WETAK ATOLL Runit (Yvonne) Cleanup and Crater Containment 20 The suggestion Commander, JTG. MG Tate reviewed the JTG plan for the selective excision of the Runit hot spots. Recognizing that the available dome space toposed by Field ected again on the of approximately 6,000 cubic yards would not accommodate all the spreading of low- contaminated soil from Fig-Quince, the JTG had developed a sequential plan for excising one-sixteenth hectare areas having transuranic readings over 160 pCi/g, working from hottest to coolest areas (highest to lowest 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. Dome capacity 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 dome capacity no longer existed. Once encapsulation of all soil ceased and capping operations became thecritical path, the USAEwould place a 12-inch blanketof relatively clean soil (less than 160 lhe Commander, maximum effort Lujor soil and to and Aomon. No . To carry out this sctive excision of )Runit.121 mand anticipated ‘ould be possible, ndicate increased sked to develop a the focus on the twas to be given l effort on Lujor; mplete the soil he plan on crater 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 DOE Fission Products Survey (subsurface). On | June 1979, the Commander, Field Command approved the JTG plan, iat excavation of : Structure would ‘nt and proposed soil wasinitially emphasizing that completion of the soil removal and the containment operation was essential to the accomplishmentof the cap completion by 15 September 1979 and subsequent demobilization on schedule. !26 uidance directed / low transuranic nsport to Runit rackfill initiated. ‘n soil transport remaining to be dor, and 4,900 een transported od soil yet to be ‘ximately 5,600 operation was sited Enewetak umand. Colonel ichspies as the Here ¢ in Hane to ch time as the oil.123 Actually, 451 Once all Boken, Enjebi, Aomon, and Lujor soil had been encapsulated, and the Fission Products Data Base Survey had shownno furthersoil 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.!27 Although this was probably the most highly contaminated soil excised on theatoll, 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 12- inch 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. d a a iW H H Hi fy i | i