— “ Runit (Yvonne) Cleanup and Crater Containment 451 Commander, JTG. MG Tate reviewed the JTG plan for the selective space excision of the Runit hot spots. Recognizing that the available dome the all te of approximately 6,000 cubic yards would not accommoda contaminated soil from Fig-Quince, the JTG had developed a sequential readings jan for excising one-sixteenth hectare areas having transuranic to lowest over 160 pCi/g, working from hottest to coolest areas (highest readings). The initial excision would be limited to 2,000 cubic yards to minimize the possibility that all of the contaminated soil stockpiled at Lujor and Aomon might not be encapsulated. Domecapacity permitting, subsequentlifts would be made based on DOE re-IMPing on a one-quarter hectare grid and newareas of highest readings determined. This procedure would be continued until all one-quarter hectare areas had been reduced to less than 160 pCi/g or domecapacity no longer existed. Once encapsulation of all soil ceased and capping operations becamethecritical path, the USAE would place a 12-inch blanketofrelatively clean soil (less than 160 pCi/g) over the Fig-Quince area.!25 This plan for selective excision of contaminated soil in the Fig-Quince area appeared to offer the best opportunity to make a substantial change in the radiological condition of Runit within the available crater dome volume, considering the potential loss of volume to other possible excision requirements on Boken and Lujor growing out of the DOEFission Products Survey (subsurface). On | June 1979, the Commander, Field Command approved the JTG plan, emphasizing that completion of the soil removal and the containment operation was essential to the accomplishment of the cap completion by 15 September 1979 and subsequent demobilization on schedule. !26 Onceall Boken, Enjebi, Aomon, and Lujor soil had been encapsulated, and the Fission Products Data Base Survey had shown nofurthersoil to be excised, the Runit excision plan was put into effect. Survey results before and after the selective lifts are shown in Figures 8-36 through 8-42. The final result, after removal of 5,015 cubic yards of soil, was a 75 percent reduction in surface contamination in the Fig-Quince area.!2? Although this was probably the most highly contaminated soil excised on the atoll, no air sampler readings exceeded the action level of 10 percent of the maximum permissible concentration (MPC), with the highest reaching 0.04 MPC. On 26 July 1979, soil cleanup operations were terminated on Runit, and final capping of the dome commenced. A final radiological characterization of the Fig-Quince area was made by DOE-ERSP, and a |2inch blanket of clean soil was placed over the excised area. As a final check, a complete surface characterization of Runit, using the IMP, was made by DOE-ERSP in December 1979.