VIII-Ⅱ-1. Project Research
Project 4

PR4Development on Neutron Imaging Application

Y. Kawabata
Research Reactor Institute, Kyoto University
OBJECTIVES AND ALLOTED RESEARCH SUBJECTS :The aim of this project research is the development
on neutron imaging and its application.
ARS-1 Development on neutron imaging application in
KUR
ARS-2 Measurements of multiphase dynamics by neutron radiography
ARS-3 Visualization of two-phase flow in a polymer
electrolyte fuel cell
ARS-4 Neutron radiography on tubular flow reactor for
supercritical hydrothermal synthesis of nanoparticles
ARS-5 Characteristics of the void fraction under a forced
convective flow boiling
ARS-6 Relationship between plant root system and water
movement in rice hull medium
ARS-7 Neutron imaging of industrial components andsimulation using VCAD system
ARS-8 Measurement of water content in hardened cement paste by neutron imaging
ARS-9 In-situ measurement of the hydraulic behavior ofhigh strength concrete under high temperature
ARS-10 Hydrazine decomposition phenomena observedby neutron radiography at a catalyst bed
ARS-11 Development of neutron imaging devices
MAIN RESULTS AND THE CONTENTS OF THISREPORT :Y. Kawabata et al. (ARS-1) did not perform their experiments in KUR.
Y. Saito et al. (ARS-2) applied a spatio-temporal filter
to high frame-rate neutron radiography to enhance qualityof images and to compare the effect of neutron flux fromthe neutron sources. The proposed one has been applied
to images obtained at the B4-port of KUR and at the
JRR-3 of JAEA. The results showd that the severe signal
noises could be removed from the original images byapplying the modified bilateral filter, while preserving theedge information.
N. Takenaka et al. (ARS-3) have measured the water
behavior in a polymer electrolyte fuel cell (PEFC) by
using neutron radiography for understanding the water

採択課題番号 24P4
（京大・原子炉）川端祐司

distributions in the PEFC with and without micro porous
layer (MPL) and show that the MPL makes change the
distribution of water condensation rate in the gas diffusion layer (GDL).
T. Tsukada et al. (ARS-4) visualized the flow in a tubular flow reactor for supercritical hydrothermal synthesis
using neutron radiography, and investigated the effects ofthe flow rates of two fluids and temperature of supercritical water on the mixing behavior in the reactor. In
this work, the effect of reactor configuration on the mixing behavior was investigated by neutron radiography. In
addition, the flow patterns and temperature distributionsin the reactor were calculated using FLUENT in which
the temperature and pressure dependencies of thermophysical properties were taken into account, and werecompared with the experimental results.
H. Umekawa et al. (ARS-5) have investigated thecharacteristics of the void fraction under several forced
convective flow boiling conditions. In this report, theresult under the downward flow condition was presented.
The purpose of this investigation is the detailed understanding of the downward flow characteristics.
U. Matsushima et al. (ARS-6) investigated the relationship between the plant root system and water movement in a rice hull medium. It is important to know how
rice hulls can be a good plant-growing medium for static
solution culture without the need for aeration.
Y. Yamagata et al. (ARS-7) conducted a comparison
study between neutron image taken at KUR E-2 port and
RIKEN compact accelerator-driven neutron source(RANS) and X-ray CT. It was confirmed that neutron
imaging has certain advantage over X-ray.
T. Numao et al. (ARS-8) evaluated the water distribution in the hardened cement paste (HPC) using neutron
radiography.
M. Kanematsu et al. (ARS-9) applied neutron radiography to detect the hydraulic behavior under high temperatures to understand the spalling phenomenon of highstrength concrete, focusing on the different type of materials and mix proportions, such as limestone aggregate,silica fume and fly ash which are commonly used as admixtures for high strength concrete.
H. Kagawa et al. (ARS-10) have succeeded in shooting
movies of hydrazine decomposition phenomena within
the catalyst bed of the mono-propellant thruster by using
Neutron Radiography. The purpose of their studies is toimprove the reliability of propulsion systems involved
visualization, facilitating the direct observation of thephysical and chemical phenomena in a thruster which isone of the most important sub-components for spacecraft.
H. Iikura et al. (ARS-11) investigated the influence ofthe thickness and prism pitch of brightness enhancement
films (BEFs) on the brightness and spatial resolution of aneutron imaging system.

中性子イメージングの高度利用

プロジェクトPR4-1

Measurements of Multiphase Dynamics by Neutron Radiography
Where, I is the original gray level, B the filtered graylevel, respectively. p(p x ,p y ) and s(s x , s y ) are positions. t p
is the time domain for smoothing in the time, which was
assumed to have the same weight in the spatial domain asshown in Fig.1.

