ground surface is caleulated using this flux density measurement together with depth distribution and soil density data obtained from an analysis of soil samples by the radiochemistry laboratory (Tab D). The average Pu concentration over an area of soil is derived from the calculated Am concentration and the Pu/Am ratio which has been determined by laboratory radiochemical analysis. b. Execution (1) The in situ measurements by helicopter and by van (including Pu/Am ratios, densities and depth profiles) and data analysis will be performed by ERDA, using available DoD personnel for assistance as needed. The Field Radiation Support Team (FRST) will conduct radiological safety monitoring as necessary during soil cleanup. Radiological counting facilities (FCDNA provided) will be managed by the FRSTto provide the radiological safety support services. (2) In situ measurements will be made on the islands listed in Tab A. (Ed. Note: Tab A, not included herein, listed islands Alice through Yvonne.) Initial measurements will be based on data derived from the AEC Survey and the aerial radiological survey. When measurements show Pu concentration levels sufficient to require, or likely to require soil cleanup, soil samples will be taken and/or additional measurements will be made on successively finer and finer grids until boundaries of the elevated Pu concentrations in soil can be well established. Soil cleanup will proceed iteratively until an acceptable concentration level is attained (See Tab E). (3) The in situ method probably will not be suitable for locating Pu contaminated soil which is buried. Thus, suspected burial sites of Pu contaminated soil (Tab B, listed Irene, Ruby, Sally, and Yvonne) will be investigated by means of a truck-mounted auger or coring device capable of drilling into the ground to depths up to 3 meters.* Material will be removed from the augeras it penetrates the ground and assayed for Am by the in situ gammaray spectrometer. If the presence of buried Pu bearing soil is indicated, further sampling and analysis will be required to define the limits and levels of contamination and to determine appropriate cleanup actions, (4) The Pu contaminated soil which is collected will be transported to Runit (Yvonne) by trucks of sufficient integrity to prevent any loss of contaminated materials. This soil will be stockpiled on Runit for subsequent crater placement. Trucks will be monitored periodically and decontaminated as appropriate. (The OPLAN contained the following section describing the purpose and operations of the Radiochemistry Laboratory. Chapter 4 of this Report provides details of actual operations.) (Annex C, App. 2, Tab D) RADIOCHEMISTRY LABORATORY l. PURPOSE: A radiochemistry laboratory (RAD LAB) will be established to support the Atoll radiological protection program and the plutonium soil assay operations. Ze CONCEPT OF OPERATIONS: a. This laboratory complex will have a capability to prepare samples for radiochemistry assay, and to analyze prepared samples for alpha, beta, and gamma radiation ineluding isotopic identification and quantification. The laboratory will have a maintenance capability to repair and calibrate its own radiation measuring equipment as well as the portable radiation instruments used during the Cleanup. It will also be capable of supporting the in situ van measurementoperations. b. All work done by the RAD LABincluding maintenance work, will be pursuant to the direction of the ERDA ERSP Manager. *This method was used only at the Aomon Crypt. Other subsurface investigations utilized a backhoe to dig a small trench for sidewall profiling. E-6