Text

Amend 26 to Psar.Seven Oversize Drawings Encl.Aperture Cards Are Available in PDR
	ML20063B120
Person / Time
Site:	Skagit
Issue date:	08/16/1982
From:	; PUGET SOUND POWER & LIGHT CO.
To:	;
Shared Package
ML20063B113	List: ML20063B110; ML20063B120;
References
	NUDOCS 8208250220
	Download: ML20063B120 (56)
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{{#Wiki_filter:S/HNP-PSAR 8/16/82 /^ \\ File this instruction sheet in the front of Volume 1 as a record of changes. The following information and check list are furnished as a guide for the insertion of new sheets for Amendment 26 into the Preliminary Safety Analysis Report for the Skagit/ Hanford Nuclear Project. This material is denoted by use of the amendment date in the upper right-hand corner of the page. New sheets should be inserted as listed below: Discard Old Sheet Insert New Sheet (Front /Back) (Front /Back) CHAPTER 2 2-iii/iv 2-iii/iv 2-v/vi 2-v/vi 1 2-xv/xvi 2-xv/xv1 2.5-17/18 2.5-17/18 2.5-19/20 2.5-19/20 2.5-20a/20b 0 2.5-20c/ blank N/ 2.5-21/22 2.5-21/22 Figure 2.5-9a Figure 2.5-9b Figure 2.5-9c CHAPTER 3 l i 3.7-1/2 3.7-1/2 3.8-43/44 3.8-43/44 I QUESTIONS AND RESPONSES l Question 231.4/231.4 (cont'd) through 231.4 (cont ' d) / blank i I Figure 231.4-1 Figure 231.4-2 Figure 231.4-3 i ,O Figure 231.4-4a Figure 231.4-4b ( ) I i 1 Amendment 26 8208250220 020816 PDR ADOCK 05000522 l l B PDR r

S/HNP-PSAR 8/16/82 Discard Old Sheet Insert New Sheet (Front /Back) (Front /Back) Figure 231.4-5 Figure 231.4-6 Figure 231.4-7 Question 231.6/231.6 (cont'd) through 231.6 1 (cont'd)/ blank Figure 231.6-1 Question 231.7/231.8 Question 231.9/231.9 (cont'd) Question 231.10/231.11 Question 231.12/ blank Figure 231.12-1 Figure 231.12-2 Question 231.13/ blank O O 2 Amendment 26 l

S/HNP-PSAR 12/21/81 ( SECTION TITLE PAGE 2.4.3 Probable Maximum Floods (PMF) on 2.4-8 Streams and Rivers 2.4.3.1 Columbia River PMF 2.4-8 2.4.3.2 Skagit/Hanford Nuclear Project 2.4-10 Watershed PMF 2.4.3.2.1 Probable Maximum Precipitation (PMP) 2.4-10 2.4.3.2.2 Precipitation Losses 2.4-11 2.4.3.2.3 Runoff and Stream Course Model 2.4-11 2.4.3.2.4 Probable Maximum Flood Flow 2.4-12 2.4.3.2.5 Water Surface Elevations 2.4-13 2.4.3.2.6 Coincident Wind Wave Activity 2.4-13 2.4.4 Potential Dar. Failures, Seismically 2.4-17 Induced 2.4.4.1 Cam Failure Permutations 2.4-18 2.4.4.2 Unsteady Flow Analysis of Potential 2.4-19 l Dam Failures 2.4.5 Probable Maximum Surge and Seiche 2.4-19 Flooding 2.4.6 Probable Maximun Tsunami Flooding 2.4-19 2.4.7 Ice Effects 2.4-20 2.4.8 Cooling Water Canals and Reservoirs 2.4-22 4 2.4.9 Channel Diversions 2.4-22 2.4.10 Flood Protection Requirements 2.4-22 2.4.11 Low Water Considerations 2.4-23 2.4.11.1 Low Flow in Streams 2.4-23 2.4.11.2 Low Water Resulting from Surges, 2.4-23 Seiches, or Tsunami 2.4.11.3 Historical Low Water 2.4-24 2.4.11.4 Future Control 2.4-26 2.4.11.5 Plant Requirements 2.4-26 2.4.11.6 Heat Sink Dependability Requirements 2.4-27 2.4.12 Dispersion, Dilution and Travel 2.4-28 Times of Accidental Releases of 4 Liquid Effluents in Surface Waters 2.4.13 Groundwater 2.4-28 2.4.13.1 Description and On-Site Use 2.4-28 2.4.13.2 Sources 2.4-33 2.4.13.3 Accident Effects 2.4-37 2.4.13.4 Mon'.toring or Safeguard Requirements 2.4-41 O 2-iii Amendment 23

S/HNP-PSAR 8/16/82 SECTION TITLE PAGE 2.4.13.5 Design Basis for Subsurf ace 2.4-41 Hydrostatic Loadings 2.4.14 Technical Specifications and 2.4-42 Emergency Operation Requirements 2.5 Geology, Seismology, and Geotechnical 2.5-1 Engineering 2.5.1 Basic Geologic and Seismic 2.5-5 Information 2.5.1.1 Regional Geology 2.5-5 2.5.1.2 Site Geology 2.5-5 2.5.1.2.1 Site Physiography 2.5-6 2.5.1.2.2 Site Lithology and Stratigraphy 2.5-8 2.5.1.2.2.1 Stratigraphy 2.5-8 2.5 1.2.2.2 Lithology 2.5-9 2.5.1.2.2.2.1 Columbia River Basalt Group 2.5-9 2.5.1.2.2.2.2 Ringold Formation 2.5-9 2.5.1.2.2.2.3 Pasco Gravels 2.5-12 2.5.1.2.2.2.4 Surficial Deposits 2.5-13 2.5.1.2.3 Site Structural Geology 2.5-13 2.5.1.2.4 Site Geologic History 2.5-16 2.5.1.2.5 Engineering Evaluations of Local 2.5-17 Geologic Features 2.5.1.2.6 Site Groundwater Conditions 2.5-18 2.5.1.2.7 Volcanic Hazards 2.5-18 2.5.2 Vibratory Ground Motion 2.5-19 2.5.2.1 Seismicity 2.5-20 2.5.2.2 Geologic Structures and Tectonic 2.5-20 Activity 2.5.2.3 Correlation of Earthquake Activity 2.5-20 with Geologic Structure or Tectonic Provinces 2.5.2.4 Maximum Earthquake Potential 2.5-20 2.5.2.4.1 Potential Sources of Earthquakes 2.5-20 2.5.2.4.1.1 Swarm-Type Earthquakes 2.5-20 2.5.2.4.1.2 Earthquakes Associated with Tectonic 2.5-20a Provinces 2.5.2.4.1.3 Earthquakes Associated with Tectonic 2.5-20a Structure 2.5.2.4.2 Vibratory Ground Motion 2.5-20a 2.5.2.4.2.1 Ground Motion from Larger 2.5-20a Earthquakes 2.5.2.4.2.2 Ground Motion from Swarm Earthquake 2.5-20b 2.5.2.5 Seismic Wave Transmission 2.5-20b Characteristics of the Site r 2.5.2.6 Safe Shutdown Earthquake 2.5-20c 2.5.2.7 Operating Basis Earthquake 2.5-20c I l 2-iv Amendment 26

S/HNP-PSAR 8/16/82 SECTION TITLE PAGE (~ / 2.5.3 Surface Faulting 2.5-21 i 2.5.4 Stability of Subsurface Materials 2.5-22 2.5.4.1 Geologic Features 2.5,-23 2.5.4.1.1 Areas of Potential Surface or 2.5-23 Subsurface Subsidence 2.5.4.1.2 Previous Loading History 2.5-23 2.5.4.1.3 Zones of Alteration, Weathering 2.5-23 and Structural Weakness 2.5.4.1.4 Unrelieved Residual Stresses in 2.5-23 Bedrock 2.5.4.1.5 Potentially Unstable Rocks or Soils 2.5-23 2.5.4.2 Properties of Subsurface Materials 2.5-24 2.5.4.3 Exploration 2.5-26 2.5.4.3.1 Type, Quantity, Extent and Purpose 2.5-26 2.5.4.3.2 Location Plans and Loos of 2.5-27 i Explorations l 2.5.4.3.3 Subsurface Soil Profiles 2.5-27 i i 2.5.4.4 Geophysical Surveyc 2.5-27 2.5.4.5 Excavations and Backfill 2.5-28 2.5.4.5.1 Extent of Excavation and Backfill 2.5-28 i 2.5.4.5.2 Sources of Backfill 2.5-28 l 2.5.4.5.3 Compaction Criteria 2.5-28 2.5.4.5.4 Engineering Properties of Backfill 2.5-29 l 2.5.4.5.5 Quality Control Program 2.5-29 l 2.5.4.5.6 Control of Groundwater 2.5-29 i 2.5.4.5.7 Inservice Surveillance 2.5-29 2.5.4.6 Groundwater Conditions 2.5-29 2.5.4.6.1 Stability 2.5-30 l 4 2.5.4.6.2 Control of Water Levels and Seepage 2.5-30 i 2.5.4.6.3 Construction Dewatering 2.5-30 i 2.5.4.6.4 Permeability 2.5-30 l 2.5.4.6.5 Groundwater Fluctuation 2.5-30 i 2.5.4.6.6 Monitoring of Wells and Piezometers 2.5-30 f 2.5.4.6.7 Direction of Groundwater Flow 2.5-30 t 2.5.4.6.8 Subsidence 2.5-31 l 2.5.4.7 Response of Soil and Rock to Dynamic 2.5-31 l Loading 2.5.4.8 Liquefaction Potential 2.5-32 2.5.4.9 Earthquake Design Basis 2.5-33 l 2.5.4.10 Static Stability 2.5-33 ( 2.5.4.11 Design Criteria 2.5-33 2.5.4.12 Techniques to Improve Subsurface 2.5-34 l Conditions 2.5.4.13 Subsurface Instrumentation 2.5-34 l l 2.5.5 Stability of Slopes 2.5-34 2.5.6 Embankments and Dams 2.5-34 { l 2.6 References 2.6-1 i / h l 2-v Amendment 26 i

S/HNP-PSAR 12/21/81 APPENDICES NUMBER TITLE 2A through 2J Not Used 2K Geophysical Investigations Umtanum Ridge to Southeast Anticline Hanford Site, Washington 2L Geophysical Investigations Skagit/Hanford Nuclear Project Site Hanford Site, Washington 2N Geologic Structure of Umtanum Ridge: Priest Rapids Dam to Sourdough Canyon 20 Gable Mountain: Structural Investigations and Analyses 2P Geonydrologic Investigations 20 Foundation Investigation and Analysis 20A Field Investigations and Results 2QB Laboratory Test Procedures and Results 2R Stratigraphic Investigation of the Skagit/Hanford Nuclear Project 2S The Origin of the Umtanum Ridge-Gable Mountain Structural Trend and Implications for a Regional Tectonic Model O 2-vi Amendment 23

