Using FLUKA for radioactive waste zoning

L. Nicolas, FLUKA meeting, March 15 2007

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.

Concept of Exemption limits (LE),i.e. threshold values of specific activity for every i radionuclides.

Zoning is a particular object of the more global ¨class¨ of radioactive studies with FLUKA.

Zoning is a particular object of the more global ¨class¨ of radioactive studies with FLUKA.

2 lists : Swiss and European.

R > 1 is a waste.

Need to list the producedresulting radionuclides.

Need to list the producedresulting radionuclides.

Irrelevant if you live in the US.

Typical card set-up for residual activation studies 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)

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 limitsLE-CH.dat and LE-EC.dat -> amend rfluka, and e.g. place these data filesin your running directory.

Tell FLUKA that it has to look for the data files with the exemption limitsLE-CH.dat and LE-EC.dat -> amend rfluka, and e.g. place these data filesin 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

235 for Bq/g

0 for cartesian mesh

If no call to LEv10 is done,the histogram willshow 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...Even nicer...

The SDUM provides a selection of useful options.

From zoning purposes...

...to checking theactivity of particular species.

Some HowTo´s from Stefan...

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/SimpleGeofrom Chris, flukaGUI from Tony, or FLAIR from Vasilis to directly display the histogram of the zoning score (or activity).

Use your favorite DaViz/SimpleGeofrom Chris, flukaGUI from Tony, or FLAIR from Vasilis to directly display the histogram of the zoning score (or activity).

For the binary kind of FLUKA user

That´s for the ASCII persons

...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...

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 !

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 fromwhichever working directory you are in.

Use the package usrsuwev.f distributed in flutil/to obtain activities. It should be available fromwhichever working directory you are in.

It will ask for the binary files to analyze, irradiationand cooling time,and rate of incidentparticles.

It will ask for the binary files to analyze, irradiationand cooling time,and rate of incidentparticles.

CAREFUL:usrsuwev does notlist nuclides with an activitybelow a certain threshold.

Modify accordingly THRESH = TOTTOT(NRN) * 0.001

in usrsuwev.f

usrsuwev outputs a ¨res¨ file with the following informations.usrsuwev outputs a ¨res¨ file with the following informations.

Care has to be taken when reading this file:The activity units dependon what you requested in the input

Also useful to know ifyou launched enough primaries, see the uncertaintieson your results.

From the list of radionuclides, you can write your own toolsto visualize an information e.g. who is the most active contributor...

From the list of radionuclides, you can write your own toolsto 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.

...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 conceptA model of a model : the non-exact geometry concept

LHC arcs, repetitive structure. Source of activation: beam-gas interactionswith 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 geometryso 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).

ATLAS detector radioactive waste zoning for ti=10 y and tc = 100 days courtesy of Zuzana and Matteo (preprz tool). Some results...

LHC dipoleLHC dipole

LHC beam dump, courtesy of Joachim LHC beam dump, courtesy of Joachim

ConclusionsConclusions

- FLUKA provides great tools for the investigation of produced radionuclides.

- Direct investigation of activity and/or zoning results is possibleby 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.