[DOE LETTERHEAD]

November 30, 2000

The Honorable John T. Conway
Chairman
Defense Nuclear Facilities Safety Board
625 Indiana Avenue, NW
Suite 700
Washington. D.C. 20004

Dear Mr. Chairman:

This responds to your August 29, 2000, letter, about Hanford high-level waste storage tank integrity. The enclosure identifies actions that address issues described in your August 4, 2000, staff report.

The Department concurs in the need for sustained close attention to preserve existing high-level waste storage tanks through chemistry control and upkeep of essential systems such as tank annulus ventilation systems. We have considered your suggestion that designating high-level waste tanks as "safety class" might improve the rigor of that effort. We have discussed the matter with your staff and reviewed your technical report DNFSB/TECH-28, Safety Basis Expectations for Existing Department of Energy Defense Nuclear Facilities and Activities. As a result, we agree to implement a Technical Safety Requirements mechanism for tank waste chemistry controls as part of the environmental protection program, which is part of the Integrated Safety Management System for the Hanford Tank Farms.

The Department has in place a systematic method for assuring long-term safety of Hanford tank waste storage through the period of this mission. There remain uncertainties in the duration of that period, in the need for replacement tanks or additional tanks, and in the projected ability of our program to preserve existing tank integrity for the extended but uncertain period of that mission. We continue to evaluate and reduce those uncertainties, but we concurrently intend to maintain existing tanks to minimize hazards and costs of long-term safe storage.

If you have any questions, please contact me or have your staff contact Mr. Mark Frei of my staff at (202) 586-0370.

Sincerely,

Carolyn L. Huntoon
Assistant Secretary for
Environmental Management

Enclosure