S/HNP-PSAR 8/16/82 I e NUMBER TITLE 2.4-46 Streamlines from S/HNP Site (Ben Franklin Dam) 2.4-47 Monitor Wells and Piezometer Roles Location Map for S/HNP Site 2.5-1 Topographic Map of the S/HNP Site Area 2.5-2 Surface Geologic Map of the S/HNP Site Vicinity (5-Mile Radius) 2.5-3 Drill Hole and Cross Section Location Map S/HNP Site Area 2.5-4 Generalized Stratigraphic Section at the S/HNP Site 2.5-5 Stratigraphic Cross Sections S/HNP Site Area Lines 1 and 4A 2.5-6 Stratigraphic Cross Sections S/HNP Site Area 4B and 4D 2.5-7 Stratigraphic Cross Sections S/dNP Site Area Lines M and M/W 2.5-8 Stratigraphic Cross Sections S/HNP Site Area Lines W and X-1 2.5-9 Structural Contour Maps of the S/HNP Site Area 2.5-9a Response Spectra Obtained Using NUREG-CR 0098 2.5-9b Response Spectra for ML 4.0 Swarm-Type Earth-quake Attenuated to km (5% Damping) 2.5-9c Response Spectra for ML 4.0 Swarm-Type Earth-quake at 8 km Compared to NUREG-CR 0098 Spectra for M3 6.5 Earthquake at 15 km 2.5-10 velocity Column S/HNP Site 2.5-11 Generalized Soil Profile 2.5-12 Site Plan 2.5-13 Generalized Subsurface Profile l 2.5-14 Excavation Plan O 2-xv Amendment 26 L

/ S/HNPrPSAR-8/16/82 l NUMBER TITLE 2.5-15 Excavation and Backfill Sections 2.5-16 Dynamic Shear Moduli 2.5-17 Damping Ratios 2.5.13 Elastic Modulus Profile 2.5-19 Foundation Settlements 2.5-20 Lateral Earth Pressures 1 3 n O I ~ O 2-xvi - Amendment 26 ,s / s 4

S/HNP-PSAR 12/21/81 (m) Site Area and the Columbia Plateau indicates that the region \\> has been tectonically stable compared to other parts of the Pacific Northwest and western North America. In addition, recent geologic and seismic history are mutually consistent and indicate a low potential for earthquakes. 2.5.1.2.5 Engineering Evaluations of Local Geologic Features Geotechnical investigations were performed to evaluate foundation conditions at the Plant facilities and to provide engineering data and analyses required for the design of foundations and subsurface walls under both static and dynamic loading conditions. The scope of the study included field and laboratory investigations, together wi th engineer-ing evaluations for foundation design. The field program comprised subsurface borings, arenching, in situ deformation testing within boreholes and trenches, subsurface soundings, in situ density measurements and undisturbed sampling for laboratory testing. The details of the field program are t'iscussed in Appendix 2Q of this PSAR. In addition, field seismic surveys were undertaken at the Plant facilities (Appendix 2L of this PSAR) and a groundwater monitoring (} system (water sampling and piezometric head monitoring) was established (Appendix 2P of this PSAR). Supplemental infor-x,f mation was obtained from general observations during the geologic investigations. 23 There are no areas of actual or potential surface or subsurface subsidence, uplift or collapse at the Plant facilities. There exist no deformational zones, shears, Joints, fractures or folds, zones of alteration, structural weakness or irregular weathering profiles which would have an influence on structural foundations. There is no evidence of faults or disturbances from past earthquakes within the foundation soils. Basalt bedrock is at a depth of approximately 700 feet at the Plant facilities, and unrelieved residual bedrock stresses would not impact structural foundations. The Plant facilities soils are derived from predominantly basaltic and silicic rock types that are chemically stable, and will not exhibit instabil-ities related to physical or chemical properties. The Site Area has not been affected by subgrade mineral extraction and there are no known minerals of commercial value specific to the Site Area. Recent reports of possible commercial natural gas in an exploratory well north of Yakima may result in the Pasco Basin being classified as a ps gas-producing basin. ) (V 2.5-17 Amendment 23

i l S/HNP-PSAR 8/16/82 i l l l The Plant facilities are underlain by about 35 ft of medium dense to dense sand to approximately elevation 490 f t (MSL), about 170 ft of very dense sand and gravel to approximately elevation 320 f t, and about 520 ft of very dense sand and gravel with hard clayey silt down to basalt bedrock at about l elevation -200 ft. The bearing capacities of the Plant l-facilities soils will be very large for the mat foundations of the major central plant structures, and settlements will be small. Because of the depth of the water table (approxi-mately 100 ft below foundation grade) and the nature and strength of the soils below the water table, the foundation materials are not susceptible to instability associated with liquefaction or cyclic-strength deterioration. Accordingly, the subsurface soils at the S/HNP Plant facilities are compe-tent to provide f oundation support f or the plant structures under both static and dynamic loading conditions. In general, overexcavation of soils at f ounding elevations and replacement with structural backfill will not be required beneath the central plant foundations. Details of the found-ation engineering properties of the Plant facilities are 23 described in Section 2.5.4 and Appendix 20. 2.5.1.2.6 Site Groundwater Conditions Groundwater occurs at the Site Area under confined and uncon-fined conditions. Water exists in an unconfined state in the glaciofluvial deposits and in a confined state in the Ringold Formation and basalts. Water in the lower part of the Ringold Formation is under a slightly higher hydraulic head than water in the upper part of the Ringold Formation. The water table at the Plant f acilities occurs at approxi-mately elevation 400 ft above mean sea level, which is about 100 ft below the base of Category I structures. Existing water-level data show that the elevation of the water table at the Plant Site has fluctuated in response to liquid waste disposal at the 200-Areas. Groundwater conditions of the Plant f acilities are discussed in detail in Section 2.4.13. 2.5.1.2.7 Volcanic Hazards Volcanic hazards at the S/HNP Site are the same as those at the Washington Nuclear Project No. 2 (WNP-2) site. Those hazards are discussed in WNP-2 FSAR (Amend 18), Section 2.5.1.2.6.1. The only potential volcanic hazard to the 26 S/HNP Site is considered to be that resulting from ashfall from a major eruption of a Cascade volcano. The composite characteristics of such an ashfall would be as follows: 2.5-18 Amendment 26

S/HNP-PSAR 8/16/82 f} o Eruptive Sources: Mount Adams or Mount Rainier at \\d a distance of 165 km and 180 km respectively. o Estimated Ash Eruptive Volume: Mount St. Helens Layer Yn (4 km3). o Duration of Ashfall: Approximately 20 hours. o Potential Thickness of Compacted Ashfall: 7.4 cm (3 inches) t o Estimated Percent Compaction of Ash: 20-40 per-t cent. l o Average Rate of Ashfall: .37 cm/hr (0.15 in/hr). 26 l o Average Density of Ash: 72 pcf (dry, loose) 96 pcf (dry, compacted) 101 pcf (wet, compacted l i Estimated Average Grain Size: 98% 0.5 mm 91% 0.35 mm 76% 0.25 mm 57% 0.15 mm i 50% 0.075 mm 1 40% 0.040 mm ( 27% 0.010 mm 20% 0.005 ma 11% 0.002 mm Design criteria f or the S/HNP meet or exceed all of the requirements of this postulated ashfall. Operating criteria and procedures addressing such an ashf all will be specified i in the S/HNP FSAR. l i 2.5.2 VIBRATORY GROUND MOTION The S/HNP Site is located approximately 5 miles west of WNP 1/4 and WNP-2 sites. Inf ormation on seismicity of the area within a 200 mile radius of the S/HNP Site and the maximum earthquake potential at the S/HNP Site is provided in 23 Sections 2.5.2.1, 2.5.2.2, 2.5.2.3 and 2.5.2.4 of Amendment 18 (October, 1981) to the WNP-2 FSAR and is incorporated herein by reference. l i ("'N l 2.5-19 Amendment 26 i l

S/HNP-PSAR 8/16/82 2.5.2.1 Seismicity Reference Section 2.5.2.1, WNP-2 FSAR. 2.5.2.2 Geologic Structures and Tectonic Activity l 23 Reference Section 2.5.2.2, WNP-2 FSAR. 2.5.2.3 Correlation of Earthquake Activity with Geologic Structure or Tectonic Provinces i i Reference Section 2.5.2.3, WNP-2 FSAR. ) 2.5.2.4 Maximum Earthquake Potential i 2.5.2.4.1 Potential Sources of Earthquakes The earthquake potential at the S/HNP Site is defined in the following subsections, in accordance with parameters defined in the WNP-2 Draft SSER (June 29, 1982) for Section 2.5.2. I i 2.5.2.4.1.1 Swarm-Type Earthquake. A swarm-type earthquake (Mg = 4.0) is assumed to occur at the closest approach of ma]or irrigation to the S/HNP Site. The Columbia River acts 26 i as a boundary to the water table influence from major irriga-tion to the north and east of the Hanford Reservation. To the south and west of the Hanford Reservation, the area i under irrigation is limited. Thus, using the guidelines set forth in the WNP-2 SSER, a swarm-type earthquake is assumed to occur to the east of the S/HNP Site at a minimum hypo-central distance of approximately 8 kilometers from the S/HNP Site. Irrigation currently taking place on the Hanford Reservation consists of (1) waste discharge to ponds, (2) waste dis-l charge to surface cribs and (3) occasional and very minor surface irrigation of solid waste disposal sites for the i purpose of establishing vegetative cover. The volumes of water associated with these usages have no significant effects on the groundwater table. 9 2.5-20 Amendment 26

