ORNL-1816 - the Molten Salt Energy Technologies Web Site

ANP QUARTERLY PROGRESS REPORT
and operation is being prepared. Modifications of
this vapor trap design could be used on other
fused salt systems in which reliable gas con-
nection is important.
ADlNG OF THE ARE
N. V. Smith
installations for the
loading of the ARE were completed during the
month of October. Transfer of the barren carrier
(NaF-ZrF,, 50-50 mole %) into the ARE fill tank
ompleted in approximately 43 hr
t. Approximately 2750 Ib of carrier
ded into the fill tank, and sufficient
n hand to fill the fuel system to
its operating liquid level.
The enriched fuel storage tank had previously
been loaded with 60 Ib of carrier material for
practice injections into the reactor. Tests indi-
cated that the semiautomatic enrichment system
was inadequately heated, and therefore equipment
for addition of portions of the fuel concentrate
(Na,UF,) directly to the circulating fuel pump
was designed and assembled.
In order to provide adequate means for ap-
proaching criticality safely, some of the original
30-lb batches of concentrate were reduced to
10-lb batches, and, similarly, to provide accurate
measurements for calibration of the control rods
after criticality, 12 small batches of approximately
0.5-lb size were prepared from a 30-lb batch.
The injection system consisted of a main con-
centrate can (containing 30, 10, or 0.5 Ib as
ed) connected to an intermediate transfer
can by a resistance-heated \-in. lnconel tube.
The intermediate transfer can was designed so
that it could be filled to a predetermined level
(approximately 5.5 Ib) when the 10- or 30-lb
batches were in position to be transferred. The
0.5-lb batches were transferred through a smaller
intermediate can, which contained the entire small
time of transfer. The intermediate can
rn, connected to the fuel pump. The
main transfer line to the pump was heated by
calrod units, while the nozzle within the pump
18
was heated by resistance heating. The close
tolerances of the injection nozzle resulted in an
inherent tendency to short out and cause the
nozzle tip to be cold. This, coupled with the
drainage of high-melting-point material from the
long transfer line, always presented the possi-
bility of a frozen-fluoride plug.
The first 30 Ib of concentrate was injected into
the fuel pump without apl;arent difficulty. After
this injection, however, difficulties in the form
of line plugs and venting troubles frequently
occurred. After 48 hr, most of these problems
were under control, and loading of the enriched
concentrate proceeded smoothly. The reactor was
brought to criticality, and small injections of
0.5-lb batches were made for the control rod
calibrations. At the completion of the final small
addition, the transfer line broke and simultane-
ously plugged at the injection nozzle. Efforts to
repair the damage were fruitless, and the final
injection of 30 Ib of the concentrate to allow ARE
operation at power was made through the sample
line into the pump.
ANALYSIS OF LEAK IN SODIUM SYSTEM
E. E. Hoffman W. H. Cook
C. F. Leitten
Metal lurgy Division
The sodium system of the ARE was filled
initially on September 26, 1954, but the sodium
had to be dumped on September 27 because of a
leak at a tube bend in the sodium purification
system. The section of austenitic stainless steel
pipe in which the leak occurred was located just
ahead of the filter traps. The system had been
filled with sodium for 37 hr and had reached a
maximum temperature of approximately 1150°F
before the leak was detected. A portion of the
section removed and the location of the leak are
shown in Fig. 1.6. The leak occurred where a
metal thermocouple protection tube had been at-
tached to the stainless steel pipe by Heliarc
welding. The attack around the weld was due to
the formation of sodium oxide as the sodium
leaked through the weld. The inside of the pipe
at the weld may be seen in Fig. 1.7. An ex-
cessive amount of penetration was obtained during
the welding operation. The large weld nugget
cracked during cooling after welding. A cross
section of the weld crack is shown in Fig. 1.8.
Examination of the pipe in this section revealed
a
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