ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
The connections of the loop tubing at the pump
have been redesigned for the second loop to provide
a filling and drain line. This will permit charging
the loop with a non-uranium-bearing fluoride mixture,
circulating it at operating temperature, and draining
it before the loop is inserted into the reactor. 'The
danger of tube rupture because of expansion of the
fuel on melting necessitates the draining and
refilling feature, if operating tests are to be carried
out. The necessary changes in the pump shield
to accominsdate the drain and fill line are being
made.
TheMetaIlurgy Division will supervise all critical
welding and has provided specifications for an
improved weld joint developed for lnconel tubing.
The components fabricated previously for the
second loop are being changed to conform to the
specifications for the new weld joints, A new
flange for closing the rear of the jacket has been
made in order to give more space for making pipe
connections to the large air lines required for the
heat exchanger.
During installation of the loop in the reactor an
unexpectedly long time was required to connect
heater leads, thermocouple leads, and air, water,
and helium piping in the confined space available
between the shielding and the instrument panel,
The piping at the reactor dace is being revised
to facilitute connection when the second loop is
ready for insertion so that installation nwy be
performed more rapidly. Modifications are 0lso
being mode to remove lag in the flow alarms for
the jacket cooling water, The oil systamfor cooling
the pumps is being rebuilt to incorporate more
reliable punips and improved flow and alarm instru-
ments.
A hydraulically operated door to match the with-
drawal shield has been installed i;i a wall of I hot
cell in preparation for handling the loop after
irradiation, A horizontal band SQW has been modi-
fied for nlnnost complete remote operation and is
being installed in the hot cell. Other remote kan-
dling tools for disassembling the loop have been
made and are being tested.
0 R Ed h G R A P H BY E R E A C T OR SOD i Ls $4 -I NC 8 N E L.
LOOP
W. E. Brundage W. 'A'. Paikinsori
Solid State Divisiori
Metallographic examination WQS completed on un
lnconel loop which had circulated sodium in hole
142
58-H of the ORNL Graphite Reactor for 218 hr with
the irradiated section at 1500°F. The unperturbed
thermal flux in this hole is about 7 x lo", and
the flux above 1 ev is a factor of 10 lower. There
was no evidence of radiation induced corrosion of
the Incanel. The temperuture of the pump cell
section was held between 1025 and 1100"F, and
that of the line entering the reactor was somewhat
higher; the temperature of the line emerging from
the reactor was about 1500°F. Before insertion
in the reactor the loop had been operated at 800
to 1000°F for 80 hr while sodium was circulated
through the loop and through a bypass filter circuit
connected to the loop.
CREEP AND STRESS-CORROSION TESTS
w. w. DClVi§
J, C. Wilson
N. E. Hinkle J. C. Zukas
Solid State Division
Development of Q suitable apparatus for in-pile
stress.corrosion experiments has bDen slow be-
cause of difficulty in securing constant heat-
transfer rates from the fuel to a heat sink where
the fission heat can be removed. In the design
shown in Fig. 9.7, fission heat is conducted from
the fuel through the stressed specimen wall to a
sodium-filled annulus. The sodium acts as an
efficient he& conductav that exerts no constraint
upon thc defo:mation of the specimen tube as it
creeps under applied stress. Part of the fission
heat is removed by gaseous convection at the outer
surface of the sodium-containing chamber and part
by conduction through a metal ring to a water
iacket. Simpler designs in which the sodium was
contained in u constant-diameter annulus did not
permit good temperature control. The temperature
gradient that resulted from simulated fission heat
input at the bottom and heat abstraction at the
top caused heated sodium to rise discontinuously
in the annulus, and temperature excursions of
100°F in 1 sec were not uncornrnon. A substantial
temperature gradinnt (500 to 800°F per in.) is
required to meet headioum requirements in the
experiniental hole and to prevent sodium distil-
lation out of the annulus.
Several designs of the sodium annulus were
tried, such as baffles and spirals, and ratios of
outs ide-to..i nsicde sodiuni-nnnu lu s di ameters were
varied but did not result in a constant temperature
-
gradient. I he appa'ratus shown in Fig. 9.7 appears
to operate satisfactorily, but more operating time