S/HNP-PSAR 8/16/82 [ )\\ 2.5.2.4.1.2 Earthquakes Associated with Tectonic Provinces, s_, The largest earthquake within the Columbia Plateau Tectonic Province assumed to occur in the site vicinity is the 1936 July 16, Milton-Freewater earthquake. The magnitude of this earthquake has been determined to be 5.7-5.8 Mg, (1,1872 WNP-2 SSER, Section 2.5.2). The epicenter of the December 1 north-central Washington earthquake is located in the Northern Cascades tectonic province whose closest approach is approximately 140-150 kilometers north of the S/HNP Site. This event has been assigned a magnitude Mg = 7.0. 2.5.2.4.1.3 Earthquakes Associated with Tectonic Structure. The Rattlesnake-Wallula (RAW) alignment is the most signifi-cant structure to the S/HNP Site. The closest approach of RAW to the S/HNP Site is 15 kilometers. The maximum cred-ible hypothetical earthquake for the RAW structure has been determined to be Ms = 6.5. A number of faults and structural features are located in the vicinity of Gable Mountain. The closest approach of 26 Gable Mountain and its associated structural features to the S/HNP Site is approximately 10 kilometers. For licensing purposes, the maximum hypothetical earthquake assumed to be associated with Gable Mountain is Ms = 5.0 (WNP-2 SSER, Section 2.5.2). s 2.5.2.4.2 vibratory Ground Motion 2.5.2.4.2.1 Ground Motion from Larger Earthquakes. Peak accelerations from earthquakes associated with tectonic pro-vinces (Section 2.5.2.4.1.2) or tectonic structures (Section 2.5.2.4.1.3) are estimated using attenuation relationships of Campbell (1981), Joyner and Boore (1981) and Woodward Clyde (Appendix 2.5K, WNP-2 FSAR). The highest acceleration values calculated are for the assumed 6.5 Mg earthquake on RAW, a distance of 15 kilometers from the S/HNP Site. Of the three relationships cited above, it is believed that Campbell's relationship is most appropriate for estimating "close in" ground motion at the S/HNP Site. Neither the Joyner and Boore nor Woodward-Clyde relationships are as specific as Campbell's relationship to the "close in" dis-tances being considered, i Campbell's attentuation relationship for a 6.5 Mg earthquake at 15 km yields acceleration values of.175g at the median level and.2579 at the 84th percentile level. The average i of the acceleration values calculated from the three l attenuation relationships referred to above is 0.201g at the l 2.5-20a Amendment 26

S/HNP-PSAR 8/16/82 h median level (range of 0.175 to 0.237) and 0.3169 at the 84th percentile level (range of 0.257 to 0.345). Ground velocity values are estimated from the attenuation relationships of Joyner and Boote (1981) and Woodward-Clyde Consultants (1978). The average of the calculated velocity values is 22.19 cm/sec at the median level (values of 19.70 and 24.67) and 39.38 cm/sec at the 84th percentile level (values of 37.81 and 40.95). Response spectra were developed using the above ground motion values and spectral amplification factors contained in NUREG/CR/0098 (Newmark and Hall, 1978). Median spectral amplification factors were used with the 84th percentile ground motion values, and 84th percentile spectral amplifica-tion factors were used with median ground motion values. The two response spectra for an Ms = 6.5 at a distance of 26 15.0 kilometers are shown on Figure 2.5-9a. For comparison purposes, a Regulatory Guide 1.60 Spectra anchored to 0.35g is also shown on Figure 2.5-9a. 2.5.2.4.2.2 Ground Motion from Swarm Earthquake. The ground motion predictions for a swarm-type earthquake of ML = 4.0 were developed by Washington Public Power Supply System in response to Question 361.16 for WNP-2. The Supply System's consultant, Woodward-Clyde Consultants, used non-linear regression techniques to predict peak acceleration as a function of distance. The predicted 84th percentile cor-rected peak acceleration value for a Mn 4.0 event at a hypo-central distance of 8.0 kilometers (the closest approach of major irrigation to the S/HNP Site) is.115g. The shape of the response spectrum associated with the swarm-type earthquake was also determined in the response to Ques-tion 361.16 (WNP-2 FSAR). This response spectrum shape anchored to the computed acceleration value of.115g is shown on Figure 2.5-9b. The resonse spectrum for the swarm earthquake is compared with the response spectra for the 6.5 Mg earthquake at 15 kilometers distance on Figure 2.5-9c. 2.5.2.5 Seismic Wave Transmission Characteristics of the Site 23 In-situ velocity measurements by crosshole and downhole techniques and surface refraction studies have been conducted in the vicinity of the S/HNP Site (Appendix 2L). The velocity column beneath the S/HNP Site from ground surface to the Elephant Mountain Basalt is shown on Figure 2.5-20b Amendment 26

i i 3/HNP-PSAR 8/16/82 2.5-10. The velocity column has been compiled f rom crosshole l26 velocity measurements at the west reactor site to a depth of approximately 200 ft, from downhole velocity measurements to a depth of 570 ft in borehole S-15, and from surface refraction data for the basalts. Velocity values between a depth of 570 ft and the top of basalt at a depth of 704 ft have been estimated from downhole velocity measurements at other locations as correlated with the coarse and fine materials indicated by the geophysical logs. The coarse 24 materials within the Ringold and lower pre-Missoula section are generally cemented, producing the high velocity (8,000 fps or greater) layers shown on Figure 2.5-10. Shear wave velocities within the Ringold section below a depth of 230 ft are estimated based on velocity measurements at other locations in the Hanford Reservation area. Compressional and shear wave velocities of the materials above basalt have also been measured at WNP-1/4 and WNP-2 (Appendix 2L of the 23 WNP-1/4 PSAR). The changes in seismic wave velocities with depth at WNP-1/4 and WNP-2 are similar to those described above for the S/HNP. The sonic velocities of the basalt flows and interbeds below the Elephant Mountain Basalt have been measured in the Rattlesnake Hills No. 1 well (Ref 16) to a depth of 3,230 m (10,600 ft). The sonic log from this well shows that the compressional wave velocity varies. Relatively high velocities of 5.0 to 5.7 km/s (16,400 to 18,700 fps) were j measured for the competent basalt flows. Lower velocities of 4.0 to 4.5 km/s (13,000 to 14,800 fps) were measured for j the interbeds. Shear wave velocities were not measured. I 2.5.2.6 Safe Shutdown Earthquake The maximum acceleration at the Site resulting from historical or instrumental earthquakes is estimated to have been 0.015g (see Section 2.5.2.6 WNP-2 FSAR). A Regulatory Guide 1.60 Spectrum anchored at a peak j acceleration of 0.35g is assigned as the Safe Shutdown i E. cthquake (SSE). The requirements of this SSE exceed those for all potential earthquakes discussed in Section 2.5.2.4. 26 2.5.2.7 Operating Basis Earthquake A Regulatory Guide 1.60 Spectrum anchored at a peak accelera-tion of 0.175g, or one-half that of the SSE, is assigned as ) the Operating Basis Earthquake (OBE). 2.5-20c Amendment 26

S/HNP-PSAR 8/16/82 ( 2.5.3 SURFACE FAULTING All available geologic and geophysical information was { evaluated to determine whether any evidence suggested that surface faulting might occur within 5 miles of the Site. l Available information was supplemented with detailed, site-specific geologic and geophysical surveys extending i beyond 5 miles in some directions and concentrated in a 2 mile radius of the Site. These surveys have included ground 4 gravity and magnetic surveys along closely spaced lines and a seismic refraction survey. The results of the geophysical 4 investigations are described in Appendices 2K and 2L. Geologic investigations undertaken specifically to supple-ment available information included photogeology, field mapping, rotary and core drilling, and stratigraphic analysis. The results of these investigations are described in Section 2.5.1.2 and Appendix 2R. 23 l i Geologic and geophysical studies have shown that the basalt l bedrock underlying the Site within a radius of at least 2 miles shows slopes with only gentle relief (generally less than 5 degrees). Sedimentary units within the Miocene-Pliocene Ringold Formation which overlies bedrock are generally horizontal or show some minor warping (slopes less i than 5 degrees). Sediments overlying the uppermost Ringold O Formation (generally considered to be part of the Hanford I ] Formation) are Pleistocene or older in age and contain a ( refracting horizon of 8,000 ft/sec velocity which is i flat-lying within a radius of 2 miles of the Site. This velocity horizon has also been found to be flat-lying over an area of approximately 28 square miles within the vicinity i of the Site. There are no photolinears within the site Area j which are structurally controlled. On the basis of these f data, there is no evidence that suggests potential for [ surface faulting; therefore, Sections 2.5.3.1 through l 2.5.3.8 do not apply. j [ f i i l I I I 2.5-21 Amendment 26 [ I i ~.... --..

S/HNP-PSAR 7/2/82 2.5.4 STABILITY OF SUBSURFACE MATERIALS Beneath a surficial layer of loose silty sand, the central Plant f acilities are underlain by geologic strata which will provide suitable f ounding materials. The loose surficial sands have an average thickness of 6 to 8 feet across the Site (mean approximate surf ace elevation 525 f eet). These sands are underlain by medium dense to dense sands of late 23 Pleistocene age to approximate elevation 490 feet (MS L), very dense sands and gravels of late Pliocene (?) to Pleistocene age to approximate elevation 320 feet, and lacustrine and fluvial very dense sands and gravels and hard silts and clayey silts of late Miocene to Pliocene age (Ringold Formation) through to basalt bedrock at approximate elevation -200 feet. The present groundwater table is at elevation 400 feet. A majority of the central Plant structures, with the excep-tion of the Ultimate Heat Sinks and Radwaste Buildings which 24 will be founded directly on the very dense sands below Eleva-tion 490', will be supported directly on structural backfill (see Figure 2.5-15). The fact that the excavation has reached the very dense (pre-Missoula) sands will be verified 25 by a qualified inspector prior to placement of backfill. The Standby Diesel Generator Fuel Storage tanks will be founded in the Missoula sand. Because of the use of large mat f oundations and the nature of the foundation materials, there is no possibility of 23 large scale movements associated with bearing capacity failure. Structure permissible total and dif f erential settlements control the allowable bearing pressures. Permanent settlements will occur under the static loads applied by the surface structures and their equipment. 24 These settlements are not expected to cause adverse effects on the structures and operating equipment. During design basis earthquake shaking, the surface l 23 structures will be subjected to dynamic pseudo-elastic 24 (recoverable) movements. The dynamic movements are not expected to have adverse effects on the Plant and equipment during the Design SSE. Because of the great depth of the water table and the nature of the geologic strata at the Site, there is no potential 23 for liquefaction of the structure foundations. In addition, there are no other foundation conditions (e.g. zones of l alteration or weathering, collapse features, poorly consolidated strata or soluble zones) which could impact foundation stability. 6 2.5-22 Amendment 25

S/HNP-PSAR 8/16/82 o,pg, [. 4,, o j i i ie i i a a a a a ai i i i i aai N REG GUIDE 160 ~ (a) ~ (bl N/ 2 10' $i \\ N e* s NUREG-CR 0098 a O / 10'V / N N e ,s f 6's DAVPiNG. s i s a aaia i a a a a : i i i iaai, PERIOD (SEC) EXPLANATION (a) 84TH PERCENTILE GROUND MOTION VALUES - MEDIAN AMPLIFICATION FACTORS (b) MEDIAN GROUND MOTION VALUES - 84TH PERCENTILE AMPLIFICATION F ACTOPS PUGET SOUND POWEP & LIGHT COMPANY SKAGIT / HANFORD NUCLEAR PROJECT PRELIMINARY SAFETY ANALYSIS REPORT RESPONSE SPECTRA n OBTAINED USING NUREG CR 0098 O FIGURE 2.5 9a Amendment 26 1