Y. Saito, D. Ito and Y. Kawabata
Research Reactor Institute, Kyoto University

INTRODUCTION: Temporal limit of neutron radiography depends on a neutron flux irradiated from a neutron
source. High speed imaging for fast processes require
short exposures in neutron radiography, which cause severe signal noise due to the statistical variation of neutron
flux. Generally, time averaging can be applied to reducesuch statistical noise from the original images. However,such time averaging cannot be used for motion pictures,
which may cause image blurring in the filtered images.
Spatial filters can be used for high frame-rate neutron
radiography, however, if the S/N ratio (signal to noise
ratio) is really poor, the spatial noise cannot be removed
just by applying such spatial filters. Thus, it is indispensable to reduce noise from an original image by applying
a temporal and spatial filter at the same time. The purpose of this study is to apply a spatio-temporal filter tohigh frame-rate neutron radiography to enhance qualityof images and to compare the effect of neutron flux fromthe neutron sources.
SPATIO-TEMPORAL FILTER:

EXPERIMENTS:
The experiments were performed by using the B4-portof the Research Reactor Institute, Kyoto University.
High-speed video camera (MotionPro Y4 Lite, IDT
Co.Ltd.) was tested to achieve high spatial resolution(1014×1014 pixels). A high-gain, fast gated image intensifier (Single MCP (GaAsP)+Booster) by HAMAMATSU was employed to amplify the light intensity ofphosphorescent images on a fluorescent converter(6LiF/ZnS:Ag). The exposure time can be adjusted by apulse generator connected to the camera sync out. The
light shielding box equipped with no optical mirror to
reduce light decay and the optical axis was inclined at
45° to the neutron beam to avoid radiation damage.
RESULTS: The proposed spatio-temporal filtering has
been applied to images obtained at the B4-port of KUR
and at the JRR-3M of JAEA. Figure 1 shows the original
and filtered images of two-phase mixture flowing images
in a small diameter tube obtained at the B-4 port of the
KUR. The exposure time was 5ms, and the successive
images are shown at every 20ms. As shown in these images, it is recognized that the severe signal noises could
be removed from the original images by applying themodified bilateral filter, while preserving the edge information.
(a)Fig. 1 Time domain and spatial domain for the modified
bilateral filtering.
In general, the value of the filtered image at a given
location is a function of the values of the input image in asmall neighborhood of the same location. Anisotropic
diffusion is a popular filtering method and the diffusion
methods average over extended regions by solving partial
differential equations, and is therefore inherently iterative.
Iteration may raise issues of stability and, depending on
the computational architecture, which are well discussed
in literatures. On the other hand, Bilateral filter smoothes
images while preserving the edge, none iterative, local
and simple. At the present study, we propose a simple
modification to the original bilateral filter as follows:∑ ∑ g ( ( p, t ) − (s, t ) , s )g (I ( p, t ) − I (s, t ), s )I (s, t )B (s, t ) =∑ ∑ g ( ( p, t ) − (s, t ) , s )g (I ( p, t ) − I (s, t ), s )
p∈N s

tp

tp

p∈N s

p

d

p

p

d

i

p

(b)

Fig.2 (a) Original two-phase flow images (b) Filteredimages.( Exposure time:5ms, tube diameter:1mm)i

採択課題番号 24P4-2 中性子ﾗｼﾞｵｸﾞﾗﾌｨを用いた混相流のﾀﾞｲﾅﾐｯｸｽ計測に関する研究 プロジェクト（京大・原子炉）齊藤泰司、伊藤大介、川端祐司

Visualization of Two-Phase Flow in a Polymer Electrolyte Fuel Cell

Graduate School of Engineering, Kobe University
1
Research Reactor Institute, Kyoto University

INTRODUCTION: Hydrogen combine with oxygento form water in the cathode reaction site in a polymer
electrolyte fuel cell (PEFC). The generated water may
affect the fuel cell performances because of blocking theoxygen from reaching the cathode reaction site. Water
management in the PEFC is important, and water distributions during the operation have been wide concern.
Recently, it is reported that micro porous layer (MPL)
improves the water transport in the cathode and the cell
performance. However, the mechanisms have not been
fully understood. Measurements of water behavior in a
PEFC were carried out by using neutron radiography forunderstanding the water distributions in the PEFC withand without MPL.
EXPERIMENTS: Visualization of a PEFC were carried out with and without MPL by using neutron radiography system at B-4 port in KUR. Geometry of the PEFC
was horizontal 9-parallel gas channels with equal widthand depth of 1 mm. The MPL is made of carbon particle,
and the thickness is about 60 μm. The MPL is put between the gas diffusion layer (GDL) and the proton exchange membrane (PEM) at the cathode side. The GDL
was TGP-H-060 (Toray Ind.) with thickness of 190 μm,
and the porosity is 0.78. The PEM was Nafion® NR-212
with thickness of 51 μm and the area of 10 × 19 mm2.
The images were taken by a cooled CCD camera. The
exposure time was set at 60 sec. The spatial resolution
which corresponds to 1 pixel was 9 μm. Experiments
were carried out at room temperature, and conditions
were a current density of 158 mA/cm2, a hydrogenflow-rate of 28 Ncc/min (utilization of 7.5%), and an air
flow-rate of 66 Ncc/min (utilization of 7.5%).
RESULTS: Fig.1 shows two-dimensional water distributions in through-plane direction at elapse times of 6
and 12 min. The water accumulation speed in the GDL
without MPL was faster than that with MPL. This tendency is remarkable at the GDL under the rib. Water
evacuation from the GDL to the channel mainly occurredat the edge of the ribs.
One-dimensional water distributions were calculated asshown in Fig.2. The water distributions in the GDL arecompletely different between without and with MPL.
Water distributions takes maximum value around between the PEM and the GDL under without MPL condition. Hence, it can be confirmed that water accumulation
easily occurred around catalyst layer which is locatedbetween the PEM and the GDL. On the other hand, water

accumulation smoothly distributed from the channel to
the GDL, and there is no peak around the catalyst layer.
These results indicate that the MPL makes change the
distribution of water condensation rate in the GDL.

