[back to index] [experiment]
FNG-ITER STREAMING EXPERIMENT
1. Name of Experiment:
------------------
FNG-ITER NEUTRON STREAMING EXPERIMENT (1997-1998)
2. Purpose and Phenomena Tested:
----------------------------
Determination of neutron reaction rates and of nuclear heating in a
neutronic mock-up of the International Thermonuclear Experimental
Reactor (ITER) shielding system irradiated with 14-MeV neutrons, in
presence of a streaming path.
3. Description of Source and Experimental Configuration:
----------------------------------------------------
The 14-MeV d-T Frascati Neutron Generator (FNG, [1]) was the neutron
source. The angular dependence of the source intensity is presented in
Figure 1. The angular dependence of the source energy distribution is
shown in Figure 2.
The x-y view of the geometry of the mock-up is outlined in Figure 3. It
consists of a combination of slabs made of the water equivalent material
Perspex and the stainless steel AISI-316 (simulating shield-blanket and
vacuum vessel) and has a front cross-section area of 100 cm x 100 cm. The
total thickness of the assembly is 94.26 cm including a 1 cm thick Cu
layer in front (simulating first wall). The assembly is provided with a
channel with high aspect ratio (inner diameter a=28 mm, length l = 39.07 cm,
channel wall thickness t = 1 mm stainless steel AISI316 ), (see Fig.3).
At the end of the channel, a cavity is also realised. A parallelepipedal
stainless steel box fitting exactly the cavity is inserted to locate the
detectors in their positions. The inner size of the box is 52 mm (z) x
148 mm (x) x 48 mm (in the deuterium beam direction-y). The cavity is
symmetrically located with respect to the channel axis.
Behind this assembly a block of Cu and SS316 plates was arranged (simulating
the coils for the toroidal magnetic field of the TOKAMAK; dimensions: depth
30.8 cm, area 47 cm x 47 cm). The rear part of the assembly was surrounded
with a polythene shield covering also the last 30 cm of the Perspex/AISI316
block in order to reduce room-return background.
The following quantities are measured :
a - Measurements in the channel :
Neutron reaction rates by activation foils to monitor the flux gradient
in the channel
b - Measurements in the cavity :
Neutron reaction rates by activation foils
c - Measurements behind the channel :
Neutron reaction rates by activation foils
Nuclear heating
d - Measurements in the SC magnet : Nuclear heating
The detectors were placed on the axis of the d-beam of the neutron generator.
All measurements (a,b,c and d) were performed with the neutron source in
axis with the channel/cavity, at 5.3 cm distance from the shielding block
surface (ON-AXIS set-up). The activation foils measurements in the channel
and in the cavity (a and b) were performed also with the neutron source
shifted with respect to the channel axis to simulate the effect of the extended
neutron source from the plasma (OFF-AXIS set-up). The source lateral shift is
5.3 cm, i.e. equal to the distance between the target and the mock-up
surface. In this case the channel mouth is located at an angle of p/4 with
respect to beam direction (see Fig.4).
4. Measurement System:
------------------
The following activation reactions were selected to measure the neutron flux:
Reaction Effective Threshold
(MeV)
93Nb(n,2n)92Nb 10.8
27Al(n,a)24Na 8.5
58Ni(n,p)58Co 2.9
197Au(n,g)198Au -
All foils had a diameter of 18 mm. 1-3 mm thick foils were used for Nb, Al and
Ni detectors (1 mm up to the depth of 38.65 cm and in the cavity, 2 mm behind
the cavity between 46.35 and 73.90 cm, and 3 mm in the last 3 positions). For
197Au(n,g)198Au reaction 0.05 mm thick foils were used.
Inside the channel the foils were located in axis with the channel, at y = 0.25,
12.95, 25.95, 38.65 cm (foil centers) from the shielding block surface. Eleven
activation foils were located inside the cavity to monitor the neutron flux
gradient and the effect of the void channel. The foils were located in the
positions shown in Fig. 4, between y = 39.12 cm and y = 43.82 mm depth (foils
centers). Eight activation foils are located behind the cavity, at depths:
y = 46.35, 53.30, 60.05, 66.90, 73.90, 80.60, 87.25, 91.65 cm (foil centers).
Nuclear heating was measured in the shielding assembly behind the
channel/cavity, in the same positions as for activation foils, and inside the
superconducting magnet, using CaF2:Tm thermo-luminescent detectors (TLD-300) of
size 0.32 x 0.32 x 0.09 cm3 provided by Harshaw Company. The measured absorbed
dose in TLD-300, Q-TLD (E) is obtained from the peak 3 response in the glow
curve relative to Co-60 calibration. The air kerma was converted into absorbed
dose in TLD-300 using the photon energy attenuation coefficient from [2].
