Benchmark Experiments of Accelerator Driven …...HPPA5, SCK･CEN, 6-9 May 2007 C. H. Pyeon, KURRI,...

HPPA5, SCK･CEN, 6-9 May 2007

C. H. Pyeon, KURRI, Japan

C. H. Pyeon, T. Misawa, H. Unesaki, K. Mishima and S. Shiroya

(Kyoto University Research Reactor Institute, Japan)

Benchmark Experiments of Accelerator Driven Systems (ADS) in

Kyoto University Critical Assembly (KUCA)



Contents

Background and PurposeA plan of ADSR (Kart & Lab. Project):Accelerator Driven Subcritical Reactor (ADSR) in Kyoto University Critical Assembly (KUCA) by using Fixed Field Alternating Gradient (FFAG) Accelerator

Neutron spectrum experiments by Foil activation method- 14MeV neutron experiment (Pulsed neutron generator)- High-energy proton experiment (FFAG accelerator)ADS collaboration research in Japan

IAEA benchmark problem

Summary



Background

ADS Research and Development:

producing energy and transmuting minor actinides

and long-lived fission products

A neutron source in next generation of KURRI andintroduction of a new accelerator

Injection of 150MeV proton beam into KUCA core (with Tungsten (W) target) on Aug. 2007

Investigation of main characteristics of ADSR using KUCA core with 14MeV pulsed neutrons generator



Purpose

Conduct feasibility study of ADSR in KURRI as Energy Amplifier System

Examine subcritical neutronic characteristics through experiments in KUCA (KUCA A core + 14MeV pulsed neutron generator)

Assess neutronic characteristics for 14MeV neutrons by MCNP analyses with nuclear data libraries

Establish measurement techniques- Reaction rate distribution, Neutron spectrum, etc.- Subcriticality, Neutron multiplication, Neutron decay constant



FFAG Accelerator

Main parameters in the FFAG accelerator

# of sectors 12 Energy 2.5 - 150MeV Repetition rate 120Hz Average beam current 1nA Rf frequency 1.5 - 4.6MHz Field index 7.5 Closed orbit radius 4.4 - 5.3m

Ion Generator

Ion Beta(FFAG Acc.) Main Ring

(FFAG Acc.)

KUCABooster

(FFAG ACC.)

100keV 2.5MeV 20MeV 150MeV

H+

Max. Power : 100WYield : 1 ×1010 n/s



KUCA A-core & FFAG Accelerator

KUCA A coreBeam LineFFAG Accelerator



KUCA A-core & 14MeV D-T Accelerator

KUCA A-core

Cockcroft-Walton type Accelerator

Accelerator (D-T reactions)

TritiumTarget

- 14MeV Pulsed Neutrons- Yield: 1×109 n/s, Intensity: 0.5mA

Critical Assembly- Highly enriched 235U- Polyethylene Reflector & Moderator- Thermal neutron field

Accelerator (D-T reactions)- 14MeV Pulsed Neutrons- Yield: 1×109 n/s, Intensity: 0.5mA

Critical Assembly- Highly enriched 235U- Polyethylene Reflector & Moderator- Thermal neutron field

BeamInjection



KUCA A-core (with Neutron guide)

Fig. Image of KUCA A-core and fuel assembly loaded

53.8cm

39.5cm

59.1cm

0.63cm(1/4")Polyethylene


0.15874cm(1/16")Enriched Uranium

152.4cm

Fuel Cell×36

Polyethylene

Fuelassembly

Aluminumsheath

Collimatorregion

Polyethylene

- KUCA A-core -A solid-moderated and reflected core

Fig. KUCA A-core with neutron guide

F F F F F

F F F F F

F F SV F F

F F SV F F

22 SV 22

s'

s s s

s s s

b bs bs bs b

b bs bs bs b

f fs fs fs f

C3 S5

S4 C1

C2 S6



Neutron Spectrum Experiments by 14MeV Neutrons

Fig. KUCA A-core with neutron guide

F F F F F

F F F F F

F F SV F F

F F SV F F

22 SV 22

s'

s s s

s s s

b bs bs bs b

b bs bs bs b

f fs fs fs f

C3 S5

S4 C1

C2 S6

Irradiation- Positions: Core center and Target- Method: Foil activation method - Irradiation time: 3 to 6 hrsSubcriticality- 0.87, 1.23, 1.75%Δk/kMCNP-4C2 and ENDF/B-VI.2

