Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.
JAEA-Review 2014-048, 69 Pages, 2015/02
JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations
Nakanishi, Chika; Hirayama, Yusuke; Akiyama, Kiyomitsu
Hoken Butsuri, 49(3), p.139 - 144, 2014/09
After the Fukushima Daiichi Nuclear Power Station accident, the Nuclear Emergency Response Guidelines developed by the Nuclear Regulatory Authority of Japan has introduced Operational Intervention Levels (OILs). Particularly, the screening level defined as OIL4 of decontamination against surface contaminations on the skin, clothes and others has adopted, and the default OIL4 value is 13,000 cpm. The count rate value indicated by GM survey meters varies according to the model. Thus, count rates measurements using the same radiation source were performed with four typical GM survey meters in this work, and the instrument efficiencies were compared. In addition, the dependences of the distance between the detector and the source are also evaluated between 1 cm and 5 cm. The screening levels corresponding to OIL4 for each GM survey meter were derived, and the value has 7,000-9,000 cpm from the instrument efficiencies. Count rates were decreased with the increasing distance from the source at the different ratios depending on the model. Then the screening levels at 5 cm between the source and the detector windows showed 3,000-6,000 cpm. This study suggested the importance to evaluate the intrinsic characteristics of the model and to derivate the appropriate screening level at a few centimeters from the screening object to detect contamination reliably.
Sato, Takeshi; Muto, Shigeo; Okuno, Hiroshi; Katagiri, Hiromi; Akiyama, Kiyomitsu; Okamoto, Akiko; Koie, Masahiro; Ikeda, Takeshi; Nemotochi, Toshimasa; Saito, Toru; et al.
JAEA-Review 2013-046, 65 Pages, 2014/02
When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) has the responsibility of providing technical support to the National government, local governments, police, fire stations and nuclear operators etc., because the JAEA has been designated as the Designated Public Institution under the Basic Act on Disaster Control Measures and the Act on Response to Armed Attack Situations, etc.. The Nuclear Emergency Assistance and Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an Off-Site Center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, dispatches specialists as required, and supplies the National Government and local governments with emergency equipments and materials. NEAT provides various exercise and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response organizations at normal times. The tasks of NEAT, with its past experiences as a designated public institution including the responses to TEPCO's Fukushima Accident, have been shifted to technical supports to the national government for strengthening its abilities to emergency responses; the NEAT therefore focused on maintenance and operation of its functions, and strengthening its response abilities in cooperation with the national government. This annual report summarized these activities of JAEA/NEAT in the fiscal year 2012.
Koarashi, Jun; Mikami, Satoshi; Miyauchi, Toru; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Nakada, Akira; Akiyama, Kiyomitsu; Momose, Takumaro
JAEA-Technology 2010-039, 34 Pages, 2010/12
The current methodology for monitoring airborne radioiodine at the Tokai reprocessing plant (TRP) was reviewed, and some investigations were made to re-evaluate collection and measurement techniques in the methodology. The investigations focused particularly on: (1) in situ collection efficiency of an iodine sampler for I and its dependence on sampling flow rate; (2) evaluation of I and I activities collected in an activated charcoal cartridge; (3) I collection capacity of an activated charcoal cartridge under reprocessing off-gas conditions; and (4) real-time monitoring system for I in airborne effluent. The results obtained gave not only the validity of the TRP's monitoring method, but also technical aspects required for establishing a more reliable and effective monitoring method for radioiodine isotopes.
Koarashi, Jun; Mikami, Satoshi; Akiyama, Kiyomitsu; Takeishi, Minoru
Hoken Butsuri, 43(4), p.366 - 370, 2008/12
A sampling system was designed to detect rapidly an unexpected release of I during a weekly batch-sampling of a stack gas. The system consisted mainly of a sampling unit and an iodine monitor with an NaI(Tl) scintillation detector. A relationship between in situ count rate of the monitor and I activity collected in the sampling unit was derived from several set of data obtained with the system in the Tokai reprocessing plant. The system and relationship allowed us to estimate the amount of I release at an arbitrary time during the batch-sampling. A different iodine monitor with a Ge detector was also tested to overcome a difficulty in selective measurement of I with the NaI(Tl) scintillation detector in the presence of Kr in the target gas. The test demonstrated a feasibility of the real-time, Kr-interference-free monitoring of atmospheric I release.
Nakada, Akira; Miyauchi, Toru; Akiyama, Kiyomitsu; Momose, Takumaro; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Otomo, Hiroyuki*
JAEA-Data/Code 2008-018, 134 Pages, 2008/10
This report provides the data set of atmospheric discharges from Tokai reprocessing plant in Tokai-mura, Japan over the period from 1998 to 2007. Daily and weekly data are shown for Kr that is continuously monitored and for the other nuclide (Alpha emitters, Beta emitters, H, C, I, I) whose activities are evaluated based on weekly batch-samplings, respectively. The data contained in this report are expected to apply for studying the behavior of the radioactive airborne effluent in the environment.