Without
Without
With MPL
With MPL
MPL
MPL(a) 6 min(b) 12 min
Fig. 1 Two-dimensional water distributions
GDL PEM GDL

AnodeWater thickness [mm]N. Takenaka, H. Asano, H. Murakawa, K. Sugimoto,Y. Kawabata1 and Y. Saito1

ChannelCathodeChannel

2000
3min
6min
1000 9min
12min
27min

0

-1000 -500 0
500
1000Distance from center of MEA [ mm](a) Without MPL

Anode

Water thickness [mm]

PR4-2

GDL PEM MPL GDLChannel

2000

CathodeChannel

3min
6min1000 9min
12min
27min

0

-1000 -500 0
500
1000Distance from center of MEA [ mm](b) With MPL
Fig. 2 Water distribution in the PEFC

採択課題番号 24P4-3
中性子ラジオグラフィによる二相流の可視化計測
プロジェクト
（神戸大・工）竹中信幸、浅野等、村川英樹、杉本勝美（京大・原子炉）川端祐司、齊藤泰司

PR4-3

Neutron Radiography on Tubular Flow Reactor for Supercritical Hydrothermal
Synthesis of Nanoparticles

T. Tsukada, K. Sugioka, K. Ozawa, S. Takami 1,
T. Adschiri2, K. Sugimoto3, N. Takenaka3, Y. Saito4
and Y. Kawabata4
Dept. of Chemical Engineering, Tohoku University
IMRAM, Tohoku University
2
WPI-AIMR, Tohoku University3
Dept. of Mechanical Engineering, Kobe University
4
Research Reactor Institute, Kyoto University
1

INTRODUCTION: Recently, a variety of metal-oxide
nanoparticles have been synthesized by supercritical hydrothermal synthesis [1]. For the design and optimization of the process, it is important to acquire the correctknowledge about the mixing behavior of cold aqueous
feed solution and supercritical water in a hydrothermal
reactor. Therefore, we used neutron radiography tovisualize the flow in a tubular flow reactor for supercritical hydrothermal synthesis, and investigated the effects ofthe flow rates of two fluids and temperature of supercritical water on the mixing behavior in the reactor [2]. In
this work, the effect of reactor configuration on the mixing behavior was investigated by neutron radiography. In
addition, the flow patterns and temperature distributionsin the reactor were calculated using a commercial software FLUENT in which the temperature and pressure
dependencies of thermophysical properties were taken
into account, and were compared with the experimental
results.

generated by the inflow of supercritical water into the topof the horizontal tube. In the case when cold water flows
downward and supercritical water is supplied into the
T-junction from the side as shown in the figure (b), it canbe seen that the temperature in the region above theT-junction becomes higher and uniform throughout thecross-section area of the tube. This is due to the buoyancy
convection there caused by the density difference between two fluid streams. In the figure (c), the supercritical water with lower density intrudes above theroom-temperature water in the left horizontal tube, andthen a density-stratified layer was generated in the tube.
Fig. 2 shows the numerical results of temperature distributions in the reactor corresponding to Fig.1(a), and adensity-stratified layer can be observed in the horizontal
tube similarly to the experimental ones.
CONCLUSIONS: In this work, the effect of the reactor configurations on the temperature distributions in thereactor for supercritical hydrothermal synthesis was investigated by neutron radiography, and also it wasdemonstrated that the numerical simulations using
FLUENT can predict well the experimental results.
REFERENCES:[1] T. Adschiri et al., Green Chemistry, 13 (2011) 1380.
[2] S. Takami et al., J. Supercrit. Fluids, 63 (2012) 46.

EXPERIMENTS: The tubular flow reactor has the
T-junction comprised of Swagelok union tee and SUS316
tubes whose outer diameter and wall-thickness were 1/8
inch and 0.71 mm, respectively. Water at room temperature (cold water), corresponding to the feed aqueous
solution, is mixed with supercritical water heated up to
approximately 390°C at the T-junction. In the experiment,pressure in the reactor was set to be 25 MPa. The flow
rates of supercritical water Q SC were 8 and 12 g/min, andthe rate of cold water Q RT was varied between 1 and 6
g/min. The T-junction in the reactor, i.e., the mixing part,was irradiated by neutron beam at 1 or 5 MW power, andthen the temperature distributions in the reactor were
determined with the relationship between the neutronmass attenuation coefficient in water and temperature.
RESULTS: Fig. 1 shows the temperature distributions
measured for three different reactor configurations, where
Q SC = 8.0 g/min and Q RT = 2.0 g/min. The figure (a) reveals that cold water injected through the horizontal tube
flows downward near the wall of the vertical tube, contacting with supercritical water at the T-junction. From
the figure, it is found that a density-stratified layer is

採択課題番号 24P4-4 中性子ラジオグラフィを利用した超臨界水反応場の in-situ 観察 プロジェクト（東北大院・工）塚田隆夫、杉岡健一、小澤恭兵、（東北大・多元研）高見誠一、（東北大・WPI）
阿尻雅文、（神戸大院・工）杉本勝美、竹中信幸、（京大・原子炉）齊藤泰司、川端祐司

