Respirable particle size

["USHINO, TOSH" <ushinot@songs.sce.com>]

     We at San Onofre Nuclear Generating Station, Southern California 
     Edison Co., are looking for information on respirable particle 
     generation and would like your help.  Based on tensil strength and 
     other physical properties, what would be the estimate for the minimal 
     particle size you can realistically produce by crushing and grinding a 
     PWR fuel pellet?  Do you know of any study that was conducted or 
     published on particle generation from PWR fuel or any other material 
     we can refer to?
     
     Thank you in advance.
     Tosh Ushino
     ushinot@songs.sce.com
     (714) 368-9523