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NAÏADE 1 Iron Benchmark (60cm)

 1. Name of Experiment: 
    Fontenay aux Roses 60cm NAÏADE 1 Iron Benchmark

 2. Purpose and Phenomena Tested: 
    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: 
    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
    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: 
    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: 

 7. Author/Organizer 
    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

    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: 

 9. References: 
    [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: 

        Filename    Size[bytes] Content 
    --------------- ----------- ------------- 
 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