Cheolho Pyeon Research Reactor Institut e, Kyoto University, Japan [email protected]

ThEC13, Geneva, 28th-31st Oct., 2013

C. H. Pyeon, Kyoto Univ. 1

Cheolho PyeonCheolho PyeonResearch Reactor Institute, Kyoto University, JapanResearch Reactor Institute, Kyoto University, Japan

[email protected]@rri.kyoto-u.ac.jp

Thorium-Loaded Accelerator-Driven Thorium-Loaded Accelerator-Driven

System Experiments inSystem Experiments in

Kyoto University Research Reactor Kyoto University Research Reactor

InstituteInstitute



ContentContentss

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



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 Background and PurposePurpose



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

ElectronLINAC

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 ADS compositioncomposition

Charge convertH- -> H+



KUCA A-core100 MeV

proton

beam

line

FFAG accelerator

ADS composition in ADS composition in KUCAKUCA



Conversion of Thorium fuel Conversion of Thorium fuel cyclecycle

- Capture reactions

( , )232 233 233 23322.3m 26.967d

Th Th Pa Un

- Fission reactions

233 U ( , )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



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

Fuelassembly

Aluminumsheath

Collimatorregion

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 KUCA core (Solid-moderated core)core)



Critical state

232232Th plate irradiation Th plate irradiation experimentsexperiments

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”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)


Fuel 395.04 mm(Unit cell 35 times+EUTh fuel)




(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)


1”Al plate (25.4 mm)

1/2”PE× 2(25.4 mm)

1/2”PE× 5+1/8”PE× 5(79.38 mm)


Fuel 395.04 mm(Unit cell 36 times)



Unit cell(10.97 mm)

1/8”PE+1/4”PE(3.09+6.30) mm

1/16”EU(1.59 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)


Fuel 395.04 mm(Unit cell 36 times)


Fig. KUCA core (232Th plate irradiation core)

232Th plate size: 2”×2” ×1/8”



Fig. Measured -ray spectrum of irradiated 232Th plate

Results of Results of 232232Th plate irradiation Th plate irradiation exp. exp.

0 500 1000 1500 2000 2500 3000101

102

103

104

105

106

Cou

nt [

s-1 ]

Energy [keV]

Irradiated Th

Reaction NuclideMeasured 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±0.081.04±0.0

5

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]



Experimental Benchmarks on Experimental Benchmarks on

the Th-Loaded ADS at KUCAthe Th-Loaded ADS at KUCAC. H. Pyeon, et al., Ann. Nucl. Energy, 38, 2298 (2011).



Th

Th

Th

Th Th

Th

Th

Th

Th

Th

Th

Th

Th

Th

Th

Th

Th

Th

8.0

cm

インジウム箔（10x10x1mm3）（50x50x1mm3） Wターゲット

φ（ 80ｘ10mm3）

Th

Th

Th

Th

Th

Th

Th

27.65 cm

27.6

5 cm

陽子ビーム

Void

Th

Void

Unit cell

Al

2.54

cm

25.4

cm

57.2

cm

下部

上部

Experimental settings

Protons SpallationNeutrons

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).



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 c

m

2.54 cm

Unit cell

下部

上部

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

38.71 cm

38.7

1 cm

Upper

Lower

10-4 10-3 10-2 10-1 100 101 10210-8

10-7

10-6

10-5

10-4

10-3

Energy [MeV]N

eutr

on f

lux

per

leth

argy

[A

.U.]

Th at 16.59 cm ThGr at 16.59 cm

Fig. Neutron spectra of 232Th-loaded cores in ADS exp.

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

TG

38.71 cm

38.7

1 cm

232232Th-loaded ADS with Th-loaded ADS with GraphiteGraphite

C. H. Pyeon, et al., Ann. Nucl. Energy, 38, 2298 (2011).



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

Nor

mal

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-2.5.0Library: JENDL High Energy232Th: ENDF/B-VII.0

Static Experiments in Static Experiments in 232232Th-loaded Th-loaded ADSADS



Comparative study onComparative study on Neutron spectrum (core)Neutron spectrum (core) Subcriticality (core)Subcriticality (core) External neutron source External neutron source

(target)(target) C. H. Pyeon, et al., Nucl. Sci. Eng., (2013). [in print]



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 [A

rbitr

ary

un

its]

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 [A

rbitr

ary

un

its]



232232Th-loaded ADS with 14 MeV Th-loaded ADS with 14 MeV neutronsneutrons

Fig. Comparison of measured 115In (n, )116mIn reaction rates in 232Th-loaded cores

Fig. Core configuration of 232Th-loaded cores

Fig. Th-PE cellsFig. 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/c

m3 /s

ou

rce

]

Th-PE

Th-Gr

Th-Be

Th-HEU-PE

NU-PE

Core region Polyethylene region




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 coreResults

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

act

ion

ra

tes

Experiment

MCNPX (ENDF/B-VII)


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



Profile of Profile of 232232Th capture reaction ratesTh 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

Wtarge

t

coreregio

n

Reflector region

0 10 20 30 400

10.0

20.0

Distance from W target [cm]

Re

act

ion

ra

tes

[1/s

/cm

3 /so

urc

e]

Th-PE

Th-Gr

Th-Be

Th-HEU-PE

NU-PE


0 10 20 30 400

10.0

20.0

30.0

40.0

Distance from T target [cm]

Re

act

ion

ra

tes

[1/s

/cm

3 /so

urc

e]

Th-PE

Th-Gr

Th-Be

Th-HEU-PE

NU-PE


Fig. Measured 115In (n, )116mIn reaction rates (14 MeV neutrons)



Pulsed neutron method (232232Th-loaded Th-loaded ADSADS)

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 MCNPX100 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 [cp

s]

He-3 #1

He-3 #2

He-3 #3

He-3 #4

eff = 8.491E-03; SRAC-CITATION 107-G, 3-D

= 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 [cp

s]

He-3 #1

He-3 #2

He-3 #3




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



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



SummarySummary 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



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/

Documents

Cheolho Pyeon Research Reactor Institut e, Kyoto University, Japan [email protected]