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Ispra Sodium Benchmark Experiment (EURACOS)

1. Name of Experiment:
 Ispra Sodium Benchmark Experiment (EURACOS) (~1986)

2. Purpose and Phenomena Tested:
 Study of the neutron deep penetration in homogeneous materials commonly used
 in the construction of advanced reactors: Na (and Fe). Flux and spectra were
 measured up to 360 cm in Na.

3. Description of the Source and Experimental Configuration:
 The neutron source in a converter disc made of 6 trapezoidal U-Al alloy
 plates forming an almost circular source with a diameter of 80 cm. The space
 dependence of the source can be approximated by a cosinusoidal radial
 profile. The spectrum is very similar to the U235 fission spectrum.
 The converter is situated at the end of the thermal column of a TRIGA MARK II
 reactor (University of Pavia) in front of the irradiation chamber which is
 surrounded by borated concrete walls of two different compositions.
 The first part extending from 35 cm to 162.4 cm from the converter mid-plane
 (see Fig. 1) consists of ordinary concrete with a density of 2.3 g/cm3. The
 second part of the tunnel shield is made of heavy concrete with a density of
 3.6 g/cm3. Its composition is listed in Table 3.
 The Na mock-up was made of 7 Fe containers filled with liquid Na, having a
 useful length of 382 cm. A Boral plate was placed between the source and the
 Na block to reduce the low energy flux originating in the thermal column.
 Use of large sulphur detectors, and low background measurements during a
 counting period of 5-6 half lives, made it possible to measure attenuation
 up to 7 decades of fast neutrons.

