[DOE LETTERHEAD]
March 23,
2006
The Honorable A. J. Eggenberger
Chairman
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.
Sincerely,
Dr. Inés R. Triay
Chief Operating Officer for
Environmental Management