of the motor
shaft.
The Delco ac-dc motor used is rated at 115 v,
13.9 amp, and b5 hp and has insulated wires. Some
substitutions of materials were made. In the first