S/HNP-PSAR 8/16/82 oIpg, [g 'oo, i i i i ii i i i i iii 1-i i iiia 10' $ 10'$(( 5 g 84TH PERCENTILE g g MEDIAN O 10 '2/ / \\ E i i i e iei .. i iiea i i e i iiii PERIOD (SEC) NOTE SPECTRAt SHAPE DIGITIZED AND SMOOTHED FROM WNP 2 FIGURE 361 16-6 PUGET SOUND POWER & LIGHT COMPANY SKAGIT / HANFORD NUCLEAR PROJECT PRELIMINARY SAFETY ANALYSIS REPORT RESPONSE SPECTRA FOR M 4.0 t O SWARM TYPE EARTHQUAKE ATTENUATED i) TO 8 km(5% DAMPING) v FIGURE 2.5-9b Amendment 26

S/IINP-PSAR 8/16/82 'o$7g, pf4 't, o g o s . i ii i i i i i ii i i iiiii 10'/ N / h-(a) (b) N I G" 10' 8 d \\ i SPECTRA FOR SWARM EARTHOUAKES f O 10' 84TH PERCENTILE 6 4 MEDIAN S [o 15'. DAVPINGi a i i ie iie i i i i e i ii i i i ii.. 10 ' 10 ' 10* 10' PERIOD (SEC) EXPLANATION (a) 84TH PEACENT!LE GROUND UCTION VALUES - t MEDtAN AVPLIFICATCN FACTORS i i (bl MfDIAN GROUND MOTION VALUES - l 84TH PE ACENTILE AVPteFICATCN F ACTORS l PUGET SOUND POWER & LIGHT COMPANY j SKAGIT / HANFORD NUCLEAR PROJECT l PRELIMINARY SAFETY ANALYSIS REPORT i RESPONSE SPECTRA FOR M 4.0 l L SWARM' TYPE EARTHQUAKE AT 8" l Cs COMPARED TO NUREG CR 0098 l [ ( ) SPECTRA FOR Ms 6.5 j l (/ EARTHQUAKE AT 15 km i FIGURE 2.5 9c j i Amendment 26 I

S/HNP-PSAR 8/16/82 Os 3.7 SEISMIC DESIGN (As referred to in 251 NSSS GESSAR, this section contains the more complete discussion of this subject.) All structures, systems, and equipment of the f acility are defined as either Seismic Category I or non-Seismic Category I (also called Category II). The requirements for Seismic Category I qualification are given in Section 3.2 with a list of structures, systems, components and equipment which are so categorized. Geology and seismology criteria related to the Site are 23 given in Section 2.5. A peak acceleration of 0.35g and 0.175g at ground surface have been assigned as the SSE and OBE, respectively. 26 3.7.1 SEISMIC INPUT 3.7.1.1 Design Response Spectra i The design response spectra for SSE horizontal and vertical \\ components are illustrated in Figures 3.7-1 and 3.7-2. These spectra define the seismic input intensity at a control point located in the free field at the finished grade level. They are selected in accordance with Regula-tory Guide 1.60, " Design Response Spectra for Seismic Design of Nuclear Power Plants." i I l l l i [ i v i .l 3.7-1 Amendment 26 l

S/HNP-PSAR 12/21/81 To establish the SSE ground accelerations, the effects of focal and epicentral distances from the Plant Site and possible faulting at or near the Plant Site are taken into account. This is discussed in Section 2.5 of this PSAR. 3.7.1.2 Design Time History Synthetic acceleration time histories have been generated for use in time history analyses. These time histories represent the seismic accelerations in the free field at the finished grade level. Response spectra produced from the horizontal and vertical SSE time histories closely approxi-23 mate the SSE design response spectra, as shown in Figures 3.7-3 through 3.7-6. The 24 second duration of the syn-thetic time histories is comparable to the duration of the time histories which form a basis for the design response spectra. The OBE time history will be one-half the SSE time history. When two orthogonal horizontal base motions are applied simultaneously, a second synthetic time-history will be used. This second time-history will also have a response spectrum which approximates the design response spectrum. 3.7.1.3 Critical Damping Values 3.7.1.3.1 Seismic Category I Structures, Systems, and Components Other than NSS System Table 3.7-1 gives the damping values for structures, systems and components. The values are in accordance with the requirements of Regulatory Guide 1.61, " Damping Values for Seismic Design of Nuclear Power Plants." Damping values higher than those given in Table 3.7-1 may be used if documented test data are provided to support higher values. 23 Soil material damping will be based upon laboratory testing, with consideration given to the magnitude of earthquake induced strains. Foundation geometrical (" radiation") damping will also be employed. 3.7.1.3.2 NSS System See 251 NSSS GESSAR. 3.7-2 Amendment 23

S/HNP-PSAR 12/21/81 Live loads including floor occupancy loads, L = laydown loads due to temporary placement of equipment; nuclear fuel and fuel transfer casks, equipment handling loads, lateral i earthfill loads, lateral and vertical sur-4 charge loads due to transport vehicles; pressure differences due to heating, cool-ing and normal atmospheric changes; roof loads due to snow and impounded rainfall, j hydrostatic loads due to compartment flood-ing. Loads due to Safety Relief Valve pressures as outlined in Appendix 6C of 23 this PSAR are included. Operating live loads likely to occur during L = o normal operation. These are the live loads to be used in seismic analysis and with seismic load combinations. The operating live load (Lo) is a relatively small fraction of the design live load (L); Lo does not include such loads as those due to laydown, maintenance, or temporary cranes or moving equipment. 3.8-42. o Thermal effects and loads during normal T = operating or shutdown conditions, based en O the most critical transient or steady state condition. l R = Pipe reactions during normal operating or o shutdown conditions, based on the most critical transient or steady state condi-tion. 3.8.6.1.2 Severe Environmental Loads Severe Environmental loads are those that could infrequently be encountered during the Plant life. Included in this cat-egory are: o Loads generated by the Operating Basis E = Earthquake (OBE). The earthquake is com-posed of two horizontal and one vertical components and the effects of the three components are combined, based on the square root of the sum of the squares. Only the dead load (D) and the operating live load (Lo) need be considered in 23 evaluating the seismic response forces. L 3.8-43 Amendment 23

S/HNP-PSAR 8/16/82 Loads generated by the design wind speci-W = fied for the Plant. 3.8.6.1.3 Extreme Environmental Loads Extreme environmental loads are those which are credible but are highly improbable. They include: Ess = Loads generated by the Safe Shutdown Earthquake (SSE). The earthquake is com-posed of two horizontal and one vertical components and the effects of the three components are combined, based on the square root of the sum of the squares. Only the dead load (D) and the operating 23 live load (L ) need to be considered in a evaluating the seismic response forces. Roof load due to volcanic ashfall (see l16 V = Section 2.5.1.2.7). 126 Wt = Effects generated by the design tornado specified f or the Plant. They include loads due to the tornado wind pressure and differential pressures, and also the energy resulting from impact of tornado-generated missiles. 3.8.6.1.4 Abnormal Loads Abnormal loads are those loads generated by a postulated high-energy pipe break accident within a building and/or compartment thereof. Included in this category are the following: Design Pressure load within or across a P = a compartment and/or building, generated by the postulated pipe rupture, including the dynamic effects due to the pressure time history and pool-swell phenomena as out-12 lined in Appendix 6C of this PSAR. Thermal effects due to thermal conditions T = a generated by the postulated break and including To. 9 3.8-44 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 within at least a five-mile radius of the proposed Skagit/Hanf ord units the applicant is to prepare and submit the following: 4

1. Fence Diagrams - Using all available geologic /geo-physical inf ormation, the applicant is to construct fence diagrams / cross sections or other graphic presen-tations as. appropriate, showing the conf iguration of the top of basalt and sub units within the overlying horizons (Ringold, Pre-Missoula, Missoula).

The purpose of this request is to demonstrate graphically the nature, density, and degree of confidence in the resolution capability of the surf ace and subsurf ace investigations conducted by various organizations (both public and private) within at least a five-mile radius of the Skagit/Hanford Site.

2. Text - A comprehensive, written discussion relative to the presence or absence of faulting (both capable, if present, and.non-capable) is to accompany the graphic presentation described above.

The discussion is to include at least the f ollowing: a. An enumeration of the various investigative tools O (both geologic and geophysical) used in the compi-lation of Item 1, above, and a ranking, with appro-priate supportive text, of the degree of confi-dence the applicant assigns that methodology for defining the presence or absence of geologic struc-ture (principally faulting) in the near Site area (within at least a five-mile radius of the Site). b. An estimate of the reliability and resolution ability (in terms of f eet or tens of f eet) of each of the above investigative methodologies to deter-mine the presence or absence of faulting or other geologic structures, such as anticlines, synclines, and monoclines. l

3. High-Lighting of Specific Area - The geographic area extending between approximate compass azimuths 1200 and 3200 centered on the Skagit/Hanford Site is an area requiring special scrutiny (in the form of fence t

diagrams and written documentation) because of-the relative decrease in density of definitive investiga-tions (principally borings and ref raction lines) when compared to the area northeast of the Skagit/Hanford l Site. \\ Q231.4-1 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd)

