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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.