CO1-1

Current Status of B–3 Beam Port of KUR, 2016

K. Mori, H. Yoshino, R. Okumura, S. Sato1, H. Hiraka2,K. Iwase3, T. Shiono4 and K. Matsuda4(a)(b)

Research Reactor Institute, Kyoto University (KURRI)
1
High Energy Accelerator Research Organization (KEK)2
Neutron Science Center, Korea Atomic Energy ResearchInstitute3
Department of Materials and Engineering, Ibaraki University
4
Graduate School of Engineering, Kyoto University
INTRODUCTION: Neutron diffraction is a powerfultool to determine precisely the positions of light elements(e.g., hydrogen and lithium) in solids. This is the mainreason why neutron powder diffractometers are criticalfor structural investigations of energy storage materials,
for example, rechargeable lithium-ion batteries and hydrogen absorbing alloys. The B–3 beam port of Kyoto
University Research Reactor (KUR) had long been used
as a four-circle single-crystal neutron diffractometer(4CND). For the last decade, however, the 4CND was so
old that its research activity on neutron science was quite
low. Recently, the compact multipurpose neutron diffractometer (CMND) has been installed instead of the 4CND.
Here, we report the current status of the B-3 beam port ofKUR.
SPECIFICATIONS: The CMND has a wide spacearound the sample, therefore we can easily install any
other system. The neutron wavelength, l, which is monochromatized by the (220) plane of a Cu single crystal(i.e., Cu monochromator), is 1 Å. The old Cu monochromator stage of the 4CND was removed, and then thenew one with two goniometers (RA07A-W andSA05B-RM, Kohzu Precision Co., Ltd.) was placed on
the B–3 beam port (see, Fig. 1). In addition, the CMND isequipped with a new beam shutter manufactured by theKURRI factory. To cover the detector area of 6 º ≤ 2q ≤150 º, twenty-five 3He tube detectors (1/2 inch in diameter) are used, where 2q is the scattering angle. The distance from the Cu monochromator to the sample is approximately 2 m, and the distance from the sample to thedetector is 1.2 m. A detector bank including the twenty-five 3He tube detectors is placed on an arm of theHUBER–440 goniometer.
CURRENT STATUS OF B–3: Paraffin blocks had frequently been used as radiation shielding properties on the4CND, however the main concern in working was flammability. Accordingly, all paraffin blocks were replaced
by nonflammable radiation shielding properties: B4C grit
mixed with resin and heavy concrete blocks (see, Fig. 2).
The CMND is shown in Fig. 3 (under construction). The
goniometers (HUBER–430 and –440) and the beam
shutter have already been installed. The detector bankwill be installed soon.

28010

Fig. 1. The Cu monochromator stage: (a) old stage on the4CND, and (b) new one on the compact multipurpose
neutron diffractometer (CMND).

Fig. 2. Radiation shielding properties: B4C grit mixed
with resin and heavy concrete blocks.

Fig. 3. The compact multipurpose neutron diffractometer,
installed at the B-3 beam port (under construction).

CO1-2Development of an Ellipoidal Supermirror with Metallic Substrate

M. Hino, S. Takeda1, T. Hosobata1, Y. Yamagata1, T. Oda,
H. Endo2, N.L. Yamada2, J. Guo1, S. Morita3, M. Furusaka4
and Y. Kawabata
Research Reactor Institute, Kyoto Univ., JapanRAP, RIKEN, Japan2
IMSS, KEK, Japan
3
Tokyo Denki Univ. Japan
4Grad. Sch. of Eng., Hokkaido Univ., Japan1

INTRODUCTION: Progress of neutron optical devices is very significant, however, it is still very difficult forneutron aspherical focusing mirror, especially, two dimensional (2D) aspherical focusing supermirror. We
proposed new fabrication method for aspherical focusing
supermirror with metal substrate [1, 2]. The metallic substrate is robust and ductile, to which able to fabricate
steeply curved surface with high form accuracy. It is also
applicable to use under high radiation irradiation andhigh-temperature filed, even at a place close to the neutron target and moderator. Furthermore, it is possible tofabricate a large focusing mirror by combining multiple
segmented mirrors with mechanical fastening entailingthe usage of screw holes and fixture tabs. The big problem was required surface roughness for neutron mirror.
The roughness should be smaller than 0.5 nm even for
m=3 supermirror coating. Here m is the maximum criticalangle of the mirror in units of critical angle of natural
nickel. By using electroless nickel-phosphorus (Ni-P)
plating, we almost overcame the problem in case of
one-dimensional aspherical focusing supermirror [3]. In
this study, we show a performance test of ellipsoidal supermirror with metallic substrates.
EXPERIMENTS: We fabricated an ellipsoidal metallic
substrates with the Ni-P plating, based on the technology
using ultrahigh precision cutting with correction processing, followed by mechanical precision polishing. The
manufacturing, polishing and cleaning of the metallic
substrate were conducted at RIKEN. The supermirror
coating was conducted with KUR-IBS [4]. The neutron
experiments were conducted at the BL06 (VIN ROSE)
beam port at J-PARC/MLF [5,6].
RESULTS: There is two neutron guide tubes at theBL06 and a cadmium pinhole in which aperture size of 1
mm was located at exit of one of the guide tubes. AU-shape slit and an ellipsoidal supermirror of 300 mm
length shown in photograph of Fig.1 were placed between the pinhole slit and a 2D neutron detector. The
distance between the pinhole slit and the detector is 2.5 m
since the semi-major axis of the mirror is 1.25 m. Without the mirror, as shown in Fig 1(a), the intensity image
was U-shape and the peak intensity was about 500 counts.
With the mirror, as shown in Fig 1(b), the intensity image
was circular spot and the spot size was almost equivalent
to that of the pinhole. The peak intensity was about 7000
counts and the intensity gain was about 14 in this setup.

