JAERI 1287 JNDC Nuclear Data Library of Fission Products Fir

JAERI 1287
2. Nuclear Data Library of fission Products
The nuclear data of fission products have been compiled for the summation calculation
of the decay power of fission products. The nuclear data to be included in the Fission Product
Nuclear Data Library are the decay data (decay constant, Q-value for beta or electron capture
decay, excitation energy of isomeric state, energies and intensities of beta-ray, positron,
gamma-ray and internal conversion electron, and branching ratio of each decay mode including
delayed neutron emission), the fission yield data and the neutron capture cross section data.
A library of nuclear data has been prepared for 1172 fission products, of which 140 are stable
and the others are unstable. Table 2.0.1 summarizes the number of nuclides for which data of
various types are available. The present library contains the decay data and the fission yield
data for 1172 fission product nuclides and neutron capture cross section data for 80 fission
product nuclides of mass number from 66 to 172.
Table 2.0.1 General contents of JNDC fission product nuclear
data library
Number of Nuclide
1172
152
1020
189
551
469
737
283
Type, Comment
Total number of nuclides in library
Stable nuclides
Unstable nuclides
Excited state nuclides
Nuclides with known decay energies
Nuclides with estimated decay energies
Nuclides with known half-lives
Nuclides with estimated half-lives
2.1 Necessary Nuclear Data for Decay Power Calculation
Buildup and decay of fission product nuclides in a nuclear reactor can be described as:
dN,
7T = - 0 i + aii,) Ni + YJi-i UjNj) + I,gi,-i(ok4>Nk) + yiF, (2.1.1)
a i j /i
where
Ni - atom number of nuclide i
^i = decay constant of nuclide i
Oi = neutron reaction cross section of nuclide i
0 = neutron flux
fj-i = production rate of nuclide / by the unit decay of nuclide j
gk-i - production rate of nuclide / by the unit neutron reaction of nuclide k
Ji = fission yield for nuclide i
F = fission rate.
The decay power of fission products can be calculated as the summation of the activities of
all fission product nuclides with the weight of decay energy of each nuclide,
i
where
P = decay power of fission products
(2.1.2)