PR4-4Characteristics of the Void Fraction under a Forced Convective Flow Boiling

H. Umekawa, T. Ami, K. Sakakura, S. Nakamura,
S. Fujiyoshi, G. Yamashina, Y. Saito1, D. Ito1 and
Y. Kawabata1
Dept. Mech. Eng., Kansai University
1
Research Reactor Institute, Kyoto University
INTRODUCTION: In this series of the project, characteristics of the void fraction under several forced convective flow boiling conditions have been estimated [1-3]. In
this report, the result under the downward flow condition
was presented. In the case of the downward flow, theflow direction takes the opposite direction of the buoyancy, thus several unsteady flow condition is easily occurred especially under low mass flux condition. These
unsteady conditions make the understanding of thedownward flow difficult. The purpose of this investigation is the detailed understanding of the downward flow
characteristics.
EXPERIMENTS: As the visualization experiment at
KUR, the void fraction of the boiling flow under upward
flow and downward flow conditions have been quantitatively estimated by using thermal neutron radiography at
B4 port. The working fluid was the degassed
ion-exchanged water. The inner diameter of the test section was 10mm, the heated length was 400mm, andheated by using D.C. power. Besides of the visualization
experiment, the measurement of the critical heat flux ofseveral sizes of test section (I.D.= 5mm, 10mm and
15mm) was conducted at Kansai University.
In this experimental apparatus, the test section was set
upon the elevating frame, and it enabled the full length
visualization of the heating section even in the B4 port.

One of the thresholds of the flow characteristics of
downward flow can be considered as the rising velocityof the Taylor bubble in the slug flow regime, and it canbe estimated by 0.35(gD)1/2. This value corresponds to
the G=95kg/m2s, thus the example of the visualization
results at the 100kg/m2s under upward/downward flow
condition are presented in Fig.1. In the figure, the void
fraction profiles along the axial direction and the radial
direction at the several distances from the inlet are plotted. The location z corresponds to the distance from theinlet, and the result of the downward flow is expressed as
the upside down to the actual arrangement.
These results were taken under the same conditions
except flow direction, but the quite different tendency
can be confirmed. Around the vapor generation point,
similar void fraction profiles can be confirmed, but withthe exaggerating of the boiling the difference between
both flow directions become clear. For example, thedrastically increasing of the void fraction of downward
flow is observed at the lower quality condition comparedwith the upward flow. Also the premature transition fromthe wall peak profile along the radial direction to thecenter peak profile can be confirmed. These tendencies
are fundamental characteristics caused by the bubble
stagnation, and the understanding of these tendencies andthe transition to the liquid film flow are very important todiscuss the downward flow.
REFERENCES:[1]H.Umekawa et al.,Physic. Procedia,43(2013)269-276.
[2] S. Nakamura et al., Proc. JSME SPES2012(2012)67.
[3] S.Fujiyoshi et al., Proc.JSME SPES2012(2012)71.

(a)upward flow(b)downward flow
Fig.1 Comparison of void fraction profiles under upward/downward flow conditions.

採択課題番号 24P4-5 強制流動沸騰系におけるボイド率挙動の定量評価に関する研究 プロジェクト（関大）梅川尚嗣、網健行、阪倉一成、中村祥太、藤吉翔太、山科剛是（京大・京大炉）齋藤泰司、伊藤大介、川端祐二

PR4-5 Relationship between Plant Root System and Water Movement in Rice Hull Medium
U. Matsushima, C. Kanno1, H. Shono and M. Okada
Faculty of Agriculture, Iwate University
Iwate Prefecture Government

1

INTRODUCTION: If a potted plant is placed in shallow
water for an extended period, the roots will rot fromremaining wet. Hence, in such watering method called“static solution culture,” it is necessary to aerate thewater to provide air to the plant root; however, rice hulls
can be a good plant-growing medium for static solution
culture without the need for aeration. It is presumed thatthe large air spaces between the rice hulls make it easy
for the roots to get the air they need. In addition, ricehulls do not retain water because of their structure. It is
not known why the proper balance of air and water isprovided in a rice hull medium. In this study, weinvestigated the relationship between the plant rootsystem and water movement in a rice hull medium.
EXPERIMENTS: A leaf vegetable Komatsuna(Brassica rapa var. perviridis cv 'Misugi') was planted in
an aluminum container (150-mm high, 50-mm wide,
20-mm deep) filled with rice hull medium. The medium
contained 70% rice hulls and 30% soil. To the total
volume, 3% of powdered charcoal and 5 g/L ofslow-release chemical fertilizer was added. After theplant root grew and reached bottom of the container, thesample plant was placed in 50-mm–deep water for 11
days.
Neutron imaging was conducted at the E2 hole of Kyoto
University Reactor (KUR). The image was captured usinga CCD camera (BU-53LN, BITRAN, Saitama, Japan)
with a 6LiF/ZnS(Ag) scintillator. Exposure time was 5
min and 1 min for a 1 MW and 5 MW operation of KUR,
respectively. The sample plant was not watered for 24 h.
During this dry period, 5 neutron images were captured,
after which the sample was placed in 50-mm–deep waterfor 24 h. During this wet period, another 5 neutron
images were captured. After the images were obtained,
the aluminum container was disassembled, and the plantwith its developed root system was carefully removed
from the rice hull medium. The bare surface of the plant
was then photographed.
Image J and NI-Vision (National Instruments, Austin,
Texas, USA) were used for image processing andanalysis.
RESULTS: Figure 1-A shows the neutron image,indicating the water distribution in rice hull medium
containing a root system. The degree of darkness is in
proportion to the water content of the medium. Figure
1-B shows a binary image of the root system that was
extracted from the photographed rice hull medium.
Figure 2 shows the changes in neutron absorption by therice hull medium in the rectangle in Fig. 1-A. The
decreasing neutron absorption during the dry period
indicated dehydration of the rice hull medium fromtranspiration by the sample plant (Fig. 2). On the contrary,

