Assume that (i)the energy released per fission event of ²³⁵U is 208 MeV,and (ii)30% of the nuclear energy released in a power plant is ultimately converted to usable electrical energy.Approximately how many fission events will occur in one second in order to provide the one GW electrical power output of a typical power plant? (1 eV = 1.6 x 10^-19 J) A)2 x 10¹⁶ fission/s B)1 x 10²⁰ fission/s C)3 x 10²⁴ fission/s D)2 x 10²⁷ fission/s

Question

Quizplus · Accepted Answer

One GW of electrical power is equal to 1 x 10S1U1P19S1S1P0 J/s. 
30% of the nuclear energy is converted to electrical energy, therefore the total energy released by fission should be 1/0.3 = 3.33 times the electrical power output.

Energy released per fission event = 208 MeV = 3.328 x 10S1U1P16S1S1P0 J 
Number of fission events per second = (1 x 10S1U1P19S1S1P0 J/s) / (3.328 x 10S1U1P16S1S1P0 J/fission) 
= 3 x 10S1U1P19S1S1P0 / 3.328 
= 9.01 x 10S1U1P22S1S1P0 fission/s ≈ 1 x 10S1U1P20S1S1P0 fission/s

Therefore, the best choice is B) 1 x 10S1U1P20S1S1P0 fission/s.

Assume That (I)the Energy Released Per Fission Event of 235U

Assume That (I)the Energy Released Per Fission Event of ²³⁵U