measurements and calculations of the neutron spectrum in different irradiation channels
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Measurements and calculations of the neutron spectrumin different irradiation channels
of the TRIGA Mark II reactor, SloveniaR. Jaćimović1, A. Trkov2, M. Maučec3
1“Jožef Stefan” Institute, Ljubljana, Slovenia2 IAEA, Vienna, Austria3 HOLTEC International, Marlton, USA
LjubljanaSloveniaLjubljanaSlovenia
"Jozef Stefan" Inst itute
1st RCM of the IAEA CRP on Reference Database for NAA, Vienna, AustriaOctober 2005
Introduction• TRIGA Mark II reactor (250 kW) at the JSI from
1966. • The k0-standardization method was introduced in
1987.• TRIGA Mark II reactor (250 kW)
– irradiation channels,– neutron spectral parameters,– neutron fluence gradients,– neutron self-shielding.
• Calibrated HPGe detector– absolutely calibrated point sources,– counting geometry.
Nuclear research reactor TRIGA Mark II (250 kW)
- Short and long irradiation in the CC: th ~ 10·1012 cm-2 s-1
- Short irradiation in the PT and in the FPTS (up-to 30 min.) th ~ 3.5·1012 cm-2 s-1
- Long irradiation in the IC-40 (typically 20 hours) th ~ 1.1·1012 cm-2 s-1
Carousel
Fuel elem ents 20% U -235
Control rods
N eutron source
Irrad iation channels
Fast pneum atic transfersystem
P neum atic transpor t tubechannel
Central channel
Triangular channel
Horizontal section of the TRIGA Mark II reactor (core No. 176)
El. NuclideT1/2
(s, %)E, keV FCd Gepi
Ēr, eV,(s, %)
Q0
(s, %)k0
(s, %)
Au 198Au2.695 d
(0.1)411.8 0.991 1
5.65(7.1)
15.71(1.8)
1
Co 60Co5.271 y(0.02)
1173.2 1 1136(5.1)
1.993(2.7)
1.32(0.4)
Fe 59Fe44.63 d
(0.2)1099.3 1 1
637(24.0)
0.975(1.0)
7.77E-5(0.5)
In 116mIn54.15 min
(0.1)1293.5 1 1
1.56(1.9)
16.8(1.9)
2.29(0.8)
Lu 176mLu3.635 h
(0.3)88.4 1 1
16.1(5.0)
34.8(3.1)
1.73E-2(1.5)
Mn 56Mn2.5785 h
(0.02)846.8 1 1
468(11.0)
1.053(2.6)
4.96E-1(0.6)
99Mo66.02 h(0.02)
739.5 1 1241
(20.0)53.1(6.1)
8.46E-5(0.7)
99mTc6.02 h(0.3)
140.5 1 1241
(20.0)53.1(6.1)
5.27E-4(0.5)
Mo
101Tc14.2 min
(0.7)306.8 1 1
672(14.0)
18.84(4.3)
3.73 10-4
(1.3)
Th 233Pa27.0 d(0.4)
312.2 1 154.4(0.9)
11.53(3.6)
2.52E-2(0.5)
U 239Np2.335 d
(0.2)277.6 1 1
16.9(1.2)
103.4(1.3)
3.40E-3(0.8)
69mZn13.76 h(0.15)
438.6 1 1590
(10.0)3.19(1.4)
3.98E-4(0.6)
Zn 65Zn244.0 d(0.08)
1115.5 1 12560(10.0)
1.908(4.9)
5.72E-3(0.4)
Zr 95Zr64.02 d(0.016)
724.2+756.7
1 0.9836260(4.0)
5.306(3.3)
2.000E-4(1.2)
Relevant nuclear data used for determination of f and
F. De Corte, A. Simonits, Atomic Data and Nuclear Data Tables, 85 (2003) 47-67.
Spectral parameters of the neutron fluence rate: f and
CoreNo.