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Fig. 1. Photograph of the ellipsoid neutron supermirror at the BL06 at the J-PARC/MLF. Neutron
intensity image at detector position (a) without and(b) with the ellipsoid neutron supermirror.
REFERENCES:[1]J.Guo, et al., Optics Express 22(2014) 063108.
[2]J.Guo, et al., Review of Scientific Instruments
86(2015) 063108.
[3]S.Takeda, et al., Optics Express 24(2016) 12478.
[4]M.Hino, et al., Nucl. Instr. and Meth., 797(2015) 265.
[5]T.Oda, Dr thesis, Kyoto University, 2015.
[6]M.Hino, et al., to be published in JNSTCO1-3 The Correlation between Microstructural Evolution and Mechanical Property Changes
in Neutron-irradiated Vanadium Alloys
K. Fukumoto, T. Onitsuka, K. Tone1 and Q. Xu2
RINE, Univ. of Fukui
1eral relationship between flow stress and strain rate, thestrain rate sensitivity (SRS) parameter is defined as follows;

Graduate school of Eng., Univ. of Fukui
Research Reactor Institute, Kyoto University

2(1)EXPERIMENTS: The majority of test specimens forthis study were prepared from V-4Cr-4Ti alloys. The tensile specimens had nominal gauge dimensions of0.25mm(t) x 1.2mm(w) x 5mm(l). Before irradiation, allspecimens were annealed in vacuum at 1000°C for 2hrs.
The specimens were irradiated in Joyo in the temperature
range from 450ºC to 650 ºC with total neutron dose from0.47 to 2.1 x 1026 n/m2. In the previous study, the ratio ofdamage level, displacement per atom (dpa) to neutron
dose in pure vanadium in Joyo MK-II was 2.5 x 10-26
dpa/Φtot. The amounts of estimated damage level ranged
from 1.2 to 5.3 dpa. Tensile tests were conducted atroom temperature and 400°C with various strain rate
ranged from 6.7x10-4 to 10-2 to obtain the information ofstrain rate sensitivity at high temperature. SEM observation for fractography after tensile test was carried out inKUR, Kyoto University.
RESULTS: Tensile tests for V-4Cr-4Ti alloys werecarried out at RT and 400 ºC at strain rates between
6.7x10-4 and 6.7x10-1/s. The strain-rate dependence wasdetermined for the lower yield stress σLYS. From the gen-28040

When the flow stress σ rises with the increase of strain
rate, i.e., m>0, slip deformation is a thermally activat-

ed process. When m<0, a barrier strength of obstacle
against dislocation slip motion is weakened and leads toreduction of the flow stress, because increasing the strain
rate decreases time available for solute diffusion to dislocations. Values of the SRS for the lower yield stresswere determined for each irradiation condition and test
temperature from a logarithmic fit to the lower yieldstrength data. Figure 1 shows the SRS of lower yieldstress dependence on the test temperature for the irradiated V-4Cr-4Ti- in this study and the previous data for
V-4Cr-4Ti (US-832665) irradiated in HFBR [1]. The dataof SRS, m in this study shows significantly positive value and larger than the m values of previous data for US
V-4Cr-4Ti alloy irradiated in HFBR. The interaction between interstitial impurities and defect clusters/dislocation is affected by the irradiation damage
process after neutron irradiation at 400 ºC. Therefore, thedynamic strain aging should be only thermal activation
process between impurity and mobile dislocation, andindependent of irradiation damage process.

Strain Rate Sensitivity

INTRODUCTION: Vanadium alloys are candidate materials for fusion reactor blanket structural materials, but
the knowledge about the mechanical properties at hightemperatures during neutron irradiation is limited andthere are uncertainties that may have influenced there-sults such as the interstitial impurity content ofspeci-mens. Recently, material irradiation technology ina liq-uid metal environment was developed andirradiation experiments in various liquid metalenvironments can be performed for vanadium alloys.
Environmental effects and irradiation effects formechanical properties should be distinguishedindependently in order to understand the essential
behavior of vanadium alloys during irradiation forfusion reactor application. The objective of this study isto investigate the mechanical properties and microstructural changes of the vanadium alloys, V-4Cr-4Ti
alloys during neutron irradiation. In this study, tensile testand microstructural observation were carried outfor V-4Cr-4Ti alloys.

