Tagged sand is prepared at ORNL, using sand indigenous to the survey 

 area. At the present time, radioactive xenon (xenon-133) is manufactured 

 only at the time of reactor shutdown and is then available for sand label- 

 ing (see Section II ). In order to minimize radioactive decay of the 

 isotope, field tests must be scheduled at times immediately following 

 periods of reactor shutdown (approximately once a month). Immediately 

 after tagging, the sand is taken as quickly as possible by common carrier 

 (usually airlines) to the test area. 



Prior to actual field tests with radioisotopic tracers, certain field 

 studies are necessary to provide a background of data against which future 

 measurements may be compared, and to provide design data for future test- 

 ing. In addition, the information collected supplements radiation surveys 

 for determining sediment movement patterns. 



Base lines were established and hydrographic profiles were completed 

 along various ranges perpendicular to the beach at Surf and around Point 

 Conception to provide data concerning the initial conditions of the beach 

 and near shore bottom. Samples of sediments were collected along the pro- 

 files at the following locations +12', +6', +3', MLLW, -6', -12', -18 , -2k, 

 -30', and -50' depths. These samples were analyzed at CERC for standard 

 size parameters. (Future studies of the heavy mineral fractions are 

 planned.) In addition, scuba divers made an inspection of the bottom 

 character. 



Aerial photographs of the coastline from Surf, around Point Concep- 

 tion, to Gaviota were taken to complement the surveys. These photographs 

 and the hydrographic surveys were correlated to the USC&GS boat sheets 

 (field survey plots) for the area. 



Just prior to the tracing survey, the navigation system was set up 

 using the previously established base line and the background radiation 

 of the area was then surveyed. All radiation surveys were conducted by 

 towing the mobile detector "ball" behind the amphibious vehicle (see 

 Section II ) . 



As soon as practicable after emplacing the tagged sand, an initial 

 radiation survey was conducted. Radiation was then surveyed on successive 

 days to define the development and changes in movement patterns. Collected 

 data were corrected for radioactive decay and background, and plotted as 

 isoactivity contour maps. 



Sea, swell, and weather conditions were monitored throughout the 

 California tests to aid in determining the relation of sediment movement 

 to oceanographic conditions. In addition to forecasts and visual ob- 

 servations , a wave gage installed at Platform "Henry" near Point Con- 

 ception was used to monitor wave conditions for the Point Conception 

 sites. Future tests will also employ current direction and velocity 

 meters emplaced in the immediate study area. 



27 



