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Yokoyama, Sumi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; Ono, Koji*; et al.
Journal of Radiation Protection and Research, 47(1), p.1 - 7, 2022/03
Background: In Japan, new regulations that revise the dose limit for the lens of the eye (the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulatory Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set to not exceed the dose limit for the lens. Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 questions. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion: With the development of guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimise radiation protection.
Yokoyama, Sumi*; Iwai, Satoshi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; et al.
Proceedings of 15th International Congress of the International Radiation Protection Association (IRPA-15) (Internet), 8 Pages, 2022/00
Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.
Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.
Hayashi, Takumi; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Oyaizu, Makoto; Edao, Yuki; et al.
Fusion Science and Technology, 67(2), p.365 - 370, 2015/03
Times Cited Count：1 Percentile：9.71(Nuclear Science & Technology)
C discharge at RI facilities; A Comparison of collection and oxidation methodsUeno, Yumi; Koarashi, Jun; Iwai, Yasunori; Sato, Junya; Takahashi, Teruhiko; Sawahata, Katsunori; Sekita, Tsutomu; Kobayashi, Makoto; Tsunoda, Masahiko; Kikuchi, Masamitsu
Hoken Butsuri, 49(1), p.39 - 44, 2014/03
The Japan Atomic Energy Agency has conducted a monthly monitoring of airborne C discharge at the forth research building (RI facility) of the Tokai Research and Development Center. In the current monitoring, C, which exists in various chemical forms in airborne effluent, is converted into CO
with CuO catalyst and then collected using monoethanolamine (MEA) as CO absorbent. However, this collection method has some issues on safety management because the CuO catalyst requires a high heating temperature (600
C) to ensure a high oxidation efficiency and the MEA is specified as a poisonous and deleterious substance. To establish a safer, manageable and reliable method for monitoring airborne C discharge, we examined collection methods that use different CO absorbents (MEA and Carbo-Sorb E) and oxidation catalysts (CuO, Pt/Alumina and Pd/ZrO). The results showed 100% CO collection efficiency of MEA during a 30-day sampling period under the condition tested. In contrast, Carbo-Sorb E was found to be unsuitable for the monthly-long CO collection because of its high volatile nature. Among the oxidation catalysts, the Pd/ZrO showed the highest oxidation efficiency for CH
at a lower temperature.
Yamanishi, Toshihiko; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Oyaizu, Makoto; Yamada, Masayuki; Suzuki, Takumi; Hayashi, Takumi
Fusion Engineering and Design, 87(5-6), p.890 - 895, 2012/08
Times Cited Count：1 Percentile：10.1(Nuclear Science & Technology)In JAEA, the tritium processing and handling technologies have been studied at TPL. The main basic R&D activities in this field are: the tritium processing technology for the blanket recovery system; the tritium behavior in a confinement; and detritiation and decontamination. The R&D for tritium processing and handling technologies to a demonstration reactor (DEMO) are also planned to be carried out in the Broader Approach (BA) program in Japan by JAEA with Japanese universities. The ceramic electrolysis cell has been studied as a tritium processing method for the blanket system. The permeation behavior of tritium through pure iron into the gas containing water vapor has been studied. As for the behavior of high concentration tritium water, it was observed that the formation of the oxidized layer was prevented by the presence of tritium in water. Tritium durability tests were also carried out for the electrolysis cell of the chemical exchange column.
Sugino, Kazuteru; Ishikawa, Makoto; Numata, Kazuyuki*; Iwai, Takehiko*; Jin, Tomoyuki*; Nagaya, Yasunobu; Hazama, Taira; Chiba, Go*; Yokoyama, Kenji; Kugo, Teruhiko
JAEA-Research 2012-013, 411 Pages, 2012/07
JAEA-Research-2012-013.pdf:18.72MB
JAEA-Research-2012-013-appendix(CD-ROM).zip:75.82MB
Aiming at evaluating the core design prediction accuracy of fast reactors, various kinds of fast reactor core experiments/tests have been analyzed with the Japan's latest evaluated nuclear data library JENDL-4.0. Totally 643 characteristics of reactor physics experiments/tests and irradiation tests performed using the critical facilities: ZPPR, FCA, ZEBRA, BFS, MASURCA, ultra-small cores of LANL and power plants: SEFOR, Joyo, Monju were dealt. In analyses, a standard scheme/method for fast reactor cores was applied including detailed or precise calculations for best estimation. In addition, results of analyses were investigated from the viewpoints of uncertainties caused by experiment/test, analytical modeling and cross-section data in order to synthetically evaluate the consistency among different cores and characteristics. Further, by utilizing these evaluations, prediction accuracy of core characteristics were evaluated for fast power reactor cores that are under designing in the fast reactor cycle technology development (FaCT) project.
