ORNL-4191 - the Molten Salt Energy Technologies Web Site

129
Table 9.8, Oepasition of Various Fission Products on Metal Specimens Inserted in MSRE Pump Bowl
Run NO.^
FPll-45 Liquid
Exposlire 2 3 5 ~
agMO 1311 1 0 RI, 13*Te 952,
Condition (,ug/ sa rnp le)
Interface
Gas
FPll-SOh Liquid
Interface
Gas
FPll-51 Liquid
In te rf R ce
Gas
FP11-54 Liquid
Interface
Gas
FDll-58 Liquid
Intcrfece
Gas
FP12-6 Liquid
Interface
Gas
Fit-" 2-27 Liquid
Interface
Gas
x 10" x 1010
0.65 0.46
1.8 1.0
1.1 1.1
3.5 12
26 90
0-2 9.2
0.3 0.1
0.85 0.85
0.4 0.6
0.42 0.22
0.72 0.70
0.42 0.55
0.05 0.11
0.15 0.28
0.18 O.GO
0.05 0.14
0.2 0.24
0.23 0.37
x 1010
0.2
1.4
0.2
0.7
2.8
0.13
0.5
0.25
0.25
1.0
0.40
0.13
0.15
0.23
0.11
0.17
0.33
0.05
0.04
0.22
x 10'
0.9
1.3
0.35
14
100
23
0.14
0.52
0.3
0.17
0.61
0.28
0.17
0.07
0.04
0.09
0.18
0.40
x lo7
0.035
10
0.80
%ampling conditions ax those shown in Table 9.2.
bSpecial sample connecting two sets of graphite immersion samples immersed for 8 hr; experimental details are
in the following section.
sampler-enricher tube during exposures had no
significant effect on deposition on fresh metal
specimens. The corisiderable additional reactor
operating time also apparently had little effect,
except for possibly a slight decrease in 99Mo and
132Te deposition for the later runs.
The deposition of noble metals was usually
heavier on the interface sections of the stainless
steel cable than on either the gas-phase or fuelimmersed
sections. This suggests the presence
of n sticky scum or froth containing noble metals
on the surface of the fuel in the pump bowl.
As previously observed3 and as verified by the
results from sampling the MSKE gas stream, the
reduction of the MSRE fuel with beryllium caused
no discernible change in deposition behavior. This
observation is difficult to reconcile with the hy-
250
310
17
1
1.5
3
1.6
3.5
3.5
0.3
0.6
0.7
0.82
0.60
0.30
0.9
1.0
1.3
21
20
5.2
35
190
60
3.5
19
6.0
6.1
5.6
2.0
8.4
3.3
2.5
22
46
60
8.2
5.6
6.6
pothesis that deposition behavior js related to the
presence of volatile noble-metal fluorides.
The deposition of noble metals on the sections
of stainless steel cable immersed in the fuel
usually paralleled their concentrations in the fuel
(see Table 9.2).
'rhe 8-hr exposure (FP11-50) revealed curious
differences in the deposition behavior of the
various fission products. The deposition of 32Te
and "Zr was about. 100 times that observed in 1-
or 10-min exposures. 'The corresponding factor
was 30 or less for 140Bal IO or less for "&IO, 3
or less for 1 " 3 and ~ ~ lo' Ru, and less than 1 for
95Nb. IJsiially, comparisons between runs have
shown similar factors for all the noble-metal fission
products. This u11Ll:jual observation indicates
that the noble metals do not travel together