ORNL-1816 - the Molten Salt Energy Technologies Web Site

ANP QUARTERLY PROGRESS REPORT
main sources: the activity of the cobalt in the
lnconel and the activity of the fission fragments
that strike the lnconel and remain there. The
analysis showed that little would be gained by
trying to obtain cobalt-free Inconel, since the
activity could not be reduced below that caused
by the fission fragments. Adjustments are being
made in the constants used in multigroup calcu-
lations in order to decrease the disparity between
the calculations and the results of critical experi-
ments.
The various types of facilities suitable for the
operation of the ART have been considered, and it
is now planned to install the reactor assembly in a
double-walled container with a water-filled annulus.
The type of container was selected after careful con-
sideration of the hazards involved in the operation
of the reactor. This typeof installation provides for
containing the products resulting from a nuclear
accident and/or chemical reaction of all combusti-
bles in the installation, minimizing the likelihood
of serious damage from an explosion caused by
sabotage or bombing, and removing and disposing
of volatile fission products evolved during the
course of operation.
3. Experimental Reactor Engineering
Progress has been made in the design and testing
of components for a horizontal, entirely enclosed
loop for insertion in an MTR beam hole. The loop
will be used to circulate proposed reactor fuels in
the MTR flux so that radiation effects on the fuel
can be studied. A layout arrangement of the loop
has been made and is being improved consistent
with specification and component changes. Tests
of two horizontal-shaft sump-type pumps were made
with the fluoride mixture NaF-ZrF, circulating at
a temperature of 135OoF for 500 and 1000 hr,
respectively. The Graphitar-lapped steel face
plates wore considerably in both tests, but they
did not fail. A single-tube salt-tooair heat ex-
changer that will fit inside the beam hole has been
fabricated.
Sump pumps of the type used in the ARE are
being evaluated for application in large-scale heat
exchanger tests, and pumps for ART use are being
developed. One ARE-type sump pump is being
tested at K-25 for performance and life determina-
tions. The pump is operating at pump speeds of
up to 1500 rpm at a maximum capacity of 40 gpm,
and it is circulating the fluoride mixture NaF-ZrF,-
UF, at a maximum pump inlet temperature of
135OOF. Operating time now exceeds 3000 hr.
The pumps for the ART inherently possess many
imposing design problems because of the- large
capacity requirements: fuel pumps, 650igpm,
50-ft head; sodium pumps, 430 gpm, 125-ft head;
NaK pumps, 2800 gpm, 280-ft head. Investigations
of impeller cavitation characteristics and inlet
and entry conditions are being made, along with
studies of sealing, cooling, lubricating, and driving
problems.
Forced-circulation corrosion and mass transfer
tests with fused salts in lnconel systems are under
way. Considerable difficulty has been experienced
with failures of the thin-walled tubing (\-in, OD,
0.020-in. wall thickness) at bends and welded
joints. The loop design has been altered by elimi-
nation of the economizer and by using 0.045-in.-
wall tubing. One loop of the modified design is
now being operated and has accumulated about 150
hr at a Reynolds number of 10,000 and a tempera-
ture gradient of 200°F.
A third bery I I i urn-sodi urn- lncone I mass transfer
test has been completed following 1000 hr of
operation. The maximum operating temperature (at
the beryllium section) was 1300°F, and the
Reynolds number was about 190,000. Another
similar loop has been fabricated and is being
assembled. A loop in which sodium will be circu-
lated in type 316 stainless steel is being fabri-
cated.
The heat exchanger test program has included a
header leak test and a series of pump tests with
an ARE moderator-coolant type of pump. The
header leak test (fuel to NaK) showed that self-
plugging of an NaF-ZrF,-UF, fuel through 0.002-
in.-dia leaks can occur. The pump tests showed
that speeds of up to 3700 rpm could be safely
achieved with this type of pump.
Developmental work on a gas-furnace heat source
that can be used in large heat exchanger tests was
continued. A sodium-cooled 100-kw furnace was
tested for about 120 hr before a gross leak termi-
nated further operation. An output of 85 kw was
obtained at a sodium outlet design temperature of
1500OF. Two natural-gas burners, based on Q
design development of the Esso Marketers, were
built and tested. Heat releases of 400 kw at
310OOF were achieved with the first burner, and
1 Mw at 330OOF was obtained with a second
burner that was improved on the basis of the data
obtained from the first burner.