RESPONSE

The Applicant has approached the investigation of the S/HNP Site vicinity for possible faults within the guidelines provided by 10 CFR, Part 100, Appendix A, and the relevant portions of Regulatory Guide 1.70 and applicable Standard Review Plans. Appendix A to 10 CFR, Part 100 (Reactor Site Criteria), requires that "The geologic, seismic and engineering characteristics of a site and its environs shall be investigated in such sufficient scope and detail to provide reasonable assur-ance that they are sufficiently well understood to permit an adequate evaluation of the proposed site..." and that the precise nature and extent of investigations required shall be determined by the geologic conditions in the Site vicinity. It then requires that additional and more detailed investigations to determine the potential hazard f rom surf ace f aulting be conducted only if f aults greater than 1,000 feet long are found within five miles of the Site. The Applicant maintains that, particularly in light of earlier investigations and NRC reviews for other facil-ities at Hanford, the S/HNP Site has been investigated in sufficient scope and detail to provide reasonable assur-ance that the geologic, seismic and engineering character-istics of the Site and its environs are suf ficiently well understood to permit an adequate evaluation of the proposed Site. These investigations have yielded no evidence of the existence of significant f aults within five miles of the proposed Site. Philosophy of Investigations Because bedrock at the S/HNP Site is overlain by a thick (greater than 500 f eet) section of sediments, geologic investigations for this Project were designed to (1) locate the Project in an area where the basalt surf ace is essentially flat-lying and, theref ore, signifi-cant bedrock structures are least likely to be present and (2) then investigate that area with a variety of geophysical and geological techniques that collectively are most appropriate for detecting any indirect or direct evidence of bedrock structures or f aults. The investigations for this project were designed in such a way that they were sufficiently sensitive (had adequate resolution) to detect f aults signficant to the Site. O Q231.4-2 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) Such faults in the Columbia Plateau generally have the following characteristics: o They are associated with anticlinal folds (or relatively steep basalt slopes). o They extend for distances of approximately a mile or more. o They have dip-slip displacement of approximately several hundred feet. o They display vertical offsets of tens of feet. Faults in the Columbia Plateau are known to be concen-trated where folding has been most intense (on the anticlines). Pre-existing zones of weakness associated with these faults have accommodated whatever strain has not been accommodated by folding. Under these condi-tions, no new fault is likely to form. Rather, it is j reasonable to assume that, if def ormation had continued, 2 those faults which formed at the time folding was most intense may have continued to experience displacement at some low rate (e.g. 0.2 in/1000 years for the central fault on Gable Mountain). This low rate of strain is, however, more than sufficient to have produced offset on the basalt surf ace of 50-60 f eet. Such offsets are well within the resolution of the investigative techniques applied in the S/HNP Site vicinity. Furthermore, the investigations conducted in the Site vicinity were designed to provide multiple and indepen-dent lines of evidence within the area immediately surrounding the Site, thus providing increased confidence in the integrated interpretation nearer the Site. The investigations were sequenced such that techniques of more direct observation and/or higher resolution might be later employed where earlier reconnaissance-type tech-niques had yielded evidence of bedrock or sedimentary features which might possibly be associated with fault-l ing. Consequently, the program was not designed to necessarily provide uniformly dense coverage with all l investigative techniques. l It should be noted that, prior to investigation of the current Site, extensive, detailed investigations were conducted on a potential site for this Project located in the vicinity of May Junction on the Hanf ord Reservation. Consequently, the Applicant came to the current site with a good understanding of the local stratigraphy and structural setting and with a suite of investigative techniques proven to be effective in this environment. Q231.4-3 Amendment 26 i

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) These techniques and their application to the current Site vicinity are discussed in greater detail below. However, prior to beginnng detailed investigations at the current Site, an attempt was made to locate the Project in an area of the Hanford Reservation unlikely to contain significant bedrock structures or faults. Site Location The Hanford Reservation is located within the Pasco Basin, a structural subdepression within the Columbia Plateau. It is generally accepted that the structures of the Columbia Plateau for at least the past 15 million years are primarily a response to north-south shortening, and a probable north-south orientation of the maximum compressive stress (WNP-2 FSAR, Appendices 2.5N and 2.50). The Washington Public Power Supply System in their response to WNP-2 Question 361.23, have proposed two tectonic models to explain the development and structural relationships of tectonic structures within the Columbia Plateau. These models are prrsented as regional counterparts to the end members of the "struc-tural spectrum" of fold-fault development originally applied to specific Plateau folds. These models are: (1) the development of both Yakima f old-type structures and those of the Rattlesnake-Wallula alignment (RAW) as a consequence of intracrustal detachment with analogy to the incipient f ormation of a thrust and fold belt of foreland type and (2) the development of Yakima f old-type structures with response to crustal buckling dynamics treating the plateau as a layered medium and including geometrically required detachments to develop as a consequence of buckling. In model 2, the structures of RAW represent interference effects between the buckled and locally detached upper crustal level and a deeper zone of diffuse and limited dextral strain. Both models require interrelationships between faulting and folding and, in both, f aults with appreciable dimensions can develop only along more highly compressed portions of major structures. Similarly, f aults associated with minor fold structures of lesser length and amplitude, whether primary or secondary in origin, are unlikely to be of significant size. The current Site for the Skagit/Hanford Nuclear Project is in a structurally low area of generally flat-lying and undeformed basalt between major anticlinal folds. Both end members cf the " structural spectrum" of regional tectonic models would indicate that this is the type of Q231.4-4 Amendment 26

S/HNP-PSAR 8/16/82 ( QUESTION 231.4 (Cont'd) area least likely to contain significant f aults. In addition, there are no known faults in the region that, when extended as much as 10 miles along trace, might come within 5 miles of the Site. There are no earthquake swarms or linear trends of recorded earthquake epicenters within 5 miles of the Site. Neither are there any nearby trends of epicenters whose linear projection might trend into the 5-mile radius around the Site. There are no epicenters of earthquakes of magnitude larger than or equal to 1.0 and f ocal depth of less than 1 kilometer located within 5 mies of the Site. Thus, preliminary indications were that significant f aults were not likely to be found in the S/HNP Site vicinity. i Investigative Techniques The following investigative techniques were used in exploring the subsurface in the vicinity of the S/HNP Site to f urther define the geologic characteristics of the Site and to attempt to locate any possible evidence of faults: (' (1) Aeromagnetics (2) Land Magnetics (3) Gravity i (4) Seismic Refraction (5) Drilling, Sampling and Logging A ranking of the relative confidence one places in the l investigative techniques might be appropriate where such j techniques compete or are mutually exclusive, but, such i has not been the case. The method in which these tech-i niques were employed by the Applicant renders such a j ranking unnecessary. Each technique is dif f erent and has different characteristics, limitations and u~ses. The Applicant views each technique as valuable in and of l itself for the information which it produces. This information has been combined into an integrated interpre-tation of the geologic conditions in the Site vicinty (5-l mile radius). It is from the comparison and integration I of multiple and independent data sets that confidence is l established in our knowledge of geologic conditions in j the Site vicinity. l The techniques employed, the manner in which they were i applied and the results of each investigation are summa-rized below. /T l (- / i l l l Q231.4-5 Amendment 26 {

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) Aeromagnetics: Aeromagnetic surveys measure variations in the earth's total magnetic field. In general, they are able to detect (1) variations in the depth to rock bodies with distinctive magnetic properties and (2) variations in the magnetic properties of near-surface earth materials. This technique is able to cover large areas quickly and economically and is particularly usef ul on the Hanf ord Reservation because of the high magnetic contrast between the sediments of the Hanf ord and Ringold f ormations and the underlying basalts, and the technique's ability to detect possible faults which might have no expression in the surface of the basalt but which juxtaposed basalt units with differing magnetic properties. Aeromagnetics, with its uniform data density and regional coverage, can be used to extrapolate regional structures into the Site vicinity as well as to recognize local structures within it. It can also be used to define the areal extent of features observed with other techniques. Several aeromagnetic surveys have been conducted over areas of eastern Washington which include the Hanf ord Reservation. The Applicant has chosen to interpret data f rom the survey perf ormed by Aeroservices f or the Washington Public Power Supply System because its flight line spacing, orientation and altitude make it the most appropriate for thu purpose of detailed structural interpretation. Main flight lines f or this survey were 0 East (normal to the oriented approximately North 40 major structaral grain of the area) and flown on half-mile spacings at a constant altitude of 1,000 f eet above terrain. Tie lines were flown orthogonal to the main flight lines at approximately 5-mile spacing. An aeromag-netic contour map with 2, 10 and 50 gamma contour inter-vals and aeromagnetic profiles generated from this data were used to extrapolate regional and subregional struc-tural trends into the Site vicinity and to identify possible previously-unknown structures in the Site l vicinity. In the Site vicinity (5-mile radius), these data can be used to identify structural features l expressed in the basalt surface having a vertical relief of 20 to 40 feet or more and a length of approximately one mile or more oriented parallel or subparallel to the structural grain of the area. The geology of the Site vicinity as interpreted from the aeromagnetic data was f ound to be consistent with our understanding of the surrounding region. Aeromagnetic l 0231.4-6 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) data in the area surrounding the S/HNP Site clearly indicate major structures such as the Rattlesnake Moun-tain anticline, Gable Mountain, the Southeast anticline, Yakima Ridge and its subsurface extension and the Cold Creek syncline. In the Site vicinity, the aeromagnetic data exhibit magnetic highs north and southwest of the Site, coincident with bedrock highs interpreted from gravity and drilling data. No aeromagnetic evidence of i faults was identified within five miles of the Site (see S/HNP PSAR Amendment 24, Appendix 2K and 2L). Land Magnetics: Land magnetic data were collected for the Skagit/Hanf ord Nuclear Project generally at 50- to 100-foot station intervals along traverses coincident with gravity traverses or lines of borings. Within the area imme-diately surrounding the plant location (approximately one-mile radius), ground magnetic data were acquired at 50-foot station intervals along traverses approximately l 1,200 feet apart. i s Like the aeromagnetic survey, this survey measures variations in the earth's total magnetic field and is sensitive to variations in the depth to highly-magnetic rock bodies and/or variations in the magnetic properties of materials near the earth's surface. The ground magnetic survey, however, provides more detail and higher j resolution along individual traverses than the aero-i magnetic survey. Land magnetic data in the Site vicinity were used to qualitatively confirm the bedrock configura-tion interpreted from gravity and drilling and to poten-tially identify faults which might have no expression in the basalt surf ace but juxtapose basalts with varying magnetic properties. We believe that, in the Site j vicinity, these data may be used to detect changes in j i elevation f rom top of basalt of 20 to 40 f eet along the j ground magnetic traverses. j l The interpretation of the ground magnetic data was f ound i to be consistent with that of other. techniques. The land I magnetic data in the Site vicinity exhibit only minor l undulations implying that the basalt surface is smoothly l varying and without abrupt of f sets (see S/HNP PSAR Amendment 24, Appendix 2K and 2L). No evidence of faults was identified within five miles of the Site. Q231.4-7 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) Gravity: Gravity surveys measure variations in the earth's gravity field. They are sensitive to variations in the depth to interfaces between relatively high and low density materials and to variations in the bulk density of near-surface earth materials. This technique is particularly applicable to exploration at Hanf ord because of the generally constant and relatively high density of the basalt bedrock and the signficant density contrast between the basalt and the overlying sediments. When properly reduced (i.e., to a residual Bouguer gravity anomaly map and profiles), these data may be used to evaluate the configuration of the top of basalt. The uppermost basalt in the Site vicinity is the Elephant Mountain basalt and little or no erosion has taken place on its surface; thus, the residual Bouguer gravity anomaly map may be viewed as an approximate structural contour map of the top of the Elephant Mountain basalt. Gravity data are particularly useful when used in conjunc-tion with borings in that they may be used to define the character and shape of the basalt surface between the discrete data points provided by borings. Gravity data collected f or the Skagit/Hanf ord Nuclear Project in the vicinity of the Site consists of traverses on approximately one-mile or closer spacing with stations at 400-foot intervals. Latitude, longitude and elevation controls are accurate to within 0.1 feet. These data have been reduced to residual Bouguer gravity anamoly maps with contour intervals of 0.2 milligals or less and are adequate to resolve elevation changes of 20 to 30 feet on the top of basalt. In areas where station and line spacings are sufficiently small (i.e., in the imme-diate vicinity of the Site where stations are on 400-foot centers), it is possible to detect elevation changes of approximately 10 to 20 feet on the top of basalt. Within the five-mile radius of the S/HNP Site, the configuration of the basalt surf ace defined by gravity data is in good agreement with that defined by other techniques, including drilling. The total and residual Bouguer gravity anomaly map of the Hanf ord Reservation study area (S/ENP PSAR Amendment 24 Figures 2K-13 and 2K-

14) and in the vicinity of the S/HNP Site (S/HNP PSAR Amendment 24 Figures 2L-8 and 2L-9) depicts the bedrock topography between the S/HNP Site Area and the nearest structures.