Sugino, Kazuteru; Ishikawa, Makoto; Yokoyama, Kenji; Nagaya, Yasunobu; Chiba, Go; Hazama, Taira; Kugo, Teruhiko; Numata, Kazuyuki*; Iwai, Takehiko*; Jin, Tomoyuki*
Journal of the Korean Physical Society, 59(2), p.1357 - 1360, 2011/08
Times Cited Count：5 Percentile：38.84(Physics, Multidisciplinary)In order to improve the prediction accuracy of core performances in the fast reactor core design study, the unified cross-section set has been developed in Japan. The unified cross-section set, which combines a wide range of integral experimental information with differential nuclear data, is produced by using the cross-section adjustment technique based on the Bayesian parameter-estimation theory. A new set ADJ2010 is currently under development. The present paper describes the results of the cross-section adjustment for ADJ2010 which is based on the JENDL-4.0 data. The evaluation of the core design accuracy for a commercial power fast reactor core is also discussed. ADJ2010 will be released soon and will be expected to be utilized for core design of future fast reactors.
Yokoyama, Kenji; Tatsumi, Masahiro*; Hirai, Yasushi*; Hyodo, Hideaki*; Numata, Kazuyuki*; Iwai, Takehiko*; Jin, Tomoyuki*; Hazama, Taira; Nagaya, Yasunobu; Chiba, Go; et al.
JAEA-Data/Code 2010-030, 148 Pages, 2011/03
JAEA-Data-Code-2010-030.pdf:3.23MB
A next generation reactor analysis code system, MARBLE, has been developed. MARBLE is a successor of the fast reactor neutronics analysis code systems, JOINT-FR and SAGEP-FR (conventional system), which were developed for so-called JUPITER standard analysis methods. MARBLE has the equivalent analysis capability to the conventional system. On the other hand, burnup analysis functionality for power reactors as improved compared with the conventional system. In the development of MARBLE, the object oriented technology was adopted. As a result, MARBLE became an assembly of components for building an analysis code (i.e. framework) but not an independent analysis code system which simply receives input and returns output. Furthermore, MARBLE provides some pre-built analysis code systems such as the fast reactor neutronics analysis code system, SCHEME, which corresponds to the conventional code and the fast reactor burnup analysis code system, ORPHEUS.
Serizawa, Hiroyuki; Kikuchi, Hironobu; Iwai, Takashi; Arai, Yasuo; Kurosawa, Makoto; Mimura, Hideaki; Abe, Jiro
JAERI-Tech 2005-039, 23 Pages, 2005/07
JAERI-Tech-2005-039.pdf:2.89MB
A high-temperature ultrasonic measuring system had been designed and installed in a glovebox (711-DGB) to study a mechanical property of nuclear fuel containing trans-uranium (TRU) elements. A figuration apparatus for the cylinder-type sample preparation had also been modified and installed in an established glovebox (142-D). The system consists of an ultrasonic probe, a heating furnace, cooling water-circulating system, a cooling air compressor, vacuum system, gas supplying system and control system. An A/D converter board and an pulsar/Receiver board for the measurement of wave velocity were installed in a personal computer. The apparatus was modified to install into the glovebox. Some safety functions were supplied to the control system. The shape and size of the sample was revised to minimize the amount of TRU elements for the use of the measurement. The maximum sample temperature is 1500 C. The performance of the installed apparatuses and the glovebox were confirmed through a series of tests.
Takeuchi, Shinji; Kashiwai, Yoshio*; Hirata, Yoichi*; Yoshida, Yukimi*; Nishigaki, Makoto*
Proceedings of 4th IEEE/LEOS Workshop on Fibres and Optical Passive Components (WFOPC 2005), p.393 - 398, 2005/00
A multi-level groundwater monitoring system using FBG sensors has been developed for measuring pore water pressure and temperature in small diameter boreholes. The system consists of packer units, temperature and pressure sensing units, and optical fiber cable connecting units. The system with two measurement sections was established as a prototype for the feasibility study. A preliminary test was carried out for about 11 months in a borehole in the Tono area central Japan. The test data obtained in early period were unstable and periods of data loss occurred. Several improvements were implemented and subsequent results show the developed system is feasible for using in slim boreholes.
