Journal of Applied Mathematics and Physics, 2014, 2, 837-842
Published Online August 2014 in SciRes. http://www.scirp.org/journal/jamp
How to cite this paper: Choo, K.-N., Cho, M.-S., Jun, B.-H., Kim, C.-J. and Park, S.-J. (2014) Neutron Irradiation of Electronic
Materials at HANARO. Journal of Applied Mathematics and Physics, 2, 837-842.
Neutron Irradiation of Electronic Materials
Kee-Nam Choo*, Man-Soon Cho, Byung-Hyuk Jun, Chan-Joong Kim, Sang-Jun Park
Department of Research Reactor Utilization, Korea Atomic Energy Research Institute, Daejeon, South Korea
Received 26 May 2014
HANARO, a 30 MW open-pool type multipurpose research reactor, has been operated as a platform
for nuclear researches in Korea, and irradiation facilities have been mainly utilized for various
nuclear material irradiation tests requested by users. Although most irradiation tests have been
related to national R&D relevant to nuclear power, demand for neutron irradiation of elec-
tro-magnetic materials is increasing rapidly at HANARO. Another research reactor, which is
named the KIJANG research reactor (KJRR), is under construction in Korea. KJRR is dedicated to
increasing the national radio-isotopes supply capacity and to the irradiation facilities including
Neutron Transmutation Doping (NTD) facilities for power semiconductor production in a large
scale and fast neutron irradiation (FNI) facility for fast neutron irradiation. The NTD and FNI facil-
ities in the KJRR reactor can be effectively utilized on the study of separated effect of thermal and
fast neutron irradiations on the properties of electro-magnetic mate ri als . HANARO will also spe-
cialize more on irradiation research, including neutron irradiation of electronic materials. The
research status and possibility of new electro-magnetic materials using neutron irradiation at
HANARO are surveyed to ascertain the utilization of neutron irradiation technology in elec-
tro-magnetic material researches.
HANARO, Neut ron , I rr adia tion , El ec tr o-Magnetic Material
The High Flux Advanced Neutron Application Reactor (HANARO) has been operating as a platform for basic
nuclear research in Korea, and the functions of its systems have been improved continuously since its first criti-
cality in February 1995. It is now being successfully utilized in such areas as fuel and material irradiation tests
and neutron transmutation doping to meet industrial, academic, and research demands. To support the national
research and development programs on nuclear reactors and nuclear fuel cycle technology in Korea, rabbit and
capsule irradiation facilities have been developed and actively utilized for the irradiation tests requested by nu-
merous users . Continuing efforts to improve the capabilities and instrumentation of the facilities have been in
progress at KAERI  . The irradiation facilities have been mostly utilized for the KAERI research projects
K.-N. Choo et al.
related to the National Nuclear R & D Projects relevant to a commercial nuclear power reactor such as the age-
ing management and safety evaluation of the components. However, some irradiation tests of electro-magnetic
materials were performed for scientific research of universities and the demand for neutron irradiation of elec-
tro-magnetic materials is increasing rapidly at HANARO. Another research reactor that will specialize in ra-
dioisotope production and the demonstration of reactor design is under construction in Korea. Therefore, HANARO
will specialize more on irradiation research. Based on its accumulated irradiation experience, HANARO has re-
cently started new support of R & D relevant to the irradiation of electro-magnetic materials.
In this paper, not only the status of HANARO irradiation facilities but also the utilization of the facilities and
the possibility of new electro-magnetic materials using neutron irradiation at HANARO are surveyed to ascer-
tain the utilization of neutron irradiation technology in electro-magnetic material researches.
2. HANARO and Utilization for Nuclear Technology
2.1. HANARO and Irradiation Facilities
The High Flux Advanced Neutron Application Reactor (HANARO) is an open pool type multipurpose research
reactor with 30 MW thermal power located at the Korea Atomic Energy Research Institute (KAERI) in Korea.
