EURISOL-DS / Task 5 “Safety & Radioprotection” 9-months Progress Report NIPNE-Bucharest (Romania) 1 Sub-Task A: Radiation, activation, shielding & doses • Neutron attenuation calculations: comparison with data Simulations with FLUKA: - HIMAC benchmarck - basic shielding studies (see next presentation)
1 Sub-Task B: Radioactivity control, safety and risks • Dispersion of radio-elements, contamination, migration: experience gained from NPPs (D. Vamanu, B. Vamanu, V. Acasandrei) Development of an integrated software platform: “Safety and Radioprotection Desktop Toolkit” and of an e-book (see presentation of B.Vamanu) Period Pers. (k€ ) Consum.(k€ ) Travel (k€ ) Total (k€ ) FTE Contr./Total (man*years) 9 months (actual) 2.8 0 1.2 4.0 0.3 / 0.8 1st year (estimation) 4.2 0 1.2 5.4 0.5 / 1.2 2nd year (request) 8.4 0 2.5 10.9 1.0 / 2.5 4 years (approuved) 16.6 3.3 8.4 28.3 2.0 / 8.0 CEA-Saclay, 27-28 October, 2005
F. Negoita,
[email protected]
EURISOL+SAFERIB Meeting CEA-Saclay, 27-28 October 2005
High energy neutron 1 attenuation studies 1
1
-status of the work-
INTRODUCTION 1 1
1 1 1
Goal: to develop a calculation strategy for a M onte Carlo simulation of EURI SOL Facility radiation protection design; FLUKA M onte Carlo calculations focused on high energy neutron behavior: - energy dependence of neutron radiation fields i - resulting ambient dose equivalent distributions; Computer simulations use simple geometry, different wall thicknesses; Two homogeneous bulk-shielding materials: iron and concrete are investigated; A comparison between the result s of the FLUKA code to data from the current literature is provided.
EURISOL Meeting, CEA Saclay, 27-28 October 2005
Modelling approach (1) 1 • •
1 •
1 • •
Source neutron Monoenergetic (1 GeV ) neutron transmission Attenuation of secondary neutrons produced by: - high energy protons - 12C heavy ions on Cu target (HIMAC- benchmarck experiment)
Geometry Plane of 4m (iron) and 5 m (concrete) thick with normal incident parallel beams
Shielding Material Iron (Density 7.87 g/cm3) Concrete (Density 2.27 g/cm3) [Type 02-a, ANL-5800, 660(1963)]
EURISOL Meeting, CEA Saclay, 27-28 October 2005
Modelling approach (2) 1
• •
•
Calculated quantities Neutron spectrum whole energy range but thermal group (0.414eV) Dose equivalent due to the neutrons; - Above 20 MeV (M. Pelliccioni at al, RPD 88, pp. 279, (2000)), fluence to ambient dose conversion coefficients Attenuation lengths in iron and concrete obtained by MINUIT/PAW fitting subroutine
EURISOL Meeting, CEA Saclay, 27-28 October 2005
Monte Carlo simulations Parameter settings FLUKA– interaction and transport code 1
1
1
Physical models* -PEANUT event generator (hadron-nucleus interactions) -RQMD & DPMJET-II external event generator (nucleus-nucleus interaction) Transport cut-off energy set at 0.414eV or 19.6MeV for high energy account Low-energy neutron cross section library (72 groups) used below19.6MeV
Biasing - Russian rullete and splitting at boundary crossing based on region relative importance - Region-dependent weight window in three energy ranges
* Fasso, A, Ferrari, A, Ranft, J, Sala P.R. Status and Proscpective for Hadronic Applications, Proceeding of the Monte Carlo 2000 Conference, Lisbone October 2000, Springler -Verlag Berlin EURISOL Meeting, CEA Saclay, 27-28 October 2005
Deep penetration Characteristics 1GeV proton on Pb target model*
CONCRETE shield 5m concrete slab
1
high energy tail major component of the spectra;
1
