MC code validations and first EURISOL radiation protection studies M. Felcini
CERN AB-ATB & UCLA on behalf of WP5-Task A: radiation, activation, shielding & doses
Contributors to this talk: CEA: J.-C. David, D. Dore, B. Rapp, D. Ridikas CERN: M. Felcini, Th. Otto FZ Jülich: R. Moormann, K.Bongardt, H.Brücher, B.Lensing, H.Schaal, K.Verfondern FI, Vilnius: A.Plukis, R.Plukiene, A. Zukauskaite UW, University of Warsaw: L. Pienkowski NIPNE, Bucharest: D, Ene, F. Negoita
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Outline - WP5 Task A: reminder of goals - Validation of MC codes: FLUKA and MCNPX vs DATA Comparisons for - isotope production – alpha emitters - neutron production - Multi MW target station: shielding requirements - Proton driver issues - Work plan and responsibilities - Summary and outlook
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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EURISOL High resolution High resolution mass mass separator separator
Post-accelerator linac Post-accelerator linac
Ion beams from pre-separators Ion beams from pre-
Beam lines Beam linesuser to to multiple multiple user areas
separators
areas
Laser input Laser input to ion to ion sources sources 3×100 kW direct irradiation
MW target area MW target area
3×100 kW direct irradiation
Fissile target + spallation nsource Fissile target + spallation >100 kWn-source Solid converters >100 kW Solid converters 4 MW Hg-jet
Proton and deuteron beams Proton and deuteron beams from driver accelerator from driver accelerator
4 MW Hg-jet
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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WP5 Task A: goals Proton driver
Target stations
Mass separator and post-accelerator
Experimental halls
WP5 Task A: radiation, doses, activation, shielding Careful design of the facility will result in an optimal layout of the shielding and the instrumentation around the target-moderator-reflector complex and around the accelerator, under the required radiation protection and safety criteria. The shielding and material disposal costs of the facility comprise a significant part of the total facility costs. November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Calculation method for doses, shielding parameters and activity Monte-Carlo particle transport code Gamma flux (x,y,z, E)
Dose rates
Neutron flux(x,y,z,E)
Shielding parameters: thickness, materials, to minimise dose rate
Residual nuclei (A,Z) from high-energy reactions
Information of residual nuclei induced by primary reactions and activation induced by secondary neutrons is combined to calculate the nuclide production rates
Activity
Nuclide inventory November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Validation of MC codes: FLUKA and MCNPX vs DATA Comparison of MC calculated cross-sections - Heavy residue isotope production and decay Published cross-sections for
- Neutron production
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
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Residue isotope production: Fluka development Development version of Fluka (A. Ferrari) d.fluka Improvement in production of alpha-emitters Z=84 – 94
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
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Residue isotope cross-sections D. Dore, M.F.
Cross-section comparisons data mcnpx (isabel-abla) d.fluka See also poster J.C. David, D. Dore
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
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Production of alpha-emitters D. Dore, M.F.
Z=84
Z=85
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Z=88
Z=89
Marta Felcini CERN & UCLA
Z=90
Z=91
Z=92
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Neutron energy distributions Energy distributions of neutron from reactions p(800 MeV)+X, X=diverse nuclei Shown here only for p(800 MeV)+U, for more see B. Rapp poster
Neutron energy distributions at different neutron emission angles
Fluka
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Ratio simulation/data Fluka and diverse Mcnpx models
Mcnpx Isabel-ral
Marta Felcini CERN & UCLA
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Neutron attenuation in iron shield A.Plukis et al. High energy neutron (up to 800 MeV) measurements in iron shields (HIMAC) Measured spectra (HIMAC) M. Sasaki et. al, Nuc. Sci. E., Vol.141, No.2, pp. 140-152, 2002 Calculated with MCNPX 2.5.0 experiment 10
1
10
0
MCNPX
Ratio of HE neutron flux through iron shielding
d=0 cm
Neutron flux, n/MeV/sr/ion
-1
10
-2
10
Ratio
20cm /0cm
40cm /20cm
60cm /40cm
Exp
0.54
0.26
0.27
MCNPX
0.21
0.23
0.27
-1
d=20 cm (x10 )
-3
10
-2
d=40 cm (x10 )
