[en] Visualization of cavitation phenomena in a Diesel engine fuel injection nozzle was carried out by using neutron radiography system in Research Reactor Institute in Kyoto University and HANARO in Korea Atomic Energy Research Institute. A neutron chopper was synchronized to the engine rotation for high shutter speed exposures. A multi exposure method was applied to obtain a clear image as an ensemble average of the synchronized images. Some images were successfully obtained and suggested new understanding of the cavitation phenomena in a Diesel engine fuel injection nozzle

[en] Full text: Good morning, distinguished delegates, ladies and gentlemen. I would like to express my deep gratitude for your presence at the 'International Conference on Fast Reactors and Related Fuel Cycles: Challenges and Opportunities' organized by the IAEA. I would like to make a brief opening address on behalf of MEXT1. Firstly, I would like to welcome all who have travelled the long distance to Japan, and to express my thanks to people in Japan for their usual acceptance and for their cooperation on the research, development and use of nuclear technology. I would also like to thank the staff of the IAEA, the Japan Atomic Energy Agency and the commissions for their commitment to organizing this meeting. Today, humankind faces global issues on a scale never before seen, including global warming and energy resource security. Under such circumstances, ensuring the energy supply is essential for solving both the energy problem and global climate change simultaneously. This is increasingly being recognized all over the world. Sharing the recognition, we promote research, development and the use of nuclear energy as the major source of electrical power. We are aiming at the establishment of the fast breeder reactor cycle, which will ensure a long term energy supply, through efficient use of uranium resources. At MEXT, we continue to promote research and development in order to achieve the early commercialization of the fast breeder reactor cycle, by utilizing the prototype Monju fast breeder reactor. We are now doing our utmost to restart Monju by the end of March 2010, with the acceptance and cooperation of the local community. After the restart, we will enhance the reliability of Monju as an operational power plant, drawing upon operational experience. At the same time, we will continue research and development of radioactive waste reduction for topics such as minor actinide burning, as well as the enhancement of nuclear non-proliferation. We hope that Monju will play an important role, not only domestically, but also globally as one of the few high-end fast reactors. This makes Monju a major global centre in the area of nuclear fuel cycle research and development. In this conference, we can share the fruits of each country's and each organization's research and development for the purpose of realizing the nuclear fuel cycle, which is the important international political theme. Finally, I would like to express my wishes that this conference contributes to the stimulation of further research and development on the fast reactor cycle through active discussions and, ultimately, brings significant benefits to all countries. Thank you for your kind attention. (author)

[en] Results of pulsed UCN experiments with a supermirror turbine in KUR and some Monte Carlo calculations are reported. A turbine efficiency and the UCN output intensity satisfying designed values are obtained. Similar UCN experiments with a cold source at an electron linac are also carried out and compared. UCN gains by a cooled polyethylene converter are derived from the experiments. From these studies, a concept of a synchronized supermirror turbine is proposed for a spallation UCN source which can serve multi-loads uses of UCN experiments. (orig.)

[en] A multilayer spin splitter (MSS) is a device which gives the same effect as a magnetic field to the Larmor-precessing neutron. Since MSS is a single mirror, a neutron spin echo (NSE) can be much smaller (less than 1 m along the neutron beam) when MSSs successfully replace the Larmor precession magnetic field. The aim of our research is to replace the precession magnetic fields in NSE spectrometer by a set of MSSs and realize a very compact neutron spin echo spectrometer. In the present report, we will present the results of the preliminary experiment of the compact NSE spectrometer, and discuss its applicability to the pulsed neutron sources

[en] Neutron resonance spin echo (NRSE) enables us to measure neutron quasielastic scattering with high energy resolution. Its energy resolution is limited by neutron beam divergence. This divergent effect can be corrected by installing guide field between pair of resonance spin flippers. In this paper, we propose a beam divergence correction coil for NRSE spectrometer and evaluate its efficiency by numerical simulations

[en] We have developed a resonance neutron-spin flipper (RSF) with high frequency applicable to pulsed sources. This flipper is necessary for new neutron resonance spin echo spectrometers installed at pulsed neutron sources. The RSF works only for monochromatic neutron beams because of the dependence of its spin-flip probability on neutron velocity. The RSF can, however, be applied to pulsed neutron beam with wide band wavelength by varying the amplitude of the applied oscillating magnetic field since the pulsed neutrons are resolved into monochromatic components according to their velocity. In this paper, we describe the RSF system applicable to pulsed neutron sources, measure the flipping efficiency and discuss the experimental results

[en] The high-contrast neutron radiography has been performed at a VCN guide (VCN) and a supermirror cold neutron guide (CN-3) in Kyoto University Reactor. The large absorption cross-section of very low-energy neutrons can show a slight change of sample which thermal neutrons can not show. The effectiveness is shown in the fields of botany, agriculture and industrial researches. A new spectrum change option using high Q_c supermirror (m=4) is attached. It can change the upper limit of the energy of exposure neutrons by reflections, and gives a high flexibility of the experimental condition

[en] Neutron resonance spin echo (NRSE) spectroscopy enables us to measure neutron quasielastic scattering with high-energy resolution. It is desirable to apply NRSE spectroscopy to pulsed neutron sources because this application allows a very wide range of the spin echo time. We have already developed the neutron resonance spin flipper applicable to a polychromatic pulsed neutron beam, which is necessary for the TOF-NRSE method. Using this flipper, we have succeeded in observing spin echo signals with visibility higher than 0.65 for the pulsed neutron beam with wavelength from 0.3 to 0.9 nm. We discuss the prospect of the NRSE spectrometer with high-energy resolution on the basis of the present result

[en] A cold neutron source with two thermal and three cold neutron guide tubes has been installed in the upgraded JRR-3. Neutron fluxes, time-of-flight spectra and the gain of the cold neutron source were measured at the end of the neutron guide tubes. The neutron beam distributions were found by neutron radiography films. (orig.)

[en] The 'development and Application of Neutron Optics (NPO)' is an approved research project having RIKEN (The Institute of Physical and Chemical Research) as a leading institute under the support of special coordination founds by the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government. Research Reactor Institute, Kyoto University (KURRI) is a member of this project and tackles two subjects; development of neutron optic devices and reconstruction of a neutron guide hole (CN-3). Two prime studies in regard to neutron optic devices are performed; (1) development and evaluation of high efficiency multilayer neutron supermirrors and other various neutron mirrors, and (2) evaluation of performance of neutron lenses, polarizers and flippers. The neutron guide hole (CN-3) of the nuclear reactor will be reconstructed to perform the following experiments: (1) Irradiation experiments by white neutrons; neutron radiography and radioactivation analysis by prompt γ-rays. (2) Beam experiments by monochromatic neutrons; neutron spin interference experiments and performance test for polarizers by polarized beams, and measurements of reflectivity by non-polarized beams. (3) Time-of-flight experiments by use of choppers. The project will continue for five years from the fiscal year of 2000. (Y. Kazumata)