SINBAD ABSTRACT NEA-1517/49
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]. 6. Special Features: ---------------- None 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 OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France ivo.kodeli@oecd.org Reviewer of compiled data: S. Kitsos OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France stavros.kitsos@free.fr 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" 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 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: 01/2002