採択課題番号 24P4-6

neutron absorption of the rice hull medium increased
during the wet period. The increase in the water content
of the medium implied by absorption was not explainedby water uptake from the bottom by capillary action. It is
not expected that water will reach a high level in the ricehull medium by capillary action, because the size of therice hull particle is too big to induce long-distance water
movement by capillary. In the rectangle in Figure 1-A,
the root system is seen as well developed and thinnerthan that in the other areas (Fig. 1-B). The structure of theroot system, which was expected to absorb oxygen, wasoften the same as that observed at the root zone in ahumid atmosphere under hydroponic methods. Roots
were also observed in the area that was immersed in the
50 mm of water column (Fig. 1-B). The sparse but thickroot system was also observed when the roots were
immersed in water. Two distinct root functions wereobserved in the rice hull medium: root system for
respiration at the upper part and root system for the
uptake of water at the bottom. However, the thin rootsystem in the upper part required a humid habitat;
therefore, the root is functioned in a manner that water isprovided to the surrounding medium and a humid habitat
is maintained.

Depth ofsuppliedwater

Fig.1 Water distribution in rice hull medium with a rootsystem. A: neutron image, B: root system

Fig.2 Changes in neutron absorption in rice hull
medium

中性子ラジオグラフィの植物研究への応用
プロジェクト（中性子イメージングの高度化と応用）（岩手大学）松嶋卯月，庄野浩資，岡田益己（京大・原子炉）齊藤泰司，川端祐司

PR4-6

Neutron Imaging of Industrial Components and Simulation Using VCAD System

Y. Yamagata1,2, K. Hirota1, S. Morita2, J. Ju2, J. Kato2,
Y. Ohtake1,3, H. Yokota1, S. Wang1, S. Mihara2,
H. Sunaga2, T. Sera1,4, S. Sato5, Y. Kawabata6, Y. Saito6,
M. Hino6, M. Kitaguchi6, M. Sugiyama6 and D. Ito6
1RIKEN Cluster for Innovation

binning, 2004x1336 pixels at 2x2 binning mode.
Detailed beam performance of RANS is still under inspection, but estimated thermal neutron flux at neutron
camera is about 1x104n/cm2/s with L/D of 50 at 100uA
proton beam current.

2

RIKEN Advanced Science Institute

3RIKEN Nishina Accelerator Research Center
4Osaka University
5

KEK

6

Research Reactor Institute, Kyoto University

INTRODUCTION:
Non-destructive testing of industrial components is becoming important for recent manufacturing engineering.
Neutron radiography (NR) has certain advantage over
X-ray that heavy metals like steel, nickel or tungsten canbe well penetrated, while light elements like hydrogengives better contrast so that liquid inside metal structure
or composite materials can be observed with better precision. However, the places where NR can be performed
are limited to large institutes having research reactor or
large accelerator facility. It is important to increase thechance of using neutron beams for industries for practical
non-destructive testing applications related to manufacturing process.
The authors have started the construction of RIKEN
compact accelerator-driven neutron source (RANS) to
increase the chance of using neutron beams and it has
started operation since January 2013. We conductedcomparison study of NR image at KUR E-2 port andRANS. Also, comparison with x-ray CT system is carriedout to illustrate the advantage of NR.
EXPERIMENTS:

Fig. 1 A panoramic photo of RANS
Fig. 1 shows a panoramic photo of RANS. A proton
linac capable of producing beam of 100A on averageconnected to target station with beryllium target inside.
Neutron beam is extracted from polyethylene moderator
to the detector box at 5m distance from the target, where
neutron camera with almost same configuration with thatat E-2 port is situated. The neutron camera is based on acooled CCD of 11 mega pixel with the size of 24x36mm.
It has 6LiF/ZnS(Ag) based scintillator with thickness of
0.1, 0.2 and 0.4mm and detection area of 150x150mm.
The cooled CCD camera has 4008x2672 pixels without

Fig2 Comparison of neutron radiography images ofsame bath toy taken at KUR E-2 port(left) andRANS(right) (E-2: 1MW 10sec 2x2 binning RANS: 5A
5min 2x2 binning)

Fig. 2 shows neutron radiography images taken at KUR
E-2 port and RANS. The quality of image at RANS israther comparable to that of E-2 considering the beam
current can be increased up to 100A, neutron radiography at RANS seems to be quite practical although E-2
port is superior in L/D.

Fig.3 Comparison of CT reconstructed image by NR(E-2)
and X-ray ( both image was volume rendered by V-Cat
using level slice)
Fig.3 shows a comparison of same bath toy CT reconstructed image by neutron radiography at E-2 port and
X-ray CT scanner with 450kV x-ray tube. X-ray reconstructed image is losing some part of outer plastic shellinformation because there are metallic objects like gearand springs inside. Meanwhile, CT reconstructed image
at E-2 shows both metallic and plastic components well.
It may be possible to extract better image using moresophisticated method of region separation, but by using
simple level-cut method, it was not possible.
CONCLUSION
We have conducted a comparison study between NR
image taken at KUR E-2 port and RANS and X-ray CT.
It was confirmed that NR has certain advantage over
X-ray. RANS will be a convenient method for NR but
KUR E-2 port has still advantage in terms of beam
flux and L/D.

