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 1. Name of Experiment:
    Balakovo-3 VVER-1000 Ex-vessel Neutron Dosimetry Benchmark

 2. Purpose and Phenomena Tested:
    The reliable determination of RPV neutron field parameters is needed for an
    evaluation of the radiation embrittlement of RPV steel. Calculational
    procedures used for the determination of neutron fluence, fluence rate and
    spectrum at critical points of Reactor Pressure Vessel (RPV) of Russian design
    water-water-power-reactor with electrical power 1000 MW (VVER-1000) are to be

    To solve this task, a neutron dosimetry experiment using activation and
    fissionable detectors was carried out at Russian NPP Balakovo, unit 3
    (Balakovo-3), during cycle 5, from March 1994 to January 1995. The detectors
    were installed in the ex-vessel cavity near the outer RPV surface.

    The purpose was to: (1) evaluate the reliability of ex-vessel dosimetry
    measurement techniques, (2) provide data for a 3D full scale validation of
    neutron transport calculations, (3) develop the regulatory guides for a RPV
    ex-vessel neutron dosimetry procedure.

    The area of neutron transport investigation extends from the reactor core
    center to the biological shield, from the core bottom to the top, and includes
    60-degree azimuthal sector (Fig. 1).

 3. Description of Source and Experimental Configuration:
    The details are available in ref. [1].

    The activation detectors were situated in aluminum capsules which were attached
    to the experimental rack. This experimental rack had azimuthal and axial rods
    which were situated in the cavity near the outer surface of the pressure vessel
    on the same reactor radius 228 cm from the center. Detail information includes
    capsules coordinates, construction and material data, and also the arrangement
    of the detector sets in the capsules.

    The reactor configuration includes:
    - the design description of the VVER-1000 reactor,
    - the azimuthal-radial geometrical approximation of the reactor (r-theta model),
    - axial-radial geometrical approximation of the reactor (r-z model),
    - material compositions of the modeled zones and temperatures of the water
    - nuclear concentrations of the zones.

    The neutron source is a 3D power reactor core with fuel assemblies of hexagonal
    form and with the same form arrangement of the fuel pins. The fuel is fresh and
    burnup uranium dioxide. The 5th fuel cycle was arranged with fresh fuel on the
    core periphery which had the initial 235U enrichment of 4.4 %. The irradiation
    period was 170.1 Effective Full Power Days (EFPD). The detail fission source
    description includes:
    - reactor operating data during the detector irradiation time (total power
      history, 2D assemblies power distributions, coolant temperature variations),
    - time-dependent neutron-physical parameters of the core:
          - 2D and 3D assemblies power distributions
          - 2D and 3D assemblies burnup distributions
          - 3D pin-to-pin power distributions of the peripheral assemblies
          - 3D pin-to-pin burnup distributions of the peripheral assemblies
          - heavy metal concentration in assemblies
          - burnup-dependence of neutron emission.

    To estimate the composition of the fuel as a function of burnup (e.g. using MCNP 
    and Monteburns) the following information can be usefull in addition to the one 
    provided in ref. [1]:
    - Balakovo-3 cooling water with boron acid H3BO3:
          EFPD = 0:      Concentration H3BO3   5.2 g/kg H2O
          EFPD = 170.1:  Concentration H3BO3   2.7 g/kg H2O
    - Average fuel temperature per VVER-1000 Full Power is 830 C degrees.

 4. Experimental data and Uncertainties:
    As experimental data to be compared with calculations were chosen the
    End-Of-Irradiation Activities (EOIAs). The analysis of data measured by the
    participants of Balakovo-3 experiment resulted in reference absolute EOIAs sets
    for capsule positions at 9.4°, 32°, 37°, 47° and 55.8° azimuth angles. The
    following dosimetry reactions were analyzed: 237Np(n,f)137Cs, 238U(n,f)137Cs,
    93Nb(n,n')93mNb, 58Ni(n,p)58Co, 54Fe(n,p)54Mn, 46Ti(n,p)46Sc, 63Cu(n,alpha)60Co,

    The experimental results include also set of evaluated Reaction Rates (RR) and
    very detailed ex-vessel azimuthal and axial distributions of the 54Fe(n,p)
    reaction rates.

    The following centers took part in measurements by their own activation
    detectors, and results of which were used in the intercomparison:
    - SEC NRS of GOSATOMNADZOR of Russia, Moscow, Russia,
    - Research Institute of Atomic Reactors (RIAR), Dimitrovgrad, Russia,
    - Moscow Institute of Engineering Physics (MIFI, Moscow) in cooperation with
      Institute of Physics Technical and Radio Technical Measurements (VNIIFTRY,
      Mendeleevo), Russia,
    - Russian Research Center "Kurchatov Institute" (KI), Moscow, Russia,
    - Forschungszentrum Rossendorf e.V. (FZR), Dresden, Germany,
    - The NRG, formed the Netherlands Energy Research Foundation (ECN), Petten,
      The Netherlands,
    - SKODA, Nuclear Machinary, Plzen, Czech Republic.

