wtp final seismic design criteria

1. WTP Final Seismic Design Criteria John Eschenberg Project Manager, WTP Office of River Protection, and Deep Boreholes Project Staff

3. Purpose and Background Purpose Update the DNFSB on the final WTP seismic design criteria Background Project seismic design basis ground motion and spectra issued in May 1999 Criteria revised in February 2005 to accommodate uncertainty in interbed velocity contrasts Deep Boreholes Project initiated in 2005 to: Obtain direct seismic velocity data and reduce this uncertainty Revise the WTP seismic analyses and produce a final WTP site-specific ground motion design response spectra (WSGM)

4. Background (cont.) The horizontal ground motion design response spectrum for WTP developed in 2005 is shown in the graph to the right (RGM-2005) The spectrum represents a �conservative envelope of the range of the mean results� DelDel

5. Deep Boreholes Project Fieldwork Drill three deep boreholes and one corehole adjacent to the WTP HLW and Pretreatment facilities Collect subsurface velocity and geophysical data in-situ and on extracted core samples Schedule and Cost ~14 months ~$18M 14 months from first drilling RFPs to final reports.14 months from first drilling RFPs to final reports.

7. Four steel-cased entry holes (9-5/8 in) to top of basalt One wireline corehole (3-1/2 in) to 1400 ft Three deep mud rotary boreholes (7-7/8 in) to ~1400 ft through four interbeds

8. Geologic Characterization

9. Boreholes Data Collection Geophysical Logging The compensated density log tool contains a radioactive source (cesium-137) and two gamma detectors (near at 20 cm and far at 35 cm). The source and detectors are heavily shielded to prevent direct detection of gamma rays from the source. The principle is to focus gamma rays from the source into the formation, where they collide with electrons in the formation (Compton-scattering) and are reflected back to one of the CsI detectors. The response of the Density tool is determined essentially by the electron density (number of electrons per cubic centimeter) of the formation. Neutron logs respond primarily to the amount of hydrogen present in the formation (i.e., water, H2O). Low hydrogen concentrations correlate to low porosity, and vice versa. High-energy (fast) neutrons from an americium-beryllium (AmBe) source collide with nuclei of the formation materials as elastic �billiard-ball� collisions. With each collision a neutron loses some of its energy. The greatest energy loss occurs in collisions with the hydrogen nucleus. Collisions with heavy nuclei do not slow the neutron down very much. Thus, the slowing-down of neutrons depends largely on the amount of hydrogen in the formation. Induction logging devices transmit high-frequency alternating current of constant intensity through the transmitter coil and output �EM conductivity� in millisiemens per meter. The alternating magnetic field induces secondary currents in the formation. These currents flow in circular ground-loop paths coaxial with the transmitter coil. The ground-loop currents, in turn, create magnetic fields, which induce signals in the receiver coil. The receiver signals are essentially proportional to the conductivity of the formation. The Full Waveform Sonic log record the full waveform for 1,024�milliseconds at an interval of one microsecond. The recording begins at a delay of 56 milliseconds after the transmitted pulse. Borehole fluid is required for the tool to function properly. The first arrival (shortest travel time) of the acoustic pulse is through the shortest distance to the borehole wall, then through the formation rock matrix to the receiver. The near and far receivers show changes in the acoustic properties of the formation matrix and are also affected by hole size conditions (washed-out zones). The Acoustic Televiewer logging sonde is designed to generate an image of the borehole wall by transmitting ultrasonic pulses from a rotating sensor and then recording the amplitude and travel time of the signal that reflects at the interface between the borehole fluid and formation (i.e., borehole wall). Geophysical Logging The compensated density log tool contains a radioactive source (cesium-137) and two gamma detectors (near at 20 cm and far at 35 cm). The source and detectors are heavily shielded to prevent direct detection of gamma rays from the source. The principle is to focus gamma rays from the source into the formation, where they collide with electrons in the formation (Compton-scattering) and are reflected back to one of the CsI detectors. The response of the Density tool is determined essentially by the electron density (number of electrons per cubic centimeter) of the formation. Neutron logs respond primarily to the amount of hydrogen present in the formation (i.e., water, H2O). Low hydrogen concentrations correlate to low porosity, and vice versa. High-energy (fast) neutrons from an americium-beryllium (AmBe) source collide with nuclei of the formation materials as elastic �billiard-ball� collisions. With each collision a neutron loses some of its energy. The greatest energy loss occurs in collisions with the hydrogen nucleus. Collisions with heavy nuclei do not slow the neutron down very much. Thus, the slowing-down of neutrons depends largely on the amount of hydrogen in the formation. Induction logging devices transmit high-frequency alternating current of constant intensity through the transmitter coil and output �EM conductivity� in millisiemens per meter. The alternating magnetic field induces secondary currents in the formation. These currents flow in circular ground-loop paths coaxial with the transmitter coil. The ground-loop currents, in turn, create magnetic fields, which induce signals in the receiver coil. The receiver signals are essentially proportional to the conductivity of the formation. The Full Waveform Sonic log record the full waveform for 1,024�milliseconds at an interval of one microsecond. The recording begins at a delay of 56 milliseconds after the transmitted pulse. Borehole fluid is required for the tool to function properly. The first arrival (shortest travel time) of the acoustic pulse is through the shortest distance to the borehole wall, then through the formation rock matrix to the receiver. The near and far receivers show changes in the acoustic properties of the formation matrix and are also affected by hole size conditions (washed-out zones). The Acoustic Televiewer logging sonde is designed to generate an image of the borehole wall by transmitting ultrasonic pulses from a rotating sensor and then recording the amplitude and travel time of the signal that reflects at the interface between the borehole fluid and formation (i.e., borehole wall).

