station -1 through +8 along range 5. To keep total activity the same as 

 in the previous test, 0.5 cubic centimeters per interval was used. 



Radiation and bathymetric surveys of the basin were made after 3, 

 9, and 22 minutes of total wave action. Radioactivity distribution was 

 monitored at 1-foot intervals along ranges 1, 3, 5, 7, and 9, using a 

 hand-held scintillation counter with a 3 by 3-inch sodium iodide crystal. 

 Figure 53 illustrates the distributions obtained with low and high specific 

 activity sand, following 22 minutes of wave action. A comparison of these 

 distribution plots indicates results with high specific activity sand 

 were nearly identical to those with low specific activity. The radiation 

 distribution plots (and the profiles) demonstrate the tendency of the 

 radioactive sand to orient in bands parallel to the shoreline and to 

 accumulate and move down the left (range 9) side of the basin following 

 the route of return water flow. 



An attempt was made to determine depth of mixing at the conclusion 

 of each test by taking cores and wrapping them with polaroid radiographic 

 film; however, the level of activity was insufficient to expose the film 

 even though it remained wrapped around the core for approximately 35 days. 



The distribution patterns obtained using high and low specific 

 activity sand indicated that the use of a smaller quantity of high speci- 

 fic activity sand made no significant difference, at least so long as 

 total activity remained the same. Results of the Shore Processes Test 

 Basin tests confirmed that xenonated sand is ideal for laboratory tests 

 involving sedimentation and beach processes. 



To better determine the necessary frequency of data points (and 

 hence serve as a guide for field programs), additional computer plots 

 using a Lourier transform series were made on the data from Run 3 (22 

 minutes total wave action) of the low specific activity test. One plot 

 used only even stations and another used only odd stations (every other 

 station was omitted). A third plot was made omitting all data for range 

 5. As shown by Figures 5^ and 55, all three plots exhibit patterns very 

 similar to that of the complete data set . From this it may be concluded 

 that from 20 to 50 percent fewer data points may be used to give signifi- 

 cant results . 



68 