In an effort to boost the nation’s research capability, HANARO was conceived and constructed in the 1980s us-
ing domestic reactor technology from KAERI . As a platform for nuclear basic researches in Korea, HANARO
has been operated, and the functions of its systems have been improved continuously since its first criticality in
February 1995; and it is now being successfully utilized in such areas as fuel and material irradiation tests, neu-
tron beam research, radioisotopes production, neutron activation analysis, and neutron transmutation doping, etc.
to meet the industrial, academic, and research demands. To support the national research and development pro-
grams on nuclear reactors and nuclear fuel cycle technology in Korea, various neutron irradiation facilities such
as the rabbit (small non-instrumented capsule) irradiation facilities, the capsule irradiation facilities, and the fuel
test loop facilities have been developed as shown in Figure 1  .
The rabbit was originally designed for isotope production, but it can be used for the irradiation test of fuels
and materials. Figure 1 shows the typical rabbit (20 mm in diameter and 30 mm in length for specimen). It is
very useful for numerous irradiation tests of small specimens at a low temperature, below 200˚C, and neutron
The instrumented and non-instrumented capsules have been developed at HANARO for new alloy and fuel
developments and the lifetime estimation of nuclear power plants (NPPs). For the development of an instru-
mented capsule system, the capsule related systems such as a supporting, connecting and controlling system
were also developed. After locking the capsule in a test hole, the instrumented capsule is fixed by a chimney
bracket and robotic arm supporting systems. The capsule temperature control system consists of three subsys-
tems: a vacuum control system, a multi-stage heater control system and a man-machine interface system. After
an irradiation test, the main body of the instrumented capsule is cut off at the bottom of the protection tube with
the cutting system, and it is transported to the Irradiated Materials Examination Facility (IMEF) using a
HANARO fuel cask.
Figure 1. Photograph of the HANARO core and irradiation facilities.
K.-N. Choo et al.
The FTL is a facility that can conduct fuel and material irradiation tests at HANARO. It is composed of an in-
pile test section (IPS) and an out-of-pile system (OPS). The IPS in the IR1 irradiation hole can accommodate up
to three pins of PWR or CANDU type fuels and has instruments such as a thermocouple, LVDT, and SPND to
measure the fuel’s performance during a test. The FTL simulates commercial NPP operating conditions such as
its pressure, temperature, flow, and neutron flux to conduct irradiation tests. The application fields of the FTL
are nuclear fuel and material irradiation tests at the operating conditions of a commercial power plant, fuel burn
up and mechanical integrity verification tests, irradiation data generation for a performance analysis model
(PWR fuel, CANDU fuel and metallic fuel), technical improvement of a design and fabrication process for ad-
vanced fuel development, fuel rod irradiation testing for performance verification and more. The typical design
pressure and temperature of the in-pile section of the FTL is 17.5 MPa and 350˚C, respectively. The commis-
sioning of the FTL was performed from April 2007 to September 2009. At present, a cold test is being per-
formed for long-term utilization. The FTL will be used for the irradiation tests of advanced fuels after comple-
tion of the commissioning.
HANARO has two irradiation holes for neutron transmutation doping (NTD) to manufacture high-quality n-
type semiconductors. A semiconductor doped with neutrons has a much better dopant distribution compared to
others made by conventional chemical doping methods, and is especially required for the effective use of
high -power operating devices such as insulated gate bipolar transistors (IGBTs), integrated gate commutated
thyristors (IGCTs), and gate turn off thyristors (GTOs). The demand for NTD silicon is increasing rapidly with
the increase of wind, solar, and fuel cell energy systems; hybrid cars and hydrogen fuel cell engines; and devices
to reduce electricity loss. A commercial NTD service for 5, 6 and 8 inch silicon ingots is being performed at
NTD1 and NTD2, where the world’s best quality products make up about 15% of the world market share as of
2012. New NTD facilities for a larger silicon ingot such as a 10 or 12 inch ingot are being planned in the new
There are two facilities used for performing a post-irradiation examination (PIE) at KAERI. These are the Ir-
radiated Material Examination Facility (IMEF) and the Post-Irradiation Examination Facility (PIEF). Detailed
information about these facilities is available on the KAERI home page (http://www.kaeri.re.kr).