Irradiation- Positions: Core center and Target- Method: Foil activation method - Irradiation time: 3 to 6 hrsSubcriticality- 0.87, 1.23, 1.75%Δk/kMCNP-4C2 and ENDF/B-VI.2

Reaction Threshold[MeV]

Size[mm3]

115In (n, n’) 115mIn 0.32

2.97

3.2592Nb (n, 2n) 92mNb 9.05 45×45×2

Normalization

56Fe (n, p) 56Mn

45×45×3

45×45×5

45×45×527Al (n, α) 24Na

1φ×0.05197Au (n, γ) 198Au

Table Activation foils with threshold energy and size



Reaction Rates Evaluation

Core Threshold[MeV]

C/E (0.87%Δk/k)

C/E (1.23%Δk/k)

C/E(1.75%Δk/k)

0.32 2.10 ± 0.05

0.20 ± 0.01

0.92 ± 0.03

None

2.97

3.25

115In

9.05

2.31 ± 0.05

0.14 ± 0.01

1.10 ± 0.03

None

2.22 ± 0.0556Fe 0.17 ± 0.0127Al 1.05 ± 0.0393Nb 0.10 ± 0.01

Table Comparison of measured reaction rates with calculated ones

Target C/E115In 4.50 ±

0.13 0.88 ±0.02 1.26 ±0.04

56Fe27Al93Nb 1.29 ±

0.04

Reaction rates evaluation

Good: 27Al within 10% error regardless of subcriticalityLarge discrepancy: 115In, 56Fe and 93NbRelationship between C/E value and subcriticality



Unfolding Evaluation

10-1 100 10110-5

10-4

10-3

10-2

10-1

100

101

Energy [MeV]

Neu

tron

flux

[Arb

trary

uni

ts]

ρ = 1.23 %Δk/k

Unfolding (SANDII)

Initial guess (MCNP)

Fig. Comparison of unfolding with initial guess

Numerical analyses

- Unfolding by SANDII (based on measured reaction rates)

- Initial guess by MCNP (ENDF/B-VI.2)

Good evaluation by unfolding analyses based on measured reaction rates



Neutron Spectrum Experiments at FFAG accelerator

50 mm

W (t = 3mm)

Nb (t = 1mm)

Bi (t = 3mm)

500mm

750mm

Beam duct 500mm

540mm

200mm

Flange

25mm

Proton beam

Proton beam (At beam dump: 70MeV, 0.4n)184W target and 93Nb (Norm. factor of neutron generation) 209Bi Threshold Energy (15 to 90MeV): 209Bi (n, xn) 210-xBi (x=3 to 12)

Fig. Top view of PoP FFAG acc. (KEK)



Neutrons and Protons Estimation

Reaction Threshold[MeV]

Measured reaction rate

209Bi (n,3n) 207Bi 14.42

22.55

29.62

38.13

45.37

54.24

61.69

70.89

78.47

87.94

-

209Bi (n,4n) 206Bi (1.51 ± 0.01) ×105

209Bi (n,5n) 205Bi (1.01 ± 0.03) ×105

209Bi (n,6n) 204Bi (2.37 ± 0.02) ×104

209Bi (n,7n) 203Bi (6.35 ± 0.16) ×103

209Bi (n,8n) 202Bi (2.74 ± 0.07) ×102

209Bi (n,9n) 201Bi -

209Bi (n,10n) 200Bi -

209Bi (n,11n) 199Bi -

209Bi (n,12n) 198Bi -

Table Measured reaction rates obtained at FFAG acc.

