Streaming Through Ducts (IRI-TUB)
1. Name of Experiment: ------------------ IRI-TUB Streaming Through Ducts (Jan. 1991) 2. Purpose and Phenomena Tested: ---------------------------- Fast and thermal neutron reaction rates were measured at several locations in the straight and bent steel-walled cylindrical ducts in concrete, irradiated with a typical reactor spectrum. The benchmark is suitable to test transport codes in real streaming problems. 3. Description of Source and Experimental Configuration: ---------------------------------------------------- A large concrete block with a density of about 2.4g/cm3, containing the cylindrical steel-walled duct, was installed in the irradiation tunnel of the 100 kW research reactor of the Institute of Nuclear Techniques (NTI) of the Technical University of Budapest. The concrete block was placed at the distance of 25 cm from the tunnel entrance, so the total distance from the core-reflector boundary to the entrance of the ducts, was about 50 cm. The geometry from the core centre to the tunnel entrance is given in Figure 1. The irradiation tunnel is placed so that its centerline goes through core midplane. At the back of the large concrete block, a small block containing the second leg of the duct with a bend of 0, 30, 60 or 90 degrees, was positioned, with the second leg upwardly directed. In this way four different duct geometries, shown in Figure 2, were created. Because the upper side of the block touched nearly the ceiling of the tunnel, the second leg of the 60 degrees bent duct was partly closed and that of the 90 degree bent duct was fully closed. It is suggested in [1] to take into account the backscattering from the ceiling of the tunnel. About 21 cm behind the last detector position in the straight and the 30 degree ducts measured along the duct axis, a shielding door filled with water was present. It is suggested in [1] and [2] that this shielding door can be neglected in the straight duct, because the last detector position in this duct was positioned further away from the shielding door and the thermal neutron flux was much higher in this duct due to the large contribution of the uncollided flux. The inner diameters of the steel duct was 11.8 cm and the wall thickness was 4.5 mm. The active core height of the NTI research reactor is 50 cm, and the horizontal cross section is approximately 36x36 cm2. The horizontal cross section of the core and reflector is shown in Figure 1. 4. Measurement System: ------------------ Neutron reaction rates were measured in the ducts by use of coupled pairs of 6LiFand 7LiF thermoluminescence dosimeters (TLD) and multiple foil activation detectors. The detector holders consisted of aluminium disks with thickness of 1.5 mm, which fitted precisely in the duct and which were kept at a constant distance from each other by thin aluminium bars. The detectors could be placed on the disk at four positions on a straight line through the disk centre at distances of 2.5 and 5.0 cm from the centre. The activation foils were irradiated in a small aluminium capsule with thickness of 0.5 mm, or in a cadmium capsule with thickness of 1 mm, while the TLD samples were irradiated in small aluminium capsules with a thickness of 1 mm. The fast neutron flux was measured using 56Fe(n,p)56Mn, 54Fe(n,p)54Mn, 58Ni(n,p)58Co and 115In(n,n')115mIn threshold reaction detectors. For the thermal and epithermal energy range the reaction rates of 55Mn(n,g)56Mn, 197Au(n,g)198Au and 45Sc(n,g)46Sc were measured. Both bare and cadmium covered foils were used. Characteristics and locations of the activation detectors used for measuring the fast and thermal neutron flux are given in Tables 1 and 2. Thermal neutron measurements were