Koarashi, Jun; Mikami, Satoshi; Nakada, Akira; Akiyama, Kiyomitsu; Kobayashi, Hirohide; Fujita, Hiroki; Takeishi, Minoru
Journal of Nuclear Science and Technology, 45(Suppl.5), p.462 - 465, 2008/06
Tokai reprocessing plant (TRP) has released radionuclides such as H, C, Kr and I into the atmosphere since the start of operation in 1977. We have established the monitoring methodologies for these nuclides, to realize an appropriate and continuous radioactive discharge control. The methodologies having various special technical considerations for matching the monitoring of reprocessing off-gas, were summarized in this paper. Briefly, H was collected by a cold-trap technique and the concentration was evaluated being independent of the water collection efficiency; C was collected by a monoethanolamine bubbler and then measured by liquid scintillation counting without any interferences from H and Kr; Kr was continuously measured by combination of two kinds of detectors to cover very wide range of the concentration; and I was collected by a charcoal filter and a charcoal cartridge in series with a relatively high collecting performance.
Koarashi, Jun; Fujita, Hiroki; Onuma, Toshimitsu*; Mikami, Satoshi; Akiyama, Kiyomitsu; Takeishi, Minoru
JAEA-Technology 2007-042, 32 Pages, 2007/07
Carbon-14 is one of the most important radionuclides from the perspective of dose estimation due to the nuclear fuel cycle. Japan Atomic Energy Agency (JAEA) has conducted the careful monitoring of C in airborne release from Tokai reprocessing plant (TRP), atmospheric CO and rice grains around TRP. This report reviewed the C monitoring data obtained over ten years from 1991 to 2001. A simple mathematical model for transfer of TRP-derived C into rice plant was tested using the data set. The model-calculated C concentrations in atmospheric CO and rice grain agreed well with the observations, suggesting an applicability of the simple modeling approach to environmental assessment for atmospheric C discharge under steady-state conditions.
Koarashi, Jun; Saito, Fumihiro; Akiyama, Kiyomitsu; Rahman, N. M.*; Iida, Takao*
Applied Radiation and Isotopes, 65(4), p.413 - 418, 2007/04
no abstracts in English
Mikami, Satoshi; Koarashi, Jun; Miyauchi, Toru; Akiyama, Kiyomitsu; Kobayashi, Hirohide
Proceedings of 2nd Asian and Oceanic Congress Radiological Protection (AOCRP-2) (CD-ROM), p.308 - 312, 2006/10
As airborne radioiodine effluent monitoring in Tokai reprocessing plant (TRP), not only a weekly evaluation of exact discharged amount of radioiodine (I) for assessing environmental impact, but also continuous monitoring of radioiodine being discharged are performed for quick recognition of unexpected effluent tendency. Furthermore, to enhance effluent monitoring activity corresponding to features reprocessing plant, sequential radioiodine monitoring system without interference by the mingled Kr has been developed and effectively functioned as an assist during plant operation. The systematic configurations having these functions for airborne radioiodine monitoring corresponding to nuclear fuel reprocessing plant have been established.
Koarashi, Jun; Mikami, Satoshi; Akiyama, Kiyomitsu; Kobayashi, Hirohide; Takeishi, Minoru
Journal of Radioanalytical and Nuclear Chemistry, 268(3), p.475 - 479, 2006/06
A simple and reliable sampling system for H and C in airborne release from nuclear facilities was designed. The sampling system can collect H and C simultaneously with a condensation technique using a commercially available cold trap equipment and a CO absorption technique using an organic alkali solution monoethanolamine, respectively. In situ performance tests for the effluent from a reprocessing plant showed that the system has the high and stable efficiencies for collecting H and C for a one-week batch sampling at a sampling flow rate of 0.4 l min. These collection techniques also provided a simple procedure of following sample preparations for activity measurement by liquid scintillation counting. The detectable concentrations of the proposed monitoring method were 3.0Bq/m for H and 1.6Bq/m for C, respectively. The sensitivity would be acceptable level for routine monitoring of airborne release at nuclear facilities.
Koarashi, Jun; Akiyama, Kiyomitsu; Asano, Tomohiro; Kobayashi, Hirohide
Journal of Radioanalytical and Nuclear Chemistry, 267(1), p.155 - 159, 2006/01
To establish a practical method for monitoringI concentration in airborne release from the Tokai reprocessing plant,I collecting performance of sampling media used in the method was tested by in situ experiments. The results indicated that the combinational use of an activated charcoal-impregnated filter paper and an activated charcoal cartridge gives the collection efficiency of more than 90% for one-week sampling of real airborne effluent at sampling flow rates of 40.6-75.0 l min-1. The sampling and measurement conditions suitable for a routine-based monitoring were demonstrated taking into account the findings.
