5 snd 7

5. NRC regulations (10 CFR 61.55) set two different limits for some radionuclides, depending on whether they are found in activated metals or not. (a) What is the meaning of activation, as used in 10 CFR 61.55? (b) Why do you suppose 10 CFR 61.55 sets higher limits for radionuclides in activated metals? 6. Cobalt, a hard, silvery-gray metal, is sometimes added to steel to create highstrength alloys. Cobalt occurs in nature as the stable isotope Co-59; however, Co-59 can be converted by neutron activation into radioactive Co- 60 . (a) Write a balanced equation for the neutron activation of Co-59. (b) Co-60 is a beta emitter having a half-life of 1925.200.25 days. 5 Write a balanced equation for the beta decay of Co-60. (c) Compute the Q-value for the beta decay of Co-60. (d) Calculate the activity (in Bq and Ci ) of a 1-gram sample of Co60. 7. Repeat the previous problem for the product of the neutron activation of Ni-62