thorium-loaded accelerator-driven system … accelerator-driven system experiments in ... energy...

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

C. H. Pyeon, Kyoto Univ. 1

Cheolho Pyeon

Research Reactor Institute, Kyoto University, Japan

[email protected]

Thorium-Loaded Accelerator-Driven

System Experiments in

Kyoto University Research Reactor Institute



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



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



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+



KUCA A-core FFAG accelerator

ADS composition in KUCA



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



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)



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


(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


(1/16”EU+1/8”PE+1/4”PE)×17


(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”



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]



Experimental Benchmarks on

the Th-Loaded ADS at KUCA

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



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.




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




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



Comparative study on

Neutron spectrum (core)

Subcriticality (core)

External neutron source (target)




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]



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




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 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 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


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


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



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




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



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



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/

http://physor2014.org/

thorium-loaded accelerator-driven system … accelerator-driven system experiments in ... energy...

Documents