March 16, 2005
The Honorable John T. Conway
Defense Nuclear Facilities Safety Board
625 Indiana Avenue, NW, Suite 700
Washington, DC 20004-2901
Dear Mr. Chairman:
The purpose of this letter is to provide for your use the enclosed report, Site-Specific Seismic Site Response Model for the Waste Treatment Plant (WTP), Hanford, Washington. This report addresses Issues # 1 through #6 described in the Program Plan provided to you on September 3, 2004. The Office of Environmental Management (EM) considers that incorporation of the revised spectra into the design and construction for the WTP will ensure adequate seismic safety. The Office of River Protection (ORP) is assessing the impact of this change in the WTP seismic design criteria. This assessment is scheduled for completion by the end of May 2005.
The Program Plan includes a commitment for a deep boring (up to 2,000 feet deep) determination. A final decision on the need for such a deep boring has not been made to date given the priority to completing the enclosed report. We believe that the revised design basis is sufficiently conservative for the purpose of completing the WTP design. I have asked ORP to brief you at your convenience on our technical understanding of the likelihood of success were we to proceed with deep borings with the purpose of measuring bedrock velocities.
The additional seismic modeling work described in Issue #7 of the Program Plan to incorporate revised attenuation relations has been delayed. Originally scheduled to be issued in December 2004, this work will not be available from the Pacific Earthquake Engineering Research (PEER) group until April 2005. The subsequent evaluations described in Issue #7 will be rescheduled once the revised attenuation relations are issued by the PEER group. The impact of these evaluations upon the WTP design and construction will be assessed at that time.
We will continue to work with you and your staff to design and construct a safe and operational WTP. If you have any further questions, please call me at (202) 586-7709 or Roy Schepens, Manager, ORP, at (509) 376-6677.
Paul M. Golan
Principal Deputy Assistant Secretary
for Environmental Management
cc: M. Whitaker, DR-1
R. Schepens, ORP