10. Initiated drilling 6/12/06 All three boreholes and corehole drilled to depth 10/12/06 Suspension (p-s) logging completed 10/17/06 Geophysical logging completed 10/28/06 Gravity-density logging completed 12/11/06 Deep downhole seismic logging completed 12/20/06 Shallow sediment logging completed 2/09/07 after casing Hanford and Ringold formations

11. Downhole Logging

12. Velocity Data Velocity data collected using an impulsive seismic source in suprabasalt sediments and upper two basalt and interbed units Data from three boreholes comparable

13. Downhole Signals

14. Velocity Data Velocity data collected using a vibratory seismic source in the basalt and interbed units Data from three boreholes comparable

15. Velocity Models Suprabasalt sediments Integrated and averaged new borehole Vs data with prior seismic cone penetrometer and downhole data Used geologists� logs to define range of geologic unit thicknesses Basalts and interbeds Integrated and averaged Texas (vibratory) and Redpath (impulsive) new borehole Vs data Used density and suspension logging Vs data to develop model to represent the change in velocity within each basalt flow top Used geologists� logs and geophysical data to define range of geologic unit thicknesses Geologists� logs in both locations on slide.Geologists� logs in both locations on slide.

16. Velocity Models - Sediments 2007 models are comparable to 2005 except: Sharp Vs contrast from Hanford sand to gravel (H2/H3) Sharp Vs contrast from Cold Creek Unit to lower Ringold Unit A High Vs in Ringold Unit A comparable to Vs in basalt flow top Near-surface, in-site sediment Vs to base of foundation - no backfill Sharp Vs contrast from Hanford Sand (H2) to Hanford Gravel (H3) Sharp Vs contrast from Cold Creek Unit (CCU) gravel ("reworked" Ringold) to lower Ringold Unit A Vs in CCU gravel possibly lower than in overlying H3 gravels High Vs in lower Ringold compares to Vs in basalt flow topNear-surface, in-site sediment Vs to base of foundation - no backfill Sharp Vs contrast from Hanford Sand (H2) to Hanford Gravel (H3) Sharp Vs contrast from Cold Creek Unit (CCU) gravel ("reworked" Ringold) to lower Ringold Unit A Vs in CCU gravel possibly lower than in overlying H3 gravels High Vs in lower Ringold compares to Vs in basalt flow top

17. Velocity Models � Basalts/Interbeds 2007 models reflect greater Vs contrasts between basalts and interbeds Vs basalts near 2005 high-range estimate Vs interbeds near 2005 low-range estimate Basalt flow top gradients individually measured thinner and stronger Includes internal flow structures Individual unit and composite Vs alternative models used in final analyses Rock-Soil velocity contrast elevated due to high Vs in Ringold Unit A New basalt Vs near previous high-range estimate New interbed Vs near previous low-range estimate New basalt flow top gradient zones thinner and stronger, individually measured Flow top Vs gradient measured for Priest Rapids basalt and additional internal flow structuresRock-Soil velocity contrast elevated due to high Vs in Ringold Unit A New basalt Vs near previous high-range estimate New interbed Vs near previous low-range estimate New basalt flow top gradient zones thinner and stronger, individually measured Flow top Vs gradient measured for Priest Rapids basalt and additional internal flow structures

18. Density Models Density measured using downhole gamma-gamma, and borehole gravity: No density measurements in Hanford sand/gravel and Ringold Unit due to steel casing Good agreement between gamma-gamma and borehole gravity Near-surface, in-site sediment Vs to base of foundation - no backfill Sharp Vs contrast from Hanford Sand (H2) to Hanford Gravel (H3) Sharp Vs contrast from Cold Creek Unit (CCU) gravel ("reworked" Ringold) to lower Ringold Unit A Vs in CCU gravel possibly lower than in overlying H3 gravels High Vs in lower Ringold compares to Vs in basalt flow topNear-surface, in-site sediment Vs to base of foundation - no backfill Sharp Vs contrast from Hanford Sand (H2) to Hanford Gravel (H3) Sharp Vs contrast from Cold Creek Unit (CCU) gravel ("reworked" Ringold) to lower Ringold Unit A Vs in CCU gravel possibly lower than in overlying H3 gravels High Vs in lower Ringold compares to Vs in basalt flow top

19. Logic Tree - 2005 Lack of Vs data for basalts and interbeds led to smaller velocity contrasts and higher probability of increased ground motion

20. Logic Tree - 2007 Uncertainty in Vs significantly reduced with site data New sediment data reflects greater damping � added site-specific soil curves

21. Inputs to Site Response Analyses and Relative Uncertainties and Impact

22. 2005 Site Response Wide range of Vs alternatives for basalts and interbeds had greatest impact on site response

23. 2007 Site Response Lower uncertainty and greater Vs contrasts result in lower relative amplification

24. Summary of Key 2005-2007 Model Differences Basalt and interbed Vs Significantly smaller uncertainty of median Vs Significantly greater contrast between basalts and interbeds Sediment dynamic properties More non-linear and greater damping based on site-specific data Wider range of alternatives

25. Derivation of RGM - 2005 RGM-2005 design response spectra (DRS) developed using 84th percentile relative amplification function (RAF) Increased peak horizontal ground motion by up to 40% over original design criteria

26. Derivation of WSGM - 2007 WSGM-2007 design response spectra developed using new 84th percentile relative amplification function Decreased peak horizontal ground motion by ~25% from 2005

27. Future Plans Secretarial Certification of Final Criteria Restart Construction of PT and HLW PT and HLW Structural Summary Reports to be issued December 2007 One year backlog between design and construction Use of final seismic criteria (WSGM-2007) limited

28. Aerial View of WTP Site

29. Reports of the Deep Boreholes Project