Fission Product Yield Data for the Transmutation of Minor Actinide ...
Fission Product Yield Data for the Transmutation of Minor Actinide ...
Fission Product Yield Data for the Transmutation of Minor Actinide ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
44<br />
The uncertainty was processed as follows:<br />
(a) Adjustment <strong>for</strong> standard fission yield:<br />
2 2<br />
( 0 S S0)<br />
DY¢ = DY¢ + DY¢ - DY¢<br />
or <strong>for</strong> fission cross-section:<br />
DY¢ = DY0¢ + Ds S¢ - Ds<br />
S¢<br />
(3.2.4)<br />
(3.2.5)<br />
where ΔY¢ is <strong>the</strong> relative uncertainty <strong>of</strong> <strong>the</strong><br />
data Y: ΔY¢= ΔY/Y. However, ΔY¢ S0 (uncertainty<br />
<strong>of</strong> <strong>the</strong> old standard) may not be<br />
included in Y 0 (total uncertainty <strong>of</strong> <strong>the</strong> data<br />
given by <strong>the</strong> author); under such circumstances,<br />
ΔY¢ S0 should be taken to be zero.<br />
(b) Gamma ray intensity adjustment: The ΔY<br />
uncertainty was not changed, because this<br />
adjustment is usually not large and <strong>the</strong><br />
uncertainty <strong>of</strong> <strong>the</strong> gamma ray intensity is not<br />
given.<br />
(c) Calculate <strong>the</strong> yield from ratio R 0<br />
(d) Calculate <strong>the</strong> ratio R 0 from R value R v :<br />
(3.2.6)<br />
(3.2.7)<br />
where ΔY¢ mxw and ΔY¢ Smxww are <strong>the</strong> uncertainties<br />
<strong>of</strong> <strong>the</strong> measured and standard<br />
nuclides, respectively.<br />
(e) Calculate ratio R 0 from fission yield: since this<br />
evaluation is <strong>for</strong> reference fission yield data,<br />
only ratios <strong>for</strong> measured relative data were<br />
used, if <strong>the</strong> details <strong>of</strong> <strong>the</strong> standards are given<br />
(o<strong>the</strong>rwise <strong>the</strong> data were discarded). Under<br />
<strong>the</strong>se circumstances:<br />
(3.2.8)<br />
If ΔY′ s is not included in <strong>the</strong> total ΔY given by<br />
<strong>the</strong> author, ΔY′ s is assigned a value <strong>of</strong> 0.<br />
The processing <strong>of</strong> <strong>the</strong> data and <strong>the</strong>ir uncertainties<br />
<strong>for</strong> each sub-entry in a paper are given in<br />
<strong>the</strong> corresponding tables <strong>of</strong> Refs [3.2.2–3.2.8].<br />
3.2.2.4. <strong>Data</strong> processing<br />
2 1 2<br />
2 2<br />
( 0 )<br />
( )<br />
2 2 1 2<br />
DY¢ = DR0¢ + DYS¢<br />
DR¢ = DR¢ + DY¢ + DY¢<br />
0<br />
2 1 2<br />
2 2 2<br />
( n mxw Smxw )<br />
( )<br />
2 2 1 2<br />
DR0¢ = DY¢ + DYS¢<br />
The collected and adjusted data with <strong>the</strong>ir<br />
(re-)evaluated uncertainties were processed with<br />
weighted averages, and simultaneously evaluated.<br />
1 2<br />
(a) <strong>Data</strong> average: <strong>Data</strong> measured at <strong>the</strong> same<br />
energy points <strong>for</strong> <strong>the</strong> same fissioning nuclide<br />
were averaged using <strong>the</strong> AVERAG code. The<br />
recommended weighted mean and external<br />
uncertainty were calculated. Tables 3.2.2 and<br />
3.2.3: <strong>Data</strong> <strong>for</strong> which averages have been<br />
calculated are marked ‘A’ in <strong>the</strong> column<br />
headed ‘PROC’, and <strong>the</strong> number <strong>of</strong> data<br />
points is given in <strong>the</strong> column headed ‘POINT’;<br />
averages have been taken in most cases.<br />
(b) Simultaneous evaluation: <strong>Data</strong> <strong>for</strong> which<br />
absolute yields and <strong>the</strong>ir ratios had been<br />
measured were simultaneously evaluated by<br />
using <strong>the</strong> ZOTT code [3.2.11]. Simultaneously<br />
evaluated data are marked ‘S’ in Tables 3.2.2<br />
and 3.2.3. There are two kinds <strong>of</strong> correlated<br />
measurements: different energy points <strong>for</strong> <strong>the</strong><br />
same nuclide, and different nuclides at <strong>the</strong><br />
same energy point.<br />
3.2.2.5. Evaluation system FYDES<br />
All data retrievals, adjustments, modifications to<br />
quoted uncertainties and data processing were<br />
per<strong>for</strong>med with <strong>the</strong> fission yield data evaluation system<br />
FYDES which has been developed to assist in <strong>the</strong><br />
evaluation <strong>of</strong> fission yield data. The following specific<br />
characteristics <strong>of</strong> <strong>the</strong>se data and <strong>the</strong> FYDES system<br />
make <strong>the</strong>m distinct from o<strong>the</strong>r data types (like crosssection<br />
data) and corresponding evaluation systems:<br />
(a) <strong>Data</strong> in <strong>the</strong> EXFOR file can also be given<br />
under <strong>the</strong> heading ‘ELEM/MASS’ (see<br />
below);<br />
(b) More fission yield data are measured on a<br />
relative basis as ratios or R values;<br />
(c) Many data need to be adjusted <strong>for</strong> <strong>the</strong><br />
standard yield, gamma ray intensity and<br />
fission cross-section and have to be recalculated<br />
from ratios or R values;<br />
(d) The dependence <strong>of</strong> yields on neutron energy<br />
appears to be linear <strong>for</strong> most cases.<br />
The fission yield data can be retrieved from<br />
<strong>the</strong> EXFOR database by target, or by incident<br />
neutron energy, or by product (if given in<br />
REACTION), using <strong>the</strong> EXFOR retrieval system.<br />
But when in an EXFOR entry <strong>the</strong> ‘variable product’<br />
<strong>for</strong>malism is used, ‘ELEM/MASS’ is given in<br />
REACTION, and <strong>the</strong> product occurs under <strong>the</strong><br />
heading ‘ELEM/MASS’ <strong>of</strong> <strong>the</strong> DATA table and<br />
cannot be retrieved this way. Some supplementary<br />
programs were developed to solve this problem,