Active Interrogation of SNMs by use of IEC Fusion Neutron ... · Kai Masuda et al. “Active...

Active Interrogation of SNMs by use of IEC Fusion Neutron Generator

Kai Masuda1, T. Masawa2, Y. Yakahashi2, T. Yagi2, R. Nakamatsu1, S. Fushimoto3

1 Inst. Advanced Energy, Kyoto Univ.2 Research Reactor Inst., Kyoto Univ.3 Pony Industry Co. Ltd.

R&D Program for Implementation of Anti-Crime and Anti-TerrorismTechnologies for a Safe and Secure Society promoted by JapanScience and Technology Agency

Kai Masuda et al. “Active Interrogation of SNMs by use of IEC Fusion Neutron Source, IEC2013, Oct. 6-9, 2013, Kyoto, Japan

Talk Outine

Introduction

Background

Project overview

Neutron-Based Rapid Screening System

System layout – container trucks, IECs, detectors,

Pulsed IEC and HV power supply

Detection Methods & Exp. Results

Delayed Neutron Noise Analysis (DNNA)

Threshold Energy Neutron Analysis (TENA)

Concluding Summary & Plans1


Nuclear Terrorism Threats

3.14m

Conventional gun-type nuclear weapon: 30 – 60 kg of 235U

2



3.14m


Modern tactical nuclear weapon: 10 – 30 kg of 239Pu

2



3.14m



235U Hiroshima-type is more troublesome.

2



3.14m



235U Hiroshima-type is more troublesome. passive detection is impossible unlike 239Pu

Pony Industry Co. Ltd.

Passive Gamma-ray detectors Effective to 239Pu

2



3.14m



235U Hiroshima-type is more troublesome. passive detection is impossible unlike 239Pu easy to make w/o test bans assembling in the target nation is possible

2



3.14m



235U Hiroshima-type is more troublesome. passive detection is impossible unlike 239Pu easy to make w/o test bans assembling in the target nation is possible identification by shape is not effective enough

2



3.14m



235U Hiroshima-type is more troublesome. passive detection is impossible unlike 239Pu easy to make w/o test bans assembling in the target nation is possible identification by shape is not effective enough

Transportation of tens kg of 235U – air cargo, land transportation, spy ship, sea container.

2


Megaports Initiative (2007) Mandatory SNM screening of all US-bound containers at their

port of origin from 2012.

400 containers / day from Yokohama

Photo by Gunnar Ries20ft container

8 ft x 8 ft x 20 ft

3




It has been delayed 2x2 years (until 2016), due to lack of SNM detection system.



8 ft x 8 ft x 20 ft

3




It has been delayed 2x2 years (until 2016), due to lack of SNM detection system.



8 ft x 8 ft x 20 ft

JPN gov. will setup 2-3 central seaports. Our proposal is to built SNM screening facilities in those

central seaports.

Very rapid (2 min/container) inspection system is required.

3


Project Overview

1. Neutron-based system

2. X-ray image

3. LCS γ-ray beamfor isotope identification 10 min / point

6m

400 containers / day 4


Project Overview


2. X-ray image


6m

400 containers / day

Scanning whole volume impossible.

4


Project Overview


2. X-ray image for determination of point(s) of interest


6m


Pony Industry Co. Ltd.

4


Project Overview

1. Neutron-based systemfor rapid screening false alarm rate < 10% 2 min. per container



6m


40

360

4


Project Overview

1. Neutron-based systemfor rapid screening false alarm rate < 10% 2 min. per container



6m

Proof-of-principle, reduced-scale prototype experiments,& scale-up design


40

360

5-year R&D from FY2010 R&D budget: 5.5M$ Estimated cost: 26.5M$

4


Neutron-Based Screening Facility

2 containers / 10 min5 min for neutron-irradiation/detection, and5 min for replacement of container trucks.

10 m

container truck

driver

IECs

5


Neutron-Based Screening System

Poly-Roof

Poly-Wall

Fast Neutron Detectors

Thermal Neutron Detectors

DD IECs

Two container trucks are inspected simultaneously with Three pulsed DD-IECs (108 n/sec), 450 3He detectors (1” dia., 1m length) or more BF3 detectors, 54 NE213 detectors (5” dia., 4” length) or fewer TMFDs.

Pulsed HV Power Supplies 6


Newly Developed Pulsed IEC

IECchamber

anode

cathode

3-stage HV feedthrough

DC PS switchescapacitor oil tank (7000L)

All in one grounded tank Low EM noise emission Dual 200 kV switches Quick pulse fall-off

7


Typical Pulse Shapes of V, I and NPR

0 20 40 60 80 100 1200

-20

-40

-60

-80

-100

time [μsec]

volta

ge [k

V]

0.45 Pa(D2)

0

5

10

15

curr

ent [

A],

neut

ron

coun

t rat

e [a

.u.]

Details will be given tomorrow.

