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Transcript of ActiWiz – optimizing your nuclide inventory at proton accelerators with a computer code Helmut...
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ActiWiz – optimizing your nuclide inventory at proton accelerators with a computer codeHelmut Vincke, Chris Theis DGS/RP
RSO committee – 1/3/2012
Remote manipulations/handling of radioactive material workshop 6/5/2013
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Contents
• Motivation for this project
• Introduction to “ActiWiz”
• Illustration of the Catalogue: “Radiological Hazard classification of Materials in CERN’s accelerator environments“
Motivation
Safety benefit
• Lower dose rates and committed doses
Operational benefit
• Reduced downtime due to faster access
• Less restrictions for manipulation & access
End of life-cycle benefit
• Smaller amount and less critical radioactive waste
• Smaller financial burden
3Project concerning the radiological classification of materials initiated by Steve Myers
• Beside other aspects also the radiological consequences of the implementation of a material have to be considered
• Level of activation depends on the type of the material
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very strong dependence on radiation environment need for “CERN specific” assessment in contrast to experience from nuclear industry
Next to target:brass vs. iron equivalent
Outside:brass vs. iron significantly worse
Use-case
Using brass instead of iron as shielding @ COMPASS-2?
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Strategy to obtain radiological material guidelines
Categorization of radiation environment
Development of ActiWiz – code assessing radiation risks, dominant nuclides etc., for arbitrary materials
Radiological hazard catalogue for materials
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Radiological assessment of materials
Energy (machine) Position in accelerator
Radiological hazard assessmentfor a given material
Time of material present in accelerator
(irradiation time)
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Categorization of the radiation environments (energy)
FLUKA calculations of typical hadronic particle spectra (p, n, p+, p-) in CERN’s accelerators
LHC
SPS
PSLinac 4
+ Booster
160 MeV (Linac4), 1.4 GeV (Booster), 14 GeV/c (PS), 400 GeV/c (SPS), 7 TeV (LHC)
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Radiological assessment of materials
35 spectra * 5 irradiation periods * 13 cooling times FLUKA isotope calculations for 69 single components(63 chemical elements + 6 isotopes)
2400 single Monte Carlo simulations 157.000 nuclide inventories (10 GB of data) ~628.000 hazard factors
ActiWiz – software evaluate radiological hazard for arbitrary materials with a few mouse clicks
Close to tunnel wall
1.E-12
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
Energy (GeV)
E*d
F/d
E
Protons
Pions+
Pions-
NeutronsClose to tunnel wall
1.E-12
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
Energy (GeV)
E*d
F/d
E
Protons
Pions+
Pions-
Neutrons13 cm lateral to beam axis
1.E-12
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
Energy (GeV)
E*d
F/d
E
Protons
Pions+
Pions-
Neutrons
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ActiWiz – program interface
1.) Select energy / location / irradiation times2.) Define material composition based on 69 chemical elements
* Many thanks to R. Froeschl for providing activation data on Zinc
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Output of ActiWiz
Nuclide inventory & dominant isotopes
Safety relevant quantities(activity, H*(10), radiotoxicity)
Radiological hazard assessment• Hazard factors allowing to compare various materials
with each other
• Program provides so-called global hazard factors for• Operation (indicator of external dose to personnel)• Waste (indicator of risk generating radioactive waste)
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Material catalogue
Material catalogue
Classification of most common materials by the use of global operational and waste hazard factors
Catalogue provides guidelines for selection of materials to be used in CERN’s accelerator environment
Authors: Robert Froeschl, Stefano Sgobba, Chris Theis, Francesco La Torre, Helmut Vincke and Nick WalterAcknowledgements: J. Gulley, D. Forkel-Wirth, S. Roesler, M. Silari and M. Magistris
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• Catalogue consists of three parts:
Catalogue for the radiological hazard classification of materials
Introduction
List of critical materials in terms of
handling & waste disposal*
Appendix with data
• Provides radiological guidelines via hazard values cannot replace Monte Carlo studies by a specialist for specific cases outside of the generic irradiation scenarios assumed
* Many thanks to Luisa Ulrici (DGS-RP-RW) for elaborating and providing the waste disposal guidelines
Catalogue structure
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160 MeV (Linac4), 1.4 GeV (Booster), 14 GeV/c (PS), 400 GeV/c (SPS), 7 TeV (LHC), energy independent
7 typical radiation fields in an accelerator
Various irradiation times
1 day, 1 week, 1 operational year, 20 years, irradiation time independent
Various energies/momenta
Materials not addressed by the catalogue can be assessed with the ActiWiz program
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Examples for using the catalogue
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Proton Beam
1 wt-% of hafnium shall be used as an additive to a copper cable. The cables are placed in cable trays attached to the concrete tunnel wall alongside to SPS magnets. Question arising: Is 1% of hafnium in terms of radiological consequences an acceptable choice?
