ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 1
Cheolho Pyeon
Research Reactor Institute, Kyoto University, Japan
Thorium-Loaded Accelerator-Driven
System Experiments in
Kyoto University Research Reactor Institute
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 2
Contents
Background and Purpose Composition of ADS in Kyoto Univ. (KUCA + 100 MeV protons) Kyoto University Critical Assembly (KUCA)
Fixed-Field Alternating Gradient (FFAG) accelerator 232Th plate irradiation experiments in critical state
Analyses of 232Th fission and capture reactions
232Th-loaded ADS experiments in subcritical state
Static analyses: 232Th capture reaction rates
Kinetic analyses: Subcriticality by varying
Core spectrum
External neutron source Summary
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 3
Background
An original concept of ADS for producing energy and transmuting MA and LLFP
Energy amplifier system and Nuclear transmutation
232Th conversion study in thorium fuel cycle
Preliminary study on fission and capture reactions leading to
conversion ratio (Capture/ Fission) in Critical state analyses
232Th-loaded ADS for the variation of
Core spectrum: Fuel -> Thorium, HEU and NU
Moderator -> Polyethylene, Graphite, Beryllium and Aluminum
External source: 14 MeV neutrons vs. 100 MeV protons
Purpose
Conduct 232Th conversion study preliminarily in critical state
Investigate the neutronic characteristics of Th-ADS through the experiments
and the accuracy of numerical (MCNPX) analyses
Background and Purpose
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 4
Main parameters in the FFAG accelerator
# of sectors 12
Energy 2.5 – 150 MeV
Repetition rate 120 Hz
Average beam current 1 nA
Rf frequency 1.5 - 4.6 MHz
Field index 7.5
Closed orbit radius 4.4 - 5.3 m
Electron
LINAC
Main ring
(FFAG acc.)
KUCA
11 MeV, 5 mA (Max.) 100 MeV H+
H-
Max. power : 100 W
Yield : 1 ×1011 1/s
Proton beam current
1 nA
ADS composition
Charge convert
H- -> H+
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 5
KUCA A-core FFAG accelerator
ADS composition in KUCA
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 6
Conversion of Thorium fuel cycle
- Capture reactions
( , )232 233 233 233
22.3m 26.967dTh Th Pa Un
- Fission reactions
233U( , )n f
However, as preliminary, attention should be paid to the following:
- Capture reactions (by thermal neutrons moderated from high-energy neutrons)
233 233
26.967dPa U
- Fission reactions (by high-energy neutrons from spallation neutrons)
232Th ( , )n f (Threshold of 1 MeV neutrons)
General conversion concept Capture / Fission
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 7
Fig. KUCA core
Fig. Image of KUCA core and fuel assembly loaded
53.8cm
39.5cm
59.1cm
0.63cm(1/4")Polyethylene
0.3086cm(1/8")Polyethylene
0.15874cm(1/16")Enriched Uranium
152.4cm
Fuel Cell×36
Polyethylene
Fuel
assemblyAluminum
sheath
Collimator
region
Polyethylene
- KUCA core - A solid-moderated and -reflected core
F F F F F
F F F F F
F F F F F
