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SBE 10.001

1. Name of Experiment:

SS Bulk Shield Benchmark Experiment at FNG/ENEA, FENDL Benchmark for IAEA/NDS, 1989

2. Purpose and Phenomena Tested:

The neutron transport of structural materials housing components of fusion devices are not well understood. Stainless steel is one such material, often used in the vacuum vessel and piping components. Neutron penetration through large distances (60 cm) of stainless steel are reported.

3. Description of the Source and Experimental Configuration:

A source of 14-Mev neutrons is generated by deuterons on a tritium target, for a total of 0.2789 neutrons per T(d,n) reaction, spread over a 60-degree forward angle, centered on the SS block face. The source is at 5.3 cm from the SS block face, 5 cm of air and 0.3 cm target source support structure. The SS is of AISI 316 type, 70 cm deep, 100 cm wide x100 cm high. SS plugs fill the central voids containing the detector foils.

4. Measurement System and Uncertainties:

The accuracy of the source measurement lay between ±4.4% and ±1.6% using a SSB detector which detects associated particles from the T(d,n)He reaction. Errors are reported for gamma-ray interference and uncertainty in the three HPGe detectors. The systematic error is the uncertainty on the neutron source intensity. Calibration of the HPGe detectors were within ±2% uncertainty. Activation reactions and nuclear data employed for detector foils follows:

Reaction Half-life Isotopic


-ray energy (keV) -ray branching
27Al(n,)24Na 14.96h 100.0 1368.6 100.00
56Fe(n,p)56Mn 2.577h 91.72 846.8 98.87
58Ni(n,2n)57Ni 1.503d 68.27 1377.6 80.0
58Ni(n,p)58Co 70.92d 68.27 810.8 99.44
115In(n,n')115mIn 4.486h 95.7 336.24 45.9
55Mn(n,)56Mn 2.577h 100.0 846.8 98.87
197Au(n,)198Au 2.696d 100.0 411.8 95.56

5. Description of Results and Analysis

The foils were placed at various depths along the central z-axis, from 5 cm to 60 cm. The background was determined to be between 4% and 8%. IRDF-90 Covariance data in 175 energy group format was used to determine the error on reaction rates due to uncertainty of the activation cross sections. Transport cross sections were used from EFF.1 and the activation cross sections for the foil detectors were taken from IRDF.90 with the exception of 55Mn(n,) which was taken from EFF.2. Data is presented by foil depth in cm, measured reaction rate, 1024 reactions/(source neutron), random error, systematic error, and the total error (%).

6. Special Features:


7. Author/Organizer

Experiment and analysis:

M. Martone, M. Angelone, P. Batistoni, M. Pillon, V. Rado

Neutronics Division - Fusion Department

ENEA - Ente per le Nuove tecnologie, l'Energia e l'Ambiente

C. R. Frascati - I - 00044 FRASCATI (Italy)

Compiler of data for Sinbad:

H. T. Hunter, ORNL, P.O. Box 2008, Oak Ridge, TN 37831-6362, USA

Reviewer of compiled data:

P. Batistoni, ENEA, Frascati, Italy

8. Availability:


9. References:

[1] M. Martone, M. Angelone, M. Pillon, "The 14-MeV Frascati Neutron Generator (FNG)", ENEA Report RT/ERG/FUS/93/65

[2] J. H. Baard, W. L. Zijp, H. Nolthenius, "Nuclear Data Guide for Reactor Neutron Metrology", Kluwer Academic Publishers for the Commission of the European Community, (1989).

10. Data and Format:


- Source, Target, and SS block diagram w/dimensions



-Eupper (MeV) I=1,172;

-Current Spectrum (N/sr/Source) 1 =1,173 (173'=total)

-Errors (fractions %) I = 1,172 (173= total)

-Spectrum normalized to one I=1,172 (173' = total)

-Source Fortran file used by MCNP.4 to calculate the FNG 14-Mev neutron source

-Geometrical Data given in MCNP input format

-Detector data with list of activation reactions, foil locations, and foil size.

-Data Results,

-Foil Position (cm);

-E = Measured Reaction Rate (1024 reactions/source neutron)

-Random Error on E, (fraction %)

-Systematic Error on E (fraction %)

-Total Error on E, (quadratic sum of random and systematic error, fraction %)

-Calculational Data

-Foil Position (cm);

-C = Calculated Reaction Rate (1024 reactions/source neutron)

-Error on C due to MCNP statistics, (fraction %)

-Error on C due to activation cross section uncertainty (fraction %)

-Total Error on C, (quadratic sum of two previous errors, fraction %)

-C/E ratios

-Total errors on C/E ratios (quadratic sum of total error on C and of total error on E, absolute)

Document is HTML v.3.02 Format with ASCII Tables and Figures in GIF format.

Abstract Generation Date: 09/97
Abstract Last Update: 06/98