Summary of situation:a) Foreseen location: concrete wall beside SPS magnetsb) Duration of its stay at this position: SPS life timec) Material choice: is 1% of hafnium acceptable?
Hazard factor comparison: Hazard factor comparison Hazard of elements per mass unit:
Operational: 1.36 (copper) versus 976 (hafnium); Waste: 2.54 (copper) versus 51200 (hafnium)
1 wt-% of hafnium in the alloy causes an 7 times higher operational and a 200 times higher waste related radiological hazard than the remaining 99.0 wt-% of copper. find another additive for the cable
Example
Parameters to be chosen for retrieving the correct data:a. Irradiation energy + location: 400 GeV/c; activation occurring close to the concrete tunnel
wall (beam loss in bulky material)b. Irradiation time: 20 yearsc. Find hazard factor of hafnium in table listing elements per mass unit
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Concrete tunnel
7 TeV protons
Proton Beam
For a test lasting one year a container for an LHC collimator has to be built. It was proposed to build the container either of Steel 316L, Titanium Grade6 or Tungsten. What is in terms of radiological consequences the best choice?
Summary of situation:a) Foreseen location: locations close to a collimatorb) Duration of its stay at this position: 1 operational year (200 days)c) Material choice: Steel 316L, Titanium Grade6 or Tungsten ?
Parameters to be chosen for retrieving the correct data:a. Irradiation location: 7 TeV; activation occurring at 10 cm lateral distance to target b. Irradiation time: 200 daysc. Compare hazard factors of compounds (Steel 316L, Titanium Grade6) and elements (Tungsten) per
unit volume respectively.
Example 2/1
Hazard factor comparison:
Operational hazard: 1.72 (Steel 316L) versus 1.06 (Titanium Grade6) versus 3.44 (Tungsten).
Waste hazard: 0.819 (Steel 316L) versus 0.972 (Titanium Grade6) versus 2.75 (Tungsten).
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Example 2/2
Hazard factor comparison:
Operational hazard: 1.72 (Steel 316L) versus 1.06 (Titanium Grade6) versus 3.44 (Tungsten).
Waste hazard: 0.819 (Steel 316L) versus 0.972 (Titanium Grade6) versus 2.75 (Tungsten).
First conclusions• Tungsten can be excluded from the choice• Waste and operational hazard ratio inverted lower external exposure but higher risk of
producing radioactive waste
Titanium Grade6 should be taken as material to build the collimator container.
How to proceed in such a case:
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Web-based catalogue: ActiWeb http://actiweb.cern.ch
Interactive web-based catalogue in collaboration with software developer Fernando Leite Pereira (DGS/RP).
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Summary
ActiWiz software allows to quickly quantify radiological hazard of material implemented into CERN’s accelerator environment.
69 elements and most common metals and construction materials were processed first version of a catalogue for CERN accelerators(LINAC4, BOOSTER, PS, SPS & LHC radiation environments)
Catalogue provides radiological guidelines supporting the user in the choice of materials to be implemented in the accelerator environment.
Currently we are in the process of promoting the catalogue & getting feedback from users.
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Thank you for your attention
www.cern.ch/actiwiz
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First example of an ActiWiz applicationComparison of ambient dose equivalent for various materials installed in a cable tray @ LHC, operating for 20 years
– Copper – Aluminum – Iron – Steel 316L
Check nuclide inventory to understand results
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Further analysis with ActiWiz
“Why is stainless steel so much worse than pure iron?”
Co-60: 99% Fe-55: 86% Sc-44: 9%
Steel 316L Iron Aluminum
Na-22: 99% Co-60: 99%
Copper
Shielding requirements for equipment: defined by dominating energy of the radio-isotopes:
Co-60: 1.33 MeV 1.17 MeV
Fe-55: X-ray due to e Sc-44: 1.15 MeV
Steel 316L Iron Aluminum
Na-22: 1.27 MeV Co-60: 1.33 MeV 1.17 MeV
Copper
Required thickness of concrete shielding for an attenuation of a factor of 10:
Co-60: 31 cm Fe-55: /Sc-44: 30 cm
Steel 316L Iron Aluminum
Na-22: 31 cm Co-60: 31 cm
Copper
Main contributor to ambient dose equivalent for a cool down of 10 years:
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FLUKA benchmarks
Fundamental quantity:calculation of radionuclide production with FLUKA
Very well benchmarked & documented:
M. Brugger, A. Ferrari, S. Roesler, L. Ulrici, Validation of the FLUKA Monte Carlo code for predicting induced radioactivity at high-energy accelerators, Proc. 7th Int. Conf. on Accelerator Applications - AccApp05, Nucl. Instrum. Meth. A562, 827-829, (2006).
M. Brugger, H. Khater, S. Mayer, A. Prinz, S. Roesler, L. Ulrici, Hz. Vincke, Benchmark studies of induced radioactivity produced in LHC materials, Part 1: specific activities, Proc. ICRS-10 (May 2004); Rad. Prot. Dosim. 116, 6-11, (2005).
