Table 2. Characteristics of the Delayed Fission Neutrons in Thermal Fission 

 

 Number of Delayed Neutrons per Fission

  

Average half-life ~ T½ (s)

U-233

U-235

Pu239

Energy (MeV)

56

     5.7•10-4

   5.2•10-4

  2.1•10-4

0.25

23

    19.7•10-4

  34.6•10-4

  18.2•10-4

0.46

6.2

    16.6•10-4

  31.0•10-4

  12.9•10-4

0.41

2.3

    18.4•10-4

  62.4•10-4

  19.9•10-4

0.45

0.61

      3.4•10-4

   18.2•10-4

    5.2•10-4

0.41

0.23

      2.2•10-4

     6.6•10-4

     2.7•10-4

 

Total delayed neutrons

     0.0066

   0.0158

   0.0061

 

Total fission neutrons

2.5

2.43

2.90

 

Delayed neutrons fraction

      0.0026

     0.0065

     0.0021