PART 1 



LEACHING AND ABPASION STUDIES ON BEACH SANDS TAGGED WITh 

 RADIONUCLIDES BY THE NRDL WATER-GLASS PROCEDURE 



INTRODUCTION 



The investigations being conducted at Point Conception, California 

 "by the U. S. Army Coastal Engineering Research Center and associated 

 agencies are for the purpose of studying littoral transport of Leach 

 materials past coastal promontories. Initially, sand labeled with radio- 

 active Xe-133 is being used to trace the littoral migration of the beach 

 materials. The xenonation technique for labeling the sand was developed 

 at Oak Ridge National Laboratory* and is similar to the familiar Krypto- 

 nation technique (Carden, I966 ) , a technique by which Kr-85 is diffused 

 at high temperatures and pressures into solid materials. Other radio- 

 isotopes, such as Ba-La-lUO and Cr-51, will be utilized (perhaps simul- 

 taneously, so that several particle sizes can be followed in the same 

 experiment) for labeling the sand in subsequent investigations at Point 

 Conception. If these latter nuclides are to be used successfully for 

 tracing sand, suitable labeling techniques are necessary to prevent the 

 radioactive nuclides from leaching or abrading away from the sand during 

 the experiment. The objective of the investigation reported in this 

 paper is to determine whether a tagging procedure developed at NRDL 

 some years ago could be utilized for sealing the radioactive nuclides 

 Ba-La-l^O and Cr-51 into the sand. 



The NRDL water-glass technique was developed to produce a fallout 

 simulant for evaluation of counter-measures for recovering military and 

 civil sites contaminated by radioactive fallout. The simulant consisted 

 of Monterey sand labeled with Ba-La-lUO activity (Owen and Sartor 1963 ) . 

 Briefly, the procedure (Crew, 1965) involved spraying the desired activity 

 on sand which was being rotated inside a concrete mixer. During the mixing 

 the sand was dried by direction of a blast of hot air into the mixer. 

 Next, a solution of sodium silicate (water glass) was sprayed on the sand 

 and the sand was dried as before with hot air. Then the labeled sand was 

 fired for an hour at 1900°F (l030°C). The fused water-glass coating on 

 the sand provided an effective seal for retarding the desorption of the 

 radioactivity into fresh water (i.e. from firehoses or rain) in the type 

 of field experiment for which it was developed. 



To determine whether the NRDL sealing technique could be extended 

 to the Point Conception project, laboratory experiments were designed 

 to measure the release of activity from tagged sand to the environment 

 by (l) the simple static leaching action of sea water and (2) the com- 

 bination of sea-water leaching and the mutual abrasive action of the 

 sand particles as would be experienced in the surf zone. The results 

 of such studies with both Ba-La-lUO and Cr-51 are summarized below. 



* F. N. Case and E. H. Acree , ORNL, personal communication 



A-3 