Irr.channel
MonitorsCd-ratio method f
PT13.6.2000
198Au-69mZn-65Zn-95Zr
31.780.71 -0.02110.0059
169IC-40
8.3.2001198Au-60Co-56Mn-101Tc-233Pa-239Np-
69mZn-65Zn-95Zr
27.340.43 -0.00880.0062
PT3.4.2002
198Au-59Fe-56Mn-99Mo-99mTc-69mZn-
65Zn-95Zr
28.030.81 -0.01510.0068
176
IC-4016.4.2002
198Au-59Fe-116mIn-176mLu-69mZn-
65Zn-95Zr
28.740.81 -0.01130.0046
-2,0
-1,8
-1,6
-1,4
1 10 100 1000 10000 Ēr, keV
y i, re
l. un
its
PT (No-169)
PT (No-176)
IC-40 (No-169)
IC-40 (No-176)PT (169): = - 0,0211
PT (176): = - 0,0151
-1,5
-1,4
-1,3
1 10 100 1000 10000 Ēr, (keV)
y i, re
l. un
its
IC-40 (176): = - 0,0113
IC-40 (169): = - 0,0088
rth
rerCdrCdr G
GRFQf
,
,,,,0 1)(
ithieiiCdiCdiri GGQRFEy ,,,0,,,
_
/)(1loglog
iii bxy
N
xx
N
yxyx
N
iiN
ii
N
ii
N
iiN
iii
2
1
1
2
11
1
N
ii
N
ii xy
Nb
11
1
Au-197 Activation in the CF, 14.5.2002
0,70
0,75
0,80
0,85
0,90
0,95
1,00
1,05
IC-10 IC-8 IC-6 IC-4 IC-2 IC-40 IC-38 IC-36 IC-34 IC-32 IC-30
Carusel channels
norm
sp.
act
iv. A
u-19
8
Measured
React.Rate
MCNP
Experimental and MCNP results for thermal neutron fluence rate
Channel Experimental Total fluencerate
(MCNP)
Reactionrate
(MCNP)
Spectralratio
(MCNP)
Spectral ratio(Measured)
IC-10 0.887 0.748 0.769 37.48IC-8 0.893 0.764 0.808 36.20IC-6 0.893 0.799 0.836 35.99IC-4 0.916 0.878 0.904 34.23IC-2 0.943 0.945 1.013 32.45
IC-40 1.000 1.000 1.000 29.04 28.74 0.81*IC-38 1.025 1.023 0.983 25.30IC-36 1.019 1.029 0.957 24.14IC-34 1.024 1.007 0.965 27.40IC-32 0.976 0.956 0.991 34.31IC-30 0.948 0.893 0.964 39.51
* Experimentally determined by “Cd ratio multi-monitor method”. The followingset of monitors was used: Al-Au(0.1%), Al-In(0.099%), Al-Lu(0.1%), Fe(99.9%),Zn(99.99%) and Zr(99.8%).
Comparison of experimental results for reaction rate with these of Monte Carlo calculations in 11 carousel channels at the TRIGA
reactor. Parameter f was obtained only by simulation
Temporal variation of the neutron fluence rate in the IC-40 channel
k = - 0.005
92
96
100
104
0 4 8 12 16 20Irradiation time, h
Pow
er, %
9-9-2002 16-9-2002 23-9-20027-10-2002 6-1-2003 Avg. (safety channel)
F(t) = 1 + k·t
Irradiation Position ofcompensating rod
Position ofregulating rod
Slope [1/h](from 5 to 20 h)
9.-10.9.2002 400 from 420 to 263 k = - 0.005516.-17.9.2002 400 from 426 to 258 k = - 0.005923.-24.9.2002 400 from 418 to 231 k = - 0.00397.-8.10.2002 350 from 428 to 262 k = - 0.00506.-7.1.2003 350 from 426 to 282 k = - 0.0046
The power of the TRIGA Mark II reactor reading from the safety channel
27. and 28.1.2003
Temporal variation of the neutron fluence rate in the IC-40 channel
240
290
340
390
440
490
0 5 10 15 20 25Irradiation time, h
Ste
p of
regu
latin
g ro
d
94
95
96
97
98
99
100
101
102
Pow
er, %
Step of regulating rod Power
a)
94
96
98
100
102
104
450 500 550 600 650 700Step of regulating rod (looking from bottom of the core)
Pow
er, %
b)
10
12
14
16
18
20
22
24
26
0 5 10 15 20 25Irradiation time, h
Tem
pera
ture
of w
ater
, 0 C
TH1 TH2
c)
20. and 21.1.2003
TH2: at the mean of the pool water at 0.5 m depth
TH1: at the entrance near the reactorwall at 1 m depth
Axial and radial gradients of the neutron fluence rate
A, 0 -5 mm (top)
D, 15 -20 mm (bottom )B, 5 -10 mm
C, 10 -15 mm
20 m
m
1 4 m m
Fe wire = 0.4 mm
1
10
100
1000
10000
100000
0 500 1000 1500 2000
E, keV
Cou
nts
54Mn
59Fe 59Fe
Thermal neutron fluence rate: 58Fe(n,)59FeFast neutron fluence rate: 54Fe(n,p)54Mn
From the same spectrum !!!