The anomalies caused by the Southeast anticline and the Gable Butte-Gable Mountain segment are Q231.4-8 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) located northeast and north of the Site. The S/HNP Site Area is separated from the Southeast anticline by a broad synclinal basin. A narrow.synclinal trough and low-amplitude arciclinal high separate the Gable Butte-Gable Mountain from the S/HNP Site Area. The S/HNP Site Area is characterized by a low gravity gradient, indicating a bedrock surface with gradual slopes. Gravity highs, indicative of minor subsurface bedrock highs, are located north and southwest of the S/HNP Site. The maximum gravity gradient in the Site vicinity is caused by the northeast flank of a northwest-southeast trending monoclinal flexure one mile southwest of the Site. The dip on the flank of this monocline is approximately 50 to the northeast (utilizing a conversion f actor of 150 f eet/milligal). The total and residual Bouguer gravity anomaly maps for the S/HNP Site Area (S/HNP PSAR Amendment 24 Figures 2L-10 and 2L-ll) delineate the detailed bedrock surface beneath the Site. The bedrock highs located to the north and southwest of the Site are at the margins of the contoured region. The gravity data indicate a bedrock surface with gradual slopes (up to 40) beneath the S/HNP Site area. There is no evidence of abrupt offsets in the basalt surface or of other features which might be indicative of faults (see S/ENP PSAR Amendment 24, Appendix 2K and 2L). Seismic Refraction: Seismic refraction profiling is the most direct geophys-ical method used to explore the S/HNP Site vicinity. This method permits the calculation of the depth to various seismic velocity interfaces from the arrival times of direct and ref racted elastic compressional waves at varying distances f rom their point of origin. Seismic refraction techniques were employed rather than reflec-tion because of their ability to directly measure and account for the near surf ace velocity variations preva-lent at the Hanf ord Reservation. Actually, two types of seismic ref raction surveys were perf ormed for the Skagit/- Hanf ord Nuclear Project: a shallow refraction survey, designed to define near-surface velocity horizons and to provide sufficient inf ormation to correct statically the deep ref raction survey f or near-surf ace velocity varia-tions; and a deep refraction survey, designed to define the bedrock topography. The primary purpose of the seismic refraction surveys in the Site vicinity was to Q231.4-9 Amendment 26

S/HNP-PSAR 8/16/82 O ll QUESTION 231.4 (Cont'd) i confirm the interpretations from magnetic and gravity techniques that the basalt surface immediately surround-ing the Site was generally flat-lying and undeformed and to ascertain that no structures undetected by other methods trended into the area immediately surrounding the Site. These surveys are able to measure the absolute depth to the top of basalt within approximately 5 to 10 percent of the total depth. Resolution is sufficient to detect any vertical of f set of 20 to 30 f eet on the basalt surface. In addition, the shallow refraction survey was used to define a high-velocity horizon lying below a magnetically-reversed section of the Pre-Missoula gravels. The data permit the resolution of the elevation of the top of this horizon to within 10 f eet. These ref raction surveys confirmed the interpretation from gravity and magnetics that the basalt in the Site vicinity is generally flat-lying and relatively unde-formed, and also demonstrated that the high velocity horizon within the Pre-Missoula gravels is essentially flat-lying within a one-mile radius of the Site. The interpretations of the seismic refraction surveys are in good agreement with those from other geophysical methods and drilling (see S/HNP PSAR Amendment 24, Appendix 2K and 2L). Drilling, Sampling and Logging Exploratory borings provide the most direct observations of the geology of the subsurface. The techniques of boring interpretation and correlation applied in the vicinity of the S/ENP Site were developed and proven to be ef f ective in the exploration of a previous site in the vicinity of May Junction. Those earlier investigations were initiated by the drilling of two core holes (Borings 1 and 3) approximately 1,300 feet apart. Analyses of cores from these holes demonstrated that the Ringold sediments present on the Hanf ord Reservation could be subdivided lithologically into four units and those units could be correlated between core holes. These core holes were then logged, using a variety of down-hole geophys-ical techniques, and it was demonstrated that the litho-logic subdivisions of the Ringold could be defined and correlated between borings on the bases of down-hole geophysics. A program of investigation was then designed to extend these Ringold unit correlations laterally, away from the inital core holes, using an array of appropri-ately spaced rotary wash borings in which the sediments were logged by down-hole geophysical techniques and l l 0231.4-10 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.4 (Cont'd) petrographic analysis of cutting samples. Additional core holes were drilled at greater distances f rom Borings 1 and 3 to corroborate the extended correlations based on rotary holes and geophysical logging. It was determined that, where more than 200 f eet of Ringold sediments were present (as in the Site vicinity), the contacts between the subdivisions of the Ringold and between Ringold and the overlying Hanf ord Formation (i.e., the base of the Pre-Missoula gravels) could be reliably correlated between geophysically logged rotary borings spaced approximately one-half mile or less apart and periodic-ally confirmed with core borings. As investigations progressed southward from the May Junction area, these techniques were applied to the present Site vicinity. This method of exploration permits the resolution of stratigraphic horizons within and bounding the Ringold Formation to within approximately five feet at rotary borings and to within approximately one f oot at core borings. Boring data were used to interpret the configuration of the top of basalt, horizons within the Ringold Formation, O and the base of the Pre-Missoula gravels (the top of the Ringold Formation). The top of basalt interpreted f rom borings was found to be in good agreement with interpreta-tions from geophysical methods and with previous interpre-tations by other investigators based on boring data. The interpreted base of the Pre-Missoula gravels was found to be generally flat-lying and conf ormable with the high-velocity horizon defined within the lower Pre-Missoula section by shallow refraction (see S/HNP PSAR Amendment 24, Appendix 2R). Interpretation: Interpretations of the geologic conditions in the S/HNP Site vicinity, based on and integrating all of the above investigations, are presented graphically in the follow-I ing figures which accompany this response: Figure 231.4-1, Location Map - S/HNP Site Vicinity. This figure shows the-location of cross-sections j presented on the other accompanying figures and of other locations referred to in the vicinity of the S/HNP Site. Figure 231.4-2, Top of Basalt Contour Map - S/HNP Site Vicinity. This figure presents an integrated interpretation (based on drilling, seismic refraction s I i Q231.4-ll Amendment 26

s S/ HHP-{SAR 8/16/82 QUESTION 231.4 (cont'd) ~ and gravity data) of the configuration of the surface of the Elephant Mountain basalt within 5 miles of the S/HNP Site and in the area of the Southeast anticline where detailed investigations were conducted outside l the five-mile radius. The contour interval of this figure is 50 feet. Figure 231.4-3, Fence Diagram - S/ENP Site Vicinity. This figure, based on S/HNP and other boring data, presents a pseudo, three-dimensional representation of the configuration of - the basalt surface and structural horizons within the overlying sediments within five miles of the S/ENP Site. Eorings and fences presented on this figure were selected to be representative and definitive of the. geologic conditions.in the Site vicinity. This figure does not attempt to present all data available in this area. This figure is verti-cally exaggerated 6.7 times in order to' accentuate the f ew structures of gentle relief found in the Site vicinity. Figure 231.4-4, Computer Illustrations of the Top of Ringold over Top of Basalt. This figure presents four illustrations ot the top of basalt and the top of the overlying Ringold formation for an area ten miles square, centered about the S/ENP Site. This figure was prepared by Washington State University, using.a modified NCAR computer program which developed'the surfaces shown from discrete data points provided. Seventy-seven data points (borings) were available to control the top of basalt surface and 59 data points were available to control the top of the Ringold. Both surfaces are vertically exaggerated 2 times in order to emphasize changes in elevation, where pre-sent, while still presenting a notmoverly-distorted view of the two surfaces. The directions of view for these illustrations were selected to look both across and along the predominant structural grain. This figure is not intended to;be,used for quantitative interpretation, but rath,e'r,to present an' objective (computer-generated), pseudo, three-dimensional repre-sentation of key stratagraphic horizons. Figures 231.4-5 through 231.4-7, Selected Cross l Sections - S/HNP Site Vicinity. These figures present selected stratigraphic cross sections in the vicin-ities of Borings 44,sS-6 and S-24. These cross sections are based on boring data presented in S/HNP PSAR Amendment 24, Ap'pendix 2R, and are consistent s: / O231.4-12 Amendment 26 l

S/HNP-PSAR 8/16/82 { i QUESTION 231.4 (Cont'd) g with the interpretations of gravity, magnetic and l seismic data presented in Appendices 2K and 2L. I As can be seen on the accompanying figures, investiga-l tions conducted in the S/HNP Site vicinity have confirmed that the Site is located in an area of generally flat-ig)ing, and only slightly-def ormed (no slopes exceeding I 5 basalt that is overlain by a thick sequence of Ringold and Hanford sediments and is located at the j approximate axis of a structural low (the Cold Creek Syncline), lying between two larger anticlinal highs (Rattlesnake Mountain and the Umtanum Ridge-Gable [ Mountain structural trend). There are some indications j (apparent on the f ence diagram, Figure 231.4-3 near j borings 44, S-6 and S-24) that minor and gentle warping i of the basalt may have developed in the Site vicinity during Ringold time (approximately 3.5 to 10 million years bef ore present). There are, however, few if any l indications that the top of the Ringold Formation (base j of the Pre-Missoula Gravels) has been significantly deformed (see Figure 231.4-3 and Figure 231.4-4). This indicates that deformation had ceased or very greatly i diminished by earliest Pre-Missoula time (greater than 730,000 years bef ore present on the basis of paleomag-i netic dating). No indication of the existence of f aults i' within the five-mile radius of the S/HNP Site was found. The areas located in the vicinity of Borings 44, S-6 and S-24, where Ringold-age warping is observed, are inter-preted to be very gentle f olds of limited amplitude and l lateral extent, without associated faulting. They pose no seismic or~ geologic hazard to the proposed facility, l but are discussed in detail below for the sake of com-t pleteness. l In the vicinity of Boring 44, there is a slope on the l basalt surface which slopes to the northeast at approxi-mately 5 between Borings 44 and 73 (see Figure 231.4-5). 0 The change in elevation of the top of basalt is about 100 f eet over a distance of approximately 1,100 f eet. Units III and IV of the Ringold f ormation are present in Boring 73, but have been interpreted to be thinner (Unit III) or i absent (Unit IV) in Boring 44. The Ringold/ Pre-Missoula contact is 49.5 feet higher in Boring 44 than in Boring l 73. These changes in elevation and thickness of strati-l graphic units occur near the projection of the geophysi-j cally-defined May Junction linear of Myers and Price (1979). This linear has been interpreted in S/HNP PSAR l Appendix 2K to represent an eastward-facing, monoclinal l [v) f old on the surf ace of the basalt, which trends North-i i I Q231.4-13 Amendment 26 I . ~

