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Table 9.7- Approximate Fission Product Distributionsa
in MSRE After 21,000 Mwhr
I _ . ~ I_ . _l_...-_..___l
_l..._l
Fuel Graphite Hasfellay N
Isotope (total (total (total
dis /min) dis/min) dislrnin)
9 9 ~ 1.7 ~ 1017~ 8.6 x 1OI6 3.2 x IOI7
132-r~ 5.3 1016' 5.9 x ioI6 4.1 x 1017
lo3Ru 2.9 x 2.2 x 1OI6 5 x 10'6
"Nb 9.6 x loL6' 1.6 x 1017 1.5 x 1017
9 5 ~ r 7.3 10': 1.8 x 1014 3.6 1014
"Sr '4.9 x 10' 1.3 1015
1311
3.5 x 10'' 4 x 10'5
.. . - __...__ ......
.. I__
aSptected mean value from fuel analyses, assume con-
centrations on grdphlte and fuel specimens are typical of
all such surface in core.
bMean of considerably scattered values.
9.4 DEPOSITION OF FISSION PRODUCTS
FROM MSRE GAS STREAM ON
METAL $~~~~~~~~
Access to the pump bowl provided by the
sampler-enricher tube has been used in a continuing
seiies of studies of deposition of gasborne
activities on metal specimens. The tests
carried out since the previous report have attempted
to observe the effect of duration of previous reactor
operation, addition of metallic beryllium, level of
liquid in the pump bowl, exposure time of specimens,
stopping of the reactor pump, length of shutdown
time of the reactor, and draining of fuel from
the reactor.
Exposure conditions were generally similar to
those used in previous tests of this kind,'-3 but
in these studies the stainless steel cables which
hold the sampler were used without additional
getter materials. To reduce the increasing fission
product contamination of the sampler-enricher
assembly, a downward flow of some 200 cc of
helium was used with all insertions after FPll-45.
The cables (in all cases except FPll-SO, described
in some detail in the following section)
attached to standard samplers for obtaining spec-
128
that had been exposed to the liquid phase, the
gas phase, or the interface region. In all cases,
the nickel-plated key exposed at the very top of
the gas phase was analyzed, but these results are
not included here. Data from seven separate tests
are showii as Table 9.8. In addition, the behavior
of '06Ru is shown in Fig. 9.8.
In virtually every case tfe specimens were
leached first with an aqueous chelating agent and
then with an oxidizing acid solution. Some iodine
and ruthenium may have been lost from the acid
leach solutions, and it is not unlikely that some
of these values are low. Table 9.8 reports, in all
cases, the sum of values obtained with both types
of leach solution.
A number of conclusions frorn the data, of which
those in Table 9.8 are typical, follow.
The deposition of noble metals on the pump bowl
specimens under normal reactor operating conditions
was quantitatively quite similar to that previously
rep~rted.~ Added purge flow down the
4 0'' -
5
I- - 0 SSL
2 }-- o SSG
imcns of fuel were exposed under conditions and FP NUMBER
for times shown in Table 9.2. The cables were
then segmented into approximately equal lengths
A
i
A KKY
0 SSI
ORNL-DWG 67 12236
Fig. 9.8. Deposition of lo6Ru in Bump Bow! Tests.
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