i i . bf " ‘ - . oO or . : : So . : : beneath the surface--the 2-5 cm layer contained more Pu on a weight basis than either the 0-2 cm or 5-10 cm layers. Thus, a 5-cm deep sample is not as ’ diluted as a 15-cm deep sample might be, and it covers the siuations where the very top layers of ground are contamination free while the next lower layers are not. The 100 em2 sample surface area was arbitrarily selected as a compromise between being large enough so that the presence of any Pu "hot particles" would not bias the sample analysis and small enough that it could be handled in the laboratory. . ~ 8! wee ’ oe . tame Tt oa vse etry torapce . . i roiue . . pee 3. Each soil sample will weigh about 750 ¢g which is considered too large to be completely analyzed by radiochecmial methods in the time available. Since aliquots (weighing about 10 g) must be taken, the entire sample will first be homogenized so that any aliquot will be representative of the entire sample. The Radiological Laboratory will include a facility to accomplish the needed homogenizing of samples. A ball-milling method similar to that used on environmental samples at the Nevada Test Site -(Reference 10) will be employed unless a more efficient alternative becomes ‘available. (A possible alternative to be investigated is high-temperature sample decomposition followed by blending.) Aliquots will be baked in a _ muffle furnace to decompose any organic matter present and convert the coral to the readily soluble calcium oxide (CaO). The aliquots will be analyzed in the on-site Radiological Laboratory as previously described and forwarded to the USAF/NCL for comparisons as necessary. Each blended sample will be retained until the island from which it was obtained is certified to be clean. Ls : Steet Rte Fa a od ek ~ ~ one cee soy oF aan . a tte tt ” 4. The Radiological Laboratory will also have a high resolution gamma-ray Spectroscopy capability iv include i sic germanium detectors and computer-based data acquisition and analysis systems. ‘As Pu concen~ trations can be estimated relatively fast by such a capability, it will be ' used in setting upper limits on concentrations in certain samples (a con- servative Am/Pu ratio, say 0.1, will be assumed) and thereby to confirm _ that_somesites do not have Pu contamination deserving. Cleanup. Additionally, the computer ‘used for spectrum analysis will also serve for the automatic contouring. “De La.Saeaey es Mebane CRELS 5. The surface samples will permit defining the perimeter of sites requiring soil removal. The amount of material to be removed from the site may be estimated from the defined area and the profile data reported in the AEC Survey. A precise estimate should not be necessary, however, as past cleanups indicate that contamination fromupper layers will spill to lower layers during soil removal operations and consequently, soil Js removed to greater depths than initially predicted. -- _ - ot Bo Sind wa CIALIS ie tae oe , wee ae Tae sot cr 6. Based on a review of the laboratory results and the other factors which enter "case-by-case" decisions, the sites requiring soil removal will be designated. These sites will be marked in the field by engincer surveyors, All debris will be removed from the site if it has not already been removed. Removal of contaminated soil will commence using appropriate earth-moving equipment. The soil will -be taken up in thin layers with " * 1 f\r. 10 ve opera eg ere eat Teter SaRH RE ECRppaiwee ge? ™. DEat OU~gb* OT TTSTE Tm SOagee: ely oeee @ hs oe ree rp : oe By soe 5. oe ' et ‘ . . . ae 7 cs ” ote gat wot ae a oe roy 1 ’ . . So pote? a!. . . . - ans '