May 21, 2004
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 a response to concerns identified by your letter of March 23, 2004. The Defense Nuclear Facilities Safety Board (DNFSB) asked how the Department of Energy (DOE) will ensure the Bechtel National, Inc. (BNI) proposed methodology for developing requirements for fire resistance for structural steel used in Waste Treatment and Immobilization Plant (WTP) facilities receives adequate review and comment through a peer review process, consistent with the process that would be expected of any consensus code requirement. The DNFSB further requested DOE to discuss why the proposed methodology should be used in lieu of recognized methods already in use in the fire protection and structural engineering communities, and address any potential structural or safety impacts on the WTP facilities.
This letter and the enclosed response address the DNFSB questions. As noted in the DNFSB’s letter, the BNI methodology for justifying a reduction in fire resistance ratings of structural steel was still evolving when the DNFSB letter was issued. As discussed in the enclosed response, a revised methodology has been proposed that is significantly different than the methodology previously discussed with DNFSB staff. Specifically, BNI does not intend to use the performance-based approach of performing heat transfer analyses coupled with limiting temperature criteria from British Standard BS 5950-8:2003, Structural use of steelwork in building, to determine the response of structural columns to fire effects. Instead, BNI will use qualitative analyses to determine the adequate protection requirements set and controls. BNI believes that the structural steel elements in the WTP process buildings may be adequately protected from postulated fire events by the existing automatic fire suppression system (wet pipe sprinkler system) and the installation of additional sprinkler heads located to protect the lower portions of structural steel columns from the effects of postulated worst-case fires. However, the potential need for fire-resistance coating will be evaluated as part of the equivalency approach. The qualitative analyses will include consideration of room heights, sprinkler actuation set points, and multiple fire magnitudes. The project Preliminary Fire Hazard Analysis reports will be revised accordingly. This approach for protecting WTP structural steel does not involve the development of an ad hoc fire protection code or standard. Rather, the equivalency provisions of the International Building Code, 2000 Edition, and DOE Standard DOE-STD-1066-97 will be used.
DOE will retain the services of an independent technical expert knowledgeable of the building code, National Fire Protection Association standards, and DOE requirements to perform an independent technical review of the BNI analyses and conclusions. The independent technical review will assess the use of active systems and passive systems. From this information and the revised BNI equivalency methodology, DOE will determine the structural steel fireproofing requirements for the W'I'P. The results of this review will be provided to the DNFSB.
Thank you for meeting with us on May 18. I realize that the Board has continuing concerns regarding the WTP and we have scheduled a follow-on meeting on June 2. As a result, we may need to provide refinements to this response.
If you have further questions, please call me at (202) 586-7709 or Ms. Patrice Bubar, Deputy Assistant Secretary for Integrated Safety Management and Operations Oversight, at (202) 586-5151.
Jessie Hill Roberson
Assistant Secretary for
Response to DNFSB Letter