Transcript info-fluka-discussion.web.cern.ch

Using FLUKA for radioactive waste zoning
L. Nicolas, FLUKA meeting, March 15 2007
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 > 1 is a waste.
Need to list the produced
resulting radionuclides.
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
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 -> 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.
For ¨zoners¨ only...
rfluka for zoning
standard rfluka
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.
Even nicer...
Some HowTo´s from Stefan...
The SDUM provides a
selection of useful options.
From zoning purposes...
...to checking the
activity of particular species.
Stricking match of the geometries...
This an exact geometry example
Check that the call of the subroutine has been done properly with COMSCW,
have a look on the .out file
Use your favorite DaViz/SimpleGeo
That´s for the from Chris, flukaGUI from Tony, or
ASCII persons FLAIR from Vasilis to directly
display the histogram of the zoning
score (or activity).
For the binary kind
of FLUKA user
...Identify the regions where the color of the histograms are such that
R > 1, and get the waste zone accordingly.
e.g. cryodipole connections.
But...
Things can go wrong... Not so rare event: Some other irradiation conditions
are needed, after the end of the Monte Carlo calculations !
Off-line treatment
Flexibility on results analysis, based on regions, give a list of radionuclides.
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 (<0)!
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.
Use the package usrsuwev.f distributed in flutil/
to obtain activities. It should be available from
whichever working directory you are in.
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
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.
From the list of radionuclides, you can write your own tools
to visualize an information e.g. who is the most active contributor...
...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.
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 / (Volume[1m] * density).
ATLAS detector radioactive waste zoning for ti=10 y and
tc = 100 days courtesy of Zuzana and Matteo (preprz tool).
Some results...
LHC beam dump, courtesy of Joachim
LHC dipole
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.