8


Experimental Pulsed Neutron Yield Experimental tests were carried out with two pulsed HV PSs. 100kV-20A PS will be used for demo. because of transportation/

space limitations and oil/radiation regulations in KUCA facility where 235U can be used.

0 20 40 60 80 100106

107

108

109

100kV-20A PS 200kV-05A PS

norm

. neu

tron

yiel

d pe

r pul

se c

harg

e [n

/C/P

a]

peak discharge voltage, Vpeak [kV]

Details will be given tomorrow.

~109n/sec(peak) with 20A

9


Neutron-In Neutron-Out Detection of SNMs

HEU

incidentneutrons

delayed neutrons （<1%）

Easier approach, but much less signals.

cf. Delayed Neutron Analysis (DNA)

prompt neutrons （>99%）

Much more plentiful, but need to separate out from probing neutronscf. Differential Die-Away Analysis (DDAA)

t

delayed

prompt

probing neutrons

A principal challenge is to distinguish the secondaryneutrons from the probing neutrons.

Either DNA or DDAA requires very intense NGs (DT mandatory).

10


Neutron-In Neutron-Out Detection of SNMs

HEU

incidentneutrons

delayed neutrons （<1%）

Easier approach, but much less signals.

cf. Delayed Neutron Analysis (DNA)

prompt neutrons （>99%）

Much more plentiful, but need to separate out from probing neutronscf. Differential Die-Away Analysis (DDAA)

t

delayed

prompt

probing neutrons

A principal challenge is to distinguish the secondaryneutrons from the probing neutrons.

New techniques are being developed.1. Delayed Neutron Noise Analysis (DNNA)2. Threshold Energy Neutron Analysis (TENA)

Either DNA or DDAA requires very intense NGs (DT mandatory).

10


What is “Neutron Noise” ?

time [sec]

neut

ron

coun

t rat

e, n

(t)[

cps]

“neutron noise” example observed in KU critical assembly (KUCA)

time avg.

fluctuation

11


“Neutron Noise” Contains Signature of

Fission Chain Reactions

Y(∞) = 0 random neutrons (Poisson distribution)Y(∞) > 0 correlated neutrons

( )( ) 1)(2

−=tnttY σ

time [sec]

neut

ron

coun

t rat

e, n

(t)[

cps]


time avg.,

fluctuation,

gate width, t( )tn

( )tσ

11


Basic Neutron Noise Analysis (NNA) Well developed method in fission reactor physics field. Characterizes neutron multiplication factor due to fission

chain reactions.

time [sec]

neut

ron

coun

t rat

e, n

(t)[

cps]


time avg.,

fluctuation,

gate width, t( )tn

( )tσ

Y(∞) = 0 random neutrons (Poisson distribution)Y(∞) > 0 correlated neutrons

( )( ) 1)(2

−=tnttY σ

11



n(t)

time, t

w/ HEUw/o HEU

incident neutron pulses from IECs

neutron count rate in detector

12



n(t)

time, t

w/ HEUw/o HEU


U

d

U-235fission fragmentdelayed neutron precursorprobing neutrons from IECdelayed neutronsneutrons from chain reactions

U

d

U

13



n(t)

time, t

w/ HEUw/o HEU


U

d


U

d

Ud

d

13



n(t)

time, t

w/ HEUw/o HEU


U

d


U

d

Ud

d

U U13



n(t)

time, t

w/ HEUw/o HEU


U-235fission fragmentelayed neutron precursorprobing neutrons from IECdelayed neutronsneutrons from chain reactions13



n(t)

time, t

dump dump dump

w/ HEUw/o HEU

Y(∞) = 0 random neutrons (Poisson distribution)Y(∞) > 0 neutrons from fission chain reactions

( )( ) 1)(2

−=tnttY σ

U-235fission fragmentelayed neutron precursorprobing neutrons from IECdelayed neutronsneutrons from chain reactions13



n(t)

time, t

Y (t

) time, t

w/ HEUw/o HEU

dump dump dump

w/ HEUw/o HEU

dump dump dump

Y(∞) = 0 random neutrons (Poisson distribution)Y(∞) > 0 neutrons from fission chain reactions

( )( ) 1)(2

−=tnttY σ

14


3He: 1”dia., 20cmL, 5atm

U-235：1.3 kg (keff = 0.12)

NPR (DT)：~105 n/sec

10 μsec, 10 Hz

ROI in DNNA: 50-100 msec

HEU

DNNA Experimental Setup in KUCAp p p p p p p p

p H5 H1 H2 H3 H4 H6 p

p p

p F F p

p F F p

p p

p p

p p p p p

F

p

HEU

10” Poly

T-Target

D-Beam

H Detector

15


DNNA Experimental Results

Clear difference in Y(t) was seen from BG w/o HEU.

w/ HEU

w/o HEU

16



A significant portion of the fission neutrons is above DD neutron energy.

