Using FLUKA for radioactive waste zoning

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Using FLUKA for radioactive waste zoning
L. Nicolas, FLUKA meeting, March 15 2007
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Zoning is a particular object of the more global
class of radioactive studies with FLUKA.
Radioactive waste zoning could be seen as the
a-priori determination of parts and locations of
the accelerator environment that will have
activated items above a particular threshold,
for a specific set of tirr and tc.
Irrelevant if you live in the US.
Concept of Exemption limits (LE), i.e. threshold
values of specific activity for every i
radionuclides.
2 lists Swiss and European.
R gt 1 is a waste.
Need to list the produced resulting radionuclides.
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Typical card set-up for residual activation
studies
- Electromagnetic processes are not needed
for LHC (not like for LEP)
- Request for low-energy neutron treatment
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On-line treatment(i.e. in the course of the
FLUKA runs)

• Nice and fast way to visualize the
• zoning via histograms.

Stefan has created a fortran routine, LEv10.f
that can be compiled and linked prior the FLUKA
runs and that is called via comscw.f
Tell FLUKA that it has to look for the data files
with the exemption limits LE-CH.dat and LE-EC.dat
-gt amend rfluka, and e.g. place these data
files in your running directory.
Request for RADDECAY, and DCYSCORE, choice of
irradiation and decay times (in seconds), and
ask for a specific weight to the results (call
of comscw) via USERWEIG
Key concept of the histogram See the
distribution of residual activity, or the
R-value for zoning purposes.
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For zoners only...
standard rfluka
rfluka for zoning
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0 for cartesian mesh
235 for Bq/g
If no call to LEv10 is done, the histogram
will show the distribution of activity (specific
if 235, volumic if 234)
As shown here, results in the output will be
frozen to IRRPROFI and DCYTIMES specs, and
dimensionless.
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Even nicer...
Some HowTos from Stefan...
The SDUM provides a selection of useful
options. From zoning purposes... ...to
checking the activity of particular species.
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Stricking match of the geometries...
This an exact geometry example
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Check that the call of the subroutine has been
done properly with COMSCW, have a look on the
.out file
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Use your favorite DaViz/SimpleGeo from Chris,
flukaGUI from Tony, or FLAIR from Vasilis to
directly display the histogram of the zoning
score (or activity).
Thats for the ASCII persons
For the binary kind of FLUKA user
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...Identify the regions where the color of the
histograms are such that R gt 1, and get the
waste zone accordingly.
But...
e.g. cryodipole connections.
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Off-line treatmentFlexibility on results
analysis, based on regions, give a list of
radionuclides.
Things can go wrong... Not so rare event Some
other irradiation conditions are needed, after
the end of the Monte Carlo calculations !
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Here the RESNUCLE field is needed with, the index
of the region where results are needed W(5), an
associated name for this detector (e.g. TUN_WALL
in W(7)), and an identifier of the resulting
file (e.g. -27 in W(2) ). Ask for a binary format
(lt0)!
As shown here, results in -26, -27, etc... are
nuclide yield per region, per incident particle.
Note RESNUCLE could be linked to a DCYSCORE too.
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Use the package usrsuwev.f distributed in
flutil/ to obtain activities. It should be
available from whichever working directory you
are in.
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It will ask for the binary files to analyze,
irradiation and cooling time, and rate of
incident particles.
CAREFUL usrsuwev does not list nuclides with an
activity below a certain threshold. Modify
accordingly THRESH TOTTOT(NRN) 0.001 in
usrsuwev.f
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usrsuwev outputs a res file with the following
informations.
Care has to be taken when reading this file The
activity units depend on what you requested in
the input
Also useful to know if you launched enough
primaries, see the uncertainties on your
results.
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From the list of radionuclides, you can write
your own tools to visualize an information e.g.
who is the most active contributor...
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...or for zoning, usrsuwev results are further
processed with a python routine (usrsuwev_LE.py)
developed by Matteo that normalizes activities
with the exemption limits.
Get your R-value in a region in one launch of a
script.
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A model of a model the non-exact geometry
concept
LHC arcs, repetitive structure. Source of
activation beam-gas interactions with a particle
loss rate of n p/m/s
Build a 50 m-long dipole and objects around.
Initiate reactions at the beginning of the
geometry so that all the produced secondaries
stay within the 50-m long model.
After the FLUKA run with a RESNUCLE request for
a particular region, feed USRSUWEV with a rate
of n / (Volume1m density).
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ATLAS detector radioactive waste zoning for ti10
y and tc 100 days courtesy of Zuzana and
Matteo (preprz tool).
Some results...
LHC beam dump, courtesy of Joachim
LHC dipole
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Conclusions
- FLUKA provides great tools for the
investigation of produced radionuclides. -
Direct investigation of activity and/or zoning
results is possible by requesting in the input
file desired irradiation and cooling
conditions - Alternative option to decouple the
FLUKA runs with subsequent analysis of induced
radioactivity can be helpful. - Best is to use
both methods to have complementary results, i.e.
to have distributions and lists. Care with
region-based results (no distribution info), and
histograms (the binning would ideally match a
region of interest). - Next is to include in the
course of the FLUKA runs not only which items
that will be radioactive waste but also the
answer of the authorities.