10-3 10-2 10-1 100 101 10210-7

10-6

10-5

10-4

10-3

10-2

Neutron energy [MeV]

Neu

tron

flux

[Arb

itrar

y un

its]

Proton beam injection

70MeV

80MeV

100MeV

Fig. Calculated neutron spectrum evaluated by MCNPX

About 60MeV neutron generation by about 70MeV proton injection onto 184WUseful foil of 209Bi covering wide rangeof threshold energy



KURRI (Kart & Lab. project): KUCA, FFAG Accelerator Thermal neutron field → Energy amplifier system

JAEA (J-PARC project): FCA, TEF-P, TEF-TFast neutron field → Nuclear Transmutation

User and support group: Tohoku Univ., Nagoya Univ., Kinki Univ., etc.

Subcriticality measurement (Noise method, NSM method, etc.)Neutronic characteristics (Neutron flux, Neutron spectrum, etc.)Nuclear Transmutation (MAs, FPs, etc.)

ADSR neutronsource (Thermal)

KUCA (Thermal)FFAG Acc. (1Gev)

KUCA (Thermal)FFAG Acc. (150Mev)

ADS TestReactor (Fast)

TEF-P TEF-TJ-PARC

LINAC 800MeV

FCA

ADSIncineration (Fast)

KURRI JAEA

ADS Collaboration Research in Japan



Phase I: Static experiments (14MeV neutrons)

Reaction rates distribution, Neutron spectrum, Reactivity

Phase II: Kinetic experiments (14MeV neutrons)

Neutron multiplication, Subcriticality measurement method(Rossi-α, Feynman-α, Pulsed neutrons and

Neutron source multiplication (NSM) methods)Phase III: Static and Dynamic experiments (150MeV protons)

Above topics, γ-ray distribution, Power monitoring, etc.

- Fuel: Highly enriched 235U, 232Th, Natural Uranium- Reflector: Polyethylene, Graphite, Aluminum, Beryllium - Core: Any combinations of Fuel & Reflector

Publish KUCA benchmark problem in a near future

IAEA Benchmark Problem



ADSR project (Kart & Lab. project) in KURRI

- Energy amplifier system by ADSR

Neutron spectrum experiments of ADSR

- 14MeV pulsed neutrons in KUCA

・ Reaction rates evaluation: Good results by foil activation method

・ Unfolding evaluation: Feasibility of SANDII code

- High-energy protons from FFAG accelerator

・ About 60MeV neutron generation by about 70MeV proton

injection onto 184W target

・ Useful activation foil of 209Bi covering wide range of threshold

From 14MeV neutron results, very important and valuable

information, for 150MeV proton analyses

Summary





KUCA A-core

Fig. KUCA A-core (Reference core)Fig. Image of KUCA A-core and fuel assembly loaded

53.8cm

39.5cm

59.1cm



0.15874cm(1/16")Enriched Uranium

152.4cm

Fuel Cell×36

Polyethylene

Fuelassembly

Aluminumsheath

Collimatorregion

Polyethylene

- KUCA A-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



Static Experiments

Reaction rates distribution (Foil activation method)Measure 115In (n, γ) 116mIn (Exp. error: 5%)Examine effects on subcriticality, configurationOptimize collimator and beam duct

0 10 20 30 40 500

0.05

0.10

0.15

Distance from target [cm]

Nor

mal

ized

reac

tion

rate

[Arb

. uni

ts] Collimator

region Fuelregion

SVregion

Subcriticality (%Δk/k)

0.68

0.70

0.90

1.34

1.76

Fig. Measured Indium reaction rates distribution.

Fig. KUCA A-core with collimatorand beam duct.