    Niobium-93 measurement data were resulted from "robin round" intercomparison,
    in which the same niobium foils were analyzed.
    Additional centers took part in this stage of intercomparison:
    - SIEMENS AG KWU, Erlangen, Germany,
    - VTT Chemical Technology, Espoo, Finland,
    - Institute for Nuclear Research and Nuclear Energy (INRNE), Sofia, Bulgaria,
    - SCK(CEN Fuel Research, Mol, Belgium.

    The detector activities were measured in participant own laboratories by using
    their own measurement techniques. The results intercomparison procedure was a
    "blind test" one. The uncertainty of reference results reflects as the
    statistical discrepancy of results of different participants (in case of
    representative statistic) and an evaluated uncertainty of participant data (in
    case of two values in the intercomparison).

 5. Comparison of Measurements and Calculations:
    The measured data are accompanied with neutron transport calculated results.
    The reference measured EOIAs (E) were compared with calculated results (C).
    The comparison of E with C resulted from DORT code (Sn method) coupled with
    BUGLE-96 library and TRAMO code (Monte Carlo method) with library based on
    ENDF/B-VI data are demonstrated by table 1.

       Table 1 - Average C/E for Balakovo-3 benchmark

         Reaction         DORT&BUGLE-96      TRAMO&ENDF/B-VI
         237Np(n,f)         0.951               0.918
         93Nb(n,n')         0.982               0.937
         238U(n,f)          0.986               0.936
         58Ni(n,p)          1.069               1.014
         54Fe(n,p)          1.097               1.043
         46Ti(n,p)          0.974               0.961
         63Cu(n,a)          0.998               1.010

 6. Special Features:
    1. Experimental reference data obtained by interlaboratory ex-vessel dosimetry
    2. Detailed reactor and neutron source description
    3. Interlaboratory neutron transport calculations by Sn and Monte Carlo methods 
       and intercomparison of results
    4. Comparison between calculated and experimental reference data

 7. Author/Organizer:
    Organization of the Ex-Vessel Balakovo-3 Exercise:
    Scientific and Engineering Center for Nuclear and Radiation Safety (SEC NRS)
    of Russian GOSATOMNADZOR, 14/23 Avtozavodskaya ul., 109280 Moscow, Russia;

    Forschungszentrum Rossendorf e.V. (FZR), Postfach 510119, 01314 Dresden, Germany.

    Compiler of data for Sinbad:
    G.I. Borodkin (SEC NRS), B. Böhmer and K. Noack (FZR)
    e-mail: borodkin@ntc.asvt.ru

    Reviewer of compiled data:
    I. Kodeli
    OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
    e-mail: ivo.kodeli@oecd.org

 8. Availability:

 9. References:
    [1] G. Borodkin, B. Boehmer, K. Noack, N. Khrennikov,
        Balakovo-3 VVER-1000 Ex-vessel Neutron Dosimetry Benchmark Experiment,
        report for SINBAD project, FZR/SEC NRS, 2002
    [2] G.I. Borodkin and O.M. Kovalevich, Interlaboratory VVER-1000 Ex-vessel
        Experiment at Balakovo-3 NPP, Report on the 9th International Symposium on
        Reactor Dosimetry, 2 - 6 Sep. 1996, Prague, Czech Republic, Report E-147,
    [3] International Workshop on the Balakovo-3 Interlaboratory Dosimetry
        Experiment, September 2 - 5, 1997, FZR, Rossendorf, Dresden, Germany.
        Minutes on the Workshop.
    [4] Borodkin, G. I., Kovalevich, O. M., Barz, H.-U., Böhmer, B., Stephan, I.,
        Ait Abderrahim, H., Voorbraak, W., Hogel, J., Polke, E., Schweighofer, W.,
        Seren, T., Borodin, A. V., Vikhrov, V. I., Lichadeev, V. V.,
        Markina, N. V., Grigoriev, E. I., Troshin, V. S., Penev I., and Kinova, L.
        Balakovo-3 Ex-vessel Exercise: Intercomparison of Results, Reactor
        Dosimetry: Radiation Metrology and Assessment, ASTM STP 1398,
        John G. Williams, David W. Vehar, Frank H. Ruddy and David M. Gilliam,
        Eds., American Society for Testing and Materials, West Conshohoken, PA,
        2001, pp. 320-327.
    [5] G. Borodkin and B. Boehmer, Validation of 3D Synthesis RPV Neutron Fluence
        Calculations using VVER-1000 Ex-Vessel Reference Dosimetry Results,
        2000 ANS Annual Meeting, June 4-8, 2000, San Diego, California, Transactions
        of the ANS, volume 82, 2000, pp. 223-225.
    [6] B. Boehmer, J. Konheiser, G. Borodkin and G. Manturov, Testing of Neutron
        Data Libraries in Application to Reactor Pressure Vessel Dosimetry, Internat.
        Conference on Nuclear Data for Science and Technology, Oct. 7-12, 2001,
        Tsukuba, Ibaraki, Japan.
    [7] GOSATOMNADZOR of Russia. Safety Guides. Procedure of Neutron Dosimetry on
        the Ex-Vessel Surface of VVER of NPP (RB-018-01). (Draft), G.I. Borodkin
        et al., November 2001.