中性子ラジオグラフィによる工業製品の内部情報取得とプロジェクトＶＣＡＤによるシミ ュレーション（理研）山形豊、広田克也、森田晋也、朱正明、大竹淑恵、横田秀夫、王盛、見原俊介、池上祐司、
島崎勝輔、（大阪大）世良俊博（KEK）佐藤節夫（京大・原子炉）川端祐司、杉山正明、齊藤泰司、
日野正裕、北口雅暁、伊藤大介

採択課題番号 24P4-7

PR4-7

Measurement of Water Content in Hardened Cement Paste
by Neutron Imaging

T. Numao, N. Kumakura, Y. Matsushima, Y. Kawabata1,
Y. Saito1, K. Watanabe2, Y. Ohno2, Y. Yamagata3, K. Hirota3
and S. Morita3
Department of Engineering, Ibaraki University
Research Reactor Institute, Kyoto University
2
Railway Technical Research Institute3
Advanced Science Center, RIKEN
1

INTRODUCTION:
In this study, two kinds of experiments were carriedout to evaluate the water distribution in the hardened
cement paste (HCP) using neutron radiography. One is anexperiment to examine influence of the specimen thickness that the neutron transmits (Test 1). The other one isan experiment to examine the precision of the dimensions of the transmission image (Test 2).

EXPERIMENTAL METHOD:
Figure 1 shows an Outline of Test 1. In this test, thetriangular HCP specimens that thickness changes inlengthwise direction were used. This specimen was covered in aluminum foil so that water is distributed equally.
Figure 3 shows the HCP specimen of the grillwork which
was used for Test 2. The central length of the lattice isprecisely 10mm.
EXPERIMENTAL RESULT AND CONSIDERATION:
Figure 2 shows an example of the result of Test 1. This
result shows that neutron transmission intensity changes atthickness around 10 mm because of the extinction and dispersion of the neutron passing the water included in thespecimen. The authors suggested a method to correct thisresult appropriately and showed that we could quantify thewater content in the specimens.
Figure 4 shows an example of the result of Test 2. This
result shows that the gaps between real dimensions anddimensions of the image enlarge as the distance from thecenter of the image becomes long. And this tendencychanges by the direction from the center. It is thought that
this tendency mainly depends on the optical characteristicof the CCD camera lens.
At the early drying period of the HCP, water distributionof the surface suddenly changes and influences the drying
shrinkage of HCP. Therefore precision less than 1mm is
required to keep the situation of the water content in HCP.
The authors suggested a method to remove this influence
appropriately.

Δ ln (I/I 0 )Outline of measurement of Test 1.

Specimen thickness (mm)Fig. 2. Relationship between thickness and transmission intensity.

Fig 3

Difference from real size(mm)OUTLINE OF EXPERIMENT
Outline of neutron radiography examination:
Measurement of neutron radiography in this study was
carried out at E2 port in KUR.

Fig.1.

0-0.1 020

The specimen of Test 2.

40

60

80

-0.2
-0.3

5MW8cm60s 0°-0.4

5MW8cm60s 90°-0.5

5MW8cm60s 180°

-0.6

5MW8cm60s 270°

-0.7
Fig.4.

Distance from center(mm)Difference between measurements and real size.

採択課題番号 24P4-8 中性子イメージングを用いたセメント硬化体中の水分測定
プロジェクト
（茨城大・工）沼尾達弥、熊倉識政、松島由布子（京大・原子炉）川端祐司、齊藤泰司（鉄道総研）渡辺 健、大野又稔（理化学研究所）山形 豊、広田克也、森田晋也

PR4-8In-situ Measurement of the Hydraulic Behavior of High Strength Concrete
under High Temperature

M. Kanematsu, M. Nakano1, M. Tamura2, N.Tuchiya2,
Y. Saito3 and Y. Kawabata3
Faculty of Science and Technology, Tokyo University of
Science1
Graduate School of Technology, Tokyo University of
Science2
Graduate School of Engineering, Tokyo University
3
Research Reactor Institute, Kyoto University

Fig. 1. Experimental setup of the heating element
INTRODUCTION: The exposure of reinforced concrete to unexpected high temperature may lead to spalling,
fracture of the heated surface. The physicochemical process of the spalling phenomena is assumed to be due tothe moisture pressure build-up inside the pore structures,
restrained thermal interaction or simultaneous action ofboth [1]. Also, it can't be ignored that the influence of
dehydrated water under high temperatures from cement
hydrate, such as CSH and calcium hydrate. However thedetailed mechanism of the explosive pressure formationof spalling has not been fully cleared yet.
In this research, we applied neutron radiography to detect
the hydraulic behavior under high temperatures to understand the spalling phenomenon of high strength concrete,
focusing on the different type of materials and mix proportions, such as limestone aggregate, silica fume and fly
ash which are commonly used as admixtures for highstrength concrete.
EXPERIMENTS: The 100x100x200 mm3 prisms wereused with a water cement ratio of 18% with various mix
proportions. The materials that were used in this sturdy
and the mix proportion are shown in table 1. The initialwater contents of the concrete samples were controlled
by oven-dry under 105°C for two days. A Liquefied Petroleum (LP) gas burner was used to raise the surface
temperature to 1000°C in 30 seconds and was held at
1000°C for the remainder of experiment (Fig.1).
The neutron radiography facility in the B-4 beam line of
KUR was used. A neutron radiograph was obtained every
15 seconds during the heating experiment. In addition,
thermal analysis by the thermogravimetry(TG) was performed to evaluate the effect of dehydrated water from
cement hydrate corresponding to the temperature.
RESULTS: As shown in Fig. 2, the water movement of
the high strength concrete (A) can be observed by thesubtracted images by NRG. This result shows that between the subtracted water content observed by NRG and
dehydrated moisture content calculated from the TG, differences were observed particularly in the region of 300
degrees or less. It is implied that the dehydrated waterfrom cement hydrate remains in situ forming a high temperature and pressure.