0 1 2 3 4 5 6 7 8 9 100.0

0.1

0.2

0.3

0.4

核分裂中性子スペクトル

χ(E) [

MeV

-1]

Energy [MeV]

2.45 MeV

DD中性子源から発生する中性子のエネルギー

30%

neutron energy from DD source (2.45 MeV)

fission spectrum

17



A significant portion of the fission neutrons is above DD neutron energy.Use of DD neutron source is mandatory. Neither DT

nor RI source is applicable.

0 1 2 3 4 5 6 7 8 9 100.0

0.1

0.2

0.3

0.4


χ(E) [

MeV

-1]

Energy [MeV]

2.45 MeV


30%


fission spectrum

17



A significant portion of the fission neutrons is above DD neutron energy.Use of DD neutron source is mandatory. Neither DT

nor RI source is applicable.Either dc or pulsed source is applicable.

0 1 2 3 4 5 6 7 8 9 100.0

0.1

0.2

0.3

0.4


χ(E) [

MeV

-1]

Energy [MeV]

2.45 MeV


30%


fission spectrum

17


TENA Experimental Setup

Cf-252

150cm

150cm

DD-IEC

detector + shielding(Pb, poly)

Cf-252

DD IEC (DC)

NE213 liquid scintillator+ 5cm Pb + 10cm Ploy

DD IEC0.1, 1.0, 2.0, 3.0x107 [n/sec]

Cf-2522.9 x104 [n/sec]

X/γ-rays are rejected, making use of induced pulse shape difference.

18


TENA Experimental Results

Clear difference between Green (signal + BG) and Black (BG only) is seen above 2.45 MeV.

0 200 400 600 800 1000

10-3

10-2

10-1

100

101

DD only Cf only DD + Cf

Cps

Channel

DD only (BG) Fission only Fission + DD (BG)

MCA channel (neutron energy)

Cou

nt ra

te [c

ps]

2.45MeV neutrons from DD fusion

19


TENA Experimental Results

Clear difference between Green (signal + BG) and Black (BG only) is seen above 2.45 MeV.BG counts above 2.45 MeV are seen due to X/γ-rays and pile-

up of less energetic neutrons.

0 200 400 600 800 1000

10-3

10-2

10-1

100

101

DD only Cf only DD + Cf

Cps

Channel

DD only (BG) Fission only Fission + DD (BG)

MCA channel (neutron energy)

Cou

nt ra

te [c

ps]

2.45MeV neutrons from DD fusion

19


Y = (5.8E-06) X2 + (6.8E-04) X + (1.1E-02)

BG count rate below 2.45 MeV [cps]

BG

cou

nt ra

te a

bove

2.4

5 M

eV [c

ps]

TENA Experimental Results (Contd.)

BG count rate above 2.45 MeV is seen to increase nonlinearly as increase of incident DD neutrons (and X-rays) from IEC.

0.1

1.0

2.0

DD-IEC NPR3.0 x 107 n/sec

20


Estimation of Required Detection Time

Poly-Roof

Poly-Wall

Fast Neutron Detectors

Thermal Neutron Detectors

DD IECs

Pulsed HV Power Supplies

Two container trucks are inspected simultaneously with Three pulsed DD-IECs (108 n/sec), 450 3He detectors (1” dia., 1m length), and 54 NE213 detectors (5” dia., 4” length).

Estimation made based on the exp. results and MCNP6 simulations.

21


Detection Time for 1kg HEU

Assumption:Nothing in the container except for 1-kg HEU.

8ft

(2.4

m)

8ft (2.4m)

0.5 1(1) 0.8

0.8 1(5) 1

0.7 0.7 0.7

0.5 0.5 0.7

0.5 0.7(1) 0.7

0.7 0.7(5) 0.8

corner: 5.8 min

detection time by DNNA(TENA) [min]

NE213

IEC

He-3

He-

3

22


Tensioned Metastable Fluid Detector (TMFD)

Centrifugal TMFD Acoustic TMFD

Blind to X/γ-rays. Blind to neutrons below a threshold energy. The threshold neutron energy variable. ~90% efficiency with 10cm x 10cm volume. Directional detection by ATMFD.

Developed by Prof. Taleyarkhan’ group in Purdue Univ. See for example, R.P. Taleyarkhan, et al., Nuclear Engineering and Design 238 (2008) 1820.

23


Concluding Summary & Plan

Nondestructive screening as fast as 2 min/container is required in order not to block sea container distribution.

Experiments have been made for the two neutron-based methods, namely DNNA and TENA.

An inspection facility has been designed, which can handle two container trucks per 10 min, including mandatory 5 min for trucks replacement.

5’x5’x5’-scale tests are planed Dec 2014 – Feb 2015 by use of a single IEC, reduced number of detectors and U-235 (natural uranium).

We also plan to test a novel fast neutron detector, TMFD, which is ideal for TENA because it is blind to X/γ-rays and neutrons below 2.45 MeV. 24

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