4. Measurement System and Uncertainties:
 The detectors used were:

 Detector                       Diameter   Thickness   Error
                                 (cm)        (cm)      (%) ---------------------------------------------------------------- S-32(n,p)P-32/under Cd          2 - 7     0.2 - 10   5.6 - 15.5 Au-197(n,gamma)Au-198/under Cd   1.0        0.01      5 - 8 H proportional counters          4.04 (spherical) ---------------------------------------------------------------- The gold foil consists of an Au/Al alloy with 0.1 wt% gold content. The thickness of the Cd-coating is 1 mm (S-32 and Au-197). The energy resolution of the proton recoil spectrometers is between 5 and 15%. 5. Description of Results and Analysis: ----------------------------------- Measurements with activation detectors were carried out at distances 18.35, 66.4, 125.2,184.5, 243.2, 302.4, 362.2 cm for S-32(n,p) and Au-197(n,gamma). The radial profiles were measured with Ni-58(n,p) at 62 cm depth in Na, and with Au-197(n,gamma) at 95.4, 121 and 213.5 cm in Na. Energy range between 100 and 650 keV was covered with hydrogen proportional counters. The spectra were unfolded by the SPEC4 code [9], and normalized with the BF3 monitor. The neutron spectra are given at 6 positions in Na (18.35, 66.4, 125.2, 184.5, 243.2, 302.4 cm). As the authors are not completely confident that the unfolding was performed according to state-of-the-art procedures, the original distributions of the impulses measured by spectrometers and the detector geometry are included as well for those who wish to carry out their own unfolding. MCNP calculations performed using various flux estimators are described in [6]. An input file for the MCNP-3 code is available in mcnp3-na.inp. See the EURACOS Iron benchmark compilation eufe-abs.htm for hints on how to prepare an input for MCNP-4c from the MCNP-3 file. 6. Special Features: ---------------- None 7. Author/Organizer ---------------- Experiment and analysis: R. Nicks, G. Perlini, H. Rief, Joint Research Centre, Ispra, 21020 Ispra (Varese), Italy Compiler of data for Sinbad: I. Kodeli OCDE/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France Reviewer of compiled data: H. Rief Joint Research Centre, Ispra, 21020 Ispra, Italy 8. Availability: ------------ Unrestricted 9. References: ---------- [1] Nicks R., Perlini G. and Rief H., Project and performances of the EURACOS II irradiation facility. Technical Note No., JRC Ispra. (1985) [2] Nicks R., Perlini G., Rief H., Fission neutron penetration in iron and sodium-I. Activation measurements. Ann. Nucl. Energy 15, p.457 (1988) [3] Perlini G., Rief H., Fission neutron penetration in iron and sodium-II. Neutron spectrometry. Ann. Nucl. Energy 16, p.189 (1988) [4] R. Nicks et al., "Iron and sodium benchmark experiments at EURACOS II- Part I: Activation measurements", NEACRP Specialists' Meeting on Shielding Benchmark, Paris, October 13-14, 1986. [5] G. Perlini, H. Rief, M.D. Carter, N.F. Murphy, The S32(n,p)P32 threshold detector and its application for fast neutron dosimetry (fast reactors and fusion reactors), Reactor Dosimetry, ECSC, ECC and EAEC, Brussels and Luxembourg, p.457 (1985). [6] H. Rief, Shamsi T. A., Aglietti-Zanon M. and Vittone E., EURACOS 10. Team EN.102/017 (1987). [7] R. Garofoli, G. Gonano, G. Perlini, H. Rief, Fast neutron attenuation in large iron and sodium columns, 9th European Triga Conference, C.R.E., Casaccia, Roma, (1986). [8] G. Perlini and S. Acerbis, Neutron spectrometry measurements in sodium. Report EUR 11095 EN, Ispra. (1987) [9] P.W. Benjamin, The analysis of recoil proton spectra, AWRE 09/68, Aldermaston, Berks (1968). [10] G. Perlini, S. Acerbis, U. Canali, G. Gonano, R. Nicks, H. Rief, Construction of a neutron deep penetration sodium shield mockup, European Appl. Res. Rept.- Nucl. Sci. Technol., Vol. 7, No.6 (1987). 10. Data and Format: --------------- DETAILED FILE DESCRIPTIONS -------------------------- Filename Size[bytes] Content ---------------- ----------- ------------- 1 euna-abs.htm 11.125 This information file 2 euna-exp.htm 19.313 Description of Experiment 3 EURNA.TB1 28.484 Tables of Neutron Spectra 4 EURNA.TB2 50.812 Tables of Measured Impulses 5 mcnp3-na.inp 16.090 Input Data for MCNP Version 3 Code 6 EURNA-1V.TIF 26.832 Figure 1: Cross-section of the EURACOS2 facility (high quality) 7 EURNA-2V.TIF 79.002 Figure 2: Schematics of the experimental configuration (high quality) 8 EURNA-3V.TIF 13.118 Figure 3: U235 neutron converter (high quality) 9 EURNA-4V.TIF 15.970 Figure 4: Activation detector support (high quality) 10 EURNA-5V.TIF 9.680 Figure 5: Positioning of gas spectrometer (high quality) 11 EURNA-6V.TIF 18.702 Figure 6: Cross-section of the sodium containers with detectors (high quality) 12 EURNA-7V.TIF 17.934 Figure 7: Sulphur detector support device (high quality) 13 eurna-8.jpg 227.694 Figure 8: 3D view of the EURACOS2 sodium experiment 14 Eurna-1v.gif 11.417 Figure 1: Cross-section of the EURACOS2 facility (preview) 15 Eurna-2v.gif 28.009 Figure 2: Schematics of the experimental configuration (preview) 16 Eurna-3v.gif 13.767 Figure 3: U235 neutron converter (preview) 17 Eurna-4v.gif 11.975 Figure 4: Activation detector support (preview) 18 Eurna-5v.gif 9.257 Figure 5: Positioning of gas spectrometer (preview) 19 Eurna-6v.gif 8.771 Figure 6: Cross-section of the sodium containers with detectors (preview) 20 Eurna-7v.gif 10.977 Figure 7: Sulphur detector support device (preview) 21 Eur_01.pdf 1.139.611 Reference 22 Eur_02.pdf 537.382 Reference 23 Eur_03.pdf 503.082 Reference 24 Eur_04.pdf 655.408 Reference 25 Eur_05.pdf 185.260 Reference 26 Eur_06.pdf 3,944.371 Reference 27 Eur_07.pdf 384.022 Reference 28 EUR_NA_8.pdf 1.505.251 Reference 29 EUR_10.pdf 599.783 Reference 30 EUR_11.pdf 208.011 Reference 31 EUR_13.pdf 404.659 Reference 32 EUR_14.pdf 313.815 Reference 33 EUR_15.pdf 397.685 Reference 34 EUR_16.pdf 823.089 Reference 35 EUR_17.pdf 432.065 Reference 36 EUR_18.pdf 638.823 Reference 37 EUR_19.pdf 440.870 Reference 38 EUR_20.pdf 318.053 Reference Files EUNA-EXP.HTM, EURNA.TB1, EURNA.TB2 contain the following tables: 5 tables of chemical compositions of materials present 9 tables of measured reaction rates 1 table presenting neutron spectra measurements conditions 9 tables of spectra derived from measurements using SPEC 4 unfolding code 9 tables of measured impulses used for unfolding an input example for SPEC 4 code. Figures are included in GIF, JPG and TIF formats. SINBAD Benchmark Generation Date: 07/1995 SINBAD Benchmark Last Update: 3/2006