ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
leakage as a function of operating time. The speed
of the pump was maintained at 2400 rpm during the
period described by Fig. 1.4 1. In addition to the
temperature fluctuations shown on the graph, the
temperature of the system was cycled 17 times
between 1300 and 1100OF. It takes approximately
I t hr to lower the temperature to llOO°F and
25 to 3 hr to increase it to 1300OF. The Iubri-
cating oil being used in the system is Gulfspin 60.
Helium is being bled down the pump barrel at a
rate of 550 liters/day, and 50 liters/day is bled
off through the catch-basin drain. Present indi-
cations are that low leakage rates and satisfactory
removal of seal oil leakage from the catch basin
can be obtained.
Thus far very little trouble has been experienced
in the operation of this pump. The hydraulic-drive
equipment has functioned satisfactorily, except for
some trouble with the hydraulic pressure indicator.
Fuel Pump Development Tests
J. J. W. Simons
The two loops designed6 for high-temperature
performance testing of the ART fuel pump and
centrifuge assembly were completed and are being
used for development tests. Water performance
data were taken on these loops to determine whether
the addition of the xenon-removal system would
have an effect on pump performance.
The head and flow curves obtained for these
loops substantiated the original water-test data.7
During the tests it became apparent, however, that
the system pressures were not stable. The fluc-
tuations in system pressure appeared to be a
function of the water level in the fuel expansion
tank and the loop resistance. In some instances
these fluctuations appeared to be large enough to
be detrimental to reactor operation.
Two types of modification will be made to the
system in an attempt to locate and remove these
fluctuations. First, the pump suction inlet con-
ditions will be improved, and, second, the xenon-
removal system will be altered to study the effects
of each of the various flow passages.
Sodium Pump Endurance Tests
S. M. Decamp
Preliminary water tests of a sodium pump that
had been installed in a test stand for endurance
50
testing indicated that leakage, or bypass flow,
around the impeller was causing ingassing of the
system. The pump and the loop were therefore
modified, as described in the following section,
by providing a pressure-breakdown labyrinth along
the shaft ond by removing the bypass vanes from
the back face of the main impeller. The system is
now being prepared for high-temperature operation.
As in the fuel pump endurance tests, described
above, seal leakage tests will be run before the
system is filled with the test fluid.
Sodium Pump Development Tests
S. M. Decamp
The original design of the ART sodium pump
(model MN) called for the bypass flow around the
main impeller to be from the expansion tank to the
pump discharge. This was to be accomplished
with the aid of vanes on the back side of the main
impeller. During the first series of tests of this
pump, however, it became evident that the system
was ingassing. In an effort to correct this situation
the bypass flow was reduced by reducing the vane
diameter on the back of the impeller, but ingassing
still occurred. It was decided then to reverse the
direction of bypass flow, that is, to allow the flow
to be from the pump discharge to the expansion
tank. This flow condition allows the gas bled
down the pump shaft to flow to the expansion tank
in the same direction and through the same opening
as that through which the bypass liquid flows.
This reversal of flow was accomplished by com-
pletely removing the bypass vanes from the back
of the sodium impeller. The amount of reversed
bypass flow was restricted by adding a pressure-
breakdown labyrinth around the shaft. Tests of the
modified pump indicate satisfactory operation.
Tests are now under way to determine whether the
expansion tank and the bypass flow lines can
handle reactor bypass flow requirements without
ingassing of the system fluid. The best sodium
pump performance data obtained to date are pre-
sented in Fig. 1.4.2.
assignment from Pratt & Whitney Aircraft.
6R. Curry and H. Young, ANP Quar. Prog. Rep. Sepf.
10, 19.55, ORNL-1947, p 44.
7R. L. Brewster et al.. ANP Quar. Prog. Rep. Sept. 10,
1955. ORNL-1947, p 29.