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> 4. Calculation <strong>of</strong> Decay Power <strong>of</strong> <strong>Fission</strong> <strong>Products</strong> 153<br />
powers.<br />
(3) The parameter a] for the total <strong>of</strong> beta and gamma decay powers are given as the<br />
sum <strong>of</strong> <strong>of</strong>f and <strong>of</strong>f.<br />
(4) The weights <strong>of</strong> (l//«) are used in the least-squares method where fn is the calculated<br />
burst-fission decay power <strong>of</strong> the «-th data point.<br />
The fitting errors are shown in Tables 4.2.3 through 4.2.11 and Figs. 4.2.1 through<br />
4.2.27. The fitting errors for the burst fission are given in Table 4.2.3 for beta+gamma decay<br />
power, in Table 4.2.4 for beta decay power and in Table 4.2.5 for gamma decay power.<br />
The results for a year's irradiation are given in Tables 4.2.6 through 4.2.8 and those for the<br />
infinite irradiation are given in Tables 4.2.9 through 4.2.11. The fitting errors for the burst<br />
fission <strong>of</strong> 235 U by thermal neutrons are shown in Fig. 4.2.1 for beta+gamma decay power, in<br />
Fig. 4.2.2 for beta-decay power, and in Fig. 4.2.3 for gamma decay power. The results for fast<br />
fission <strong>of</strong> 238 U and thermal fission <strong>of</strong> 239 Pu are shown in Figs. 4.2.4 through 4.2.6 and Figs.<br />
4.2.7 through 4.2.9, respectively. The results for a year's irradiation are shown in Figs. 4.2.10<br />
through 4.2.18, and those for the infinite irradiation in Figs. 4.2.19 through 4.2.27.<br />
It is seen from these tables and figures that the fitting errors are very small. The fitting<br />
errors are especially small (± 0.03%) for the cooling times less than 10 6 s after a year's irradiation<br />
for the beta+gamma decay power for thermal fission <strong>of</strong> 235 U. The error increases<br />
to ± 0.3% as the wider cooling time ranges up to 10 10 s. The fitting errors are <strong>of</strong> the same<br />
order <strong>of</strong> magnitude for fast fission <strong>of</strong> 238 U and thermal fission <strong>of</strong> 239 Pu. The fitting error<br />
decreases with irradiation time; ± 0.5% for burst fission, ± 0.3% for a year's irradiation, and<br />
±0.1% for infinite (10 13 s) irradiation for the above three types <strong>of</strong> fission. The maximum<br />
fitting error for beta+gamma decay power is -0.6% at 2 X 10 7 s after burst fission <strong>of</strong> 233 U<br />
by thermal neutron among the ten fission types.