SINBAD ABSTRACT NEA-1517/101
JANUS Phase I (Neutron Transport Through Mild and Stainless Steel)
1. Name of Experiment:
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JANUS Phase 1 (1986)
2. Purpose and Phenomena Tested:
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Neutron transport in regions of mild steel and stainless steel. The
purpose was to test the prediction of neutron penetration through
stainless steel when the incident spectrum was typical of that
emerging from a fast reactor.
3. Description of the Source and Experimental Configuration:
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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 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 steel plates which give
thicknesses of 17.85 cm mild steel, 40.39 cm stainless steel, and
56.72 cm mild steel. The initial region of mild steel modifies the
spectrum of neutrons incident upon the stainless steel to make it
closer to that leaving a fast reactor. The array has a 61 cm thick
biological shield of concrete behind this.
4. Measurement System and Uncertainties:
------------------------------------
The activation detectors used were:
Typical Counting Systematic
Detector Diameter Thickness Mass System Absolute
(mm) (mm) (g) Calibration
(uncertainty)
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Mn55(n,g)/Cd 12.7 0.15 0.12 NaI 1.5%
Au197(n,g)/Cd 12.7 0.05 0.12-0.13 NaI 0.9%
Rh103(n,n') 12.7 0.015 0.20 NaI 3.0%
S32(n,p) 38.1 2.41 5 Plastic 5.0%
Pressed Pellet Scintillator
S32(n,p) 51 5.6 22 Plastic 5.0%
Cast Pellet Scintillator
----------------------------------------------------------------------
The Mn and Au foils were contained in cadmium boxes of thickness
0.05 inches.
In addition neutron spectrum measurements were made at three locations
with three hydrogen proportional counters and an NE213 scintillator.
5. Description of Results and Analysis:
-----------------------------------
Measurements of the reaction rates for S32(n,p)P32, Rh103(n,n')Rh103m,
Mn55(n,g)Mn56 Under Cd, and Au197(n,g)Au198 Under Cd were made at
intervals of approximately 4.5cm through the stainless steel, and 5.1cm
in the regions of mild steel. Lateral scans were made with sulphur,
rhodium, and gold at selected positions.
In addition, during all irradiations of activation detectors within the
shields, three sulphur pellets were placed in locations at the centre of
the front face of the fission plate to monitor its run-to-run power via
the S32(n,p)P32 reaction.
The fast neutron spectra (E>52.5keV) were measured at three locations
within the region of stainless steel. The reaction rates for S(n,p)
and Rh(n,n') as derived from the spectra are compared with those
measured directly.
The results were corrected for the background responses due to the NESTOR
core. For the low energy detectors measurements were made with the plate
fuelled and unfuelled. For the threshold detectors the hydrogen
filled proportional counters of the TNS system were used in conjunction
with the boral shutter for Cave C at NESTOR. For the low energies the
background varied from 19% close to the fission plate to 2% at deep
penetrations. For the threshold detectors the corrections were small
being typically 1% to 3%.
Calculations were carried out with the Monte Carlo code McBEND Version 9B
[4], [5].
More recently the MCNP5 models were prepared [86] and are also incuded in
this compilation.
6. Quality Assessment:
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The JANUS-1 experiment is ranked as benchmark quality experiment.
The major drawback in the available experimental information is
represented by the specifications concerning the detectors arrangement.
7. Author/Organizer
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Experiment and analysis:
I.J. Curl, A K McCracken, P C Miller
AEA Technology
WINFRITH, Dorchester
Dorset DT2 8DH
UK
Compiler of data for Sinbad:
A. Avery
Performance and Safety Services Department,
AEA Technology
WINFRITH, Dorchester
Dorset DT2 8DH
UK
Reviewer of compiled data:
I. Kodeli
OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
Quality assessment:
A. Milocco
Universita' di Milano-Bicocca, piazza della Scienza 3, Milano, Italy
8. Availability:
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Unrestricted
9. References:
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[1] M. J. Armishaw, J. Butler, M. D. Carter, I. J. Curl, A. K. McCracken,
"A Transportable Neutron Spectrometer (TNS) for Radiological
Applications", AEEW-M2365 (1986).
[2] I. J. Curl,
"CRISP - A Computer Code to Define Fission Plate Source Profiles",
RPD/IJC/934.
[3] J. Butler et al.
"The PCA Replica Experiment, Part 1. Winfrith Measurements and
Calculations", AEEW-R1763
[4] Wright G. A., Curl I. J., Hoare C. J., McCracken A. K., Miller P. C,
and Ziver A. K., "Monte Carlo Sensitivity Analysis of Winfrith
Benchmark Experiment using JEF-1 Cross-Sections", Proceedings of the
7th International Conference on Radiation Shielding, Bournemouth, p725,
Sept. 1988.
