Since that report was issued in August 2000, DOE has funded research and development on the three alternative processes, and significant progress has been made in ameliorating many of the technical uncertainties. DOE noted in its briefings to the committee that tests of all three treatment alternatives have demonstrated their ability to meet functional requirements. On that basis, and with the associated changes in the work programs of the three alternatives and their management, the DOE Technical Working Group (TWG)1 has produced downselection criteria. These were presented to the committee at its first meeting on 20-21 November 2000 (Harmon, 2000a, b), and represent the basis for this report.

DOE SELECTION CRITERIA AND GOALS

The TWG and its associated committees and consultants employed systematic and relatively transparent approaches for devising quantifiable evaluation criteria. Using information gathered from other DOE sites and other organizations, they began with twenty criteria and reduced them to the final eleven in an effort to eliminate redundancy and criteria unable to discriminate among the alternatives. The final set of criteria (see Box 1) was approved by the DOE Office of Environmental Management for use in making recommendations on process downselection.

1  

The TWG has the lead responsibility for developing recommendations on both research and development (R&D) direction and the bases for subsequent recommendations on process selection. This group, using input from a technical advisory team and the Tanks Focus Area (TFA), interacts with a representative of the DOE Office of Environmental Management responsible for the process development and recommendation for downselection. This representative recommends to the DOE Assistant Secretary for Environmental Management the final determination on the downselection outcome.



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OCR for page 3
EVALUATION OF CRITERIA FOR SELECTING A SALT PROCESSING ALTERNATIVE FOR HIGH-LEVEL WASTE AT THE SAVANNAH RIVER SITE: INTERIM REPORT Since that report was issued in August 2000, DOE has funded research and development on the three alternative processes, and significant progress has been made in ameliorating many of the technical uncertainties. DOE noted in its briefings to the committee that tests of all three treatment alternatives have demonstrated their ability to meet functional requirements. On that basis, and with the associated changes in the work programs of the three alternatives and their management, the DOE Technical Working Group (TWG)1 has produced downselection criteria. These were presented to the committee at its first meeting on 20-21 November 2000 (Harmon, 2000a, b), and represent the basis for this report. DOE SELECTION CRITERIA AND GOALS The TWG and its associated committees and consultants employed systematic and relatively transparent approaches for devising quantifiable evaluation criteria. Using information gathered from other DOE sites and other organizations, they began with twenty criteria and reduced them to the final eleven in an effort to eliminate redundancy and criteria unable to discriminate among the alternatives. The final set of criteria (see Box 1) was approved by the DOE Office of Environmental Management for use in making recommendations on process downselection. 1   The TWG has the lead responsibility for developing recommendations on both research and development (R&D) direction and the bases for subsequent recommendations on process selection. This group, using input from a technical advisory team and the Tanks Focus Area (TFA), interacts with a representative of the DOE Office of Environmental Management responsible for the process development and recommendation for downselection. This representative recommends to the DOE Assistant Secretary for Environmental Management the final determination on the downselection outcome.

