ORNL-1816 - the Molten Salt Energy Technologies Web Site

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In further chemical studies of corrosion, informa-
tion was obtained on the effect of temperatures
and of chromium additions on the corrosion of
Inconel by fluoride melts with NiF, additions.
7. Metallurgy and Ceramics
The nickel-molybdenum-base alloys are being
studied extensive1 y as possible reactor structural
materials withqualities superior to those of Inconel.
Attempts are being made to improve the ductility
and the fabricability of commercial Hastelloy B
through purification and to find another suitable
and improved nickel-molybdenum-base alloy that
has the strength and corrosion resistance of Hastel-
loy B. The results of attempts to improve the
fabricability of the materials are being evaluated
by extrusion experiments because extruded seamless
tubing will be required if any of these alloys are
to replace Inconel as a reactor structural material.
Temperature-cycling tests in air were performed
with Hastelloy B and other nickel-molybdenum
alloys to determine the behavior to be expected in
an NaK-to-air heat exchanger such as will be
required for aircraft application. These tests have
shown that oxidation protection will be required.
Three radiator test specimens have been con-
structed of Hastelloy B for studying the fabrication
methods and for determining the thermal shock and
oxidation resistance of a complicated assembly.
The specimens contained 20 tube-to-header joints,
which were inert-arc welded by using semiautomatic
welding equipment, and 3 in. of Inconel-clad copper
fins spaced 15 fins per inch and brazed to the tube
with Coast Metals alloy No. 52. The individual
tube-to-header joints were back-brazed, The fabri-
greatly improved by an aging treatment prior to
on the creep properties of Hastelloy B, Inconel,
and other alloys for use at high temperatures.
PERIOD ENDING DECEMBER 10,1954
Several of the new nickel-molybdenum alloys are
being tested to determine their load-carrying abili-
ties.
A study of the flow of metals during an impact
extrusion is being made as a part of the efforts
to produce duplex seamless tubing that will have
good oxidation resistance on the outer surface and
good corrosion resistance on the inner surface.
Several sui tab1 e B4C-contai ning compositions
have been developed for the shield for the ART
heat exchanger; various nonmetallic bonding ma-
terial s can be used.
Thirty-five control rods are being prepared for
the GE-ANP project that contain a mixture of 50%
aluminum powder and 50% B,C. Fuel plates are
being prepared for a study of the effect of delayed
neutrons on the over-all shield weight of circu-
I ating-fuel ref1 ector-moderator reactor s.
A finned surface for a fused salt-to-air heat
exchanger being considered for use in conjunction
with an in-pile forced-circulation loop was fabri-
cated and tested for corrosion resistance to the
fused salt. The corrugated fins were formed from
0.010-in.-thick nickel sheet and were brazed to a
3/8-in.-OD lnconel tube with cin 82% Au-18% Ni
brazing alloy. A 0.020-in.-dia nickel wire was
used as a spacer between eac:h fin segment, and
it served to provide a capillary path for the braze
alloy, which was preplaced at the fin interlock
joint only. The braze alloy used was found to have
excellent resistance both to air and to the fused
sa It.
Beryllium oxide ceramics were produced, proba-
bly for the first time, by casting from a basic slip.
Hitherto an acid had been considered to be neces-
ip. This
ing done in an effort to prepare beryllium
8. Heat Transfer and Physical Properties
forced-convect i on hea t tran s fer
ith the ARE fuel, NaF-ZrF,-UF,
(55.5-40-6.5 mole %), in an lnconel tube, yielded
heat transfer coefficients which differed from
expected values by only 24% after 115 hr of oper-
determined. The
mathematical velocity and temperature distributions
for severa I free-convection vo Iu me-heat-source
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