OFFICE OF RIVER PROTECTION
July 19, 2007
The Honorable A. J. Eggenberger
Defense Nuclear Facilities Safety Board
625 Indiana Avenue, N.W., Suite 700
Washington, D.C. 20004-2901
Dear Mr. Chairman:
THE U.S. DEPARTMENT OF ENERGY (DOE), OFFICE OF RIVER PROTECTION (ORP) STATUS OF STRUCTURAL STEEL FIRE PROTECTION AT THE WASTE TREATMENT AND IMMOBILIZATION PLANT (WTP)
References: 1. DNFSB letter from A. J. Eggenberger, Chairman to S. W. Bodman, Secretary of Energy, dated October 17, 2005.
2. ORP letter from Roy J. Schepens, Manager to A. J. Eggenberger: Chairman of DNFSB, "Status and Path Forward for the Seismic Ground Motion Issue at the Waste Treatment and Immobilization Plant (WTP)." dated June 28, 2006.
3. DNFSB Seventeenth Annual Report from A. J. Eggenberger; Chairman, John E. Mansfield, Member; Joseph F. Bader, Member; Larry W. Brown, Member; Peter S. Winokur, Member to the Congress of the United States, dated February 28, 2007.
This letter explains the design approach that OW and the WTP Contractor are using to determine which structural steel members in plant facilities will be provided with two hour fire protection, as identified in Reference 1 and 2.
The W'I'P strategy is to provide fire protection for selected structural steel members based on their role in supporting the structure during and after a fire. In Reference 1, the Defense Nuclear Facilities Safety Board (DNFSB) stated this methodology would be acceptable provided it can be reasonably shown that unprotected structural members with reduced material properties due to a fire would not be relied upon to support the building. In addition, Reference 3 noted that the WTP Contractor is expected to develop a technically sound methodology for identifying structural steel members that do not require fireproof coating; and structural analyses should support the conclusion that such a structural steel member could fail without impacting the structure or adjacent safety systems.
While the final resolution requires the detailed design to be complete, the WTP Contractor has made measurable progress by incorporating methodologies in the WTP Structural Design Criteria (SDC), Revision 12, to address how each facility shall be designed to preserve confinement capability, and protect important-to-safety structures, systems, and components, while accounting for degradation of the non-fireproofed steel members as the result of a fire. These measures include increase in tributary areas for loading, and increase in unrestrained lengths and spans of the fireproofed members due to non-fireproofed members considered inactive during and immediately after a fire event. The SDC also identifies additional load combination and stability evaluations required to be considered for the fire events. Attached for your information is Section 4.19, Fire Resistant design of structures, from the SDC, Revision 12 (Attachment l), that describes these changes.
The WTP Contractor also continues to incorporate the revised SDC methodology into the structural design calculations. The calculations are on-going and commensurate with the design schedule as identified in Attachment 2.
The DNFSB technical staff has also raised additional concerns regarding the risk to the plant operations due to a fire event. OW acknowledges that a fire unmitigated could impact non-safety related equipment necessary to operate the plant. However, ORP considers the risk of damage to non-safety related equipment from unprotected steel in a credible fire scenario to be extremely unlikely mitigated, since the WTP plant is provided with multiple levels of defense-in-depth controls, including fire barriers, administrative procedures for combustible control, automatic fire sprinkler protection systems, fire alarm and detection systems, and automatic fire department notification. The fire sprinkler systems are expected to control the credible fires as discussed in the Preliminary Fire Hazards Analyses.
The SDC incorporated requirements of primary (fireproofed) members to retain their design capacity, post fire to account for the low-risk event of a fire. If a fire occurs, an assessment of the damage of other affected structures, systems and components, and subsequent repair and/or replacement will occur prior to the restart of the plant as part of the post-fire recovery.
DNFSB technical staffs have been informed of the details of these changes to the SDC. ORP will continue to keep the DNFSB informed on the completion calculations.
If you have any questions, you may contact me, (509) 372-3062.
Shirley J. Olinger, Acting Manager
Office of River Protection
J. F. Bader, DNFSB
J. Blackmann, DNFSB
J. E. Mansfield, DNFSB
C. March, DNFSB
R. B. Matthews, DNFSB
R. G. Quirk, DNFSB
C. E. Anderson, EM-1
M. B. Whitaker, HS-1.1
S. W. Bodman, S