carried out by pairs of 6LiF (TLD600) and 7LiF (TLD-700) TLD samples with size of 3.1 x 3.1 x 0.89 mm3. The TLD600 samples are sensitive to thermal neutrons by means of the (n,a) 1/v capture reaction in 6Li (absorption cross-section is about 940 barn at 0.025 eV). All the TLD600 samples were equally sensitive to neutrons within 5% (one standard deviation) and to gamma rays within 3%. The TLD700 samples were equally sensitive to gamma rays within 3%. Although the capture cross section of 7Li is virtually zero, the TLD700 samples are slightly sensitive to neutrons due to the presence of a small amount of 6Li in these samples (~0.07%). The TLD samples were irradiated pairwise (two TLD600 samples at the one side of the disk and two TLD700 samples at the other side, symmetrical with respect to the centre of the disk). The results of the TLD700 sample measurements were used to correct the TLD600 count yields for the gamma ray contributions, and vice versa for gamma flux determination. In this way both the gamma dose and the neutron (n,a) reaction rate could be determined. 5. Description of Results and Analysis: ----------------------------------- The detector positions in the ducts are given in Figure 2. Only a limited number of measurement results is available. The measured reaction rates for 115In(n,n')115mIn in the straight duct, 55Mn(n,g)56Mn in the 30 degree duct, 197Au(n,g)198Au and 55Mn(n,g)56Mn in the 90 degree duct are given in Tables 3 to 5 (Figures 5, 6 and 7), respectively. Using the measured and calculated saturation activities per target nucleus of each foil, and cross sections from IRDF85, IRDF90 and DOSCROS84, spectrum adjustment calculations was done by SANDBP code (see [1], [2]). Such adjusted spectra in the straight duct at the entrance (1st measurement position) and at fourth position are given in Tables 6 and 7 (Figures 8, 9), respectively. The relative neutron responses of the TLD samples for all geometries are available only in graphical form and are given in Figure 11. The responses are normalised to the response of the first detector of each geometry. The energy dependent response function of the TLD samples was obtained from an adjoint transport calculation using the 1-dimensional discrete ordinates code XSDRNPM-S (see refs. [1] and [2] for details). The response function for the TLD600 and TLD700 samples is listed in Table 8, compared to those obtained by approximate analytical expressions [1]. No information on gamma-ray measurements was found in the literature. Error Assessment: Counting statistic uncertainties were 3%, 5% and 8%, for 197Au(n,g)198Au, 115In(n,n')115mIn and 55Mn(n,g)56Mn measurements, respectively. The TLD calibration error was about 5 % for neutron, and 1 % for gamma calibration. Standard deviation (1s) of the measurements were about 12%. Example of Experiment Analysis: The calculations using the DOT3.5 and MORSE-SGC/S codes are described in refs. [1] and [2]. Several DOT3.5 input and output files used for in this analysis are included here (see 10. Data and Format). The files correspond to the calculational models A, B, C, D and E described in ref. [1]. 6. Special Features: ---------------- None 7. Author/Organizer: ---------------- Experiment and analysis: Jan Leen Kloosterman Interfaculty Reactor Institute Delft University of Technology Mekelweg 15, NL-2629 JB Delft The Netherlands Email: J.L.Kloosterman@iri.tudelft.nl Tel: +31 15 2781191 Fax: +31 15 2786422 Dr. Zsolnay Éva Mária BME Nukleáris Techn. Int. (Institute of Nuclear Techniques, Technical University of Budapest) H-1521 Budapest, Hungary tel.: 463 1563 zsolnay@reak.bme.hu Compiler of data for Sinbad: I. Kodeli Institute Jozef Stefan, Jamova 39, 1000 Ljubljana, Slovenia E-mail: Ivan.Kodeli@ijs.si 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] J. L. Kloosterman, "On Gamma Ray Shielding and Neutron Streaming Through Ducts", PhD Thesis, Delft University of Technology (1992). [2] J. L. Kloosterman, J. E. Hoogenboom, Experiments and Calculations on Neutron Streaming Through Bent Ducts, Journal of Nuclear Science and Technology, Vol. 30, No 7, p. 611-627, July 1993. 