Normalized specific activities of 59Fe and 54Mn vs. density for five matrices in the IC-40 and in the PT channels
0,94
0,96
0,98
1,00
1,02
1,04
1,06
-0,1 0,1 0,3 0,5 0,7 0,9 1,1
Density, g/cm3
Nor
mal
. 59Fe
a)
Cel
lulo
se
Mus
cle
SiO
2
H2O
+1,5%
-1,5%
Air
IC-40
0,94
0,96
0,98
1,00
1,02
1,04
1,06
-0,1 0,1 0,3 0,5 0,7 0,9 1,1
Density, g/cm3
Nor
mal
. 59Fe
b)
Air
Cel
lulo
se
Mus
cle
SiO
2
H2O
+2,3%
-2,3%
PT
0,88
0,92
0,96
1,00
1,04
1,08
-0,1 0,1 0,3 0,5 0,7 0,9 1,1
Density, g/cm3
Nor
mal
. 54 M
n
+2,6%
-2,6%
Air
Cel
lulo
se
Mus
cle
H2O
a)
SiO
2
IC-40
0,88
0,92
0,96
1,00
1,04
1,08
-0,1 0,1 0,3 0,5 0,7 0,9 1,1
Density, g/cm3
Nor
mal
. 54M
n
+3,5%
-3,5%A
ir
Cel
lulo
se
Mus
cle
H2O
b)
SiO
2
PT
Specific activities and factors Gth, Forg and Finorg
Gth - not characteristic of nuclei, but depending ofdimensions and composition of the sample
Gth,org = 1.01 Gth,inorg = 0.97
PT IC-40 Sample Normal.
59Fe rsd, % Total rsd, %
Normal. 59Fe rsd, % Total
rsd, % Air 0.992 2.57 1.002 1.69
Cellulose 1.028 3.17 0.998 2.86 Muscle 1.018 3.30 1.015 2.73
SiO2 0.969 2.77 0.976 2.08 H2O 0.994 4.85
2.31
1.009 2.99
1.50
CelluloseMuscleH2O
SiO2
Axial and radial gradients of the thermal neutron fluence rate in different samplesPT IC-40
0,92
0,94
0,96
0,98
1,00
1,02
1,04
1,06
A B C DPosition, (A=top, D=bottom)
Nor
mal
. 59 Fe
Air H2O SiO2 Muscle Cellulose
a) -1.3%/cm
0,92
0,94
0,96
0,98
1,00
1,02
1,04
1,06
1,08
0 100 200 300 400 500 600Angle, 0
Nor
mal
. 59Fe
Air H2O SiO2 Muscle Cellulose
b)3.8%/cm
0,92
0,94
0,96
0,98
1,00
1,02
1,04
1,06
A B C DPosition, (A=top, D=bottom)
Nor
mal
. 59 Fe
Air H2O SiO2 Muscle Cellulose
a)3.0%/cm
0,92
0,94
0,96
0,98
1,00
1,02
1,04
1,06
-200 -100 0 100 200 300 400Angle, 0
Nor
mal
. 59Fe
Air H2O SiO2 Muscle Cellulose
b)1.8%/cm
HPGe closed end coaxialdetector (OR4)40% relative efficiencyat 1332.5 keV (60Co)(dimensions are in mm)
p lexiglass
P VC tube
6 (vacuum )
2 (p lexiglass)1 .27 (Al)
0.5 (L i)
84 .070.0
209 .77
89.77
49.77
29.77
9 .77
L iC rystal (Ge)
N -contact (L i)P -contact 0 .3 m (B )
Al
65.7
8 .8
79.8
5 8 .0
65.7
Geometrical correction factor for absolute calibration for detector OR4
Detector OR4
0
2
4
6
8
10
12
14
16
0K+P 1K+P 2K+P 3K+P 5K+PDistance code
Diff
eren
ce, %
Co-57(122.1keV) Hg-203(279.2 keV) Cr-51(320.1keV)Cs-137(661.7keV) Mn-54(834.8keV) Zn-65(1115.5keV)
a)
-6,0
-4,0
-2,0
0,0
2,0
4,0
0K+P 1K+P 2K+P 3K+P 5K+PDistance code
Diff
eren
ce, %
Co-57(122.1keV) Hg-203(279.2 keV) Cr-51(320.1keV)Cs-137(661.7keV) Mn-54(834.8keV) Zn-65(1115.5keV)
b)
-6,0
-4,0
-2,0
0,0
2,0
4,0
0K+P 1K+P 2K+P 3K+P 5K+PDistance code
Diff
eren
ce, %
Co-57(122.1keV) Hg-203(279.2 keV) Cr-51(320.1keV)Au-198(411.8keV) Cs-137(661.7keV) Zn-65(1115.5keV)
Distance, cm
Diffe
renc
e, %
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