F F F F F
12
C3 S5
S4 C1
C2 S6
KUCA core (Solid-moderated core)
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 8
Critical state
232Th plate irradiation experiments
F F F F F
F F F F F
F F UT F F
F F F F F
18
C3 S5
S4 C1
C2 S6
Polyethylene
(PE)
(486.68 mm)
Polyethylene
(PE)
(512.10 mm)
1”Al+1/2”PE×2
(50.80 mm)1/2”PE×5+1/8”PE×5
(79.38 mm)
Reflector 537.48 mm
(Lower)
Fuel 395.04 mm
(Unit cell 35 times+EUTh fuel)
Reflector 591.48 mm
(Upper)
(1/16”EU+1/8”PE+1/4”PE)×18
(Unit cell 18 times; 197.46 mm)
(1/16”EU+1/8”PE+1/4”PE)×17
(Unit cell 17 times; 186.49 mm)
(1/16”EU+1/8”Th+1/4”PE)
(10.97 mm)
Polyethylene
(PE)
(486.68 mm)
Polyethylene
(PE)
(512.10 mm)
1”Al+1/2”PE×2
(50.80 mm)1/2”PE×5+1/8”PE×5
(79.38 mm)
Reflector 537.48 mm
(Lower)
Fuel 395.04 mm
(Unit cell 35 times+EUTh fuel)
Reflector 591.48 mm
(Upper)
(1/16”EU+1/8”PE+1/4”PE)×18
(Unit cell 18 times; 197.46 mm)
(1/16”EU+1/8”PE+1/4”PE)×17
(Unit cell 17 times; 186.49 mm)
(1/16”EU+1/8”Th+1/4”PE)
(10.97 mm)
Polyethylene (PE)
(486.68 mm)
Unit cell
(10.97 mm)
1/8”PE+1/4”PE
(3.09+6.30) mm
1/16”EU
(1.59 mm)
Polyethylene (PE)
(512.10 mm)
1”Al plate
(25.4 mm)1/2”PE×2
(25.4 mm)
1/2”PE×5+1/8”PE×5
(79.38 mm)
Reflector 537.48 mm
(Lower)
Fuel 395.04 mm
(Unit cell 36 times)
Reflector 591.48 mm
(Upper)
Polyethylene (PE)
(486.68 mm)
Unit cell
(10.97 mm)
1/8”PE+1/4”PE
(3.09+6.30) mm
1/16”EU
(1.59 mm)
Polyethylene (PE)
(512.10 mm)
1”Al plate
(25.4 mm)1/2”PE×2
(25.4 mm)
1/2”PE×5+1/8”PE×5
(79.38 mm)
Reflector 537.48 mm
(Lower)
Fuel 395.04 mm
(Unit cell 36 times)
Reflector 591.48 mm
(Upper)
Fig. KUCA core (232Th plate irradiation core)
232Th plate size: 2”×2” ×1/8”
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 9
Fig. Measured -ray spectrum of irradiated 232Th plate
Results of 232Th plate irradiation exp.
0 500 1000 1500 2000 2500 300010
1
102
103
104
105
106
Co
un
t [s
-1]
Energy [keV]
Irradiated Th
Reaction Nuclide Measured RR
(1/s/cm3) C / E
Capture 233Pa (5.82±0.04)×106 2.18±0.04
Fission
91Sr (1.42±0.04)×105 1.39±0.05
92Sr (1.46±0.05)×105 1.36±0.06
97Zr (1.47±0.02)×105 1.35±0.03
135I (1.50±0.04)×105 1.32±0.04
142La (1.56±0.05)×105 1.27±0.05
Table Measured reaction rates (RR) and C/E values
Measurement Calculation C / E
Thermal neutron flux (1/s/cm3)
(5.87±0.05)×107 - -
Cd ratio 2.93±0.02 3.04±0.08 1.04±0.05
Table Neutron flux and Cd ratio
- Critical exp. (Confirmed)
Necessity of high-power operation in the core
Accuracy of numerical analyses by MCNPX
Discrepancy of 232Th fission and capture
reaction rates between exp. and cal.
Probability of subcritical experiments?
C. H. Pyeon, et al., Nucl. Sci. Eng., (2013). [in print]
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 10
Experimental Benchmarks on
the Th-Loaded ADS at KUCA
C. H. Pyeon, et al., Ann. Nucl. Energy, 38, 2298 (2011).
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 11
Void
Th
Void
Unit cell
Al
2.5
4 c
m
25
.4 c
m57.2
cm
下部
上部
Experimental settings
Protons Spallation
Neutrons
W target
Thorium core
Protons
W target
(80 mm dia.