the intermediate energy spectra are closed to 1/E distribution;
1
Energy spectra of neutrons at various concrete depths 1.0E+0 1.0E-1
in the low energy region concrete has a high shielding performance due to elastic scattering effect of hydrogen;
E* dF/dE (cm^-2 pr^-1)
•
1.0E-2 1.0E-3 1.0E-4 1.0E-5 1.0E-6
100cm 200cm
1.0E-7 1.0E-8
300cm 400cm 500cm
1.0E-9 1.0E-9
1.0E-7
1.0E-5
1.0E-3
Energy (GeV) *
Baseline parameters from Eurisol-DS #3 “100kW direct target station” EURISOL Meeting, CEA Saclay, 27-28 October 2005
1.0E-1
Deep penetration Characteristics 1GeV proton on Pb target model*
IRON shield •
Energy spectra of neutrons at various iron depths
4m iron slab
1.0E+0
300 cm
1 1
1
typical equilibrium spectra with a shape which is independent of the shield thickness; attenuation of the neutron spectrum with increasing shield thickness; major energy component shifts towards the low energy range due to elastic scattering and 24 keV iron resonance;
E*dF/dE (cm^-2 pr^-)1
1.0E-1
1
100 cm 200 cm
1.0E-2 1.0E-3 1.0E-4 1.0E-5 1.0E-6 1.0E-7 1.0E-8 1.0E-10
low energy neutron flux (E< hundreds of keV) attenuates slower than high energy tail being build-up from the inelastic scattering of high energy neutrons
1.0E-8
1.0E-6
1.0E-4
1.0E-2
Energy (GeV)
* Baseline parameters from Eurisol-DS #3 “100kW direct target station” EURISOL Meeting, CEA Saclay, 27-28 October 2005
1.0E+0
Deep penetration Characteristics 1GeV proton on Pb target model*
DOUBLED-LAYERED shield , case 1 1 1 1
(1m Iron + 4m Concrete) slab
Neutron energy spectra four a double- layered shield, case 1 1.0E+1
50cm 100 cm 200 cm 300 cm
high energy neutron tail is the major component in the outer layer of the shield; influence of concrete component in absorbing low energy neutron the shield performance for a source strength of 6.242E+14 p/s (corresponding to I=1001A) has to be improved
E * dF/dE (cm^-2 pr^-1)
•
1.0E+0
400 cm
1.0E-1
500cm
1.0E-2 1.0E-3 1.0E-4 1.0E-5 1.0E-6 1.0E-7 1.0E-8 1.0E-101.0E-9 1.0E-8 1.0E-7 1.0E-6 1.0E-5 1.0E-4 1.0E-3 1.0E-2 1.0E-1 1.0E+0
Energy (Gev)
* Baseline parameters from Eurisol-DS #3 “100kW direct target station” EURISOL Meeting, CEA Saclay, 27-28 October 2005
Deep penetration Characteristics 1GeV proton on Pb target model*
DOUBLED-LAYERED shield , case 2 Neutron energy spectra for a double-layer shield, case 2
1
neutron flux is dominated by the contribution of the low energy neutron in the outer iron layer;
1
The low energy flux is reduced quite effectively by the concrete layer;
1
shielding potential of this double layered shield w.r.t. case 1
Fluence (cm^-2 pr-1)
(4m Iron + 1m Concrete) slab
•
1.0E+0 1.0E-1 1.0E-2 1.0E-3 1.0E-4 1.0E-5 1.0E-6 1.0E-7 1.0E-8 1.0E-9 1.0E-10 1.0E-11 1.0E-12 1.0E-13 1.0E-10
100cm 200cm 300cm 400 cm 500 cm
1.0E-8
1.0E-6
1.0E-4
Energy (GeV)
* Baseline parameters from Eurisol-DS #3 “100kW direct target station”
EURISOL Meeting, CEA Saclay, 27-28 October 2005
1.0E-2
1.0E+0
HIMAC benchmarck SELF-TOF detector configuration experiment arrangement
EURISOL Meeting, CEA Saclay, 27-28 October 2005
HIMAC benchmarck SELF-TOF detector configuration geometry model
EURISOL Meeting, CEA Saclay, 27-28 October 2005
HIMAC benchmarck SELF-TOF detector configuration Iron shielding -Preliminary results (1) 2
Comparison of measured and calculated neutron fluences (n sr-1 ion-1) Thickness (cm) Experiment 20 2.3290E+00
2
FLUKA 1.2516E+00
C/E 0.54
40
6.0284E-01
4.0127E-01
0.67
60
1.6060E-01
1.3848E-01
0.86
Attenuation length of the neutron fluence for SELF-TOF detector (cm) Experiment 123.
