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 ...
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210<br />
4.6. FISSION YIELDS IN NUCLEON INDUCED REACTIONS<br />
AT INTERMEDIATE ENERGIES<br />
Results are presented <strong>of</strong> an activation<br />
experiment on proton induced fission <strong>of</strong> nat W, 197 Au,<br />
nat Pb, 208 Pb and 232 Th at 190 MeV. <strong>Fission</strong> product<br />
yields have been measured and an attempt has been<br />
made to reconstruct <strong>the</strong> charge and mass yield<br />
curves. This is followed by <strong>the</strong> description <strong>of</strong> a new<br />
<strong>the</strong>oretical approach to predict fission fragment<br />
mass yields <strong>for</strong> both actinides and sub-actinides in<br />
<strong>the</strong> incident energy range between 10 and 200 MeV.<br />
Temperature dependent fission barriers and prescission<br />
shapes are determined within a<br />
temperature dependent version <strong>of</strong> <strong>the</strong> Brosa model.<br />
These quantities combined with <strong>the</strong> original<br />
random neck rupture model and <strong>the</strong> existing<br />
nuclear reaction code ALICE-91 provide a new way<br />
<strong>of</strong> calculating fission fragment and product yields.<br />
The predictive power <strong>of</strong> this method is tested<br />
against a set <strong>of</strong> experimental data.<br />
4.6.1. Introduction<br />
The absence <strong>of</strong> a satisfactory <strong>the</strong>oretical<br />
description to predict isotope yields as well as <strong>the</strong><br />
need <strong>for</strong> experimental fragment mass and charge<br />
distributions at intermediate energies <strong>for</strong>m <strong>the</strong><br />
motivation <strong>of</strong> this contribution. The work<br />
per<strong>for</strong>med in <strong>the</strong> framework <strong>of</strong> <strong>the</strong> CRP consists <strong>of</strong><br />
four separate topics:<br />
(1) Compilation <strong>of</strong> proton induced fission product<br />
and fission fragment mass distributions from<br />
literature;<br />
(2) Experimental ef<strong>for</strong>ts aimed at measuring<br />
proton induced fission product yields at<br />
190 MeV <strong>of</strong> 232 Th and several sub-actinide<br />
targets;<br />
(3) Development <strong>of</strong> a new computational method<br />
to predict intermediate energy nucleon<br />
induced fission product mass yields using a<br />
combination <strong>of</strong> <strong>the</strong> existing nuclear reaction<br />
code ALICE-91 and <strong>the</strong> Brosa model<br />
extended with a temperature dependence;<br />
(4) Theoretical predictions <strong>of</strong> fission fragment<br />
and fission product mass yield curves <strong>for</strong> all<br />
reactions specified by <strong>the</strong> CRP benchmark.<br />
M.C. Duijvestijn, A.J. Koning<br />
Nuclear Research and Consultancy Group, Ne<strong>the</strong>rlands<br />
Several parts <strong>of</strong> this research have already<br />
been published in journals and conference<br />
proceedings [4.6.1–4.6.8]. A more detailed<br />
description <strong>of</strong> <strong>the</strong> experimental as well as <strong>the</strong><br />
<strong>the</strong>oretical work can be found in Ref. [4.6.9].<br />
4.6.2. Compilation <strong>of</strong> proton induced<br />
fission product isotope yields<br />
<strong>Fission</strong> product isotope yield and mass yield<br />
data have been ga<strong>the</strong>red <strong>for</strong> proton induced<br />
reactions on actinide targets. The search has been<br />
limited to <strong>the</strong> intermediate energy region (i.e.<br />
proton energies ranging from 15 to 200 MeV). The<br />
data are taken from 14 references. The reaction<br />
specification is found in Table 4.6.1, as are <strong>the</strong><br />
incident proton energies, <strong>the</strong> type <strong>of</strong> compiled data<br />
(mass yields/isotope yields), <strong>the</strong> compilation <strong>for</strong>m<br />
(read from figures or tables) and <strong>the</strong> reference. In<br />
<strong>the</strong> case <strong>of</strong> data read from figures, an extra<br />
uncertainty has been added to <strong>the</strong> published one<br />
because <strong>of</strong> <strong>the</strong> inevitable amount <strong>of</strong> arbitrariness<br />
linked to estimating data from figures. The files<br />
containing <strong>the</strong> compiled experimental data can be<br />
downloaded from web site: http://ndsalpha.iaea.org/<br />
fycrp/<br />
All data taken from a single reference are<br />
collected in one file. Each entry starts with a title<br />
revealing <strong>the</strong> necessary in<strong>for</strong>mation regarding <strong>the</strong><br />
target and <strong>the</strong> incident proton energy, which is<br />
followed by <strong>the</strong> reference, comments and <strong>the</strong> data<br />
points. The comments concern <strong>the</strong> given uncertainties,<br />
whe<strong>the</strong>r data are taken from tables or<br />
figures, and a description <strong>of</strong> <strong>the</strong> contents <strong>of</strong> <strong>the</strong><br />
columns containing <strong>the</strong> data points. In case <strong>of</strong> more<br />
incoming proton energies or target nuclides, entries<br />
are concatenated.<br />
4.6.3. Activation experiment on proton induced<br />
fission <strong>of</strong> nat W, 197 Au, nat Pb, 208 Pb and 232 Th<br />
at 190 MeV<br />
Several sub-actinide targets and a 232 Th target<br />
have been irradiated with a 190 MeV proton beam<br />
from <strong>the</strong> AGOR cyclotron at <strong>the</strong> KVI, Groningen.