10 mm thick)
In foils
(10*10*1 mm3
50*50*1 mm3)
Upper
Lower
Fuel size: 5×5
Volume: 27.65×27.65×25.40 cm3
keff = 0.03250 (ENDF/B-VII.0)
232Th(n, f ) threshold: 1.0 MeV
115In(n, n’)115mIn threshold: 0.3 MeV
Protons: 100 MeV, 50 mm dia., 30 pA
Exp. Settings of 232Th-loaded ADS Exp.
C. H. Pyeon, et al., Ann. Nucl. Energy, 38, 2298 (2011).
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 12
Fuel size: 7×7
Core volume: 38.71 x 38.71x 30.48 cm3
(2.4 times than Th-core)
keff = 0.02399 (ENDF/B-VII.0)
30.5
cm
2.54 cm
Unit cell
下部
上部 Upper
Lower
10-4
10-3
10-2
10-1
100
101
102
10-8
10-7
10-6
10-5
10-4
10-3
Energy [MeV]
Neutr
on
flu
x p
er
leth
arg
y [
A.U
.]
Th at 16.59 cm
ThGr at 16.59 cm
Fig. Neutron spectra of 232Th-loaded cores in ADS exp.
232Th-loaded ADS with Graphite
C. H. Pyeon, et al., Ann. Nucl. Energy, 38, 2298 (2011).
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 13
Confirmation of 232Th fission reactions generated by spallation neutrons
(using “fission turnoff” option in MCNPX)
232Th fission reactions by Monte Carlo approach
Solution
Convert Th fission reactions to capture reactions
(“fission turnoff” option)
Finally,
total source fissionRR RR RR
'fission total total captureRR RR RR RR
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
No
rmal
ized
Rea
ctio
n R
ate
[A.U
.]
Distance from core surface [cm]
Th_Experiment
Th_ENDF/B-VII
Th_ENDF/B-VII-No fission
Fig. Comparison of measured and calculated reaction rates in 232Th-loaded core
'total source captureRR RR RR
Code: MCNPX-2.5.0
Library: JENDL High Energy 232Th: ENDF/B-VII.0
Static Experiments in 232Th-loaded ADS
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 14
Comparative study on
Neutron spectrum (core)
Subcriticality (core)
External neutron source (target)
C. H. Pyeon, et al., Nucl. Sci. Eng., (2013). [in print]
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 15
X-sec. proportionality and Spectrum
----- 232Th capture
----- 115In capture
Fig. Proportionality of X secs. of 232Th and 115In in thermal neutron range
10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 10210-8
10-7
10-6
10-5
10-4
10-3
Th-PE
Th-Gr
Th-Be
Th-HEU
NU-PE
Neutron energy [MeV]
Ne
utr
on
flu
x p
er
leth
arg
y [
Arb
itra
ry u
nits]
Fig. Neutron spectrum in injection of 14 MeV neutrons
Fig. Neutron spectrum in injection of 100 MeV protons
- Measurement (Foil activation method)
Source:
14 MeV neutrons -> 93Nb(n, 2n)92mNb
(9 MeV threshold)
100 MeV protons -> 115In(n, n’)115mIn
(0.3 MeV threshold)
Core: In capture (~ Th capture; Proportionality)
-> 115In(n, )116mIn reactions
10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 10210-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Th-PE
Th-Gr
Th-Be
Th-HEU
NU-PE
Neutron energy [MeV]
Ne
utr
on
flu
x p
er
leth
arg
y [
Arb
itra
ry u
nits]
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 16
232Th-loaded ADS with 14 MeV neutrons
Fig. Comparison of measured 115In (n, )116mIn reaction rates in 232Th-loaded cores
