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