I S/HNP-PSAR 8/lG/82 QUESTION 231.4 (Cont'd) south and has a length defined by gravity of approxi-mately 3 miles. Magnetic, gravity and seismic refraction surveys in the vicinity of Boring 44 are in agreement with the drilling data and indicate that the slope of the basalt is gentle and continuous, without abrupt offsets. There is no indication of faults. In the vicinity of Boring S-6, there is a small rise in the basalt surf ace. The maximum slope on the flanks of this rise is approximately 3.50 between S-6 and 15 (see Figure 231.4-6). The basalt surf ace is 144 f eet higher in S-6 than in Boring 15. The contacts between the over-lying Ringold units (I-IV) generally conform to the shape of the basalt surface between Borings S-6 and 15, but the Ringold/ Pre-Missoula contact is 24.5 f eet higher in Boring S-6 than it is in Boring 15, approximately 2,400 feet to the northeast. Gravity data indicate that this small rise in the basalt surface is about one mile long and trends approximately east-west. Magnetic and gravity surveys indicate that the basalt slopes gently and continuously between borings and there is no indication of faults. On Line 4D, between Borings S-24 and S-18, there is a change in elevation on the basalt surface of 207 feet (see Figure 231.4-7). This is equivalent to a slope of about 5 to che northeast. Ringold Units III and IV are present in Boring S-18, but have been interpreted to be absent in Boring S-24. The Ringold/ Pre-Missoula contact is 5.5 feet lower in Borino S-24 than in Boring S-18. Thus, the Ringold/ Pre-Missoula contact is observed to slope very slightly in a direction opposite to that of the basalt surface. Magnetic and gravity data indicate that the slope is gentle and continuous. Therefore, there is no evidence of faults on this slope.

== Conclusions:==

1. Prior to detailed investigations of the area immedi-ately surrounding the Site, extensive investigations carried out in the Site region for the Skagit/Hanf ord Nuclear Project and others provided definite indica-tions of the type of geophysical and drilling proce-dures necessary to provide the maximum information in the Site vicinity.

2. Geophysical investigations in the form of aeromag-netics, ground magnetics, gravity and seismic refrac-tion surveys provide a clear picture of the nature of Q231.4-14 Amendment 26

S/HNP-PSAR 8/16/82 ( QUESTION 231.4 (Cont'd) i the basalt surface in and near the Site vicinity. They also clearly indicate regional structures and their relationship to the Site.

3. Numerous drill holes at and near the Site provide a high degree of confidence in the nature of the geo-logic section being investigated and the correlation of stratigraphic units over a wide area.

4. The configuration of the top of basalt was determined independently by borings and various geophysical techniques.

There is a striking agreement in the interpretations resulting f rom using the inf ormation from these many techniques. Thus, the individual investigative techniques support and lend credence to one another, increasing the confidence that can be placed in the integrated interpretation. I

5. The Applicant and others have conducted investigations in the vicinity of the S/HNP Site sufficient in scope and detail to provide reasonable assurance that the geologic, seismic and engineering characteristics of the Site are sufficiently well understood to permit an adequate evaluation of the proposed Site.

These investigations indicate that the Site is located in a structurally low area of generally flat-lying and nearly undeformed basalt, overlain by a thick sequence of sediments and lying between two larger anticlinal folds. There are no indications of capable or other f aults within a five-mile radius of the proposed Site. References

1. Fecht, K. R.

and Lillie, J. T., A Catalog of Borehole Lithologic Logs f rom the 600 Area, Hanf ord Site, RHO-LD-158, Rockwell Hanf ord Operations, Richland, WA l (1982).

2. Myers, C. W and Price, S.

M., Geologic Studies of the Columbia Plateau; a Status Report, RHO-BWI-ST-4, i Rockwell Hanf ord Operations, Richland, WA (1979).

3. Myers, C. W.

and Price, S. M., editors, Geology of the Cold Creek Syncline, RHO-BWI-ST-14, Rockwell Hanford Operations, Richland, WA (1981).

4. Washington Public Power Supply System, Final Safety Analysis Report, WPPSS Nuclear Project No.

2, Richland, WA (1981). l Q231.4-15 Amendment 26

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l S/BNP-PSAR 8/16/82 ( QUESTION 231.6 Define the term " Pre-Missoula Gravels" and present data showing the stratigraphic relationship between Corehole E-20 and the other sampled sections, including Corehole PM-2 (see Sierra Geophysics draft report of May, 1982). Discuss the relationship between sections containing i reversed' polarity.

RESPONSE

Pre-Missoula and Missoula Gravels are informal names used I in Appendix 2R of the Skagit/Hanf ord Nuclear Project Preliminary Saf ety Analysis Report to distinguish two sequences of flood deposits within the Hanf ord Formation of Rockwell (1981). Pre-Missoula Gravels pre-date Missoula flood deposits and post-date Ringold Formation sediments. The Missoula Flood deposits were the result of the last major episode of glacial flooding in central Washington, and have been dated as 13,000 to 18,000 years B.P., based on the presence of Mount St. Relens "S" ash near the top of the unit (Mullineaux and others, 1977) + and the ages of glaciation in southern Canada and the Northwestern United States (Fulton and Smith, 1978, Clague and others, 1980). The upper Ringold Formation in the White Bluffs contains rodent fossils dated at 3.7 to 4.8 million years old (Rockwell, 1981). The Pre-Missoula Gravels are, therefore, older than 13,000 to 18,000 years B.P. (the maximum age of the Missoula flood Gravels) and younger than 3.7 million years B.P. (the-minimum age of the Upper Ringold Formation). The Pre-Missoula Gravels are recognized as a strati-graphic unit based on their composition and degree of cementation. These gravels are predominantly granite, quartzite, gneiss and rhyolite, with subordinate amounts of basalt. They are typically embedded in a silty sandy matrix. Thin silt and very-fine to coarse-grained sand lenses are locally present. The gravels are typically weakly indurated with calcareous cement or detrital clay. I The Pre-Missoula Gravels are distinguised from gravels of the underlying Ringold Formation on the basis of a lesser amount of induration in the Pre-Missoula Gravels and complete lack of the yellow cement rinds, with adhering sand grains, which are distinguished from the overlying Missoula Gravels in that the Pre-Missoula Gravels contain i less basalt than the Missoula Gravels. Missoula Gravels typically contain more than 50 percent basalt clasts. Q231.6-1 Amendment 26 i

S/HNP-PSAR 8/16/82 QUESTION 231.6 (Cont'd) Pre-Missoula Gravels contain less than 50 percent basalt clasts in the upper part of the unit and less the 20 percent basalt clasts near the base of the unit. Figure 231.6-1 shows the stratigraphic relationship between sampled sections in coreholes E-20 and PM-2 based on nearby holes E-19 (in the case of E-20) and 111 (in the case of PM-2) which penetrated the complete supra-basalt sedimentary section. The locations of coreholes E-20 and PM-2 were selected because relatively fine-grained sediments had been recognized within the flood gravels immediately overlying the Ringold Formation. The target depths (f rom which the paleomagnetic samples were subsequently obtained) were those depths at which the fine-grained sediments had been observed in E-19 (in the case of E-20) and hole 111 (in the case of PM-2). In both E-20 and PM-2, the samples which showed reversed magnetization were obtained from below the Missoula Flood Gravels and above the Ringold Formation. The flood gravels between these two units are the Pre-Missoula Flood Gravels. At the time the results of the paleomagnetic analyses for corehole E-20 became available, no other data had been collected which suggested a minimum age greater than approximately 200,000-300,000 years for Pre-Missoula Flood Gravels in the Pasco Basin. To lend confidence to the results of the work then in progress on E-20, an outcrop sampling program was initiated because such a program could be undertaken quickly, inexpensively and without the logistical requirements associated with core drilling. The locations selected for sampling (Yakima Bluffs, Klona, Kennewick gravel pit and Marengo) were those in which flood gravels (with finer sediments interbedded) had been dated as older than several hundred thousand years. The dates on these deposits had been obtained using the uranium-thorium technique from caliche developed within the flood deposits (Tallman and others, 1978, and John Lillie, personal communication, 1981) and were considered to be minimum ages. No inference was made regarding the correlation of flood deposits in the sampled outcrops with the Pre-Missoula Gravels cored in E-20. The purpose in sampling and analyzing these sediments was to determine if any flood deposits outcropping in or near the Pasco Basin were reversely magnetized. The fact that samples from two outcrops (Yakima Bluffs and Marengo) were found to contain reversely magnetized sediments supports the 0231.6-2 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.6 (Cont'd) conclusion that some flood gravels in or near the Pasco Basin were deposited prior to 730,000 years ago. The fact that reversely magnetized sediments were also later f ound in core PM-2 f urther supports the conclusion that the lower Pre-Missoula Gravels on the Hanford Site were deposited prior to 730,000 years ago. It is not necessary to establish a direct correlation between known occurrences of Pre-Missoula Gravels nor should it be expected in this type of deposit. The signif icant information is that a widespread blanket of gravels, with an age greater than 730,000 years, exists between the top of the Ringold and the base of the Missoula flood deposits and that these older gravels serve as a datum plane reflecting all deformation younger than 730,000 years.