0.06

Unirr
Irr.-HFBR-0.5dpa
Irr.-JMTR-0.008dpa
Irr.-JMTR-0.064dpa
Irr.-JOYO-1.6dpa

0.04
0.02

LYS

0-0.02
0200

400

600

800

Test temperature (C)Figure 1 : The strain rate sensitivity (SRS) of lower yieldstress dependence on the test temperature for the irradiated V-4Cr-4Ti alloy in this study and the previous datafor V-4Cr-4Ti irradiated in HFBR [1].
Reference[1] A. F. Rowcliffe, S. J. Zinkle and D. T. Hoelzer. J.
Nucl. Mater., 283-287 (2000) 508-512

Preliminary Study of Radiation Resistivity of Bacillus subtilis natto

Faculty of Pharmaceutical Sciences, Chiba Institute ofScience
1Research Reactor Institute, Kyoto University
2Department of Life Science, Kurashiki University of Science and the ArtsINTRODUCTION: Bacillus subtilis natto (BSN) isone of famous bacteria in Japan, because Japanese traditional food 'natto' is made of soybeans by fermentation using BSN. Since BSN produces biologically active substances: nattokinase [1], water-soluble vitamin K [2] etc,
the detailed mechanism of BSN growth would provide
useful information for improvement of quality and quantity of the production of this nutritional food.
The growth of BSN is entirely different from Escherichia coli (E. coli), which is the most popular bacteriumin the field of bacteriology. E. coli increase by only simple
cell division, and when their population reach the limit,
cell division is suppressed. On the other hand, BSN transform themselves to spores like seeds of plants, under theirexcess pupation. The spores have high resistance to various severe conditions such as starvation, heat, cold, dry,chemical reagents (fungicides). Of course, they have highradiation resistance [3].
The aim of this project is to investigate radiation resistivity of BSN not in its spore state but in its growth state.
Generally, the radioresistance of Bacillus subtilis is believed to be derived from the formation of spores (sporulation). It would be true, but vegetative cells of BSN might
have different property of radioresistance from other bacteria, too.
In our previous study, radioresistance of vegetative
cells of E. coli was investigated in detail. We tried to establish experimental procedure of the assessment of the radioresistance of vegetative cells of BSN, in the same manner as that of E. coli. Here is the first preliminary report ofthis experiment.
EXPERIMENTS: First, cell cloning was carried out using Bacillus subtilis natto Miyagino. The obtained clone
was confirmed by the fibrin plate method that assesses thefibrinolysis activity of nattokinase, which is abundantly
produced in BSN. Prior to irradiation experiments, thegrowth curve of BSN in LB medium was determined.
Glycerol stock (40 L) of the BSN clone was inoculated
in 4 mL LB liquid medium in a test tube, and then preincubated at 42 °C with the shaking at 1,200 rpm for 16–
20 hours. Pre-cultured medium (40 L) was inoculated in4 mL LB liquid medium, and incubated with the same condition as the pre-incubation. Optical density at 600 nm(OD600) was monitored for 8 hours during the incubation.
Irradiation experiment was carried out at the Co-60
Gamma-ray Irradiation Facility of Kyoto University Research Reactor Institute. Incubated medium (500 L) with28049

OD600 of 0.536 was sealed in a 1.5 mL plastic tube. Fivesamples were prepared, and irradiated with gamma rays at
a dose of 0, 50, 100, 200, and 400 Gy at a dose rate of 24
Gy/min. Temperature of the experimental room was 15 °C.
After the irradiation, each liquid medium was diluted by
LB medium, and plated on standard method agar "Nissui".
Colony formation units were counted after 8 hour incubation at 42 °C.
10600-nm optical density

Y. Yanagisawa, T. Chatake1, T. Saito1, T. Ohsugi2,H.Sumi2

10510
incuba on me (hr)

0.1

0.01

Fig. 1.

Growth curve of BSN in LB medium.

100

the survival rate (%)

CO1-4

101
0100

200
the absorbed dose (Gy)300

Fig. 2.

Cell survival curve of BSN.

400

RESULTS: As shown in Fig. 1, the growth of BSN is in
an exponential phase for 1–4 hours from the inoculation.
The corresponding OD600 are 0.01–0.98. In this phase,
sporulation is thought to rarely occur. The optimum condition for irradiation experiment is estimate to be OD600 =0.2–0.8 (3–3.5 hours incubation).
Fig. 2 shows our preliminary result of the radioresistance of vegetative cells of BSN in this project. D10value (10% survival dose) was about 250 Gy. The present
result suggests that vegetative cells of BSN do not have sohigh radioresistance as spore of BSN. On the other hand,
we found a few different features in the cell survival curvefrom that of E. coli.
In order to discuss the radioresistance of BSN in detail,improvement of our experimental procedure and repeatedirradiation experiments are in progress.
REFERENCES:[1] H. Sumi et al., Experentia. 42 (1987) 1110–1111.
[2] H. Sumi, Y. Yanagisawa, N. Kishimoto, Nippon
Nogeikagaku Kaishi 73 (1999) 599–604.
[3] P. Setlow, J. Appl. Microbiol. 101 (2006) 514–525.