-4
10
-5
10
-3
d=60 cm (x10 ) -6
10
-7
10
100
200
300
E, MeV November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
400
500
Marta Felcini CERN & UCLA
600
- Good agreement for shields of different thickness. - Some discrepancy between shielded and unshielded flux (possible saturation of detector ) 11
Multi MW Target Configurations Standard Configuration 15 cm radius Hg target
A. Herrera & Y. Kadi
Reflector
Intermediate Configuration 8 cm radius Hg target Reflector
UCx UCx Hg
Hg
20 cm
20 cm
The UCx configuration is a study case. The final configuration mayl use ~1/10 of this UCx volume shown (L. Tecchio) 12 November 29th 2005 Marta Felcini Eurisol Town Meeting .- GANIL, Caen
CERN & UCLA
Neutron flux from Multi MW target Hg converter
Comparison MCNPX & FLUKA results for neutron flux produced by 5 MW-1GeV beam on MMW target Hg converter MCNPX simulation preliminary; details of the simulation (beam geometry, flux binning, etc.) being checked A, Plukis et al EURISOL DS Task 2: FLUKA simulation A.Herrera,Y.Kadi, 2005
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
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A first look at dose rate outside concrete shielding Dose equivalent rate for concrete shielding
5 MW - 1 GeV Proton beam on standard configuration 15 cm radius Hg target
target
with 2m concrete shielding
F L U KA simulation
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
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A first look at dose rate outside concrete shielding The dose rates outside shielding are consistent with -t/λ values predicted by Sullivan’s formula
H = H0 e
From formula, dose rate is reduced by a factor ~2 x10-3 through 2m concrete shielding, comparable to dose reduction factor by FLUKA calculation (cf. dose before and after concrete in previous picture)
Dose rate outside 2m concrete shielding: 100 Sv/h Max dose rate allowed on ground people: 0.1 µ Sv/h Must reduce dose rate by a factor 109 . Use Sullivan’s formula to calculate thickness of earth, above concrete Shielding, to reduce dose rate to the allowed value. Find:
/R 2
t = shielding thickness R=distance in m
material iron
λ
(cm) 17.4
concrete
43
earth
56
Required underground depth > 9 x ln(10) x λ (earth) ~ 12 m Other questions and possible answers, to be investigated: - Activation of ground water -> target station in a layer of impermeable material, to avoid activated water to run away - Activation of air -> target station in vacuum? - Access to underground target station for maintenance -> manned or robotized? - Evaluate costs November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Nuclide inventories in a Hg MW target R. Moormann et al. Nuclide inventories in the MW target: Safety and decomissioning for EURISOL depend to a large extent on a reliable knowledge of the nuclide inventory in the MW (Hg) target and on the total toxicity. A report on the radiotoxicity and on the conventional toxicity of the Hg available
Comparison of activities in an HgHg-target and in a research fission reactor
1A list of activities for 500 nuclides is now available.
1The conventional Hg-toxicity cannot be neglected. 1Most safety relevant nuclides are: Hg-194, Hf-172, Gd-148, Hg-203, I-125, Au-195 1The radiotoxic inventory is similar to that of a neutron generating research reactor. 1For nuclide masses < 100 additional calculations are required. November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Proton driver Which radiation in the accelerator tunnel? Prompt radiation : Radiation in the tunnel is due to beam halo and beam losses. Beam particles interacts with components along the accelerator and produces neutron, gammas and other secondqry pqrticles Residual radiation: During operation beam losses and secondary particles activate materials and tunnel walls; Predictions of prompt and residual radiation in the accelerator tunnel is important for Shielding design optimization and for scheduling access of maintenance personal in the tunnel after beam termination. Dose rate distributions, etc, depend on the position, dimensions qnd mqteriqls of the different accelerator elements (collimators,magnets, accelerating cavities, beam diagnostic instruments, etc.) Which proton driver for EURISOL? Baseline parameters? Realistic beamp loss characteristics ? November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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An existing 5 MW proton driver design Superconducting Proton Linac: design in progress (towards CDR2) CEA (F), CERN, Frankfurt University (D), GSI (D), INFN-Milano (I), IN2P3 (F), RAL (GB), KFZ Juelich (D)
95 keV
3 MeV
10 m
H-
RFQ chopp.
