SINBAD ABSTRACT NEA-1517/78
NAÏADE 1 Iron Benchmark (60cm)
1. Name of Experiment:
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Fontenay aux Roses 60cm NAÏADE 1 Iron Benchmark
2. Purpose and Phenomena Tested:
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Determination of the fission neutron transport in iron for penetration
up to about 80 cm depending on the dosimeter energy range.
3. Description of the Source and Experimental Configuration:
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The source is a fission plate irradiated by a beam of purely thermal
neutrons coming from the graphite reflector of the ZOE heavy water reactor
located in France at Fontenay aux Roses. The plate is 1 square meter and
the thickness of the fissile part is 2 cm. It consists of 9 square tiles
0.333 m along the side, made of natural uranium claded with 1 mm of aluminum.
Behind the fission plate, which generates fission neutrons, there is a
large experimental area (27 cubic meter) in which the iron block is placed.
A boral screen separated the fission plate from the experimental area to
avoid thermal neutron backscattering. The iron block thickness was 150 cm
and its section was 2.00m x 2.00m surrounded by a neutron shield (wood and
concrete).
The absolute fission neutron source distribution is determined by Monte
Carlo calculation (TRIPOLI 4) using the thermal neutron flux measurements
(Mn-55) for the source term. This determination take into account all
fissions (U-235 and U-238) provided by the neutron diffusions in the converter
itself, in structures and in the mock-up (sub critical system with a source
of thermal neutrons). In this experiment, the diaphragm diameter was 60 cm.
In the iron block a central hole of diameter 3cm can be stopped up with steel
plugs of various thicknesses; the irradiated dosimeters are positioned
between the plugs.
4. Measurement System and Uncertainties:
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The following detectors were used:
1. P-31(n,p) thickness 3mm
2. WIGNER Si based upon damage formation in a silicon diode 5 mm in diameter
and 0.25 mm in thickness
3. Rh-103(n,n’) thickness 0.2mm
4. Np237 fission chamber
5. Bare Mn-55 and Mn-55 clad in Cadmium
6. In-115(n,gamma) clad in Cadmium with a deposit of 0.1 mg/cm2
7. Au-197(n,gamma) clad in Cadmium with a deposit of 0.1 mg/cm2
8. Fission chambers (U-235 and Pu-239)
All dosimeters were calibrated in well known fluxes depending on their
characteristics: Maxwellian thermal flux at 27°C in a reference block, fission
spectrum with correction tacking into account the diffusion effects altering
slightly the pure fission spectrum, constant flux per unit of lethargy.
The iron specific gravity was 7.85 ± 0.02 g/cm3. The precision of the fission
plate power varies between 1% when the measurements are made close together in
time (a few days) and 5% when the measurements are separated by several months.
During the dosimeter irradiation, the observed stability is (delta P)/P = 0.5%.
The dosimeter position uncertainty estimated by the experimental team itself
is ±0.1cm.
Note of the data compiler:
If we analyze the total dispersion of the conventional fluxes measured at the
same points during successive irradiations, we obtain the following values:
- Fast flux dosimeters ±8%
- Epithermal flux dosimeters ±11%
5. Description of Results and Analysis:
-----------------------------------
All results are expressed in conventional fluxes. (Equivalent fission flux,
flux per unit of lethargy, equivalent thermal flux at 2200 m/s). The
corresponding mean cross section or integral of resonance are given. The
measured experimental results are given on the converter axis for several
distances. A calibrated dosimeter reassessment resulting from the nuclear data
improvements was made recently (2003-2004) and published.
The interpretation using the French CEA Monte-Carlo code TRIPOLI 4 was made on
this iron benchmark. A background noise evaluation was also determined using
at the same time TRIPOLI 4 calculations and fast and epithermal neutron flux
measurements without converter plate. The two corresponding input data sets
are included.
6. Special Features:
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None
7. Author/Organizer
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Experiment and Analysis:
M. Lott, P. Pepin, L. Bourdet, G. Cabaret, J. Capsie, M. Dubor, M. Hot,
C Goulet;
CEA (French Atomic Energy Commission), DPA/DEP/SEPP,
92260 Fontenay aux Roses
France
Compiler of data for SINBAD and experiment interpretation using TRIPOLI 4:
J.C. Nimal
CEA Centre de Saclay DEN/DM2S/SERMA/LEPP,
91191 Gif sur Yvette Cedex ; France
Reviewer of compiled data:
I. Kodeli
OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
8. Availability:
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Unrestricted
9. References:
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[1] M. Lott, P. Pepin, L. Bourdet, G. Cabaret, J. Capsie, M. Dubor, M. Hot,
C. Goulet: Etude expérimentale de l’atténuation des neutrons dans
différents matériaux de protection à l’aide du dispositif NAÏADE I du
réacteur ZOE, Note CEA 1386, Dec. 1970
[2] J. Brisbois, M. Lott, G. Manent:
Mesure des flux de neutrons thermiques intermédiaires et rapides au moyen
de détecteurs par activation, Rapport CEA R 2491 August 1964.
[3] J.P. Both, Y.K. Lee, A. Mazzolo, O. Petit, Y. Peneliau, B. Roesslinger,
M. Soldevila: TRIPOLI-4 – A Three Dimensional Polykinetic Particle
Transport Monte Carlo Code, SNA’2003, Paris, September 2003.
[4] J.P. Both, A. Mazzolo, Y. Peneliau, O. Petit, B. Roesslinger:
Notice d’utilisation du code TRIPOLI-4.3 : code de transport de particules
par la methode de Monte Carlo, rapport CEA-R-6043, 2003.
[5] J.P. Both, A. Mazzolo, Y. Peneliau, O. Petit, B. Roesslinger:
User manual for version 4.3 of the TRIPOLI-4 Monte Carlo method particle
transport computer code, rapport CEA-R-6044, 2003.
[6] J.C. Nimal: Nouvelles interprétations des expériences NAÏADE 1, 1ere
Partie : Expériences sur le fer et le graphite, rapport NEA/NSC/DOC(2005)15,
JT00194885, 25-Nov-2005.
[7] J.C. Nimal: New interpretation of the NAÏADE 1 experiments, Part 1: the
Iron and Graphite Experiments,
Report NEA/NSC/DOC(2005)15, JT00194842, 24-Nov-2005.
[8] J.C. Nimal: New interpretation of NAIADE benchmarks,
Proc. ANS 14th Biennial Topical Meeting of the Radiation Protection and
Shielding Division, Carlsbad, New Mexico, USA. April 3-6, 2006
10. Data and Format:
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DETAILED FILE DESCRIPTIONS
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Filename Size[bytes] Content
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1 naiade-fe.htm 8.624 This information file
2 NSCDOC_2005_15 EN.pdf 2.170.594 Description of Experiment, Ref. [7]
3 NSCDOC_2005_15 FR.pdf 1.084.441 Description of Experiment, Ref. [6] (in French)
4 RPSD2006-JCN.pdf 578.237 Ref. [8]
5 naiadefer_60_fission.data 57.072 TRIPOLI 4 input (direct flux)
6 bruitdefond_fer_60_fission.data 58.679 TRIPOLI 4 input (background scattering)
SINBAD Benchmark Generation Date: 12/2006
SINBAD Benchmark Last Update: 12/2006
