ORNL-1771 - Oak Ridge National Laboratory

ANP PROJECT ESS T
PART 1. REACTOR THEORY, COMPONENT
DESIGN AND TESTING, AND CONSTRUCTlQN
Circulating-Fuel Aircraff Reactor Experiment
The water tests of the fuel and the sodium cir-
cuits of the ARE system at room temperature were
completed (Sec. 1). The sodium circuit was pres-
sure-filled with water from the sodium fill tanks,
while the fuel system was vacuum-filled ‘io ensure
the elimination of gas pockets in the fuel system.
Both systems were found to function properly, and
the fiiiing, circulating, and draining operations
%ere effected with a minimum of difficulty. After
the water was drained, the system was dried by
heating it to approximately 600°F. The electrical
heating system was found to be satisfactory in
the check thus afforded.
The final system completion work is now under
way, that is, removal of the sodium system reactor
bypass, completion of the fuel-enrichment system
installation, completion of thermocouple and insu-
lation installation, and other minor modifications.
When this work is completed, sodium will Le
charged to the system and the high-temperature
checkout phase of the experiment will be initiated.
The neutron source was put into the reactor, and
the nuclear instrumentation was checked out.
Also, mechanical checks were made of the per-
formance of the safety and control rods. The
building electric and helium systems were made
ready to accommodate the loading facilities, and
final arrangements were completed for attaching
the fuel-sampling equipment.
Radiation damage experiments indicated the de-
sirability of providing gamma shielding at several
points where elastomers were used (belts, dia-
phragms, etc.). Where shielding was impractical,
the composition diaphragms were replaced with
metal diaphragms.
The results of operation of the reactor system
component test loop at K-25 are encouraging in
that the loop has now been operated without major
difficulties for more than 1800 hr. None of the
minor difficulties encountered would indicate that
serious problems might arise in operation of the
ARE,
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Reflector-Moderated Reoctar
The program for the development arid construc-
tion of the Circulating-Fuel Reactor Experiment
(CFRE) has been outlined, and many of the de-
velopment psolects are under way. Tentative
design data have been compiled and a flow sheet
has been prepared (Sec. 2). The first priority
development proiect, the test of beryllium in con-
tact with sodium and lnconel under thermal stress,
has been completed, The results of this test were
needed in the determination of the amount of
poison to Le expected in the reflector. The test
indicated that. beryllium will not crock under the
thermal stresses involved in the temperature range
1000 to 1300°F. Since corrosion and mass transfer,
a5 well as thermal stress, will be important in the
beryllium-lnconel-sodium system, many static and
dynamic tests under various conditions have been
made. There is considerable evidence to indicate
satisfactory compatibility in the bery Ilium-lnconel-
sodium system at temperatures up to 1200°F.
The temperature coefficient of reactivity for the
CFRE was computed on the UNIVAC and, for rapid
temperature changes, was found to be -3.5 x
lO-’/’F. The critical mass computed for the
shomticuboctahedral critrcal assembly was rede-
termined because of errors found in the original
data. The redetermined value agreed closely with
the experimental value, but, since the critical
mass is not very sensitive to errors in detail,
further evaluation of the agreement must await
additional experimental results..
Experimental Reactor Engineering
The emphasis in the engineering work is now
on development of components for an in-pile loop
for insertion in a horizontal beam hole of the MTR
and the design and construction of forced-circu-
lation corrosion testing loops (Sec, 3). The in-pile
loop for insertion in the MTR is a joint ORNL and
Pratt & Whitney Aircraft Division project. It is
to circulote proposed fuel mixtures in the high-flux
of the MTR so that the extent of radiation damage
to materials of constructton and the effect of radi-
ation on the fuel can be determined. Two types
of pumps have been developed for in-pile use: a
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