Shono, Akira; Sato, Wakaei*; Hazama, Taira; Iwai, Takehiko*; Ishikawa, Makoto
JNC TN9400 2003-074, 401 Pages, 2003/08
JNC-TN9400-2003-074.pdf:48.95MB
Nuclear design accuracy on the BN-600 hybrid core has been evaluated using the JNC's nuclear analysis system for FBR cores, by utilizing the critical experiment analysis results on BFS-62 configuration that had been obtained under JNC's efforts for Russian surplus weapons plutonium disposition. In the BN-600 hybrid core design, a part of the current UO2 fuel region is replaced by MOX fue1, and the Peripheral blanket region by stainless steel reflectors, respectively. These changes were simulated in a series of critical experiment configurations (BFS-62-1 to 4). Based on the analysis results on both BFS-62 configurations and other fast reactor cores, nuclear design accuracy on the BN-600 hybrid core has been evaluated by applying both the group constant adjustment method and the bias method. Evaluated nuclear parameters include, the criticality, fission rate distribution, sodium void reactivity, control rod worth, burn-up reactivity loss, etc. It is concluded, by applying the group constant adjustment method, that the evaluated accuracy (uncertainty) of most of the nuclear parameters can be decreased to less than half of those based on the basic nuclear constant without reflecting any experimental data. The improvement was mainly achieved by reducing the covariance of the iron elastjc cross section. This significant effect results from the feature of the BN-600 hybrid core, which has relatively larger power density, adopts U235 as the main fissile nucljde, and has the stainless steel reflector surrounding the fuel region. In addition, good consistency of analysis results between the BFS and other fast reactor cores is confirmed. Information obtained by BFS-62 experiment show significant contribution to the accuracy improvement. It is also found that the bias method shows less significant effects on the accuracy improvement than the group constant adjustment method. Furthermore, the bias method may degrade the accuracy for certain nuclear parameters that have large e
Ando, Masaki; Iijima, Susumu; Ishikawa, Makoto*; Iwai, Takehiko*
JAERI-Tech 2000-025, p.45 - 0, 2000/03
JAERI-Tech-2000-025.pdf:1.77MB
no abstracts in English
Iwai, Takehiko*; Sugino, Kazuteru; Ishikawa, Makoto
PNC TN9410 98-079, 54 Pages, 1998/07
In the Reactor Physics Research Section, O-arai Engineering Center, a Standard Data Base for Nuclear Design is under development to improve the accuracy of FBR nuclear design calculations. The Reactor Integral Test Working Group of the Sigma committee is compiling data from TCA (Tank Type Critical Assembly), STACY (Static Experimental Critical Facility) and FCA (Fast Critical Assembly), for a set of nuclear data benchmark problems. An FBR benchmark problem from the Working Group has been added to the Data Base: the ZPPR-9 core, simplest of the JUPITER-I series, recommended for its ease of use. The compiled nuclear parameters are Criticality; Reaction rate data(Reaction rate ratio & Reaction rate distribution); Control rod worth; Sodium void reactivity and Sample Doppler reactivity. The benchmark problem definition is an idealization of the experimental geometly; we used detailed analytical methods to prepare correction factors, so that users of the benchmark can compare their results with the experiment. Wide use of the benchmark problem is anticipated. However, the calculation of correction factors is affected by the mesh size, the number of energy groups and the definition of cross sections, so it is necessary to use detailed analytical methods to produce modified correction factors when one uses a calculational model in which mesh size etc. are different.
Ishikawa, Makoto; Sato, Wakaei*; Sugino, Kazuteru; Yokoyama, Kenji; Numata, Kazuyuki*; Iwai, Takehiko*
PNC TN9410 97-099, 512 Pages, 1997/11
A Standard data base for LMFBR core nuclear design has been developed to improve analytical methods and prediction accuracy of nuclear design for large fast breeder cores such as demonstration or commercial FBRs. To develop the data base, extensive work has been prerformed to accumulate and evaluate many kinds of results from fast reactor physics experiments and their analyses. The present report summarizes the analytical results of the JUPITER experiments, using the most recent nuclear data library (JENDEL-3.2) and the lates analytical methods in a consistent manner. In the present work, a great emphasis was placed on guaranteeing the essential requirements for this kind of general data base, that is, "Accountability", "Traceability" and "Consistency". In other words, consistent strategies and analytical methods were applied to all calculations, including detialed corrections; the enormous analytical input data generated were all saved in the form of computer files, so that reanalysis of any experiment could be easily performed for verification or in response to future improvement in nuclear data or analytical methods. The main results of the present JUPITER analysis are as follows: (1) The C/E(calculation/experiment) values of criticality were slightly underestimated by -0.7
-0.3%
k. (2) The reaction rate ratio of C28/F49 was overestimated by +4+6% with the standard analytical method. However it was found to improve about 2% after the cell factors were revised using the Monte Carlo method. (3) The radial space-dependency of the reaction rate distribution and control rod worth almost disappeared in the homogeneous cores. (4) The previous overestimation of sodium void reactivity was greatly improved in the homogeneous cores.
