SINBAD ABSTRACT NEA-1517/62
SBE 1.013

1. Name of Experiment:

SDT 11. The ORNL Benchmark Experiment for Neutron Transport Through Iron and 
Stainless Steel, Part I - 1974

2. Purpose and Phenomena Tested:
    
This experiment was designed to verify the accuracy of iron and stainless steel 
cross sections used in transport calculations.

3. Description of the Source and Experimental Configuration:

The source used was the Tower Shielding Reactor at the Tower Shielding Facility 
located in Oak Ridge National Laboratory. A series of transmission measurements 
through various thickness of iron slabs up to 3 feet and also through a 12 inch 
stainless steel slab were performed using a collimated beam of reactor neutrons.
These measurements were made behind various combinations of thin 5 ft x 5 ft slabs. 
All were taken with a 4.25-inch-diameter collimator made of lithiated paraffin 
bricks and water.

The density of the Type-304 stainless steel slabs averaged 7.86 g/cm3, and the 
density of the iron slabs averaged 7.79 g/cm3. It was observed that the iron slabs 
were actually carbon steel.

4. Measurement System and Uncertainties:

The transmission neutron spectra from ~80 keV to 10 MeV were measured with two 
detectors: (1) a NE-213 liquid scintillator, and (2) a Benjamin proton recoil 
spectrometer. The NE-213 spectrometer was used to determine the spectra in the 
energy range from 0.8 to 10 MeV. The Benjamin spectrometer was used to determine the
spectra in the range from ~80 keV to 1.5 MeV. In addition, a set of three BF3 
detectors ("Bonner balls") were used to obtain weighted integral flux measurements.

The accuracy of the incident absolute neutron 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. Because 
of the underestimation of the background measurements, the Bonner ball data is 
accurate to about 10%.

5. Description of Results and Analysis:

Spectra were measured behind six different iron slab thickness: 1.5, 4, 6, 12, 24, 
and 36 inches, and behind one stainless steel slab with a thickness of 12 inches.

The spectra measurements obtained from the NE-213 scintillator 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 by high/low values for the NE-213. The calculations were done by 
multigroup Monte Carlo techniques employing "point" cross sections.

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, ORNL-TM-4222

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, "SDT 11. The ORNL Benchmark Experiment for Neutron Transport 
    Through Iron and Stainless Steel, Part I," ORNL-TM-4222 (ENDF-188), Oak Ridge 
    National Laboratory (1974).
[2] R.E. Maerker, F.J. Muckenthaler, "Final Report on a Benchmark Experiment for
    Neutron Transport Through Iron and Stainless Steel," ORNL-4892, Oak Ridge 
    National Laboratory (April 1974).
[3] R.E. Maerker, "SDT 1. Iron Broomstick Experiment -- An Experimental Check of
    Neutron Total Cross Sections," ORNL-TM-3867 (ENDF-166), Revised, Oak Ridge 
    National Laboratory (1972).
[4] 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).
[5] R.E. Maerker and F.J. Muckenthaler, "The Absolute Neutron Spectrum emerging through 
    a 15-1/4-IN.Collimator from the TSR-II Reactor at the Tower Shielding Facility," 
    ORNL-TM-4010.

10. Data and Format:

Tables:
    (1) Source spectrum at the end of the collimator in neuts/cm2/min/W/Group
    (2) Energy resolution of the NE-213 spectrometer system
    (3) Bonner ball description
    (4) Bonner ball response functions
    (5)-(6) Experimental configurations for the iron and stainless steel slabs
    (7)-(12) NE-213 spectrum
    (13)-(16) Benjamin counter spectrum
    (17) Bonner ball counting rates

Figure:
    (1) Schematic of the experimental geometry for the 4.25 in diameter collimator


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SINBAD Abstract Generation Date: 06/98

SINBAD Abstract Last Update: 06/98