Table VII
PLUAONIGA
TP SCTE Cone FAM CUATHER CONTATINIAG
Left Core
Section
No
Pu
em
0-6
2
6-13
3
13-22
4-5
22-28
Total Pu
Ripht Core
Depth
i
LAREN PILCeS FROM MUFT-27
ng
<
«<
Section
wwNO
hopth
em
Fu
— Sp
3.30
1
Q-)
0,63
2
1-i0
19.26
3
1n-16
0.19
0.03
4
16-2)
0.05
5-7
21-28
22.46
3.97
1087.
£0.05
1093.
side of the chamber. Theanalyses for these cores are
given in Tables VIII and IX.
4. MHFT-23. We started testing a Fuel Sphere
Assembly (FSA) in an environmental chamberon a
sandy soil under humid winter conditions. The
chamber has now been changed to humid summer
conditions. The Graphite Impact Shell (GIS) con-
tains MHFT-23, an iridium clad PPO sphere that
has not been subjected to an impacttest. At the time
we placed the FSA in the chamber, we found a small
center of the tray. The PPO material was positioned
in the center of the circular section. The water that
percolates through the soil in the twosections is
collected separately for plutonium analysis. Initially
the two chambers were on a winter cycle with humid
conditions, but now have been changed to summer
humid weather.
The volume of water that percolated through the
soil was much lowerin the inner compartment than
in the outer compartment, especially in the chamber
containing the large pieces, because the outer com-
amount of alpha particle contamination on the out-
side of the iridium shell, but the outer surface of the
GIS was nominally free of contamination. There was
a small amount of plutonium contamination in this
chamberthat remained after cleanup from its use for
testing the PISA that contained MHFT-27. Thefirst
rainwaters and dehumidifier condensates contained
very small amounts of plutonium, but. most of the
analyses have been indistinguishable from
' background since then. Two soil cores have been
partment has three times the area and because the
heat from the plutonium dioxide dries the soil in the
inner compartment more rapidly between rains.
The volumeof water collected per rain from both the
inner and outer compartments in both chambersincreased in the summerrains over the winter rains,
contrary to the expectation from the results with the
Table VIII
PLUTONIUM FN SOIE CORES FROM CHAMRER CONTAINING FINE MATERIAL FROM MHPT-SO
Inner Compartment
Depth
=e
Pu
ig
1
Q-3
143.8
2
355
0.106
5
$+?
0.054
3
7-21
4
7-38
4
11-15
5
$-10
$
15-19
6
1o- 32
0.076
?
zi-24
0.0438
3
24-27
0.042
3
27-08
0,043
10
28-30
__ 0-041
chambers containing the MHFT-12 material. The
ratio of the volumes from the outer compartment to
those of the inner compartment increased by 50°; in
the summerfor the fines, compared with a factor-oftwo decrease for the large pieces. This latter decrease
probably indicates that the greater evaporation of
water from the surface of the outer compartment due
to the summerheat partially balances the effect of
the evaporation in the inner compartment by the
heat from the large pieces on the volumeratio of the
two compartments. In the case ofthe fines, the sam-
ple produces much less heat, so the effect is small.
The outer-to-inner ratio for plutonium was two
orders of magnitude higher for the large pieces over
the fines, as expected from the spallation ofthe large
pieces, in the winter rains. However, before the
summerrains, water had overflowed from the inner
compartment to the outer one in the fines chamber
because of a valve malfunction. This carried
plutonium to the outer compartment, resulting in a
much higher outer-to-inner ratio in the summerfor
this chamber. The plutonium in the dehumidifier
condensates from the large piece experiment was
five times that from the fine particle experiment.
Twosoil cores were taken from each chamber during
the humid winter cycle, one just inside and onejust
outside the circular isolating partition on the left
Outer Compertment
Section
Ko. _
6-31
Section
—Ne.
Depth
fe
i
a-5
2
3-7
< 0.05
~
0.046
10-21
<n.or
144.0
Pu
—na_
253
0.033
49.4
0.050
38.0
341
Table Ix
PLUTONIUM TA SOTL CORES FRO CHAMBER CONTAINING LARGER FIRCES FROM MHFT-59
Inner Compartment
Section
No.
Depth
ca
1
0-2
2
2-3
3
3-4
4
Quter Compartment
fu
4
Section
- NOs
Depth
~A_.
Pu
an.
1
a-3
za.
z
3-7
0.10
0.72
5
1-9
0.041
4-7
1.7
4
9-13
0.10
5
7-6
0.66
s
13-18
6
a-11
t.12
6-106
8-30
7
di-22
o.53
a
12-15
0.96
9
18-18
0.42
10
13-25
235
i929,
73.7
2009
0.034
< 0.03
_
218.2