Sugino, Kazuteru; Yokoyama, Kenji; Ishikawa, Makoto; Sato, Wakaei*; Numata, Kazuyuki*; Iwai, Takehiko*
PNC TN9410 97-098, 247 Pages, 1997/11
The present report compiles the advances in experiment analyses of JUPITER, which was joint research programs between U.S.DOE and PNC of Japan, using the Zero Power Physics Reactor (ZPPR) large fast critical facility at ANL-Idaho in 1978 to l988. The advances here are use of the latest nuclear data library and the application of analytical methods which treat mechanisms in more detail or use fewer modeling approximations. As a result of using the latest nuclear data library, C/E values of nearly all characteristics approached unity, and the discrepancies between cores were reduced. Thus it is shown that the latest data library is effective for an analysis of nuclear characteristics. Further, an advance in analytical methods brought C/E value close to unity, and it clarifies the causes of differences between the calculational and experimental values. The current evaluation for each nuclear palameter shows following: (1)Criticality. The C/E values are from 0.993 to 0.997, a systematic underestimate. This underestimation is much smaller than the error caused by the uncertainty in nuclear data, which is the dominant error for this characteristic. In terms of analytical method, there are significant differences in calculation results between present and Monte-Carlo based methods, so more investigation will be required in future. (2)Doppler reactivity. The C/E values are from 0.8 to 0.9, a systematic underestimate. The analytical method, which is stood for by the use of ultra fine energy structure analysis, is so detailed that there is little room for improvement in that term. Therefore, some evaluation of the self-shielding factors and comparison with other Doppler reactivity experiments will be required. (3)Reaction rate distribution. It is judged that the present analytical method has an adequate accuracy for the core regions of homogeneous and axially heterogeneous cores, because the C/E values varied from unity by less than 2% for Pu-239 fission, U-235 fission ...
Kitahara, Yoshihisa; Yamato, Aiji; Iwai, Makoto;
PNC TN8420 86-10, 166 Pages, 1986/12
An accident took place at the Chernobyl nuclear power plant in USSR in the early hours of 26 April 1986. The plant caught fire and some degree of reactor inventry was released to the environment. Following the accident, debris of the radioactivity from Chernobyl was detected in all the European countries and countermeasures were taken in some countries. In Japan, many kinds of radionuclides were detected in rain, airbone dust and other environmental samples from 3 May and "Headquaters for Radioactivity Countermeasure" was organized in the Japanese Government. Health and Safety Division at the Tokai Works, PNC, performed the environmental monitoring for the Chernobyl accident in addition to the statutory monitoring program. This report presents results of the environmental monitoring performed at Tokai Works. Furthermore, study on the environmental transfer parameters and preliminary estimation of the committed dose equivalent to the public around Tokai area are discussed.
*; Ishida, Junichiro; Iwai, Makoto
PNC TN8520 86-011, 559 Pages, 1986/04
This manual includes standard procedures for environmental sampling, sample preparation and radionuclide analysis and is applied to the environmental monitoring around the Tokai Works of PNC. The fourth edition was published in 1983 (PNC TN852-83-15). Almost all analytical procedures have been modified for these three years, so the fifth edition revised entirely was to be published this time. [First Edition PNC1 N841-72-29 (August, 1972)] [Revision 1 PNC T852-75-08 (March, 1975)] [Revision 2 PNC T852-79-09 (April, 1979)] [Revision 3 PNC TN852-83-15 (June, 1983)]
Iwai, Makoto; Ishida, Junichiro; *; Asano, Tomohiro
PNC TN8440 86-001, 149 Pages, 1986/02
This report presents current information from the Environmental Protection Section, Tokai Works, PNC, on the radiation monitoring around the reprocessing plant during 1985. The report consists of general interpretive report on the results, individual interpretive reports and maximum radiation dose which may be received by hypothetical inhabitants, due to the discharges of radioactivity into both marine and terrestrial environments. Subsequent supplements include tabulations of results, including meteorological observations and radioactivity measurements on waste effluent from the plant. The environmental radiation monitoring around the Tokai reprocessing plant has been performed since 1975, based on the safety standard of the Plant.
