ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
PUMP DEVELOPMENT
E. R. Dytko' A. G. Gindell
Bear in g-a nd-Sea I Deve I opme n t
W. L. Snapp1 W. K. Stair2
The maximum operating temperature expected in
the lubricating and cooling fluid used in the ART
reactor pumps is approximately 220OF. For an
operating period of 500 hr, with an oil dilution
factor of approximately 0.03, the integrated radiation
dose absorbed by this pump lubricant is calculated
to be 3 x lo8 rep. Therefore it will be
possible to use a lubricant with a mineral-oil base
for the ART pumps.
Since a petroleum product could not be used if
the operating conditions given above became more
severe, tests were continued3 in an effort to find
a liquid more suitable for higher performance.
Important factors affecting the choice of liquid are
compatibility with the materials of construction
(that is, elastomers) and process fluids, radiation
stability, thermal stability, heat removal capacity,
and lubricating properties. The loads that will be
imposed on the pump bearings will be light, and
therefore the lubricating properties are of only
secondary importance. The other considerations
listed are all of primary interest and are closely
interrelated.
After the failure of the UCON fluids to perform
sati~factorily,~ the next synthetic liquid investigated
was an organic-phosphate-based material
manufactured under the trade name "Cellulube" by
the Celanese Corp. of America. Cellulube 150
was the particular grade selected for evaluation
testing, since it most nearly approximated the
operating properties of the I iquids previously
tested.
The initial test of Cellulube was made at a temperature
of 210 to 220OF in a fuel pump (model MF)
rotary element in a mechanical shakedown test
stand. Over the entire operating period of 636 hr,
the leakage of the lower seal was too small to be
measured. The total leakage of the upper seal was
'On assignment from Pratt 8 Whitney Aircraft.
Consul tant, off i I iated with the University of Tennss see.
3W. L. Snapp and W. K. Stair, ANP Quat. Ptog. Rep.
Match 10, 1956, ORNL-2061, p 43.
46
1.4, COMPONENT DEVELOPMENT AND TESTING
H. W. Savage
430 cm3. The unit was disassembled after this
636-hr period of satisfactory operation, and inspec-
tion revealed fully developed uniform wear patterns
on both seals. However, the wear path on the
upper seal rotor exhibited a ring, which, upon
examination, proved to be a copper deposit, Al-
though it was known that Cellulube would attack
copper at high temperatures, attack was not ex-
pected at the operating temperature of this test.
With the exception of the upper seal, which was
replaced entirely, the unit was reassembled, in-
stalled in the same stand, and operated under the
same conditions for an additional 480 hr. During
this period the operation was, again, completely
satisfactory, with the total leakage of the upper
seal being 70 cm3. Since all the leakage occurred
during the first 24 hr of operation, it may be con-
sidered as "run-in" leakage. The lower seal
leakage totaled 40 cm3 for the 480-hr period. This
low leakage rate is particularly significant because,
when seals tested with other fluids were dis-
assembled, inspected, reassembled, and tested
again, with the same fluid, the retest leakage rates
were always higher than those measured initially.
Inspection of both seals after the test revealed a
very light reflective film of copper on all surfaces
exposed to the Cellulube.
A second test of Cellulube, again at a tempera-
ture of 210 to 22OoF, was conducted on a model MF
fuel pump rotary element mounted in a bearing-and-
seal test stand which permitted the application of
transverse shaft loads. The total operating time
was 595 hr, with an equivalent iournal bearing
load of 150 Ib being applied for the last 504 hr.
The iournal bearing, which was designed for a
load of only 70 Ib, suffered no measurable wear,
and seal performance throughout the test was
satisfactory. Both the upper and the lower seals
had well-developed wear patterns, with a very
slight trace of copper plating visible on all sealing
surfaces. It should be noted that all the copper
plating experienced during the testing of Cellulube
was far less than that resulting from operation with
the UCON fluid^,^ and it did not appear to have a
marked effect on seal performance.
All the elastomer O-ring seals used in the -
Cellulube tests had a Buna-N base. Such com-
pounds have a tendency to swell, become tacky,
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