Nuclear Fission

The splitting of a large nucleus into two smaller, more stable nuclei by bombarding it with a neutron.

When and by whom was nuclear fission discovered?

"Nuclear fission was discovered on 19 December 1938 in Berlin by German chemists Otto Hahn and Fritz Strassmann."

How did physicists Lise Meitner and Otto Robert Frisch contribute to the understanding of nuclear fission?

"Physicists Lise Meitner and her nephew Otto Robert Frisch explained it theoretically in January 1939."

What is the analogy for the process of fission?

"Frisch named the process 'fission' by analogy with biological fission of living cells."

What is the primary form of energy released during nuclear fission?

"The fission process often produces gamma photons."

How does the energy released during fission compare to traditional radioactive decay?

"The fission process...releases a very large amount of energy even by the energetic standards of radioactive decay."

What condition must be met for fission to produce energy?

"For fission to produce energy, the total binding energy of the resulting elements must be greater than that of the starting element."

Is the resulting element from fission the same as the original parent atom?

"Fission is a form of nuclear transmutation because the resulting fragments (or daughter atoms) are not the same element as the original parent atom."

What is the average mass ratio of the resulting fragments in binary fission?

"The two (or more) nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio of products of about 3 to 2."

How frequently does ternary fission occur?

"Occasionally (2 to 4 times per 1000 events), three positively charged fragments are produced, in a ternary fission."

What distinguishes fission from quantum tunneling processes?

"The unpredictable composition of the products (which vary in a broad probabilistic and somewhat chaotic manner) distinguishes fission from purely quantum tunneling processes."

What are the two main uses of nuclear fission?

"Nuclear fission produces energy for nuclear power and drives the explosion of nuclear weapons."

How does the energy density of nuclear fission compare to chemical fuel?

"The amount of free energy contained in nuclear fuel is millions of times the amount of free energy contained in a similar mass of chemical fuel such as gasoline."

What is the major disadvantage of nuclear fission in terms of waste?

"The products of nuclear fission...are on average far more radioactive than the heavy elements which are normally fissioned as fuel, and remain so for significant amounts of time, giving rise to a nuclear waste problem."

What is the aim of nuclear reprocessing?

"Nuclear reprocessing aims to recover usable material from spent nuclear fuel to both enable uranium (and thorium) supplies to last longer and to reduce the amount of 'waste'."

How do fast breeder reactors contribute to fission?

"Fast breeder reactors can fission them all albeit only in certain configurations."

What is the term for a process that fissions all or nearly all actinides?

"The industry term for a process that fissions all or nearly all actinides is a 'closed fuel cycle'."