JAERI 1287 JNDC Nuclear Data Library of Fission Products Fir
JAERI 1287 JNDC Nuclear Data Library of Fission Products Fir
JAERI 1287 JNDC Nuclear Data Library of Fission Products Fir
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<strong>JAERI</strong> <strong>1287</strong> 2. <strong>Nuclear</strong> <strong>Data</strong> <strong>Library</strong> <strong>of</strong> <strong>Fission</strong> <strong>Products</strong><br />
high energies are too dense and complicated for existing gamma-ray detectors to detect and<br />
resolve all transitions from them. The oversimplification <strong>of</strong> the high energy part leads to an<br />
underestimation or a missing <strong>of</strong> the beta strength at high energy, and leads to an overestimation<br />
<strong>of</strong> Ep and an underestimation <strong>of</strong> £r 40) . As is shown by solid line with (A) in Figs. 2.3.3<br />
and 2.3.4, a full adoption <strong>of</strong> experiment-based values <strong>of</strong> Ep and Er results in an overestimation<br />
<strong>of</strong> the beta-ray component <strong>of</strong> decay power and an underestimation <strong>of</strong> the gamma-ray component.<br />
This defect <strong>of</strong> the preliminary version <strong>of</strong> <strong>JNDC</strong> FP DECAY DATA FILE (1980) was<br />
revised by replacing the experimental values <strong>of</strong> Ep and Er by the theoretical values calculated<br />
with the gross theory for all short-lived FPs with Q-values larger than 5 MeV. 96 Y has been<br />
excluded from the group because this nuclide has a large contribution to the decay power<br />
and needs a special consideration. The accuracy <strong>of</strong> the decay power calculation has been<br />
greatly improved not only for 235 U as is seen in Figs. 2.3.3 and 2.3.4 (solid line with(B)) but<br />
also for 239 Pu and 241 Pu. The final version <strong>of</strong> <strong>JNDC</strong> FP <strong>Nuclear</strong> <strong>Data</strong> <strong>Library</strong> adopted the<br />
theoretical values <strong>of</strong> Ep and ET for all FPs whose beta decay Q-values are larger than 5 MeV<br />
though experimental branching ratios are available for 87 nuclides <strong>of</strong> them. This is because the<br />
theoretical values <strong>of</strong> Ep and Er for high Q-value FPs are more reliable than the experimental<br />
sion<br />
r/fis<br />
(Me\<br />
0-1<br />
X<br />
f(t)<br />
power<br />
decay<br />
pa<br />
1.0<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
10 u<br />
\^ I I I I I I I I I I I I I I I I I I I I I<br />
• ORNL (1980)<br />
• SRRC(1970)<br />
i i i i i i i i i i i i i i i i i<br />
10 1 10 2<br />
Cooling time , t (s)<br />
Fig. 2.3.4 Effect <strong>of</strong> using theoretical values <strong>of</strong> Ep on the calculated results <strong>of</strong> 23S U beta<br />
decay power. See the caption <strong>of</strong> Fig. 2.3.3 for the further details. The experimental<br />
data are taken from the papers by ORNL (Ref. 3), and by SRRC<br />
(Scotisch Research Reactor Center; MacMahon T.P., Wellum R., and Wilson<br />
H.W. : J. Nucl. Energy 24 (1970) 493).<br />
10 3