ORNL-2106 - the Molten Salt Energy Technologies Web Site

the first 200OF and B0F/sec for the next 10OOF.
The final 100°F drop is at a slower rate in order
to allow the outlet temperature to level out
properly. The transition from power to isothermal
operation is accomplished at a rate of 10°F/sec
for the first 100°F, S°F/sec for the final 1OOOF.
The radiator has been cycled 20 times, ahd the.
cycling program is continuing.
The air pressure drop datalo obtained for York
radiator No. 9 substantially agree with the data
for York radiators Nos. 1 and 2, and the heat
transfer data substantially agree with the datalo
for Cambridge radiators Nos. 1 and 2. Thus far
the NaK pressure drop has increased 119% above
the initial level (219% of ,the initial value). This
radiator is the first 500-kw radiator of the revised
designll to be tested, and it is identical to York
radiator No. 7 illustrated in Fig. 1.4.8 of the sub-
sequent section, “Small Heat Exchanger Tests,”
of this chapter.
ORNL heat exchangers Nos. 1 and 2, type
IHE-3 (ref. 12), were removed from intermediate
heat exchanger test stand B and are undergoing
metallurgical inspection. Preliminary results of
this insp,ection reveal that heat exchanger No. 1
(NaK-to-fuel heat exchanger) failed in the hot end
between the header,weld and tube bends (see
Chap. 3.4, “Welding and hating Investigations”).
Severecorrosion was evident on the fuel side of the
tubes. Five tubes had obvious cracks in the
tension side. The frequency and severity of the
cracks were most pronounced in the end row of
tubes where the distance between the tube bends
and header was the shortest. A maximum of 15 mils
of moss-transferred deposit was measured on the
NaK side of this heat exchanger (Fig. 1.4.7). No
evidence of mass transfer was detected in heat ex-
changer No. 2 (fuel-to-NaK heat exchanger). Mass
transfer buildup would account for he NaK pres-
sure drop increase experienced during nonisothermal
operation. Pressure drop was not measured in the
individual heat exchangers. However, if it is
assumed, on the basis of the mass-transfer evi-
dence, that al l the pressuredrop increase occurred
in heat exchanger No. 1, the total pressure drop
l0J, C. Amos, ANP Quar. Pmg. Rep. March 10, 1956,
ORNL-2061, p 54.
llE. R. Dytko et aL, ANP Quat. Pmg. Rep. March 10,
1956, ORNL-2061, P 52.
12R. D. Peak et al., ANP Quar. frog. Rep. Dec. 10,
1955, ORNL-2012, P 41.
PERIOD ENOlNG JUNE 10, 7956
TUBE INSIDE WALL
3.004 -
DD02 -
D.003
0.004 __
KO05
0.006 -
OL07
-%-
0 I
- 5 --
_. _-
0*04 _. 4 -
0.042
O.Ot3
-- 0.014
- 0.015
0.046
Fig. 1.4.7. Maximum Mass Transfer Found in
NaK Circuit of NaK-to-Fuel Heat Exchanger (ORNL
No. l), Type IHE-3, Which Operated 1825 hr in
Intermediate Heat Exchanger Test Stand B. (M
WirktaPtidR)
increase for this heat exchanger was approximately
180%.
Black, Sivalls and Bryson Nos. 1 and 2 heat ex-
chcingers, type IHE-3, were installed in test stand
B, and test operations were resumed. The stand is
currently operating on a constant-power endurance
run to provide corrosion information for comparison
with the data for ORNL heat exchangers Nos. 1 and
2. During shutdown of the test stand, instrumenta-
tion was added to allow separate measurements of
heat exchanger pressure drop. After 362 hr of
power operation, the NaK pressure drop has in-
creased 140% in heat exchanger No. 1 (NaK-to-fuel).
No increase has occurred in heat exchanger No. 2
Cambridge radiators Nos. 1 and 2, which have
operated for 820 hr under nonisothermal conditions,
have experienced a NaK pressure drop increase
of 84% A tabulation of the NaK pressure drop
variations that have occurred in he various heat
exchanger tests is presented in Table 1.4.3.
Construction work on stand C, to be used as an
ART prototype radiator test stand, is continuing.
57