March 23, 2006
The Honorable A. J. Eggenberger
Defense Nuclear Facilities Safety Board
625 Indiana Avenue, NW, Suite 700
Washington, D.C. 20004-2901
Dear Mr. Chairman:
Thank you for the opportunity to discuss the Sodium Bearing Waste (SBW) treatment project with the Defense Nuclear Facilities Safety Board (Board) on March 3, 2006. The briefing provided a project overview and the facility technical and safety basis.
As was discussed in the briefing, the Department of Energy (DOE) has reviewed the safety aspects of this project thoroughly, with both an extensive review conducted through the DOE-Idaho SBW Treatment Project Integrated Project Team and a review conducted by our nuclear safety experts at Headquarters. As a result of these reviews, DOE and its contractor responsible for the SBW Treatment Project have made decisions regarding both the facility hazard category and Natural Phenomena Hazard (NPH) design criteria. In summary, the facilities (both the treatment and product storage) have been determined to be hazard category 2 nuclear facilities. The NPH performance category for the facility structures, based on a seismic event, assumes performance category (PC)-2 for the treatment facility including the cell structures for processing and packaging and PC-3 for the product storage vault. The Preliminary Documented Safety Analysis, using conservative accident analysis assumptions, indicates that no systems, structures or components (SSCs) other than the storage vaults and canisters are designated as safety significant or safety class. However, the facility designs for the treatment area include designated safety significant SSCs to provide defense in-depth worker protection.
We have also determined that a modest upfront investment will mitigate potential regulatory risks associated with the current waste disposition baseline and allow for facility mission flexibility for potential calcine treatment in the future. These enhancements result in thicker process walls and more exact seismic assessments and profiling that is reasonable with the PC-3 approach. By redoubling our efforts toward assessing facility safety early i n design, and by mitigating project risks, we are improving the overall safety posture as well as our ability to address future mission needs.
In keeping with your DOE oversight role, please advise me of any concerns the Board may have with the current approach for the SBW Treatment Project. If you have further questions, please call me at (202) 586-0738 or Mr. Dae Chung, Acting Deputy Assistant Secretary for Integrated Safety Management and Operations Oversight, at (202) 586-5151.
Dr. Inés R. Triay
Chief Operating Officer for