ORNL-4191 - the Molten Salt Energy Technologies Web Site

difficulties in the system, there was sufficient
lubrication, and no noticeable damage was ob-
served.
Although the temporary strainer in the CCP dis-
charge line worked satisfactorily, a more efficient
strainer, which had been on order for a year, was
received and installed in the line. Over an eight-
month period the temporary strainer accumulated
-30 to 50 g of black, dry powdery material that
appeared to be dust from abrasion of the drive
belts. The new stiainer, however, has a 100-mesh
screen and a 0.2-psi pressure drop as compared
with a %6-in. pore size and a 0.5-psi pressure
drop in the old strainer.
The improved performance of the blower belt
drives, which have not needed replacing during the
past nine months, is attributed to less frequeiit
staiting and stopping of the blowers as well as to
the reinforced motor support. During early opera-
tion, the blowers were alternated twice a month;
now one blower is operated continuously during a
run.
‘The stainless steel strainer which was removed
had been in contact with condensate containing
dilute HNO, while in service (see “Containment,”
p. 33). After being decontaminated, the strainer
was examined and was found to be in vety good
condition. The surface was slightly etched, but
no more than would be caused by the decontamina-
tion process.
Blower CCP-3, which cools out-of-containment
freeze valves, failed on April 19 after more than
5000 hr of operation. A bearing galled and damaged
the drive shaft. Operation continued without inter-
ruption by using air from the service air compres-
sor. Blower CCP-3 has been repaired and can no:v
be used when required.
Salt Bump Oil Systems
A. I. Krakoviak
The lubricating oil systems for both salt pumps
have been in continuous service except during the
planned oil change during the shutdown after run
11. At this time the oil was sampled, drained, and
replaced with new oil. The oil, which had been
in service since August 1966, showed no signifi-
cant change in its physical or chemical properties.
During the steady full-power operation in run 11,
very good balances were obtained on the oil sys-
tem inventory changes, indicating little or no loss
30
by leakage into the pump bowl. The measured
amounts removed for analysis and accumulated in
the catch tanks actually slightly exceeded the ob-
served decreases in supply reservoir contents.
In March and April the difference was 65 cm3 in
the fuel pump system and 210 cm3 in the coolant
pump system
The oil leakage through the lower seal of the
fuel-pump shaft had previously accumulated at the
rate of 5 cm3/day; it has now decreased to * 1
cm3/day. The leakage past the lower seal of the
coolant salt pump averaged 17 cm3/day during run
11 arid 30 cm3/day during run 12; the present ac-
cumulation rate is 15.
Automatic siphons were originally installed on
the oil collection tanks from both pumps to meas-
ure and dispose of seal leakage without manual
draining to keep the level in the sensitive (reduced
cross-sectional area) range of the level-measuring
leg of the collection tanks. These siphons have
failed to funct-ion properly at the low oil leakage
rates that actually occurred. The oil simply flows
over the high point of the siphon tube, much like a
liquid flowing over a weir, without bridging the
tube to form a siphon. The overflow points for the
coolant pump and fuel pump oil collection tanks
were reached in March and April respectively.
For the remainder of run 11 the only indicators of
leakage rate were the supply reservoirs, which
are much less sensitive than the leakage collec-
tion tanks, After run 11 the collection tanks were
drained, and the average leakages for the latter
part of the run were determined by measuring the
total accumulated oil leakage. The collection
tanks were drained again after run 12, and periodic
drainings are planned to keep the oil level. below
the siphon (overflow) level. (3ecause there is a
high radiation field at the collection tanks, during
power operation the draining operations must be
performed only when the nuclear power is low. If
high leakage rates (500 to 1000 cm3/day) develop,
the antomatic siphons are expected to function as
de signed,
Although the oil from the coolant pump seal
when sampled had a dark appearance, spectro-
graphic and infrared spectrophotometric analyses
showed no significant difference between the seal
leakage oil and a sample of unused oil. The dark
appearance and the somewhat increased leakage
rate past the seal could be an indication of ab-
normal wear at the Graphitar-stainless steel
rotary seal. of the salt pump. The soinewhat lower