ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
decrease in ductility observed in either alloy.
The ductility of lnconel remained constant between
800 and llOOOF at the slower strain rate and
between 800 and 12OOOF at the faster strain rate.
At higher temperatures the ductility steadily in-
creased. The ductility of Nichrome V decreased
steadily as the temperature was increased from
800 to 14OOOF.
Both alloys showed stress fluctuations at both
strain rates, the fluctuations being more noticeable
at the slower strain rate, but this may have been
the result of the inadequacy of the recording
system at high speeds. In the tests on lnconel
the stress fluctuations were present at tempera-
tures from 500 to 12OOOF and were largest in
number and amplitude between 600 and 9500F.
The lower temperature limit of these fluctuations
has not yet been determined for Nichrome V, but
the upper limit seems to coincide with that of
Inconel.
Specimen2 of Monel, Inconel, and Nichrome V
have been prepared for testing in the LlTR (and
later in the MTR) to determine the effect of irradi-
ation on ductility. Out-of-pile tests will be made
on the Hastelloys.
EFFECT OF RADIATION ON STATIC
CORROSION OF STRUCTURAL MATERIALS
BY FUSED-SALT FUELS
W. E. Browning H. L. Hemphill
The study of the effect of radiation on the corrosion
of lnconel capsules containing static fusedsalt
fuels was ~ontinued.~ Two additional lnconel
capsules containing the fuel mixture (No. 30)
NaF-ZrF,-UF, (50-46-4 mole %) were irradiated
in the MTR for six weeks each at 15oooF at a
power density of approximately 3.5 ckw/cm3. Two
other lnconel capsules containing the fuel mixture
(No. 44) NaF-ZrF,-UF, (53.5-40-6.5 mole %) are
being irradiated at 15oooF at a power density of
approximately 6 kw/cm3.
Further mockup tests were run on Hastelloy B
capsules under simulated MTR conditions. A
method was developed for mounting thermocouples
on the capsules without damaging the chromiumnickel
plating required to protect the capsule from
the atmosphere. Hastelloy B capsules are being
prepared for bench tests and for MTR irradiation.
7W. E. Browning and H. L. Hemphill, ANP Quar. Ptog.
Rep. March 10. 19-56, ORNL-2061, p 192.
238
They will be filled with an NaF-YF-LiF-UF, fuel hs
mixture containing approximately 25 wt % enriched
uranium and LiF enriched in Li7.
LlTR VERTICAL IN-PILE LOOP
D. E. Guss'
M. F. Osborne
W. E. Browning
H. E. Robertson
R. P. Shields
A vertical in-pile loop, which was essentially
the same as the one operated previously,' was
installed in the LlTR and put into operation; how-
ever, the pump stalled when the reactor was
started. By reducing the pump temperature it was
possible to operate the loop with the reoctor at
500 kw; but at higher power levels the temperature
drop in the loop wos great enough to freeze the
fuel in the cold leg. The pump stalled permanently
during an effort to increase the pump temperature
gradually so that the reactor could be brought to
full power. The specifications for the power
characteristics of the loop were: toto! power,
11.5 kw; maximum specific power, 577 w/cm3;
dilution factor, 7.64.
While the cause of the pump failure cannot be
precisely determined until the loop has been
examined, it is known, from the sounds emanating
from the pump and heard through a microphone,
and from variations in electric power demands of
the motor, that contact of moving solid parts
overloaded the motor.
The parts that had already been fabricated for
three additional loops will be changed to eliminate
most of the possible causes of pump failure. The
changes will include a shorter, more rigid impeller
shaft and improved bearings. Also, pump models
are being tested to determine the effect of in-
creasing the clearance around the pump impeller.
When these tests are completed, existing parts
will be modified and assembled for bench and in-
pile tests.
Although failure of the pump prevented operation
of the loop, the experiment provided a test for the
reliabil ity of other components. Thermocouples,
heaters, safety circuits, the temperature control
system, the tachometer, the lead wires, and the
entire instrumentation system performed satis-
factorily. Platinum-platinum-rhodium thermo-
'On assignment from United States Air Force.
'G. W. Keilholtz et al., ANP Quar. Prog. Rep. Sept.
10, 1955, ORNL-1947, p 164.