2 PURPOSE AND NEED FOR ACTION
In the Draft SIS EIS, DOE and Ecology identified a purpose and need to resolve
near-term tank safety issues associated with hydrogen gas generation in
Watchlist tanks while continuing to provide safe storage for other Hanford
wastes. These Watchlist tanks were identified pursuant to P.L. 101-150,
section 3137 "Safety Measures for Waste Tanks at Hanford Nuclear Reservation"
of the National Defense Authorization Act 1991. Since the issuance of the
Draft SIS EIS, use of the mixer pump in Tank 101-SY has been successful in
mitigating issues associated with hydrogen production, pressure generation,
and unacceptable high flammability levels for hydrogen. DOE now believes that
through continued use of mixer pumps, waste exhibiting gas release activity
may continue to be safely stored in existing tanks and may not need to be
removed and diluted prior to final treatment for disposal.
Consistent with the Draft SIS EIS, DOE and Ecology recognize the need to
continue to provide safe storage of high-level radioactive tank wastes while
supporting tank farm management and operations prior to implementing decisions
made in the TWRS EIS. To minimize the risk of managing tank waste, a modern,
safe, reliable, and regulatory compliant replacement cross-site transfer
capability is needed to move wastes between the 200 West and 200 East Area
tank farms in support of the Tri-Party Agreement Milestone M-43-07A. This is
especially true in the 200 West Area where there is far less useable DST
capacity than there is waste in SSTs. The replacement waste transfer
capability would provide the means to move waste to the available DST capacity
located in the 200 East Area.
However, the ECSTS has been recently tested for integrity and was found
suitable for pumping selected wastes such as supernatant from 102-SY and SWLs.
Wastes such as these may be pumped, subject to periodic integrity testing,
while compliant transfer capability is under development.
This Final SIS EIS analyzes the following alternatives to support continued
safe storage and tank farm waste management activities: preferred
alternative; truck transfer alternative; rail transfer alternative; new
storage alterative; and no action alternative. Additionally, this EIS will
identify those alternatives which have been dismissed based on their inability
to resolve safety issues expeditiously within the confines of an interim
action.
The alternatives evaluated in this Final SIS EIS would provide DOE the ability
to manage Hanford tank waste safely and in compliance with RCRA, 40 CFR
264.193 and Washington State Dangerous Waste Regulations, WAC 173-303-640.
Based on current tank waste management and operation activities, the SIS Final
EIS addresses the need to do the following:
. Remove SWLs from older SSTs to reduce the likelihood of liquid waste
escaping from the corroded tanks into the environment. Many of these
tanks have leaked and new leaks are developing in these tanks at a rate
of more than one per year.
. Provide ability to transfer the tank wastes via a compliant system to
mitigate any future safety concerns and use current or future tank space
allocations.
. Provide adequate tank waste storage capacity for future waste volumes
associated with tank farm operations and other Hanford facility
operations.
. Mitigate hydrogen generation in Tank 101-SY.
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