10. Data and Format: --------------- Filename Size[bytes] Content ------------ ----------- ------------- 1 iritub-a.htm 15.645 This information file 2 iritub-e.htm 19.695 Description of Experiment and Results 3 dot35-a.inp 233.798 Input for DOT3.5 k-eff calculations (R-core=18) 4 dot35-b.inp 233.806 Input for DOT3.5 k-eff calculations (R-core=19.9) 5 dot35-b.out 1.756.983 Output data of DOT3.5 calculations 6 dot35-c.inp 233.853 Input for DOT3.5 k-eff calculations (expanded geometry) 7 dot35-c.out 1.850.108 Output data of DOT3.5 calculations 8 dot35-d.inp 233.796 Input for DOT3.5 k-eff calculations (reduced geometry) 9 dot35-d.out 1.730.426 Output data of DOT3.5 calculations 10 dot35-e.inp 273.000 Input for DOT3.5 k-eff calculations (perturbed materials) 11 dot35-e.out 1.847.498 Output data of DOT3.5 calculations 12 duct-f1.gif 11.971 Figure 1: Geometry from core to tunnel entrance (preview) 13 duct-f1.tif 10.593 Figure 1: Geometry from core to tunnel entrance 14 duct-f2.gif 7.626 Figure 2: 0, 30, 45 and 90 degree duct geometries (preview) 15 duct-f2.tif 8.719 Figure 2: 0, 30, 45 and 90 degree duct geometries 16 duct-f3.gif 7.310 Figure 3: Reactor calculational geometry for DOT3.5 (preview) 17 duct-f3.tif 18.394 Figure 3: Reactor calculational geometry for DOT3.5 18 duct-f4.gif 9.312 Figure 4: Straight duct geometry for MORSE (preview) 19 duct-f4.tif 9.483 Figure 4: Straight duct geometry for MORSE 20 duct-f5.gif 8.195 Figure 5: In reaction rates in straight duct (preview) 21 duct-f5.tif 9.773 Figure 5: In reaction rates in straight duct 22 duct-f6.gif 8.246 Figure 6: Mn reaction rates in 30 degree duct (preview) 23 duct-f6.tif 12.189 Figure 6: Mn reaction rates in 30 degree duct 24 duct-f7.gif 8.142 Figure 7: Au and Mn reaction rates in 90 degree duct (preview) 25 duct-f7.tif 8.908 Figure 7: Au and Mn reaction rates in 90 degree duct 26 duct-f8.gif 16.547 Figure 8: Neutron spectra at duct entrance (pos. 00.1) (preview) 27 duct-f8.tif 14.961 Figure 8: Neutron spectra at duct entrance (pos. 00.1) 28 duct-f9.gif 16.865 Figure 9: Neutron spectra deep in straight duct (pos. 00.4) (preview) 29 duct-f9.tif 14.853 Figure 9: Neutron spectra deep in straight duct (pos. 00.4) 30 duct-f10.gif 12.473 Figure 10: Capture probabilities for TLD600 and TLD700 samples (preview) 31 duct-f10.tif 13.129 Figure 10: Capture probabilities for TLD600 and TLD700 samples 32 duct-f11.gif 14.511 Figure 11: Relative TLD responses in ducts (preview) 33 duct-f11.tif 52.897 Figure 11: Relative TLD responses in ducts 34 thesis.pdf 11.997.656 Reference 35 nst93.pdf 3.278.544 Reference The file iritub-e.htm contains the following tables: Table 1: Activation detectors for fast neutron flux measurement. Table 2: Activation detectors for thermal/epithermal neutron flux. Table 3: Measured reaction rates for 115In(n,n')115mIn (straight duct). Table 4: Measured reaction rates for 55Mn(n,g)56Mn (30 degree duct). Table 5: Measured reaction rates for 197Au(n,g)198Au and 55Mn(n,g)56Mn in the 90 degree duct. Table 6: Adjusted neutron spectrum in the straight duct (position 1). Table 7: Adjusted neutron spectrum in the straight duct (position 4). Table 8: Response function for TLD600 and TLD700 samples. Figures are included in GIF (preview) and TIF formats. SINBAD Benchmark Generation Date: 10/2001 SINBAD Benchmark Last Update: 10/2001
