APPENDIX B SITE SELECTION PROCESS
TABLE OF CONTENTS
SITE SELECTION PROCESS B-1
B.1 SITE SELECTION FACTORS B-1
B.1.1 ENGINEERING CONSTRAINTS B-1
B.1.2 HUMAN SAFETY B-2
B.1.3 COST B-2
B.1.4 ENVIRONMENTAL IMPACT B-2
B.2 SUMMARY OF SITING PROCESS B-3
APPENDIX B SITE SELECTION PROCESS
This appendix discusses the site selection factors and summarizes the siting process for the RCSTS and the NTF.
B.1 SITE SELECTION FACTORS
Site selection for the main components, the RCSTS and NTF of the SIS program was based on several factors. The factors discussed in this section include engineering constraints, human safety, cost, and environmental impact.
B.1.1 ENGINEERING CONSTRAINTS
Design requirements and existing site features can be engineering constraints.
A list of the major engineering constraints follow.
. The RCSTS would be designed to drain by gravity in case of failure of the
pump system. The middle was to be the high point so that it would drain
both ways. It was to be sloped at least 0.25 percent to preclude
accumulation of solids in the line. For radiation and freeze protection,
the lines were to be buried at least the appropriate minimum depth to
assure that protection. To meet these requirements and minimize cost and
environmental impact, the route must fit the existing topography.
. The point at which the RCSTS can exit the 200 West Area tank farm is
dictated by the requirement to avoid going through existing facilities
and contamination areas. That constraint limits the route options
available for that segment of the RCSTS.
. The NTF also requires a large uncontaminated area that would not conflict
with other existing or proposed facilities.
. Existing critical utility links are to be avoided by both the NTF and
RCSTS.
B.1.2 HUMAN SAFETY
The primary safety consideration is to avoid routing the RCSTS or siting the NTF in or through areas with radioactive contamination that would unnecessarily expose construction workers. In addition, other facilities with exclusion zones that cannot be invaded for safety reasons must be avoided.
B.1.3 COST
The overall objective of this factor is to minimize the cost without compromising
safety, schedule, or other factors. Important cost considerations are:
. Minimize the amount of pipe by picking the shortest RCSTS route
. Minimize the amount of cut and fill (trenching and berming) by choosing
the flattest RCSTS route
. Construct the NTF (if needed) near the RCSTS to minimize the amount of
pipe needed.
B.1.4 ENVIRONMENTAL IMPACT
Several guiding principles regarding environmental impacts were used in site
evaluation where they did not compromise human safety, major engineering
constraints, or meeting the schedule. In some cases, a comparison between
alternative routes or sites was made to determine if an alternate route or site
would reduce impacts. If it would not, the proposed route and site would be as
good as an alternate, and cost and schedule concerns would cause it to be
selected. The guiding principles to minimize environmental impact are:
. Use existing corridors and parallel the existing ECSTS to reuse
previously disturbed areas.
. Minimize the disturbance of shrub-steppe habitat, a priority habitat
designated for protection by the WDFW.
. Use as small an area as reasonable to minimize the overall impacts.
B.2 SUMMARY OF SITING PROCESS
The original route for the RCSTS and sites for NTF identified in the Draft EIS were selected primarily on the basis of safety and engineering constraints. The first guiding principle concerning environmental impact and cost considerations were also considered. After the Draft EIS was issued, additional siting and routing studies were conducted. The determination that only two tanks would be evaluated in the Final EIS new storage alternative, created more flexibility concerning siting because less area would be required. This change allowed consideration of smaller alternative sites, such as an alternate site inside the 200 East Area in the interest of minimizing potential impacts (see Section 4.4.1). However, when safety considerations concerning contamination and exclusion zones and engineering constraints were applied, only sites that had mature big sagebrush were found. One of these is analyzed in the Final EIS as an alternate site for the 200 East Area tank location. Because there would be little difference in environmental impact between these sites, other selection criteria would be the primary determinants of any site selected to build new tanks. A siting review group for the RCSTS comprised of DOE-RL, Dames & Moore, WHC, and PNL staff reviewed the siting criteria and determined what alternate routes and sites could be considered. The group met on the site and toured the possible locations on March 21, 1995. During this review, two alternate segments for the RCSTS were found that had the potential of reducing the amount of mature sagebrush habitat that would be affected (Figure 3-4). The first alternate segment was from the vent station eastward, where the RCSTS route could parallel the ECSTS into the 200 East Area. Because of the uncertainty of contamination from the ECSTS, the new route would have to be far enough away that it could not use the existing access road. Evaluation found that this route would affect about 2 ha (5 acres) more mature sagebrush and offered no other advantages over the proposed route. The second alternate route would extend from the 200 West Area fence to the vent station and would parallel an existing road and the ECSTS, using the access road along the north side of the ECSTS. Careful evaluation of this route alternative found that it would affect only about 0.6 ha (1.6 acres) less than the proposed route. This route had serious schedule and cost impacts as it increased the overall length of the corridor by over 300 m (1,000 ft). There is so little difference in impact that the schedule and cost considerations were of primary importance in selecting a preferred alternative route for the RCSTS. The conclusion from this additional siting evaluation is that no alternate routes and sites were to be found that met the safety and engineering constraints and would have significantly less environmental impact. This process and conclusion was discussed with the Natural Resource Trustees Council, made up primarily of representatives of certain Federal and state regulatory agencies and tribes, on May 12, 1995.
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