F F F F F

F F F F F

F F SV F F

F F SV F F

22 SV 22

s'

s s s

s s s

b bs bs bs b

b bs bs bs b

f fs fs fs f

C3 S5

S4 C1

C2 S6



MCNP Analyses for Static Experiments

MCNP eigenvalue and point source calculationsGood evaluation by MCNP within experimental error

Experiment(%Δk/k)

MCNP (JENDL-3.3)

(%Δk/k)

MCNP (ENDF/B-VI.2)

(%Δk/k)

-0.68±0.04 -0.68 (1.4%) -0.67 (1.8%)

-0.89±0.05 -0.98 (5.7%) -0.91 (3.5%)

-1.34±0.07 -1.35 (0.3%) -1.40 (3.9%)

-1.76±0.09 -1.71 (2.9%) -1.72 (2.4%)

Table Comparison of measured subcriticality with calculated one.

0 10 20 30 40 500

0.02

0.04

0.06

0.08

0.10

Distance from target [cm]

Rea

ctio

n ra

te [A

rb. u

nits

]

Collimator region

SV region

Fuelregion

Experiment

MCNP (JENDL-3.3)

Fig. Comparison of measured In reaction rates distribution with calculated one.

( ): Relative difference, Cal. error: 0.03%Δk/k



Optical Fiber Detection System

0 5 10 15 20 250

0.2

0.4

0.6

0.8

1.0

1.2

Subcriticality ρ [%Δk/k]

0.411.102.274.03

Distance from the center of core [cm]

6 Li re

actio

n ra

te [A

rbtra

ry u

nits

] Coreregion

Reflectorregion

0 1.00 2.00 3.00 4.00 5.000

100.00

200.00

300.00

Subcriticality | ρ| (%Δk/k)

Neu

tron

mul

tiplic

atio

n M

Meff = 1 / ( 1 - keff )

Mexp-abs (Absolute value)

Mexp-rel (Relative value)

Mcal-abs (Absolute value)

Mcal-rel (Relative value)

Fig. Li reaction rates by optical fiber detectionsystem, along to subcriticality.

Fig. Neutron multiplication by Area ratio methodapplied to Li reaction rates.

Optical fiber detection system・ LiF (ZnS): 6Li (n, α) reaction

for thermal neutrons ・ ThO2 (ZnS): 232Th fission reaction

for fast neutrons

Area ratiomethod



Dynamic Experiments (Optical fiber system)

Pulsed neutron method (PNM)Good evaluation of subcriticality at both core and reflector positionsExamine methodology and position dependency

Fig. Measured neutron decay behavior by opticalfiber detector system.

F F F F F

1/2φ F F F F F

F F F F F

F F F F F

FC2 S6

S4 C1

C3 S5

Core

Reflector

0 0.002 0.004 0.006 0.008 0.0110-3

10-2

10-1

100

Time [Sec.]

Rel

ativ

e Li

reac

tion

rate

[Arb

. uni

ts]

- Core - Experiment MCNP

- Reflector - Experiment MCNP

ThO2 fiber

LiF fiber



Subcriticality (Source Multiplication Method)

Ref. Exp. value

(%Δk/k)

MCNP(%Δk/k)

Higher-mode SM method(%Δk/k)

-0.72±0.06 -0.69 (4.2%) -0.67 (6.9%)

-2.72±0.22 -2.88 (5.9%) -2.52 (7.4%)

-5.96±0.45 -6.44 (7.5%) -5.19 (12.9%)

-8.66±0.69 -10.46 (20.8%) -7.09 (18.1%)

Table Comparison of measured subcriticality with calculated ones (with JENDL-3.3).

( ): Relative difference, Cal. error: 0.03%Δk/k

F F F F F

F F F F F

F F SV F F

F F SV F F

22 SV 22

s'

s s s

s s s

b bs bs bs b

b bs bs bs b

f fs fs fs f

C3 S5

S4 C1

C2 S6

BF

BF

BF

BF 252Cf

BF3 detectors

Subcriticality (Source Multiplication method)Measurement techniqueDetector position dependencyImprovement of precision and methodology

Date post:	24-Feb-2020
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times

Benchmark Experiments of Accelerator Driven …...HPPA5, SCK･CEN, 6-9 May 2007 C. H. Pyeon, KURRI,...

Documents