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SINBAD ABSTRACT NEA-1517/100

ASPIS Neutron/Gamma-Ray Transport Through Water/Steel Arrays




 1. Name of Experiment:
    ------------------
    ASPIS Neutron/Gamma-Ray Transport Through Water/Steel Arrays (~1987)


 2. Purpose and Phenomena Tested:
    ----------------------------
    Both neutron activation and gamma-ray dose-rate were measured in the
    experimental configuration comprising the shield of iron and water and
    the neutron source generated in a U-235 fission plate.

    The experiment was performed in the ASPIS facility of the NESTOR reactor
    at AEE Winfrith.


 3. Description of the Source and Experimental Configuration:
    --------------------------------------------------------
    The source is a fission plate constructed of 93% enriched uranium aluminium
    alloy driven by a thermal flux from the extended graphite reflector of the
    NESTOR reactor. The effective radius of the fission plate is 56.1 cm and the
    thickness 2 mm. The energy spectrum of the source is that of neutrons
    emitted from the fission of U-235. The absolute source strength is determined
    by fission product counting and the spatial distribution via detailed low
    energy flux mapping with activation detectors.

    The fission plate is followed by the experimental configuration comprising
    several layers of mild steel and two about 20 cm thick water filled
    containers made of stainless steel (see Figure 5). The array has a biological
    shield of concrete behind this.


 4. Measurement System and Uncertainties:
    ------------------------------------
    Responses of several neutron detectors and of the gamma-ray dose-rate
    have been measured, detectors being positioned on the horizontal
    centre-line of the configuration.

    The activation detectors used were Rh103(n,n'), S32(n,p) and Mn55(n,gamma)
    (bare and under Cd).

    Gamma-ray measurements were made using the Thermoluminescence Detectors (TLD)
    LiF and BeO. Ionisation chamber type IG8 C/150/CO2. The calibration
    uncertainty is 3%.

    Statistical and systematic uncertainties are provided with the measurements.


 5. Description of Results and Analysis:
    -----------------------------------

    Measurements of the reaction rates for S32(n,p)P32, Rh103(n,n')Rh103m,
    and Mn55(n,g)Mn56 bare and Under Cd were made in the gaps between the steel
    layers at intervals of approximately 5 cm and at different distances in the
    two water tanks. Vertical scans were made with Mn and TDLs at selected
    positions.

    The gamma expositions were corrected for the background responses due to the
    NESTOR core. The background varied from as much as ~35% close to the fission
    plate to ~1% at deep penetrations. The background corrections for neutron
    detectors, not included here, are discussed in compilations NESDIP-3, JANUS I.
    For the neutron threshold detectors the corrections are small, typically 1%
    to 3%.

    The activation detector results are given in units of Bq/atom per NESTOR
    Watt, and the TLD and ionisation chamber results in Roentgen/10kW/Hour.

    Calculations were carried out with the Monte Carlo code McBEND [2].

    More recently the MCNP5 models were prepared [11] in the scope of the
    quality review process and are also included in this compilation.


 6. Quality Assessment:
    ------------------
    The Water/Steel experiment is ranked as an experiment of BENCHMARK QUALITY.
    The major drawbacks in the lack of detailed experimental information of:
    - the detectors arrangement
    - bowing of the water tanks
    - background subtraction
    - cave walls

 7. Author/Organizer
    ----------------
    Experiment and analysis:
    A. F. Avery, J. Butler, I. J. Curl, C. J. Hoare, P. C. Miller, A. Packwood, C. Pike
    AEA Technology
    WINFRITH, Dorchester
    Dorset DT2 8DH
    UK

    Compiler of data for Sinbad:
    I. Kodeli
    Institute Jozef Stefan, Ljubljana, Slovenia (ivan.kodeli at ijs.si)
    & UKAEA/CCFE Culham, UK (ivan.kodeli at ukaea.uk)

    Reviewer of compiled data:
    S. Kitsos
    OECD/NEA, 2 rue Andre Pascal, 75775 Paris Cedex 16, France
    stavros.kitsos at free.fr

    Quality assessment:
    A. Milocco, 
    Universita' di Milano-Bicocca, piazza della Scienza 3, Milano, Italy