REFERENCES:

1. Clague, J. J., Armstrong, J. E., and Mathews, W. H., 1980, Advance of the late Wisconsin Cordilleran ice sheet in southern British Columbia since 22,000 yr. B.P.: Quat. Res., v. 13, p. 322-326, 2. Fulton, R. G., and Smith, G. W., 1978, Late Pleisto-cene stratigraphy of south-central British Columbia: Canadian Jour. of Earth sci., v. 15, p. 971-980. 3. Mullineaux, D. R., and others, 1977, Age of the last major Scabland flood of eastern Washington, as inf erred f rom associated ash beds of Mount St. Helens Set S: Geol. Soc. Amer. Abstracts with Programs,

v. 9, no. 7, p. 1105.

4. Rockwell Hanford Operations, 1981, Subsurface geology of the Cold Creek syncline: RHO-BWI-ST-14, Richland, WA. 5. Tallman, A. M., Lillie, J. T., and Caggiano, J. A., 1978, Basalt Waste Isolation Program Annual Report: RHO-BWI-78-100, Rockwell Hanford Operations, Richland, WA. O l Q231.6-3 Amendment 26 l -

a~~ e NW SE E-19 E-20 (Elevation A D'OXImate) 520 - y}l!- e ~ 70 f t. = % oca* M_ lif il*.' - Missoula Gravels

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Missoula Gravels Q M e). 'o- ' o p.. Y ,.i.E-g .o. .f_ ; z. EXPLANATION y,................,,,,,,,,,,................... -g 8 l y.l ] Gravei NR e i 1 iii mM c ] Siity Gravel l'i ii g ]p t ] Silty Sandy Gravel t-3(! ] Sandy Gravel o '., Pre-Missoula Gravels a o o-NR - W ] Gravelly Silty Sand y ET5 N, ] Silty Sand

a g

] Sand d EOH h Sandy Silt {o 114.4 f t. { Clayey Silt 8a

O.

] Clay [ Calcic Horizon Ringold Formation o hR No Sample Recovery en Misaou a NGET SoVND NWER & UGHT CNMNY and Pre-Misaoula SKAGIT 1 HANFoRD NUCLEAR PROJECT Flood Graveis PRELIMINARY SAFETY ANALYSIS REPORT 3 Interval from which STRATIGRAPHIC COLUMNS OF reversely magnetized DRILLHOLES E-10, E-20,111 samples were taken AND PM-2 SHOWING RELATIONSHIPS BETWEEN SECTIONS CONTAINING REVERSED POLARITY Figure 2 31.6-1 i Amendment 26

l l S/HNP-PSAR 8/16/82 1 j jf QUESTION 231.7 Provide estimates of the rates of deposition for the Pre-Missoula Gravels and specifically for the sedimentary intervals from which the samples presented in this report were obtained.

RESPONSE

Pre-Missoula Gravels were deposited during multiple glacial flood events which inundated the Pasco Basin. i The poor sorting of the matrix-filled Pre-Missoula Gravels suggests that the rate of deposition was rapid. Although no studies have been published on the rate of-deposition of the Pre-Missoula Flood Gravels, some infer-ence may be made on the basis of the Missoula floods. Baker (1978) suggests that the floods which deposited the Missoula Gravels probably lasted over a period of time measured in weeks and that peak flooding probably lasted only hours. If earlier flood gravels were deposited under similar c6nditions, it is probable that the sedi-ments within each sampled interval in core and in outcrop were deposited within periods of time no greater than several weeks. j

REFERENCES:

1. Baker, V. R., 1978, Paleohydraulics and hydrodynamics of Scabland floods, in The Channeled Scabland (Baker, V. R., and Nummendal, D., editors). National Aero-nautics and Space Administration, Field Conf. in the Columbia Basin. 4 4 Q231.7-1 Amendment 26 -m-- ,,,w, ,g ,,e, - - -,, _ _,,,,,, - -,. - - .w w .W-- -t-"'-- --W-ver tg uy-w-e--r-MM4-*9PWeT-'r--- T---w--y-

S/HNP-PSAR 8/16/82 QUESTION 231.8 Describe the relative position of sampled levels of reversed polarity samples within the Marengo section.

RESPONSE

The stratigraphic position of the reversed polarity samples within the Marengo section are shown on Figure 11 in the report by Van Alstine (1982).

REFERENCES:

1. Van Alstine, D. R. 1982, Paleomagnetic investigation of Pre-Missoula Gravels, Pasco Basin and vicinity, Washington: Report prepared for Golder Associates, Inc., by Sierra Geophysics, Inc., Redmond, WA. O l l 9 l Q231.8-1 Amendment 26 I

i S/HNP-PSAR 8/16/82 l QUESTION 231.9 Indicate whether samples were collected from sands and gravels themselves or from silt / clay interbeds within the sections.

RESPONSE

The location and lithology of samples f rom each of the sampled areas are as follows: Corehole E-20 Figure 4 in the report by Van Alstine (1982a) shows sample locations and numbers and a stratigrahic column of the sampled interval for Corehole E-20. All samples were from sand and silt, with the exception of sample #24, which was a large basalt pebble collected to test whether the drill string was imparting an appreciable magnetiza-tion to the core samples. Colehore PM-2 Figure 2 in the draf t report by Van Alstine (1982b) shows sample locations and a stratigraphic column of the sampled intervals for corehole PM-2. All samples were from silt or clay units. Yakima Bluffs Ten samples were collected from the Yakima Bluffs local-ity. The uppermost samples (#1) is from a sand lens near the base of a coarse flood gravel. Eight other samples are from underlying cJays, silts and sands deposited in fine-upward sequences of graded beds. One sample (49) was collected from one of many fine-grained clastic dikes that cut the Yakima Bluffs section. I Kiona Ten samples were collected from a gravel pit near Klona. l Eight samples were from two sandy interbeds in the coarse flood gravel and two samples were collected from over-lying loess deposits. \\ Q231.9-1 Amendment 26 _~

S/HNP-PSAR 8/16/82 QUESTION 231.9 (Cont'd) Kennewick Gravel Pit l Ten samples were collected from a gravel pit near Kennewick. The samples were from silt and sared lenses in coarse flood gravel. i Marengo Figure 11 in the report by Van Alstine (1982a) shows sample locations and numbers and a stratigraphic column of the Marengo section. Twenty-five samples were col-lected from loess and calcic paleosols between two coarse flood gravels.

REFERENCES:

1. Van Alstine, D. R., 1982a, Paleomagnetic investigation of Pre-Missoula Gravels, Pasco Basin and vicinity, Washington: Report prepared for Golder Associates, Inc., by Sierra Geophysics, Inc., Redmond, WA. 2. Van Alstine, D. R. 1982b, Paleomagnetism of Pre-Missoula Gravels from corehole PM-2 on the southeast anticline, Hanford Site, Washington: Draf t report prepared f or Golder Associates by Sierra Geophysics, Inc., Redmond, WA. i l l i l 9 Q231.9-2 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.10 Provide reference to paleomagnetic investigations pre-viously conducted in sands.

RESPONSE

Over 40 years of research on the paleomagnetism of sedi-ments, including sands, have recently been reviewed by Verosub (1977). As he notes, the most important factors related to acquisition of detrital remanent magnetization (DRM).in sediments are the sediment-particle size, shape and mineralogy as well as the magnetic-particle size and composition. In the Pre-Missoula Gravels, the presence of basalt grains indicates a ready source of detrital magnetite, and the poor sorting of these deposits indi-cates that magnetite with a variety of grain sizes (including silt) is probably present in even the coarsest sands. Moreover, the high stability of the reversed-polarity magnetization observed in some E-20 samples suggests that this magnetization might be a chemical remanent magnetization (CRM) residing in authigenic hematite, as can be demonstrated in corehole PM-2 (Van Alstine, 1982).

REFERENCES:

1. Van Alstine, D. R., 1982, Paleomagnetism of Pre-Missoula Gravels from corehole PM-2 on the southeast anticline, Hanf ord Site, Washington: Draft report prepared for Golder Associates by Sierra Geophysics, Inc., Redmond, WA. 2. Verosub, K. L., 1977, Depositional and postdeposi-tional processes in the magnetization of sediments: Rev. of Geophys, and Space Phys., V. 15, p. 129-143. Q231.10-1 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.11 4 Provide a discussion of the basis for determining that each of the sampled sections was Pre-Missoula in age.

RESPONSE

For cores E-20 and PM-2, selection of location and inter-vals for sampling was not based on assumptions regarding the age of Pre-Missoula Gravels. Depth intervals selected for sampling in these cores were based on the results of previous drilling which showed relatively fine-grained sediments above the Ringold Formation and below the Missoula Gravels (ref er to Figure 231.6-1). The selection of locations for outcrop sample was based on the available information concerning the location of flood gravels dated at greater than several hundred thou-sand years (Tallman and others, 1978, and John Lillie, personal communication, 1981). These outcrops were assumed to be older than Missoula age (13,000-18,000 years) on the basis of uranium-thorium dates. The strati-graphic position of these gravels relative to the Plio-cene upper Ringold Formation cannot be observed in out-crop. The absence of yellow sandy cement rinds typical of the upper Ringold Formation indicates that the flood deposits dc not correlate with the upper Ringold. The weakly indurated character of sediment samples taken from outcrops suggests that they are younger than the typi-cally better-cemented upper Ringold Formation. There-fore, the flood deposits in the sampled outcrops occupy a similar stratigraphic position (bracketed by Missoula gravels and the upper Ringold Formation) as the sediments sampled in cores E-20 and PM-2.

REFERENCES:

1. Tallman, A. M., Lillie, J. T., and Caggiano, J. A., 1978, Basalt Waste Isolation Program Annual Report; RHO-BWI-78-100, Rockwell Hanford Operations, Richland, WA. 1 O l Q231.11-1 Amendment 26

S/HNP-PSAR 8/16/82 QUESTION 231.12 Provide a plan showing the location of Corehole E-20 in relation to other test holes and the plant facilities.

RESPONSE

Figures 231.12-1 and 231.12-2 show the location of Core-hole E-20 in relationship to other test holes and the plant facilities. l ( l O O Q231.12-1 Amendment 26

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<,'8 N ? ? 2*o Q FEET PUGET SOUND POWER & LIGHT COMPANY SKAGIT / HANFORD NUCLEAR PROJECT PRELIMIN ARY SAFETY ANALYSIS REPORT l LOCATION MAP FOR COREHOLE E 20 SHOWING OTHER TEST HOLES & (_/ PLANT FACILITIES FIGURE 231.12-2 Amendment 26 b-

S/HNP-PSAR 8/16/82 QUESTION 231.13 Provide a detailed stratigraphic log of Corehole E-20. 1

RESPONSE

Figure 231.6-1 presents a detailed stratigraphic log of Corehole E-20. ) i I i e I Q231.13-1 Amendment 26 . - _ -.. _ - - _ -. - - - -.. - _, _....}}

ML20063B120

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