Question

A Charpy specimen made of iron with dimensions of 10 mm x 10 mm x 55 mm is irradiated in a thermal reactor with a flux of 1012neutrons cm-2s-1for 30 days. The resultant activity is due to neutron absorption in the 0.31% 58Fe present in the specimen. Iron has an effective atomic mass of 55.85 and a density of 7.87 g/cm3.

Determine:a) the activity (Bq) of the Charpy specimen upon removal from the reactor;

b) the maximum energy of the beta(minus) particle emitted by radioactive decay of 59Fe

c) the activity 60 days after removing theCharpy specimen from the reactor?

58Fe has a thermal neutron absorption cross-section of 1.2 barns, and 59Fe has a 45 day half life, emitting a beta-minus particle during transmutation to 59Co, which is a stable isotope.Atomic mass data (in amu): 58Fe 57.933276; 59Fe 58.9348755; 59Co 58.933195.

Answer 1