TLO 3 Production Of Heat From Fission

Question 1

ELO 1 Describe the energy released immediately from fission.

Answer 1

~187 MeV is instantaneous energy most of which is kinetic energy of the fission fragments.

Question 2

ELO 1 Describe the delayed fission energy (Decay Heat)

Answer 2

~13 MeV releases sometime after the instant of fission - made up of Beta particles & gamma rays.

Question 3

ELO 2 Describe which fission products nuclides are most likely to result from fission.

Answer 3

Normally, one fission event releases 2 or 3 fast neutrons. Most likely fission fragments resulting from fission of U-235 are Cesium and Rubidium.

Question 4

ELO 3 In fission, describe the energy released from a change in binding energy.

Answer 4

The energy liberated is equal to the increase in the total binding energy of the system.
Less accurate calculation.
Energy released = BEproducts - BEreactants.

Question 5

ELO 3 In fission, describe the energy released by Conservation of Mass-Energy.

Answer 5

During fission, a decrease in the system mass occurs. The loss of mass equals the energy liberated.
The instantaneous energy released = the energy equivalent of the mass lost.
Find: Mass of reactants - mass of products, then figure the energy equivalent: Mass × 931.5 MeV/amu.

Question 6

ELO 3 In fission, describe the energy released from decay energy.

Answer 6

The additional energy added to the instant fission reaction when the fission fragments decay by beta emission.

Question 7

ELO 3 The change in binding energy per nucleon between the fissile nuclide and the fission products is used to calculate _____.

Answer 7

Energy released by fission

Question 8

ELO 4 Describe how heat is produced as a result of fission.

Answer 8

Fission fragments, beta particles and gamma rays cause ionization directly as they remove orbital electrons from the surrounding atoms, increasing temperature. Fission neutrons also interact through elastic scattering which increases temperature.