Source
Front-end
180 MeV
83 m DTL- CCDTL- SCL
1-2 GeV
350 m
β=0.65 β=0.8 β=1
β=1
Superconducting
Normal Conducting
LINAC 4
1 – 2 GeV EURISOL
http://ps-div.web.cern.ch/ps-div/SPL_SG and thanks to R. Garoby, F.Gerick, M. Vretenar
RF cavity
3.5 GeV
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
3.5 GeV to PS & Accumulator ring (Neutrino facility)
Beam Diognostic
Quadrupole
10 m Cryomdule 10 m
dump
Marta Felcini CERN & UCLA
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Dose rates in the 1 Gev-1MW proton driver for the SNS
I.Popova and F. Gallmeier Full scale radiation dose analysese for the SNS accalerator system Realistic beam losses (calculated from beam dynamics) during Linac normal operation used to evaluate the dose rate during and after beam operation
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Proton driver shielding design considerations
Accelerator shielding: A report on transfer of experience in shielding items of the ESS accelerator to the EURISOL driver accelerator is in progress (to be finished: R. Moormann et al.
Mid of 2006). Main items are: • Shielding for local beam losses: calculation of dose rates to workers, shielding requirements on soil thickness •Shielding against skyshine: For the start-up phase of the accelerator, skyshine may become a problem to the public in conservative estimations (point source assumptions) leads to about 1 mSv/y in 250 m of distance). More detailed estimations are required.
Nuclide
Maximu m Specific Activity [Bq/g] in soil
H-3
Free handling
Normal waste*
Radioactive waste
1.5
< 60
< 103*
> 60** (> 103*)
Na-22
0.08
< 0.1
< 4*
> 0.1** (> 4*)
Co-60
0.2
< 0.09
< 4*
> 0.09** (> 4*)
Eu-152
2
< 0.2
< 8*
> 0.2** (> 8*)
• Selection of shielding material under disposal aspects: Pros and cons of soil and concrete shielding are compiled: Concrete is more expensive in shielding manufacture, but less expensive in disposal (see soil activation after 10 y). November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
German Limit of Specific Activity [Bq/g] for
Specific activities (Bq/g (Bq/g)) in CERN soil adjacent to the inner concrete shielding of a MW accelerator (10 y after shutshut-down, thickness of the inner concrete shielding: 0.6 m) and corresponding German thresholds (Bq/g (Bq/g)) for waste classification (* 1000 t/y) Marta Felcini
CERN & UCLA
Working plan Early 2006
- Finalise MC validations (CEA, CERN, FI, UW)-> Reports
During 2006 - realistic calculations for shielding, dose rates and activation -> Reports Proton driver - CERN with FLUKA (cross-checks with MCNPX by CEA and/or FI); FZ Jülich transfer of experience in shielding items of the ESS accelerator to the EURISOL driver Target stations - CERN with FLUKA (cross checks with MCNPX by CEA and/or FI); FZ Jülich transfer of experience in activity calculations of the ESS Hg target to the EURISOL MMW target. Mass separator and post-accelerator - CEA with PHITS (dose from stopping ions) and CERN calculation (dose from decay of implanted ions) Experimental halls - CEA with PHITS and CERN calculation
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Inputs needed from all WPs EURISOL is a high-intensity challenge… also for Radiation Protection (high intensity=high radiation). New and innovative technical solutions will have to be devised to meet the high-radiation challenge. This takes work and time WP5 Task A needs baseline parameters from all the WPs, in particular for: Proton driver Target stations (a proposal exist for MMW target) Mass separator and post-accelerator Experimental areas So that we can provide feedback and proposals for solutions, in an iterative process
November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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Summary and outlook Benchmark studies comparing measured cross sections and differential distributions to results of Fluka and MCNPX codes have been performed for reactions, energy and materials of interest for EURISOL. Good agreement ( in most cases within less than a factor of twowrt measurements) is found. Where bigger discrepancies, improvements are being worked out (Fluka). A report on the MC validation is in preparation (by Febr.2006) -> deliverable of WP5 task A Work on targets and proton driver has started: we need to have baseline parameters to start to work out solutions to the many challenges (=problems) that this facility offers.
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Thank you November 29th 2005 Eurisol Town Meeting .- GANIL, Caen
Marta Felcini CERN & UCLA
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