[5] Curl I. J., Calamand D., and Muller K. I., "The Role of the JANUS
Experimental Shielding Programme in the Assessment of the Shielding
Methods Employed for EFR", New Horizons in Radiation Protection and
Shielding - ANS Topical Meeting, Pasco, p345, April 1992.
[6] A. Avery, JANUS Phase 1 Benchmark Experiment Data for Inclusion in
the SINBAD Database, Jan. 1998
[7] A. Avery, A review of Shielding Benchmarks for the Validation of
JEF 2.2, JEF/DOC-666, Nuclear Energy Agency, Paris, France, 1997.
[8] A. Milocco, Quality Assessment of Evaluated Experiments
NESDIP-2, NESDIP-3,JANUS-1 and JANUS-8, IJS-DP-11195, June 2012.
10. Data and Format:
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DETAILED FILE DESCRIPTIONS
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Filename Size[bytes] Content
---------------- ----------- -------------
1 jan1-abs.htm 11.065 This information file
2 jan1-exp.htm 34.633 Description of Experiment
3 MCBEND.inp 301.814 Input Data for McBEND M/C Code
4 FIG1.TIF 135.496 Figure 1: The ASPIS Mobile Shield Tank in the NESTOR Cave C
5 FIG2.TIF 178.240 Figure 2: Schematic Side Elevation of the Experimental Shield of
the JANUS Phase 1 in the ASPIS Trolley
6 FIG3.TIF 156.226 Figure 3: The Enriched U/Al Alloy Fission Plate
7 FIG4.TIF 203.604 Figure 4: Details of the Fuel Loading Pattern When Viewed Looking Towards
the NESTOR Cave
8 FIG5.TIF 153.738 Figure 5: The Individual U/Al Alloy Fuel Element
9 FIG6.TIF 176.778 Figure 6: The Fuel Element Configuration and Manganese Foil Positions
10 FIG7.TIF 117.838 Figure 7: Mesh Boundaries for the Fission Plate Source
11 FIG8.TIF 130.445 Figure 8: Location of Fission Discs in the Demountable Fuel Element
12 FIG9.TIF 287.269 Figure 9: Measurement Locations for JANUS Phase 1
13 FIG10.TIF 121.929 Figure 10: A Schematic for the Arrangement of the Spectrometer at
the Measurement Locations
14 FIG1.gif 19.324 Figure 1: The ASPIS Mobile Shield Tank in the NESTOR Cave C (preview)
15 FIG2.gif 24.192 Figure 2: Schematic Side Elevation of the Experimental Shield of
the JANUS Phase 1 in the ASPIS Trolley (preview)
16 FIG3.gif 17.999 Figure 3: The Enriched U/Al Alloy Fission Plate (preview)
17 FIG4.gif 20.477 Figure 4: Details of the Fuel Loading Pattern When Viewed Looking Towards
the NESTOR Cave (preview)
18 Fig5.gif 16.245 Figure 5: The Individual U/Al Alloy Fuel Element (preview)
19 Fig6.gif 23.546 Figure 6: The Fuel Element Configuration and Manganese Foil Positions (preview)
20 Fig7.gif 12.619 Figure 7: Mesh Boundaries for the Fission Plate Source (preview)
21 Fig8.gif 13.990 Figure 8: Location of Fission Discs in the Demountable Fuel Element (preview)
22 Fig9.gif 28.184 Figure 9: Measurement Locations for JANUS Phase 1 (preview)
23 Fig10.gif 19.648 Figure 10: A Schematic for the Arrangement of the Spectrometer
at the Measurement Locations (preview)
24 janus1.pdf 2.172.714 Reference
25 jef-666.pdf 750.902 Reference
26 QualityAssessment.pdf 458.860 Document on JANUS-1 quality assessment
27 J1Mn.i 19.609 MCNPX(5) input model with the Mn activation foils
28 J1SRhAu.i 20.484 MCNPX(5) input model with the S, Rh, and Au activation foils
29 J1Sp.i 18.529 MCNPX(5) input model with the whole set of spectrometers
File JAN1-EXP.HTM contains the following tables:
One table (1) of axial dimensions and (2) of material specifications, two
tables (3 & 4) describing the source distribution, one table (5) of the
measured reaction rates, four tables (6-9) showing the lateral scans,
and three tables (10-12) giving the measured spectra.
Figures describing the geometry of the experiment are included in
TIFF5 compressed and GIF (preview) format .
SINBAD Benchmark Generation Date: 1997
SINBAD Benchmark Last Update: 1/2013