SINBAD ABSTRACT NEA-1517/63
SBE 1.014
1. Name of Experiment: SDT12. A Benchmark Experiment for Neutron Transport in Thick Sodium - 1974 2. Purpose and Phenomena Tested: This experiment was designed to verify the accuracy of sodium cross sections to be used in transport calculations. 3. Description of the Source and Experimental Configuration: The source used was a collimated beam of reactor neutrons from the Tower Shielding Reactor at the Tower Shielding Facility located in Oak Ridge National Laboratory. Measurements of neutron fluence and neutron spectra were made behind various combinations of four 11-ft-diameter cylindrical aluminum tanks filled with solid sodium up to 15-ft-thick. Concrete, at least 1.5-ft-thick, surrounded the periphery of the tanks to reduce the effects of transverse leakage from the slabs. The average thickness of the four sodium tanks, including 1 inch of aluminum, was 29.91 +/- 0.22, 60.08 +/- 0.52, 59.86 +/- 0.42, and 29.56 +/- 0.53 inches for tanks 1, 2, 3, 4 respectively. The density of the sodium tanks averaged 0.945 g/cm3, which is accurate to 1%. 4. Measurement System and Uncertainties: The spectral measurements were taken using two types of spectrometers: (1) a NE-213 scintillator, and (2) a Benjamin proton recoil spectrometer. The NE-213 was used to determine the spectra in the energy range of 0.8 to 15 MeV. The Benjamin spectrometer was used to determine the spectra in the range of ~70 keV to 1.5 MeV. In addition, a set of spherical BF3 detectors ("Bonner balls") were used to obtain integral flux measurements. The accuracy of the incident absolute source spectrum is estimated to be +/- 10% down to 200 keV and +/- 20% below 200 keV. All the measurements have an estimated reproducibility of +/- 5%, due primarily to power calibration uncertainties. 5. Description of Results and Analysis: Measurements were obtained behind sodium thicknesses of 2.5, 5, 10, 12.5, and 15 feet and covered an energy range of ~70 keV to 11 MeV. Measurements of the incident neutron beam were made with each detector to obtain an absolute energy spectrum. The spectra measurements obtained from the NE-213 were unfolded by the FERDoR computer code. The spectra measurements obtained from the Benjamin spectrometer were unfolded by the SPEC4 computer code. Spectral errors in the data unfolding statistics are shown by one sigma percentage values for the Benjamin counters and high/low values for the NE-213. The results were obtained using multigroup Monte Carlo, MORSE, and two-dimensional discrete ordinates code, DOT-III. 6. Special Features: The NE-213 energy resolution and the Bonner ball response functions are included to aid in computational comparison with results. 7. Author/Organizer: Experiment and Analysis: R. E. Maerker and F. J. Muckenthaler, ORNL-4480 Compiler of data for SINBAD: Jennifer Parsons, Radiation Shielding Information Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6362 Reviewer of compiled data: Hamilton Hunter, Radiation Shielding Information Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6362, fax 423-574-6182, e-mail h3o@ornl.gov 8. Availability: Unrestricted 9. References: [1] R.E. Maerker, F.J. Muckenthaler, R.L. Childs, M.L. Gritzner, "Final Report on a Benchmark Experiment for Neutron Transport in Thick Sodium," ORNL-4880, Oak Ridge National Laboratory (January 1974). [2] R.E. Maerker, F.J. Muckenthaler, J.J. Manning, J.L. Hull, J.N. Money, K.M. Henry, Jr., and R.M. Freestone, Jr., "Calibration of the Bonner Ball Neutron Detectors Used at the Tower Shielding Facility," ORNL-TM-3465, Oak Ridge National Laboratory (1971). [3] G.L. Simmons, Editor, "Shielding Benchmark Problems," ORNL-RSIC-25 (ANS-SD-9), Oak Ridge National Laboratory (1974). [4] F.J. Muckenthaler, R.R. Spencer, H.T. Hunter, J.L. Hull, and A. Shono, "Measurements for the Jasper Intermediate Heat Exchanger Experiment," ORNL-TM-12064 (July 1992). 10. Data and Format: Tables: (1) Source spectrum at the end of the collimator (2) NE-213 resolution function (3) Bonner ball description (4) Bonner ball response functions (5) Experimental configurations (6)-(8) NE-213 spectrum (9)-(13) Benjamin counter spectrum (14)-(22) Bonner ball counting rates Figure: (1) Side-view of reactor and sodium shield geometry Document is HTML v.3.02 Format with ASCII Tables and Figures in GIF format. SINBAD Abstract Generation Date: 06/98 SINBAD Abstract Last Update: 06/98