Involves estimates of probability and consequences. The Becquerel is a unit used to measure radioactivity. One Becquerel is that quantity of a radioactive material that will have 1 transformation in one second. Bq in one curie. Large amounts of beta radiation may cause skin burns, and beta emitters are harmful if they enter the body.
Beta particles can penetrate the skin a fraction of an inch.
Beta particles are easily stopped by a thin sheet of metal or plastic. The resulting steam can be used directly to drive a turbine.