5. Description of Results and Analysis:
-----------------------------------
Measured neutron reaction rates are given in Tables 5-7. They were compared
with the same quantities calculated with the same tools used in the ITER
design, i.e. MCNP 4A/B [10] code and FENDL-1/FENDL-2 [11,12] nuclear data
libraries. Analysis was performed also using the EFF-3 [13] library. Dosimetric
cross sections were taken from IRDF-90 [14] to compute the nutron reaction
rates in the MCNP run. The geometry model for MCNP-4B used in the calculation
of reaction rates, including neutron source backing and the experimental
environment (walls, floor, racks, ...) is given in mcnpfoil.inp.
C/E values were provided for all measured reaction rates, they are reported
in Tables 9-11.
Measured absorbed dose in TLD-300 is given in Table 8. It is compared
with the same quantity calculated with MCNP code and FENDL-1/FENDL-2, EFF-3.1
nuclear data libraries.
The geometrical model for MCNP used in the calculation of nuclear heating,
is given in mcnp_nh.inp. The comparison with TLD measurements requires, however,
the calculation of the absorbed dose in TLD, taking into account
the effects of the electron transport at the interface between the TLD and the
surrounding material. The absorbed dose in TLD (QTLD) is related to total dose
in material Q according to the following expressions:
Q = Qn+Qp
(QTLD ) = Cp Qp + Ce Cn Qn (1)
where QTLD is the absorbed dose in TLD,
Qn, Qp is the absorbed dose due to neutrons, photons in material (i.e. steel or
copper),
Cn is the ratio of the TLD/materialabsorbed neutron dose,
Cp is the ratio of the TLD/material absorbed photon dose,
Ce is the TLD neutron dose efficiency with respect to the photon dose efficiency,
taken from published data and weighted over the neutron spectra.
Simplified models have been adopted representing a smaller region limited to the
TLD volume and to a sufficient amount of surrounding material, to calculate Qn, Qp,
Cn and Cp. A neutron or photon surface source is applied to the boundary of the
limited region in the simplified models, with energy spectra recorded from the
mcnp_nh.inp run. These models are given in mcnp_hss.inp, mcnp_hcu.inp and
mcnp_tld.inp for steel, copper and TLD material respectively.
The Cn, Cp, Ce factors and Qn, Qp calculated using FENDL-1, FENDL-2 and EFF-3.1
are used to derive the calculated dose in TLD according to Eq.1. For all calculated
absorbed doses the fractional standard deviation is about 5% or less. C/E values
are given in Tables 12.
The calculations performed using the 2D discrete ordinates transport method is
described in [5] and [15]. The input data are also provided, including inputs for
the codes TRANSX, GIP, GRTUNCL and DORT.
6. Special Features:
----------------
None
7. Author/Organizer:
----------------
Experiment and analysis:
P. Batistoni, M. Angelone, M. Pillon, L. Petrizzi
ENEA
Centro Ricerche Energie Frascati
UTS Fusione
Via E. Fermi 27
C.P. 65
I-00044 Frascati (Rome)
Italy
Compiler of data for Sinbad:
P. Batistoni
ENEA
Centro Ricerche Energie Frascati
UTS Fusione
Via E. Fermi 27
C.P. 65
I-00044 Frascati (Rome)
Italy
E-mail: batiston at efr406.frascati.enea.it
Reviewer of compiled data:
I. Kodeli
OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
e-mail: ivo.kodeli at oecd.org
Acknowledgement
---------------
The experiment and the corresponding analysis was performed in the framework of
the EFDA (European Fusion Development Agreement) ITER Task (T-362-1997).
8. Availability:
------------
Unrestricted
9. References:
----------
[1] M. Martone, M. Angelone, M. Pillon, The 14 MeV Frascati Neutron
Generator, Journal of Nuclear Materials 212-215 (1994) 1661-1664;
[2] J.H. Hubble, Photon mass attenuation and energy-absorbtion
coefficients from 1 keV up to 20 MeV, Int. J. Appl. Rad. Isot. 33
(1982) 1269
[3] P. Batistoni, M. Angelone, L. Petrizzi, M. Pillon, “Neutron streaming
experiment for ITER bulk shield at the Frascati 14-MeV neutron
generator”, Proceedings of the 20th Symposium on Fusion Technology,
Marseille, France, 7-11 September 1998, Edited by B. Beaumont, P.
