Actual photo peak computation methods used by the RADLAB are an adaptation of computer routines originally written by Dr. Frank Markwell of DOE, Dr. John Tipton and Mr, Al Villaire of EG&G and were modified for the specific RADLAB hardware by EIC personnel. The Enewetak soil was the best natural matrix standard for processing along with the samples analyzed at the Enewetak RADLAB. The Enewetak soil sample was analyzed and determined to contain very low concentrations of the radionuclides of interest and was, therefore, used as a control sample. This soil sample was "spiked" with known amounts of the radionuclides routinely analyzed at the RADLAB. This served as part of the internal quality control program to cheek the accuracy of the laboratory analyses. Reagent spikes and blanks were processed with routine samples at the RADLAB as another check for accuracy and specifically to check cross-contamination. Calcium carbonate was also used to prepare blank and spike samples with a known concentration of radionuclides to be analyzed. Another aspect of the internal QC program was processing of 5 percent of all samples through the RADLAB as duplicates. The duplicate analyses were reported as part of the quality control program. Another check on precision was based on the results obtained on the Enewetak soil which was processed with each set of samples analyzed in the laboratory. Other precision checks were based on the results obtained on the Janet standard soil processed with each group of samples analyzed in the laboratory. The precision measurements were based on the analysis of duplicates and standard soil. , 4.4.2 External Quality Control - Precision and Accuracy The determination and comparison of crosscheck sample results analyzed by the Enewetak laboratory and other laboratories served to satisfy the external quality control program requirements and to eStablish the quality of the on-site analyses. A large soil sample was collected from the island of Janet for the external quality control program. This soil was prepared in the same manner as the Enewetak soil. The Janet soil, from the vicinity of location NW] 2-4, was sent to various laboratories for analysis in order to establish the concentration of the various nuclides of interest. The Janet soil was the natural matrix standard used to check RADLAB accuracy based on results obtained from the other laboratories. laboratory results is presented in Table 4-8, with the RADLAB shownas Lab A, TABLE 4-8 A comparison of EXTERNAL QUALITY CONTROL dpm/gm + 2¢ Lab A 241 am 238 py 31.7 + 0.6 32.9 + 0.4 1.30 + 0.06 32.4 + 0.4 B 23.0 + 2.3 Cc 30.0 + 1.0 D 33.0 + 1.4 1.20 + 0.10 239, 240p, 13%Cs 905, 64.0 + 0.6 108 + 1.0 177 +3 77.2 + 4.6 119 +8 102+ 19 66.0 + 6.0 120 +2 71.0 + 10.0 114 +2 134 110 + 1.0 - 106+ 5