Operational Procedure 



Injections were made at three locations: one northward of Point Conception, 

 one on the Point, and one southward of the Point in ~30 ft of water. In 

 each injection kO liters of sand tagged with ~1.2 Ci of 13 \e was used. The 

 sand was placed on the "bottom with the clamshell device, and surveys were 

 made of all three sites by alternating from one site to the next. 



The first injection was southward of the Point and all equipment functioned 

 properly except the detectors, which required frequent calibration. This 

 calibration problem was due to gain shift, which resulted from severe vibra- 

 tions caused by pulling the equipment across large rock outcrops. These 

 outcrops made surveying extremely difficult. 



The second injection was made northward of the Point, and survey conditions 

 proved to be even more severe than those of the first injection. 



The third injection, which was delayed several times because of bad weather, 

 was placed directly on the Point. Because of a large rock outcrop (~12 ft 

 tall), the detector could not be pulled to the survey area from the beach 

 but had to be lowered to the bottom from the survey vessel. This proved to 

 be extremely difficult because the winch did not have adequate power to 

 properly control the detector assembly, which weighs approximately U00 lb; 

 however, the detector assembly was successfully placed on the bottom sev- 

 eral times and surveys were accomplished. 



A fourth batch, which consisted of only 1 liter of sand tagged with 200 mCi 

 of 13 ^fe, was placed in the breaker zone as a preliminary test to observe 

 the dispersal rate that would be encountered in future tests planned for 

 the surf zone. 



Observations 



All the injections were successful. The new data system worked well but 

 the 10 -sec collection period seemed to be too long. Rocks in the survey 

 areas and the necessity of. pulling the detector assembly from the beach 

 to the area caused some difficulty with the detectors. Because of gain 

 shift and noise, frequent adjustments were required, making it difficult 

 to correlate radiation data on a day-to-day basis. Although survey areas 

 were covered many times, very little radiation data were collected (see 

 pages 59-65). Two explanations are possible: either the sand was buried 

 or it was not transported. In the latter case, radiation detection would 

 be obscured because it is virtually impossible to place the detector as- 

 sembly directly on the injection point. In future tests an attempt will 

 be made to determine which explanation is valid. 



The preliminary test (fourth injection) for determining whether there 

 would be any future problems associated with surf zone surveys went well. 

 Initial conclusions are that the system can function in the surf zone. 



C-18 