Fig. Core configuration of 232Th-loaded cores
Fig. Th-PE cells Fig. Th-PE cells Fig. Th-Be cells
Confirmed
Effect of neutron spectrum on profile of 232Th capture reactions for 14 MeV neutrons
10 11 12 13 14 15 16 17 18 19 20
O
P
Q
R
T TP TP TP TP TP
U TP TP TP TP TP
V TP TP TP TP TP
W TP TP TP TP TP
X TP TP TP TP TP
Y
Z
In wire position
10 11 12 13 14 15 16 17 18 19 20
O
P
Q
R
T TB TB TB TB TB
U TB TB TB TB TB
V TB TB TB TB TB
W TB TB TB TB TB
X TB TB TB TB TB
Y
Z
In wire position
10 11 12 13 14 15 16 17 18 19 20
O
P
Q
R
T TH TH TH TH TH
U TH TH TH TH TH
V TH TH TH TH TH
W TH TH TH TH TH
X TH TH TH TH TH
Y
Z
In wire position
10 11 12 13 14 15 16 17 18 19 20
O
P
Q
R
T NP NP NP NP NP
U NP NP NP NP NP
V NP NP NP NP NP
W NP NP NP NP NP
X NP NP NP NP NP
Y
Z
In wire position
0 10 20 30 400
10.0
20.0
30.0
40.0
Distance from T target [cm]R
ea
ctio
n r
ate
s [
1/s
/cm
3/s
ou
rce
]
Th-PE
Th-Gr
Th-Be
Th-HEU-PE
NU-PE
Core region Polyethylene region
C. H. Pyeon, et al., Nucl. Sci. Eng., (2013). [in print]
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 17
Exp. vs. Cal. (14 MeV neutrons)
Fig. Core configuration of 232Th-Poly. cores
Fig. Comparison between measured and calculated 115In (n, )116mIn reaction rates in Th-PE core
Results
Good agreement with measured and calculated
(MCNPX) reaction rates
No difference between ENDF/B-VII.0 and JENDL-3.3
10 11 12 13 14 15 16 17 18 19 20
O
P
Q
R
T TP TP TP TP TP
U TP TP TP TP TP
V TP TP TP TP TP
W TP TP TP TP TP
X TP TP TP TP TP
Y
Z
In wire position
0 10 20 30 400
0.020
0.040
0.060
0.080
0.100
Distance from T target [cm]N
orm
aliz
ed
re
actio
n r
ate
s
Experiment
MCNPX (ENDF/B-VII)
Core region Polyethylene region
Core keff
Th-PE 0.00613
Th-Gr 0.00952
Th-Be 0.00765
Th-HEU-PE 0.58754
NU-PE 0.50867
Table MCNPX results of keff in Th cores
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 18
Profile of 232Th capture reaction rates
Fig. Measured 115In (n, )116mIn reaction rates (100 MeV protons)
Fig. Core configuration of 232Th-loaded core
Effects
1) Neutron spectrum in core
2) External neutron source at target
(14 MeV neutrons vs. 100 MeV protons)
Note: Protons; 100 MeV, 50 mm dia., 0.1 nA
Target; W, 50 mm dia., 9 mm thick
W
target core
region Reflector
region
0 10 20 30 400
10.0
20.0
Distance from W target [cm]
Re
actio
n r
ate
s [
1/s
/cm
3/s
ou
rce
]
Th-PE
Th-Gr
Th-Be
Th-HEU-PE
NU-PE
Core region Polyethylene region
0 10 20 30 400
10.0
20.0
30.0
40.0
Distance from T target [cm]
Re
actio
n r
ate
s [
1/s
/cm
3/s
ou
rce
]
Th-PE
Th-Gr
Th-Be
Th-HEU-PE
NU-PE
Core region Polyethylene region
Fig. Measured 115In (n, )116mIn reaction rates (14 MeV neutrons)
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 19
Pulsed neutron method (232Th-loaded ADS)
Fig. Core configuration of 232Th-Poly. Cores (100 MeV protons)
Fig. Results in Th-HEU-PE with 100 MeV protons
Fig. Results in Th-HEU-PE with 14 MeV neutrons
Cal. Exp.
