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• <br />difficult to obtain smooth surfaces. Generally, excess amounts of insoluble material in the bottom <br />of the cavity may be removed by jetting through the tubing. <br />Conclusions <br />When fresh water is introduced into a solution cavity, gravity segregation of the circulating <br />water takes place and a salinity profile is developed within the cavity. This salinity profile is in- <br />fluenced by [he relative positions of the water inlet and outlet and by the flow rate. Cavity shape <br />can be controlled by initiating the proper leaching conditions through manipulation of these param- <br />eters and a known rate of increase in the amount of blanket material. <br />Four controlled washing techniques are described. Each was found to be effective in forming <br />cavities of various predetermined shapes. The effectiveness of these [echniques is directly related <br />to the accuracy with which the cavity progress is monitored. <br />The effects of insoluble material on cavity shape are not too serious and can be controlled to <br />a large extent. Other problems which may arise, such as accumulation of insoluble material in <br />the bo[rom of the cavity, can be minimized by correc[ planning and selection of pipe sizes to affect <br />the required discharge velocity for adequate removal. <br />Expanded technology in leaching operations may be a contributing factor in meeting the com- <br />plex requirements for future underground storage cavities. <br />ACKNOWLEDGMENT <br />Au[hors are indebted to the Nevada Operations Office of the United States Atomic Energy <br />Commission for a grant under which the above described work was performed, and acknowledge <br />the permission to publish this material. <br />APPENDIX <br />Consider Fig. 10 where an intermediate step in the washing process is represented schemat- <br />ically. The shape of the portion of the cavity occupied by the blanket material can be determined <br />by solving the relationship. --_ . <br />volume of cavity volume of material volume of brine <br />space occupied by = removed or - remaining in <br />blanket material dissolved cavity <br />in terms of the simultaneous equations listed below.' <br />Pt = Pt + 0.00694 W [ 2g + L (1 + ff)] <br />M <br />Pt - P4 1 + ZnRT <br />Swc (D - h) (0.434) <br />V~ = Vwo (1 + Fwo) - Vwt ~ 1 1 Fwo + Fwt J <br />r 2 <br />LPy + 2~' + Z, + HA - Fly - HE _ <br />W - Zb(ff) = W + 2g bb + Zb <br />'All spmbols defined as end of Appendix. <br />------------------------- (1) <br />------------------------- (2) <br />+ Vtac Fwc + Vt ---------- (3) <br />[ V + S + Zb ] <br />3os <br />r <br />