2.2. Utilization of HANARO for Nuclear Technology
As a platform for nuclear researches in Korea, the irradiation facilities of HANARO have been actively utilized
for various nuclear fuel and material irradiation tests requested by users from research institutes, universities,
and industries. Since 1995, 12,000 specimens from research institutes, nuclear industry companies and universi-
ties have been irradiated at HANARO for 123,000 cumulative hours using the developed capsule and rabbit ir-
radiation systems. One of the major irradiation fields is the support of national research and development pro-
gram relevant to the commercial nuclear power reactor such as ageing management and the safety evaluation of
its components. Another field is the progress of science and technologies (fundamental research, future nuclear
systems). Figure 2 shows a typical contribution of neutron irradiation at HANARO for the National Nuclear R
& D Programs. Based on its accumulated experience and the sophisticated requirements of users, HANARO
Figure 2. Contribution of neutron irradiation at HANARO for
the national nuclear R & D programs.
VHTR high-Temp. Materials for
: Core Materials
U-Mo Plate Fuel
RPV steel for Doosan
: Steam Generator Materials
Nuclear Fuel Assembly Parts for
KEPCO Nuclear Fuel Co.
Control Rod Materialsfor
KNF/WEC AP1000 (U.S.)
Irradiation for Nuclear Fuel
K.-N. Choo et al.
has recently started a new support of R & D relevant to new nuclear systems including the System-integrated
Modular Advanced Reactor (SMART) and future nuclear systems of the very high temperature reactor system
(VHTR) and sodium cooled fast reactor system (SFR). To effectively support R & D relevant to new nuclear
systems, the development of advanced irradiation technologies is being actively developed at HANARO.
3. Irradiation of Electro-Magnetic Materials at HANARO
3.1. Irradiation Tests of Electro-Magnetic Materials
As a national platform for basic and nuclear research, HANARO irradiation facilities have been actively used
for irradiation tests of basic research requested by users from research institutes and universities. The irradiation
tests requested from users, as shown in Table 1, have been sponsored by the National Project for Active Utiliza-
tion of HANARO since 2000. The project has a call for research proposals every year. Proposals submitted
Table 1. Neutron irradiation tests of electro-magnetic materials at HAN ARO.
Research Field Materials & Topics
Mono-crystal NFG products
Thermal Diffusion Coefficient UO2/UO2+Addition Mono-crystal
Fission gas release research
NFG/Grain Boundary Effect FGR/GB effect research
Xenon Gas Diffusivity in U-N Fuel U-Nitride Fuel/Xe Diffusivity
Reactor Structural Materials
Irradiation Damage/Recovery RPV/nano ODS materials
Nuclear Fuel Carrier Stack cask
Fracture Characteristics Cask mater. SA240 SS, 350LF3, 508 4N
Fracture Analysis, Database
Zr-based Reactor Core material
Micro-structu re/Corr osion Zr -base new alloys, Zr-Nb-Ni-Cr
Korean Nuclear Fuel Cladding
Pro-Environmental RPV material
Microstructure of Nano-Materials Ferritic low alloy steel/HT9M
Al alloys, Alumina, Cu-Nb Nano-Composite
Neutron Irradiation Damage Zircaloy-4, Zr (Tube, Plate)
Cold Working, HT, grain size, ppt, Dislocation
Zr-based Alloy Embrittlement Zr-Cu, Zr-Mn Fuel Cladding Materials
RPV Welds Irradiation Damage Welding Technology of SA 508 cl.3
STS deformation Property STS304, STS430, HLSA
Broad Banded Semi-Conductor
Irradiation Defect WBG Semi-Condu ctor (ZnO, GaN)
Pure Silicon Crystal (Wafer)
Irradiation Point Defects Mass Production of Uniform Semi-conductor
Degradation of Dielectric Devices Si Semiconductor, Performance & Credibility
Irradiation of Oxide Transistor Oxide TFT, Degradation mechanism
Super-Conductor Improvement of Superconductivity YBCO, MgB2/Electromagnetic properties
Superconductivity of MgB2 by thermal neutron irradiation MgB2/Surface Resistivity & Conductivity
Optical / Electro-magnetic material Irradiation SrTiO 3, MgO, ZnO Nano lattice defect measurement
Amorphous Ribbon/Wire Magnetic Fe-Zr amorphous ribbon/Fe-based wire
Magnetic Semi-Cond. Irradiation GaMnAs, GaMnN, ZnO Magnetic Semi-Con.