10. Data and Format:

  FILE     NAME      bytes   Content
  ---- -----------  ------   -------
   1  balak3-a.htm   16,695 This information file 
   2  balakovo.pdf  627,029 Reference 1 with the description of Experiment 
   3  gip-b3.inp      3,109 Input data for GIP cross-section mixing code
   4  dort-b3.inp    90,096 Input data for DORT transport code
   5  fig1.gif       10,750 Fig. 1: VVER-1000 60-degrees sector with dosimetry
                            positions for Balakovo-3
   6  fig2.gif       23,994 Fig. 2: VVER-1000 radial-axial model used for Balakovo-3
   7  fig3.gif        8,611 Fig. 3: 30-degree scheme of VVER-1000 baffle
   8  fig4.gif       21,514 Fig. 4: Arrangement and description of VVER-1000 fuel assemblies 
   9  fig5.gif        7,887 Fig. 5: Numeration of pin positions in VVER-1000 fuel assembly
  10  fig6.gif        4,056 Fig. 6: Scheme of capsule in which dosimeters were irradiated
  11  figA1.gif      10,260 Fig. A.1: TRAMO input spectra and adjusted spectra
                            (single spectrum adjustment – SSA, multi spectrum adjustment
                             – MSA) for two detector positions.
  12  figB2.gif       8,219 Fig. B.2: Absolute calculated neutron spectra at 55.8° 
                            ex-vessel position.
  13  table 1.1.xls  15,360 Table 1.1: NPP and core design parameters
  14  table 1.2.xls  16,384 Table 1.2: Fuel assembly description
  15  table 1.3.xls  14,848 Table 1.3: Dosimetry irradiation description
  16  table 1.4.xls  16,896 Table 1.4: Material (zone) numbers and compositions 
  17  table 1.5.xls  14,336 Table 1.5: Densities and chemical compositions
  18  table 1.6.xls  14,336 Table 1.6: VVER-1000 baffle channels 
  19  table 1.7.xls  17,408 Table 1.7: Total power history during detector irradiation
  20  table 1.8.xls  16,384 Table 1.8: Nuclear concentration of zones
  21  table 1.9.xls  15,360 Table 1.9: Reference Measured absolute End-Of-Irradiation Activities
  22  table 1.10.xls 14,848 Table 1.10: Measured absolute End-Of-Irradiation Activities (EOIA)
  23  table 1.11.xls 13,824 Table 1.11: Evaluated photofission effects 
  24  table 2.1.xls  14,336 Table 2.1: Average Relative Standard Deviations for Reference EOIA
  25  table 2.2.xls  18,432 Table 2.2: Ratios of calculated-to-measured fuel assembly powers 
  26  table 2.3.xls  14,336 Table 2.3: Correction factors to account for local power history
  27  table A.1.xls  13,824 Table A.1: Calculation Positions
  28  table A.2.xls  14,848 Table A.2: Relative Standard Deviations (RSD) for different
                            spatial points
  29  table A.3.xls  14,848 Table A.3: Auto Correlation Matrix and RSD for Point 6 
                            (PVC, theta=9.4)
  30  table A.4.xls  14,848 Table A.4: Cross Correlation Matrix for 1/4 RPV thickness position
                            and a cavity position
  31  table A.5.xls  16,896 Table A.5: Fluence and dpa values before and after adjustment
  32  table A.6.xls  14,848 Table A.6: Relations between MSA and SSA results for fluence integrals
  33  table B.1.xls  14,336 Table B.1: Comparison of calculated fluence rates at 55.8° position.
  34  table B.2.xls  14,336 Table B.2: C/E data for 3D synthesis DORT using different libraries.
  35  table B.3.xls  14,848 Table B.3: C/E data for 3D synthesis DORT/BUGLE-96t with 
                            different dosimetry files.
  36  table B.4.xls  16,384 Table B.4: Absolute evaluated experimental reaction rates and 
                            C/E ratios. 
  37  table B.5.xls  14,848 Table B.5: C/E results for different calculations.
  38  table B.6.xls  14,848 Table B.6: C/E for Cd covered (n,gamma)-detectors (3D synthesis).
  39  table B.7.xls  14,336 Table B.7: C/E for bare (n,gamma)-detectors (3D synthesis calculations).
  40  FILE_1.DAT      1,782 Assembly burnup per effective full power days (EFPD)
  41  File_2.dat      2,354 Emitted neutrons per EFPD interval
  42  File_3.dat     16,960 Axial burnup distribution per EFPD
  43  File_4.dat     17,154 Relative axial neutron source distributions per EFPD interval
  44  File_5.dat    221,170 Pin numbers in assembly
  45  File_6.dat    177,872 Pin numbers in assembly
  46  File_7.dat      2,597 Total power history during detectors irradiation

SINBAD Benchmark Generation Date: 6/2003
SINBAD Benchmark Last Update: 6/2003