OCR for page 3
EVALUATION OF CRITERIA FOR SELECTING A SALT PROCESSING ALTERNATIVE FOR HIGH-LEVEL WASTE AT THE SAVANNAH RIVER SITE: INTERIM REPORT BOX 1 DOE Criteria for Process Selection at the Savannah River Site Schedule risk—Risk to the overall project schedule due to high-risk technology issues not being resolved in time to support downselection [to be made in June 2001]. Project cost reduction potential—Potential that cost savings in the total project cost can be identified (generally due to flow sheet or equipment arrangement changes that would allow facility footprint reductions). Life-cycle costs through decontamination and decommissioning (D&D)—Total costs to complete all salt processing (including HLW system costs). The focus is on life-cycle costs, but the separate components ' total project cost and operating cost also are examined for key differences. Technical maturity—The overall technical maturity of the process flow sheets (including the required strontium and actinide removal steps). EM-50 [DOE Environmental Management Office of Science and Technology] stages of maturity are applied to each unit operation and the results are averaged. Implementation confidence—Amount of relevant process experience (large-scale demonstration or deployment) in the DOE complex and industry for the key equipment used for each cesium removal process. This criterion also includes commercial availability of key components and chemicals. Minimize environmental impacts—Comparative assessment of environmental impacts from secondary waste streams, airborne emissions, and liquid effluents. This criterion also includes the number of Saltstone vaults required for each process. Impacts of the interfaces at the Defense Waste Processing Facility (DWPF)—Cost of implementing the changes (physical modifications) to the interfacing systems and the loss of [glass] canister production caused by outages for equipment installation or transfer line tie-ins. Process simplicity to interfacing systems—The simplicity of interfacing the alternative cesium removal processes with other high-level waste systems. The simplicity is measured by the number of process unit operations needed for the interface times a difficulty factor for each interface unit operation. Levels of safety control mitigation—Number and type (e.g., passive, active, administrative, preventive, and mitigative) of controls required to maintain the facility in a safe configuration and to protect the worker, public, and environment. Maximize process flexibility in throughput—Capability to operate the process at a higher or lower throughput (turn-up or turn-down) based on the equipment in the current pre-conceptual designs. Maximize process simplicity (operability)—Simplicity of the process as indicated by the number of pieces of equipment (in both the non-radioactive areas and the remotely operated area) and number of jumpers (piping connections) required inside the remotely operated area. SOURCE: Harmon, 2000a, 2000b (viewgraph on p. 20 entitled “Criteria Weights–Case A”), and H. Harmon, DOE, email communication, January 5, 2001.

OCR for page 3
EVALUATION OF CRITERIA FOR SELECTING A SALT PROCESSING ALTERNATIVE FOR HIGH-LEVEL WASTE AT THE SAVANNAH RIVER SITE: INTERIM REPORT In recognition of some commonalties, the eleven criteria for process selection were grouped by the TWG under the set of six goals shown in Box 2. The criteria were used as a measurement for the effectiveness in reaching these goals. BOX 2 DOE Goals for Process Selection at SRS Goal 1: Meet schedule (Criterion 1) Goal 2: Minimize cost(Criteria 2 and 3) Goal 3: Minimize technical risk (Criteria 4 and 5) Goal 4: Minimize environmental safety and health impacts (Criteria 6 and 9) Goal 5: Minimize impact to interfaces(Criteria 7 and 8) Goal 6: Maximize process flexibility (Criteria 10 and 11) SOURCE: Harmon, 2000b, viewgraph on p. 14 entitled “Criteria Aligned by Goal” Other possible goals, such as ‘minimize tank space requirements' and ‘stakeholder acceptance,' were not included by DOE, because they were considered to be integral to the goals listed above or were not considered to be good discriminators among the alternatives. The TWG employed a series of steps to develop and implement the proposed criteria. In particular, they used several groups of experts to carry out preliminary application of the criteria to evaluation of the three processing alternatives. This preliminary screening was intended to determine if the criteria were capable of distinguishing among the alternatives and to determine to what extent the outcome might depend on the relative weighting assigned to each of the criteria. In conducting this preliminary screening, each alternative was evaluated by the group of experts and assigned an integer score from 1 (worst score) to 5 (best score). The resulting scores were then normalized to generate ‘utility values'2 that ranged from 0 (worst) to 1 (best). Finally, each utility value was multiplied by a weighting factor ranging from 0.03 (low weight) to 0.14 (high weight); the highest weighting was given to technical risk (Criteria 4 and 5). Finally, a total score for each of the alternatives was calculated by summing the eleven individually weighted utility values. Several preliminary scoring exercises (carried out by various advisory and management groups of the TWG) were reported at the November committee meeting. In all of the exercises the resulting total scores for the three alternative processes all fell within the range of 0.60 to 0.69; in one exercise the identical total score of 0.63 was calculated for all three alternative processes. The actual scoring and weightings were consensus values arrived at in review meetings among the experts following extensive discussion. This consensus represents the 2   The utility value is computed by the formula ui= 0.25 (Ai-1), where Ai is the score from 1-5 for criterion i. The total score is then determined by multiplying each utility value by an assigned weighting factor (ki) and summing the weighted scores. Total Score = ∑ (ui kI)