Technical Basis for Certification of Seismic Design Criteria for the Waste Treatment Plant, Hanford, Washington
- Pacific Northwest National Laboratory, Richland, WA (United States)
- Geomatrix Consultants, Inc., Oakland, CA (United States)
- C.J. Costantino and Associates, Valley, NY (United States)
- U.S. Department of Energy, Office of River Protection, Richland, WA (United States)
In August 2007, Secretary of Energy Samuel W. Bodman approved the final seismic and ground motion criteria for the Waste Treatment and Immobilization Plant (WTP) at the Department of Energy's (DOE) Hanford Site. Construction of the WTP began in 2002 based on seismic design criteria established in 1999 and a probabilistic seismic hazard analysis completed in 1996. The design criteria were reevaluated in 2005 to address questions from the Defense Nuclear Facilities Safety Board (DNFSB), resulting in an increase by up to 40% in the seismic design basis. DOE announced in 2006 the suspension of construction on the pretreatment and high-level waste vitrification facilities within the WTP to validate the design with more stringent seismic criteria. In 2007, the U.S. Congress mandated that the Secretary of Energy certify the final seismic and ground motion criteria prior to expenditure of funds on construction of these two facilities. With the Secretary's approval of the final seismic criteria in the summer of 2007, DOE authorized restart of construction of the pretreatment and high-level waste vitrification facilities. The technical basis for the certification of seismic design criteria resulted from a two-year Seismic Boreholes Project that planned, collected, and analyzed geological data from four new boreholes drilled to depths of approximately 1400 feet below ground surface on the WTP site. A key uncertainty identified in the 2005 analyses was the velocity contrasts between the basalt flows and sedimentary interbeds below the WTP. The absence of directly-measured seismic shear wave velocities in the sedimentary interbeds resulted in the use of a wider and more conservative range of velocities in the 2005 analyses. The Seismic Boreholes Project was designed to directly measure the velocities and velocity contrasts in the basalts and sediments below the WTP, reanalyze the ground motion response, and assess the level of conservatism in the 2005 seismic design criteria. The characterization and analysis effort included 1) downhole measurements of the velocity properties (including uncertainties) of the basalt/interbed sequences, 2) confirmation of the geometry of the contact between the various basalt and interbedded sediments through examination of retrieved core from the core-hole and data collected through geophysical logging of each borehole, and 3) prediction of ground motion response to an earthquake using newly acquired and historic data. The data and analyses reflect a significant reduction in the uncertainty in shear wave velocities below the WTP and result in a significantly lower spectral acceleration (i.e., ground motion). The updated ground motion response analyses and corresponding design response spectra reflect a 25% lower peak horizontal acceleration than reflected in the 2005 design criteria. These results provide confidence that the WTP seismic design criteria are conservative. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21326069
- Report Number(s):
- INIS-US-10-WM-08188; TRN: US10V0447067434
- Resource Relation:
- Conference: WM'08: Waste Management Symposium 2008 - HLW, TRU, LLW/ILW, Mixed, Hazardous Wastes and Environmental Management - Phoenix Rising: Moving Forward in Waste Management, Phoenix, AZ (United States), 24-28 Feb 2008; Other Information: Country of input: France; 14 refs
- Country of Publication:
- United States
- Language:
- English
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