 8. Availability:
    ------------

    Unrestricted

 9. References:
    ----------
    [1] A. F. Avery, J. Butler, I. J. Curl, C. J. Hoare, P. C. Miller, A. Packwood,
        C. Pike, "A Benchmark Experiment to Validate Coupled Neutron/Gamma Ray
        Transport Methods for Water/Steel Arrays", RP&SG/IJC/P(87)52 (1987)
    [2] S. J. Chucas, A. F. Avery, I. J. Curl, C. J. Hoare,
        "The Implementation and Validation of a New n-g Coupled Capability in the
        Monte Carlo Code MCBEND"
    [3] A. Milocco, B. Zefran, I. Kodeli. Validation of nuclear data based on the ASPIS
        experiments from the SINBAD database. V: Proc. R5:43 PM 27-May-20PSD-2018, 20th Topical meeting
        of the radiation protection and shielding division, 26-31 August 2018, Santa Fe.,
        American Nuclear Society. 2018.
    [4] A. Milocco, Quality Assessment of SINBAD Evaluated Experiments ASPIS Iron
        (NEA-1517/34), ASPIS Iron-88 (NEA-1517/35), ASPIS Graphite (NEA-1517/36),
        ASPIS Water (NEA-1517/37), ASPIS N/G Water/Steel (NEA-1517/49), ASPIS PCA
        Replica (NEA-1517/75), Dec. 2015.

10. Data and Format:
    ---------------

    DETAILED FILE DESCRIPTIONS
    --------------------------
        Filename     Size (bytes)   Content
    ---------------- ----------- -------------
  1 asp-ng-a.htm          8.644    This information file
  2 asp-ng-e.htm         35.953    Description of experiment
  3 fig1.tif            135.496    Figure 1: The ASPIS mobile shield tank in the NESTOR cave C (high quality)
  4 fig2.tif             65.999    Figure 2: Schematic side elevation of the experimental shield (high quality)
  5 fig3.tif            120.806    Figure 3: Fuel loading pattern viewed looking towards NESTOR cave (high quality)
  6 fig4.tif             47.633    Figure 4: Mesh boundaries for the fission plate source (high quality)
  7 fig5.tif             89.943    Figure 5: Measurement locations (high quality)
  8 fig6.tif            144.195    Figure 6: 55Mn(n,g)56Mn axial scan (high quality)
  9 fig7.tif            137.690    Figure 7: 103Rh(n,n')103mRh and 32S(n,p)32P axial scans (high quality)
 10 fig8.tif             58.439    Figure 8: LiF Vertical scans (high quality)
 11 fig9.tif            136.476    Figure 9: Gamma-ray exposure measurements (high quality)
 12 fig1.gif             19.324    Figure 1: The ASPIS mobile shield tank in the NESTOR cave C (preview)
 13 fig2.gif             13.592    Figure 2: Schematic side elevation of the experimental shield (preview)
 14 fig3.gif             15.784    Figure 3: Fuel loading pattern viewed looking towards NESTOR cave (preview)
 15 fig4.gif             12.697    Figure 4: Mesh boundaries for the fission plate source (preview)
 16 fig5.gif             11.949    Figure 5: Measurement locations (preview)
 17 fig6.gif             25.178    Figure 6: 55Mn(n,g)56Mn axial scan (preview)
 18 fig7.gif             23.139    Figure 7: 103Rh(n,n')103mRh and 32S(n,p)32P axial scans (preview)
 19 fig8.gif              9.047    Figure 8: LiF Vertical scans (preview)
 20 fig9.gif             22.345    Figure 9: Gamma-ray exposure measurements (preview)
 21 asp-ng1.pdf       1.724.323    Reference
 22 asp-ng2.pdf         716.870    Reference
 23 rpsd18.pdf        4.323.119    Reference
 24 QualityAssess.pdf 6.851.768    Document on quality assessment of ASPIS experiments
 25 rh49.i                7.597    MCNPX(5) input model with Rhodium detector 
 26 s49.i                 7.597    MCNPX(5) input model with Sulphur detector 
 27 mn49.i                7.609    MCNPX(5) input model with Manganese detector 

    File asp-ng-e.htm contains the following tables:
   Table 1: Axial dimensions
   Table 2: Material specifications
   Tables 3&4: Neutron source distribution
   Tables 5-7: Activation detector measurements
   Tables 8-13: TLD Measurements
   Tables 14&15: Ionisation chamber Measurements

   Figures are included in TIFF format using LZW compression and GIF format (preview).

SINBAD Benchmark Generation Date: 09/2001
SINBAD Benchmark Last Update: 05/2017