S. Mallows. T. Otto, Measurements of the induced radioactivity at CTF-3, ARIA workshop 08 – PSI, (2008).
M. Brugger, D. Forkel-Wirth, S. Roesler, J. Vollaire, Studies of induced radioactivity and residual dose rates around beam absorbers of different materials, Proceedings of HB2010, Morschach, Switzerland, (2010).
J. Vollaire, M. Brugger, D. Forkel-Wirth, S. Roesler, P. Vojtyla, Calculation of water activation for the LHC, Nuclear Instruments and Methods in Physics Research A, Volume 562, Issue 2, p. 976-980, (2006).
M.Brugger, F.Cerutti, A.Ferrari Ferrari, E.Lebbos, S.Roesler, P.R.Sala,F.Sommerer, V. Vlachoudis, Calculation of Induced radioactivity with the FLUKA Monte Carlo code, ARIA workshop 08 – PSI, (2008).
non exhaustive list
G. Dissertori, P. Lecomte, D. Luckey, F. Nessi-Tedaldi, F. Pauss, T. Otto, S. Roesler, C. Urscheler,A study of high-energy proton induced damage in cerium fluoride in comparison with measurements in lead tungstate calorimeter crystals, Nuclear Instruments and Methods in Physics Research A, p. 41-48, Vol. 622, (2010).
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Categorization of the radiation environments (position)
beam impact area
within bulky material (e.g. magnet) surrounding the beam impact area
adjacent to bulky material surrounding the beam impact area
close to concrete tunnel wall (loss on bulky object)
behind massive concrete shielding
10 cm lateral distance to a target
close to concrete tunnel wall (loss on target)
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Concrete tunnel
7 TeV protons
Proton Beam
A support for a beam loss monitor foreseen to be installed close to LHC magnets has to be designed. A choice between Aluminium 5083 and Steel 316L in terms of materials to be used to build the support has to be made.
Summary of situation:a) Foreseen location: beside LHC magnetb) Duration of its stay at this position: LHC life timec) Material choice: either Aluminium 5083 or Steel 316L
Parameters to be chosen for retrieving the correct data:a. Irradiation energy + location: 7 TeV; activation occurring adjacent to bulky material (e.g. magnet)
surrounding the beam impact areab. Irradiation time: 20 yearsc. Compare hazard factors of compounds per unit volume
Example 1
Hazard factor comparison: Operational: 0.227 (Aluminium 5083) versus 2.36 (Steel 316L)
Waste: 0.179 (Aluminium 5083) versus 7.18 (Steel 316L)
Aluminium 5083 provides a 10 times lower operational radiological hazard and a 40 times lower waste related hazard factor than Steel 316L.
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Concrete tunnel
7 TeV protons
Proton Beam
For a test lasting one year a container for an LHC collimator has to be built. It was proposed to build the container either of Steel 316L, Titanium TiNb or Tungsten. What is in terms of radiological consequences the best choice?
Summary of situation:a) Foreseen location: locations close to a collimatorb) Duration of its stay at this position: 1 operational year (200 days)c) Material choice: Steel 316L, Titanium TiNb or Tungsten ?
Parameters to be chosen for retrieving the correct data:a. Irradiation location: 7 TeV; activation occurring at 10 cm lateral distance to target b. Irradiation time: 200 daysc. Compare hazard factors of compounds (Steel 316L, Titanium TiNb) and elements (Tungsten) per
unit volume respectively.
Example 4/1
Hazard factor comparison:
Operational hazard: 1.72 (Steel 316L) versus 1.63 (Titanium TiNb) versus 3.44 (Tungsten).
Waste hazard: 0.819 (Steel 316L) versus 1.91 (Titanium TiNb) versus 2.75 (Tungsten).
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Example 4/2
Hazard factor comparison:
Operational hazard: 1.72 (Steel 316L) versus 1.63 (Titanium TiNb) versus 3.44 (Tungsten).
Waste hazard: 0.819 (Steel 316L) versus 1.91 (Titanium TiNb) versus 2.75 (Tungsten).
First conclusions• Tungsten can be excluded from the choice• Waste and operational hazard ratio inverted lower external exposure
Call RP for further advice in that matter.
How to proceed in such a case:
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Hazard factor types
• Applications for “hazard factors per volume unit”:1. Choosing material for non-bulky objects (the thickness of the object for which the
material is chosen should be less than 10 cm iron equivalent).2. For choosing material for massive objects (thickness of more than 10 cm iron
equivalent) if the density variation between the different materials is < 2.
• Applications for “hazard factors per mass unit”:1. Evaluation of the influence of chemical elements on the hazard factor of a compound
(e.g.: change of hazard factor of a compound when x wt% of element A is added). 2. Massive objects of a thickness of more than 10 cm iron equivalent if the density
variation between the different materials is > 2 (ActiWiz program has to be used).
Two hazard factor types are available
Hazard factor per volume unit Hazard factor per mass unit
MAIN APPLICATION