FLUKA 117.4
C/E 0.95 EURISOL Meeting, CEA Saclay, 27-28 October 2005
HIMAC benchmarck SELF-TOF detector configuration Iron shielding -Preliminary results (2) Comparison of measured and calculated neutron energy spectra SELF-TOF Iron 20cm
SELF-TOF Iron 60cm
SELF-TOF Iron 40cm
1.0E+0
1.0E+0
1.0E-2
1.0E-3
1.0E-4
Fluence (n/MeVsr//ion)
1.0E-1
Fluence (n/MeV/sr/ion)
Fluence (n/cm^2/sr/ion)
1.0E-1
Experiment
1.0E-3
FLUKA Experiment
FLUKA
1.0E-2 1.0E-3 1.0E-4 1.0E-5 1.0E-6
FLUKA Experiment
1.0E-4
1.0E-5
1.0E-7 1.0E-5
1.0E-6
1.0E-8 1.0E+1
1.0E+2
1.0E+3
1.0E+1
Enegy (M ev)
1.0E+2
SELF-TOF Iron 80cm
SELF-TOF Iron 100cm FLUKA
Fluence (n/MeV/sr/ion)
Exp e rime n t
Fluence (n/MeV/sr/ion)
1.0E+2
1.0E-3 FL U KA
1.0E-4
1.0E-5
1.0E-6
Experiment
1.0E-4
1.0E-5
1.0E-6
1.0E-7
1.0E-7 1.0E+1
1.0E+1
Energy (MeV)
Energy(Mev)
1.0E-3
2
1.0E+3
1.0E+2
Energy (MeV)
1.0E+3
1.0E+1
1.0E+2
1.0E+3
Energy (MeV)
EURISOL Meeting, CEA Saclay, 27-28 October 2005
1.0E+3
HIMAC benchmarck SELF-TOF detector configuration Concrete shielding -Preliminary results (1) 2
Comparison of measured and calculated neutron fluences (n sr-1 ion-1)
Thickness (cm) Experiment
2
FLUKA
C/E
50
2.526
1.371
0.543
100
0.655
0.453
0.691
Attenuation length of the neutron fluence for SELF-TOF detector (cm) Experiment 86.9
FLUKA 78.2
C/E 0.90
EURISOL Meeting, CEA Saclay, 27-28 October 2005
HIMAC benchmarck SELF-TOF detector configuration Concrete shielding -Preliminary results (2) Comparison of measured and calculated neutron energy spectra SELF-TOF concrete 50cm 1.0E-1
FLUKA
FLUKA Experiment
1.0E-2
1.0E-3
1.0E-4
Experiment
Fluence (n/MeV/sr/ion)
Fluence (n/MeV/sr/ion)
SELF-TOF concrete 100cm 1.0E-2
1.0E-3
1.0E-4
1.0E-5
1.0E-6
1.0E-5
1.0E-2
1.0E-2
1.0E-1
1.0E+0
1.0E-1
1.0E+0
Energy (MeV)
Energy (MeV)
SELF-STO concrete 200cm
SELF-TOF concrete 150cm
FLUKA Experiment
1.0E-3
1.0E-03
Fluence (n/MeV/sr/ion)
Experiment
1.0E-04
1.0E-05
1.0E-06
1.0E-07 1.0E-02
Fluence (n/MeN/sr/ion)
FLUKA
1.0E-4
1.0E-5
1.0E-6
1.0E-7
1.0E-8 1.0E-01
Energy (MeV)
1.0E+00
1.0E-2
1.0E-1
1.0E+0
Energy (MeV)
EURISOL Meeting, CEA Saclay, 27-28 October 2005
HIMAC benchmarck Discussions 1
1
Neutron spectra on the detector surface were obtained by surface current; Real model of the 12C on Cu target neutron source has been done by using RQMD-DPMJET FLUKA external event generator;
1
A FLUKA source subroutine of experimental secondary neutrons distribution has been created for comparison purposes;
1
Presented results are preliminary. Statistic should be improved;
1
Comparison of simulation results are in generally good agreement with experimental data.
1
Other two configurations of the HIMAC test problem: Ne213 detectors and Bi & C activation detectors have been modeled and calculations are in progress. EURISOL Meeting, CEA Saclay, 27-28 October 2005
Conclusions 1
1 1 1 1
Applicability of FLUKA Monte Carlo simulation in the design of biological shield of the high intensity neutron sources has been investigated; Basic shielding studies focused on the layout of the target station shield have been performed; Specific variance technique have been improved as a major part in the development of a design strategy ; Works are in progress to test the developed method by comparison with experimental data. A generally good agreement has been obtain; Technique developed can be easily extended to design studies of other installation components: accelerator, beam dump, etc
EURISOL Meeting, CEA Saclay, 27-28 October 2005