採択課題番号 24P4-9

Table 1. Mix propotions
Sa
mp
le

W
/
B

W

Mass fraction
Admix.
Air
Bind replace-er place- Sand Gravel
ment

Materials(%) (kg/m3) (kg/m3)(%)(kg/m3)(kg/m3)(%)

AB

18 160 888.9
18 160 888.9

10
0

425
425

1060.21060.2

2
2

Silica fumeC

18 160 888.9

10

425

1060.22D

18 160 888.9

10

425

1060.2

2

Silica fume +limestone
Fly asha) Subtracted images of the high strength concreteb) Comparison of subtracted water destribution withanalytical value calculated from the TG
Fig. 2 The hydraulic behavior of concrete (sample A)
REFERENCES:[1] F.J.Ulm, O. Coussy, Z.P.Bazant, Journal of Engineering Mechanics 125(3) (1999)272-282

中性子ラジオグラフィによる高温加熱時のプロジェクトコンクリート内部の水分挙動に関する研究（京大・原子炉）川端祐司、齊藤泰司、（東京理科大学・理工）兼松 学、中野昌宏（東大・工）田村政道、(建築研究所)土屋直子

Hydrazine Decomposition Phenomena Observed by Neutron Radiography
at a Catalyst Bed

INTRODUCTION: Neutron radiography can reveal invisible objects such as fluids using X-ray technology. We
tried to apply this technology to observe a thruster which isone of the most important sub-components for spacecraftthat uses fluids as propellants. One of our studies to improve the reliability of propulsion systems involved visualization, facilitating the direct observation of the physicaland chemical phenomena occurring within the catalyst bedof the mono-propellant thruster. We have succeeded inshooting movies of hydrazine decomposition phenomena
by using Neutron Radiography at Kyoto University Research Reactor.
EXPERIMENTS: We prepared two kinds of 1N classthruster to observe hydrazine decomposition at the catalyst
bed. One had been used for JAXA's satellite propulsion
system and the other is designed to extend the mission life
both which were prepared by IHI Aerospace. Two thrusts
were installed to the portable test equipment in parallel
which was shown in Fig.1.
Safety Case

Quick
Disconnect

200kPａ
P

P

3MPａ

5th

6th

7th

8th

9th

10th

The sample image of extend life type injector design wasshown in Fig. 4. The injector was designed to diffusion
hydrazine at the upper area of the catalyst bed. White areain the first pulse of the difference image is smaller than its
penetrate type injector image. This fact shows that hydrazine penetrated widely area of catalyst bed to give soft
contact to brittle catalyst granules.
2nd

3rd

4th

5th

6th

7th

8th

9th

10th

GN2 Pressurant Gas（1.0MPａ(Max))T

Neutron

1MPａ P

4th

0.1 sec ON / 0.9 sec OFF @ 2.4MPa G

1stP

VacuumBuffer
Tank
(30l)

3rd

Fig. 3 The present injector design image

GN2 Purge Gas（0.1MPａ)

Filter2 Micron

Vacuum
Pump

2nd

Raw
Image

Quick
Disconnect

UltimageTM

P

Vacuum
Pump

1st

Raw
Image

Propulsion Group, Japan Aerospace Exploration Agency
Research Reactor Institute, Kyoto University

1

tor design was shown in Fig.3. The upper images weretaken raw images and the lower images were processed
images. Liquid hydrazine will absorb more neutrons andthe raw image was made slightly dark at the hydrazine injection area. The dark area had though liquid hydrazine
will present. The down row images show processed image
to extend the difference before hydrazine injected and after
injected. The white area part is considered liquid hydrazine
has penetrated. The first pulse had wide while area.

Difference
image

H. Kagawa, T. Nagata, T. Masuoka, K. Kajiwara, D. Ito1,
Y. Saito1 and Y. Kawabata1

1N monopropellant
thruster

GN2
70cm3

Hydrazine

Difference
image

PR4-9

0.1 sec ON / 0.9 sec OFF @ 2.4MPa G

Fig. 1 The Visible Object Equipment

Fig. 4 The long life injector design image

The observation unit was installed between the high speed
observation unit and KUR B-4 imagining port, while thethrusters were operated at four feed pressure points, 2.4,
1.5, 1.0 and 0.5MPaG respectively. The imaging system isshown in Fig.2. The hydrazine injection ON time is 0.1
second, the pulse width is 0.9 second, pulse repeat number
is 10. We had taken hydrazine decomposition image during
hydrazine decomposition by the digital high speed camera.
The image frame rate is 100 images per second.