Multiferroics LiFePO4, Li(Ni-M n)O4, Cu(Fe-Ga)O2
Neutrino Production Cr, W, Pd wire
Stress Evaluation of Irradiated Gra. Graphite, Physical Properties
Development of Neutron Detectors Si/SiC Semiconductor, Severe Environments
K.-N. Choo et al.
through the homepage (http://www. nrf.re.kr) of the National Research Foundation of Korea (NRF) are competi-
tively selected on the basis of an independent peer review that utilizes expert reviews from universities, national
laboratories, and industry.
Various specimens such as nuclear fuels and materials, and new functional materials including conductors and
optical/electrical materials have been irradiated using capsule and rabbit systems. The electro-magnetic and opt-
ical properties of the materials are closely dependent on the size and density of their internal defects, and neu-
tron irradiation is a very effective method to produce micro-defects in these materials. Therefore, neutron tech-
nology can be applied effectively toward the development of new materials. Recently, several efforts have been
made at HANARO to evaluate the effect of neutron irradiation on the physical properties of various functional
3.2. Additional Works near Future
As neutron irradiation provides 1) Preservation of stoichiometric composition and average number of electrons
pre an atom; 2) Opportunity of preservation of macro- and micro-homogeneity of samples; 3) Opportunity of
making of defects of various sorts with smooth changing of their concentration. These opportunities of neutron
irradiation are unattainable by using any other traditional technological methods. Therefore, the study of a re-
sponse of a crystal to irradiation influence allows observing unique information about electron states, magnetic
interaction and cetera.
The electrical and magnetic properties of electronic materials are extremely dependent upon disorder in lattice
structure. Neutron irradiation of these materials greatly increases this disorder through the creation of various
defects. Thermal neutron damage is thought to consist of point defects such as divacancies, di-interstitials, and
vacancy-impurity clusters. Fast neutron damage consists of extended defect clusters which may contain as many
as 1000 defects .
Although several impressive effects of neutron irradiation on the properties of electronic materials were re-
ported at HANARO -, it was difficult to interpret clearly their behaviors due to the broad energy spectrum
of the neutron as shown in Figure 3. The undesirable effects due to thermal and fast neutrons should be reduced
to separate each neutron’s effect on the properties of the sample. Following the experience with HANARO,
KIJANG research reactor (KJRR) is now being constructed by KAERI, dedicated to increasing the national ra-
dio-isotopes supply capacity including the self-sufficiency of Mo-99. And the KJRR is also expected to have the
capability to provide the neutron irradiation service for power semiconductor production in a large scale. This
service includes not only NTD facility for ingot irradiation, but also fast neutron irradiation (FNI) facility for
wafer irradiation. Fast neutron irradiation for wafer is a promising technology for efficiency gain and life exten-
sion of the power semiconductor. The FNI facility can be effectively utilized on the study of separated effect of
fast neutron irradiation on the properties of electro-magnetic materials. The foundation for the research of mate-
rials using neutron irradiation has a great possibility in the field of original information of electro-magnetic ma-
Figure 3. Neutron energy spectrum at HANARO and plan view of the KJRR core.
Neutron Spectrum in Inconel 690 Specimens (CAR=450 mm)
1 E -5
1 E -4
1 E -3
1 E -2
1 E -1
1E-4 1E-31E-2 1E-1 1E+0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8
Neutron Energy (eV)
Normalized Flux per Unit Letha
K.-N. Choo et al.
HANARO irradiation facilities have been mainly utilized for various nuclear material irradiation tests requested
by users. Although most irradiation tests have been related to national R & D relevant to nuclear power, the de-
mand for neutron irradiation of electro-magnetic materials is increasing rapidly at HANARO. Following the ex-
perience with HANARO, KIJANG research reactor (KJRR) is now being constructed by KAERI, dedicated to
increasing the national radio-isotopes supply capacity and to the irradiation facilities including NTD facilities
for power semiconductor production in a large scale and FNI facility for fast neutron irradiation by shielding
thermal neutron. The NTD and FNI facilities in the KJRR reactor can be effectively utilized on the study of se-
parated effect of thermal and fast neutron irradiations on the properties of electro-magnetic materials. The foun-
dation for the research of materials using neutron irradiation seems to have a great possibility in the field of re-
search of electro-magnetic materials.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea gov-
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