Mr. Busby - thanks for pointing out the site with the DoE study guides ( http://cted.inel.gov/cted/eh_mat.html). RadSafe: I just looked at them. Very nice. A resource like this can save everyone a lot of time in preparing study/teaching material. If you are involved in training/education put this site on your save list. A little risk adds spice to life. slaback@MICF.NIST.gov