Relay Lens

Fluorescence converter
Catalyst Bed

High speed Camera
USB

Image
IntensifierF-C

1 : 1.8

1.5
2
1.5

105mm

F-C

2.5
2
3
2.5

NIKKOR

3

Mirror22 16 11 8 5.6 4 2.8 1.8105mm Telephotographic Lens
Nikon Micro-Nikkor

SYNC OUTHigh voltage supply
for I.I. unit

FOV:
10 X 74
Neutron Beam [mm]Collimator

Lens Controller

Gain adjuster
for I.I. unit

Neutron Source

Fig. 2 The Image Acquisition System

RESULTS: The sample taken image of present type injec-

CONCLUSIONS: Shooting of neutrons at KUR was conducted using real hydrazine propellant and the simulated
1N thruster. The movie images showed the hydrogen liquidand hydrazine decomposition phenomena. Those images
showed the hydrazine decomposition area is not depended
on the injection pressure and the cold start affects the hydrazine penetrated area to wide and deep point of the 1N
thruster catalyst bed. This results and technologies will be
progress JAXA's longer life and high reliability thruster
development activities.
REFERENCES:[1] Hideshi KAGAWA and Yasushi SAITO, et.al, Neutron
radiography used on a mono-propellant thruster, AIAA-2011-5841, 47th Joint Propulsion Conference, 2011[2] Kenichi KUSHIKI, et.al, Visualization of propellant
behavior of catalyst thruster using Neutron Radiography,
B20, 49th Conference on Aerospace Propulsion and Power,
2009[3] Kenichi KUSHIKI, et.al, Visualization of Propellant
Behavior inside Catalyst Thruster Using Neutron Radiography, AIAA-2009-4972, 45th Joint Propulsion Conference,
2009

採択課題番号 24P4-10
宇宙用部品の中性子イメージングによる検査手法の開発
プロジェクト(京大・原子炉）伊藤大介、齊藤泰司、川端祐司（JAXA）香河英史、長田泰一、升岡正、梶原堅一

PR4-10Development of Neutron Imaging Devices

H. Iikura, T. Sakai, R. Yasuda, T. Nojima,
M, Matsubayashi, Y. Kawabata1 and Y. Saito1
Table 1. Configuration of the BEFs
Quantum Beam Science Directorate, Japan Atomic Energy Agency
1
Research Reactor Institute, Kyoto University

INTRODUCTION: We previously devised a technique for increasing the light intensity of a camera reception using brightness enhancement films (BEFs) [1]. This
technique is very simple and only requires attachment of
BEFs on the output surface of a scintillator for neutron
imaging. In this study, the influence of the thickness andprism pitch of BEFs on the brightness and spatial resolution of a neutron imaging system were investigated using
several different types of BEFs.

BEF
BEF-1
(BEF II 90/24)
BEF-2(TBEF2-T(24)n)
BEF-3(TBEF2-T(19)n)
BEF-4(TBEF2-GT(24))

prism
pitch
(m)

total

polyester

24

140

127

standard type

24

62

50

standard type

19

60

50

standard type

24

65

50

high gain typethickness (m)prism material

EXPERIMENTS: Neutron imaging was carried out at
the neutron radiography facility (E-2 beam hole) installed
in KURRI. The camera system consists of a BU-53LN
cooled charge coupled device camera (BITRAN) and an
85 mm lens (Nikon Nikkor, F = 1.4) with extension rings(Nikon). In this study, a commercial type scintillator
called an NR-converter (Kasei Optonix) was used as theneutron detector. Two BEFs were stacked perpendicularly
and placed on the output surface of the NR-converter, andsilica glass was pressed on the films in order to stick to
the converter. In this study, we investigated the brightness
and spatial resolution by using 4 kinds of BEFs (Table 1).
RESULTS: Figure 1 shows a comparison of thebrightness using each BEF. The value of the brightness
was obtained by subtracting the dark current from thesignal counts for the camera. The exposure time was 10
min at 1 MW or 2 min at 5 MW in reactor output. By
using BEFs, the brightness was increased by approximately 2.5 ~ 2.8 times in comparison with that with no
BEF. The detailed spatial resolution was evaluated basedon the calculation via Fourier transformation of the modulation transfer function (MTF). The MTF was obtained
from the neutron transmission ratio, and 10% of the MTF
was introduced from two polynomial function curves
fitted to the experimental data (Fig. 2). With respect tothe spatial resolution, improvement was achieved whenusing a BEF with a thinner polyester substrate. In thiscase, because the area for scattering of the visible lightinside the thinner polyester substrate is reduced, thespread of the positional information about the captured
neutrons should also be reduced [2].
REFERENCES:[1] H Iikura et al., Nucl. Instr. and Meth., 651 (2011)100-104.
[2] H Iikura et al., Physics Procedia, 43 (2013) 161-168.

Fig. 1. Comparison of the brightness as a functionof the type of BEF.

Fig. 2. MTF values using an NR-converter with
BEF-1 or BEF-2. The curves were approximatedusing a two polynomial function to calculate each
10% MTF.

採択課題番号 24P4-11
中性子イメージングデバイスの高度化
プロジェクト(日本原子力研究開発機構・量子ビーム応用研究部門)飯倉寛、酒井卓郎、安田良、野島健大、
松林政仁 （京大・原子炉）川端祐司、齊藤泰司