Libeyre, B. de Gentile, G. Tonon, CEA Cadarache 1998, Vol.2, pag. 1417
[4] M. Angelone, P. Batistoni, L. Petrizzi, M. Pillon, “Neutron streaming
Experiment at FNG :results and analysis”, Fusion Engineering and
Design 51-52, (2000) 653-661
[5] L. Petrizzi, P. Batistoni, I. Kodeli, “Sensitivity and uncertainty
analysis performed on a 14-MeV neutron streaming experiment”, Fusion
Engineering and Design 51-52, (2000) 843-848
[6] K. Seidel, M. Angelone, P. Batistoni et al., “Investigation of
neutron and photon flux spectra in a streaming mock-up for ITER”,
Fusion Engineering and Design 51-52, (2000) 855-861
[7] Nucl. Sci. Eng, 126, 176-186 (1997)
[8] P. Batistoni et al, ITER Task T.362: Neutron Streaming Experiment - Final
Report, EFF-Doc-639, July 1998
[9] P. Batistoni, L. Petrizzi, Analysis of the Neutron Streaming Experiment
using FENDL-1.0/2.0 and EFF-3.0/3.1 nuclear data libraries, EFF-DOC-673
[10] J. F. Briesmeister (Ed.), MCNP - A General Monte Carlo N-Particle
Transport Code, Version 4B, Report, Los Alamos National Laboratory,
LA-12625-M, March 1997.
[11] S. Ganesan and P. K. McLaughlin, FENDL/E - evaluated nuclear data
library of neutron interaction cross-sections and photon production
cross-sections and photon-atom interaction cross-sections for fusion
applications, version 1.0, Report IAEA-NDS-128, Vienna, May 1994.
[12] M. Herman, A. B. Pashchenko, Extension and improvement of the FENDL
library for fusion applications (FENDL-2), Report INDC(NDS)-373, IAEA
Vienna, 1997.
[13] A. J. Koning, H. Gruppelaar, A. Hogenbirk, Fusion Eng. Des. 37 (1997)
211-216.
[14] N. P. Kocherov, P. K. McLaughlin, The International Reactor Dosimetry
File (IRDF-90), Report IAEA-NDS-141, Rev. 2, Oct. 1993.
[15] I. Kodeli, Report on the 1999 Activity on ND-1.2.1 Subtask: Processed
Multigroup Covariance Files with extended options for EFF-3, EFFDOC-698
10. Data and Format:
---------------
FILE NAME bytes Content
---- ----------- ------ -------
1 fngstr-a.htm 17,611 This information file
2 fngstr-e.htm 58,935 Description of Experiment
3 mcnpfoil.inp 73,096 3-D model for MCNP-4A calculations of neutron
activation reaction rates
4 mcnp_nh.inp 86,865 3-D model for MCNP-4A calculations of nuclear
heating
5 mcnp_hss.inp 11,787 3-D simplified model for MCNP-4A calculations
of nuclear heating in stainless steel
6 mcnp_hcu.inp 11,837 3-D simplified model for MCNP-4A calculations
of nuclear heating in Copper
7 mcnp_tld.inp 12,110 3-D simplified model for MCNP-4A calculations
of nuclear heating in TLD-300
8 source.for 45,178 FORTRAN subroutine for MCNP source description
9 trx-fng.inp 1.777 Input data for TRANSX cross-section preparation
10 dort-fng.inp 10,880 Input data for GIP cross-section mixing, GRTUNCL
first collision source and DORT transport codes
11 fig1.gif 5.242 Fig. 1: Angular dependence of the source
12 fig2.gif 9.505 Fig. 2: Energy/angular dependence of the source
13 fig3.gif 20,911 Fig. 3: Geometry of the experimental mock-up
14 fig4.gif 14,342 Fig. 4: Activation foils position in the
channel and in the cavity
15 fig5.gif 9,633 Fig. 5: Geometry of the source
16 fed2000.pdf 455,809 Reference 4
17 fed2000a.pdf 699,972 Reference 5
18 eff-639.pdf 700,204 Reference 8
19 eff-673.pdf 66,110 Reference 9
19 eff-698.pdf 336.644 Reference 15
File fngstr-e.htm contains the following tables:
Tab. 1: Angular dependence of the source
Tab. 2: Angular/energy dependence of the source energy distribution
Tab. 3: Geometrical arrangement of the bulk shielding assembly
Tab. 4: Chemical composition of stainless steel AISI316
Tab. 5: Experimental results (E) of reaction rates measurements along the
central mock-up axis (ON-AXIS)
Tab. 6: Experimental results (E) of reaction rates measurements inside
the cavity (ON-AXIS)
Tab. 7: Experimental results (E) of reaction rates measurements in the
channel and in the cavity (OFF-AXIS)
Tab. 8: Measured dose in TDL-300, QTLD(E)
Tab. 9: Calculated reaction rates (C) along the central mock-up axis.
Comparison between calculated and measured values (C/E ratios)
(ON-AXIS)
Tab. 10: Calculated reaction rates (C) in the cavity. Comparison between
calculated and measured values (C/E ratios) (ON-AXIS)
Tab. 11: Calculated reaction rates (C) in the channel and in the cavity.
Comparison between calculated and measured values (C/E ratios).
(OFF-AXIS)
Tab. 12: Calculated reaction rates (C) in the channel and in the cavity.
Comparison between calculated and measured values (C/E ratios).
The figures are included in gif format.
SINBAD Benchmark Generation Date: 6/2003
SINBAD Benchmark Last Update: 6/2003