Core MCNPX 100 MeV Protons
14 MeV Neutrons
Th-HEU-PE 0.5876 0.7346 0.6577
Table Results in keff (3He #3; Area ratio method)
20 19 18 17 16 15 14 13 12 11 10
K
J
I
H
G TH TH TH TH TH
E TH TH TH TH TH
D TH TH TH TH TH
B TH TH TH TH TH
A TH TH TH TH TH
A'
In wire position
3He #1
3He #2
3He #3
3He #4
0 0.002 0.004 0.006 0.008 0.0110-4
10-3
10-2
10-1
100
101
102
Time [s]
Co
un
t [c
ps]
He-3 #1
He-3 #2
He-3 #3
He-3 #4
eff = 8.491E-03; SRAC-CITATION 107-G, 3-D
a = 5065 ± 28 (100 MeV Protons)
5288 ± 13 (14 MeV Neutrons)
0 0.002 0.004 0.006 0.008 0.0110-4
10-3
10-2
10-1
100
101
102
Time [s]
Co
un
t [c
ps]
He-3 #1
He-3 #2
He-3 #3
C. H. Pyeon, et al., Nucl. Sci. Eng., (2013). [in print]
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 20
Th-loaded ADS benchmarks
Core Cell patter keff
Th-PE 1/8”Th+1/2”PE 0.00613
Th-Gr 1/8”Th+1/2”Gr 0.00952
Th-Be 1/8”Th+1/2”Be 0.00765
Th-HEU-PE 1/8”Th+1/16”HEU+3/8”PE 0.58754
NU-PE 1/8”NU+1/2”PE 0.50867
Th-HEU-5PE 1/8”Th+5*(1/16”HEU+3/8”PE) 0.85121
Th-HEU-Gr-PE 1/8”Th+4*(1/16”HEU+1/2”Gr)+1/8”PE 0.35473
Table List of Th-loaded ADS cores
* Contributed for IAEA on Feb. 2013
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 21
Core 14 MeV neutrons 100 MeV protons
PNS method Noise method PNS method Noise method
Th-PE Available Available - -
Th-Gr Available Available - -
Th-Be Available - - -
Th-HEU-PE Available Available Available Available
NU-PE Available - - -
Th-HEU-5PE Available Available Available Available
Th-HEU-Gr-PE Available Available Available Available
Table List of subcriticality data in all the cores shown in previous page
Subcriticality measurements
* Contributed for IAEA on Feb. 2013
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 22
Summary
ADS project in Kyoto Univ. Research Reactor Institute Energy amplifier system using ADS with high-energy protons
232Th plate irradiation experiments
Conversion study on 232Th fission and capture reactions in critical state: -> Discrepancy between experiments and calculations Thorium-loaded ADS experiments ADS experiments with 100 MeV protons and 14 MeV neutrons Static: Reaction rate analyses of 232Th capture reactions Kinetic: Subcriticality by the Pulsed neutron method by varying Neutron spectrum in the core External neutron source at the target Future plans Subcritical multiplication analyses of M and k-source Critical experiments on investigation of further captures (232Pa -> 233U) and fissions (233U) Investigate the probability of conversion analyses in subcritical states
ThEC13, Geneva, 28th-31st Oct., 2013
C. H. Pyeon, Kyoto Univ. 23
PHYSOR2014 in Kyoto
Int. Conf. Physic of Reactor in 2014 (PHYSOR2014; ANS Topical Mtg.) 28th Sep. to 3rd Oct. 2014 Sub-title: “The Role of Reactor Physics towards a Sustainable Future” Key dates - Start “Paper submission” and “Registration” on 25th Oct. 2013 - Deadline of paper submission on 20th Dec. 2013 Technical sessions 15 Tracks, 8 Special sessions, One-day Workshop (such as ADS ) Access to, http://physor2014.org/
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