Koarashi, Jun; Isaka, Keisuke*; Yokota, Tomokazu*; Kozawa, Tomoyasu*; Mikami, Satoshi; Kiyomitsu, Akiyama,; Kobayashi, Hirohide
JNC-TN8410 2005-005, 55 Pages, 2005/05
Some investigations were made for re-evaluating collection and measurement techniques in an airborne C discharge monitoring at the Tokai reprocessing plant (TRP), which include (1)collection efficiency of CO in a carbon sampler using monoethanolamine as CO absorbent;(2)affect of incorporating tritiated water into the carbon sampler on quantitative estimation of C activity in airborne effluent; (3)affect of leakage in air sampling on evaluating airborne C discharge; and (4)determination of chemical forms of C in airborne release from the TRP. The results presented not only the validity of the TRP's monitoring method, but also the technical aspects required for establishing a more reliable and effective monitoring method.
Koarashi, Jun; Yokota, Tomokazu*; Kozawa, Tomoyasu*; Isaka, Keisuke*; Mikami, Satoshi; Kiyomitsu, Akiyama,; Kobayashi, Hirohide
JNC-TN8410 2005-004, 73 Pages, 2005/05
Some investigations were made for re-evaluating collection and measurement techniques in an airborn H discharge monitoring at the Tokai reprocessing plant (TRP), which include (1)collection efficiency of water in a tritium sampler; (2)quench correction in H activity measurement by liquid scintillation counting; (3)affect of leakage in air sampling on evaluating airborne H discharge; and (4)determination of chemical forms of H in airborne release from the TRP. The results presented not only the validity of the TRP's monitoring method, but also the technical aspects required for establishing a more reliable and effective monitoring method.
Koarashi, Jun; Mikami, Satoshi; Akiyama, Kiyomitsu; Asano, Tomohiro
Journal of Radioanalytical and Nuclear Chemistry, 262(3), p.569 - 572, 2005/01
A method using a system with two sampling units was proposed to determine the chemical forms of tritium released into the atmosphere from the Tokai Reprocessing Plant (TRP). The main advantage of the method is that no carrier gas is required for sampling in the case that air to be sampled has high specific activity of tritiated hydrogen (HT). Obserbations using this method showed that 19.1-28.3% of totak airborne tritium was released as HT from the TRP during reprocessing operation. No clear relationship was found between the ratios of HT release and the types of spent fuels reprocessed.
Koarashi, Jun; Akiyama, Kiyomitsu; Asano, Tomohiro; Yokota, Tomokazu*
Journal of Radioanalytical and Nuclear Chemistry, 262(3), p.771 - 774, 2005/01
Effect of incorporating tritiated water into a C sampling system on sample preparation and C activity measurement by liquid scintillation counting were investigated. Experiments derived the limit of water content in prepared sample, and also demonstrated that C activity can be determined without any interference fromH contamination for clear-solution sample. The results enabled us to estimate permissible reelative humidity of air required for accomplishing sample preparation and C activity measurement. These showed that for sampling of air with less than the permissible relative humidity, total C activity in airborne effluent can be evaluated accurately with no dehumidification of air.
Koarashi, Jun; Akiyama, Kiyomitsu; Asano, Tomohiro; Kobayashi, Hirohide
Radiation Protection Dosimetry, 114(4), p.551 - 555, 2005/00
Fuel reprocessing plant is one of the most important sources of anthropogenicC in the environment. A method was developed to determine the amount and chemical composition of airborne C release from the Tokai reprocessing plant, Japan. Effluent monitoring using the method showed most of the C is released in CO form and the ratio of C in hydrocarbons to the total is less than 3%, not depending on the type of fuel reprocessed. This evaluation would provide improved information on dynamical behavior of C in the environment and assessment of radioecological impact from nuclear fuel cycle.
Koarashi, Jun; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Isaka, Keisuke*; Kiyomitsu, Akiyama,; Asano, Tomohiro
JNC-TN8410 2004-003, 49 Pages, 2004/07
Radioactive airborne effluent discharged from Tokai reprocessing plant (TRP) contains tritium, carbon-14 and radioiodine. These radionuclides are collected with appropriate methods, respectively, in stacks to monitor their concentrations and discharged amounts. This report describes (1) the methods for collecting these radionuclides in TRP; (2) evaluations of the concentrations and discharged amounts; and (3) investigations on estimating performances of the collecting methods. The investigations showed that the collecting methods used in TRP have collecting efficiencies of more than 90% for tritium and radioiodine, and almost 100% for carbon-14. Considerations concerning collection of radionuclides in airborne effluent, made in this study, provided some technical aspects required for establishing more reliable monitoring systems.
Ozeki, Kiyoshi; Akiyama, Kiyomitsu; Ishida, Junichiro
PNC-TN8410 93-286, 73 Pages, 1993/11
Ozeki, Kiyoshi; Akiyama, Kiyomitsu; Ishida, Junichiro
Dai-6-Kai "Kokyu Hobo Ni Kansuru Kokusai Kaigi", ,