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Appendix G - Detailed Description of Altt:rnative 4: DOFJRL-2001-11
^ Entombment with Internal and External Waste Disposal Rev.1 Draft li
Redline/Strikeout
1 would be to place some of the equipment either in cell 3 or into containers placed into the
2 galleries.
3
4 G.lA.1.2 Demolition of the 271-U O[fice Bullding. The 271-U Oftice Building would be
5 demolished in Alternative 4. The 271-U Office Building has a basement, three floors, and a
6 reinforced concrete slab roof. There is a concrete masonry perimeter wall supported on a
7 basement wall, with interior masonry walls within the building. The roof is a reinforced concrete
8 slab similar to the floors. The third floor is a chemical makeup area with floor slabs up to 03 m
9 (1 ft) thick that support chemical tanks.
10
11 Additional building features included in the demolition are a stack on the roof (296-U-10), an
12 elevator, a second floor vault, and mechanical equipment in the basement. Demolition would
13 use typical building demolition techniques. The resulting rubble would be left in place alongside
14 221-U and the area filled and compacted as part of the clean fill around the canyon.
15
16 G.1.4.1.3 Decontamination and Decommissioning (D&D) of Stairways on 221-U Building.
17 Eight stairwells on the northwest side of 221-U are light construction and would be demolished
18 using typical building demolition techniques. Ten stairwells on the southeast side of 221-U are
19 thick wall, lightly reinforced concrete construction. The heavy construction of these stairwells
20 would be factored into the demolition costs. Any contamination found in the stairwells on the
(0-'\ 21 canyon's southeast side would be fixed in place prior to demolition. All stairwell demolition
22 waste would be disposed adjacent to 221-U where it would be protected from infiltration by the
23 environmental barrier.
24
25 C.1.4.1A D&D Other Aboveground Structures. All other aboveground structures identified
26 in Assumption 2 at the beginning of this appendix that are within the footprint of the 221-U
27 environmental cap would be decommissioned as part of Alternative 4 activities.
28
29 G.1A.2 D&D of Buried Piping. Buried piping not already addressed in the preparation of the
30 complex function would be ttrouted in place or removed prior to the placement of engineered Cill
31 around 221-U . based on the outcome of risk assessment work . In addition to the miscellaneous
32 piping to be removed, the exhaust ventilation tunnel would be removed. This tunnel is a
33 reinforced tunnel connecting the canyon air ventilation tunnel to the stack and filter. The tunnel
34 is approximately 60 m long and runs from the end of the ventilation tunnel in section 3 to the
35 fans.
36
37 G.1.4.3 Confirm Remediated Waste Sites Within Environmental Cap Footprint-
38 Altemative 4 includes covering 221-U with an environmental cap. It is assumed that the waste
39 sites located within the environmental cap, as identified in Assumption 4 at the beginning of this
40 appendix, would be remediated by other projects prior to the start of Alternative 4 and
41 construction of the environmental cap. All remediation wastes would be disposed at ERDF.
42
43 G.1AA Confirm Well Decommissioning. Three wells are located within the footprint of the
44 environmental cap. It Is assumed that these wells would be decommissioned by other projects
Final Feasibility Studyfor the Canyon Disposition lnitietive (221-U Facility)
)uno?003 G-14