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Journal Articles

Units of radiation (radioactivity)

Takahashi, Fumiaki

Genshiryoku No Ima To Ashita, p.109 - 111, 2019/03

The Atomic Energy Society of Japan has planned to publish a document for public, entitled "Current and tomorrow of atomic energy, -Experiences from the accident at the Tokyo Electronic Power Company Fukushima Dai-ichi NPPs-". The documents give us basics and usages of radiations, in addition to nuclear power plants and the accident at TEPCO Fukushima Dai-ichi NPPs. This manuscript explains physical quantities (e.g., absorbed dose), protection quantities and operational quantities that are used for radiation measurement and protection. The unit of radioactivity is also explained, because radioactivity is measured for work places in a radiation facility for internal exposure protection. In addition, radiation dose constants that relate radiation dose to the activity are also introduced, as useful radiation units for radiation protection.

JAEA Reports

Annual report on the present state and activities of the Radiation Protection Department, Nuclear Fuel Cycle Engineering Laboratories in fiscal 2009

Radiation Protection Department

JAEA-Review 2015-003, 187 Pages, 2015/03


This annual report summarizes the various activities on radiation control at the nuclear fuel cycle facilities in Nuclear Fuel Cycle Engineering Laboratories, which were undertaken by the Radiation Protection Department in fiscal 2009. In the Laboratories, the Tokai Reprocessing Plant (TRP), MOX fuel fabrication facilities, the Chemical Processing Facility (CPF), and various other radioisotopes and uranium research laboratories have been operated. The Radiation Protection Department is responsible for the radiation control in and around the facilities, including personnel monitoring, workplace monitoring, consultation on radiological work planning and evaluation, monitoring of gaseous and liquid waste effluents, environmental monitoring, radiological standards, maintenance of radiation monitoring instruments, quality management, and the related research. In fiscal 2009, the results of radiological monitoring showed the situation to be normal, and no radiological incident or accident occurred. The maximum annual effective dose to radiation workers was 9.7 mSv and the mean annual effective dose was 0.2 mSv. Individual doses were kept within the annual dose limit specified in the safety regulations. The estimated effective dose caused by gaseous and liquid effluents from the TRP to imaginary members of the public around the Laboratories was 1.8$$times$$10$$^{-4}$$ mSv. The environmental monitoring and effluent control were performed appropriately in compliance with safety regulation and standards. As for the quality management activities, the inspection by the government, the internal audit, and the maintenance to revise the documents have been continued in accordance with the quality management system which had been introduced to safety regulation since fiscal 2004.

JAEA Reports

Radiation control in Naka Fusion Research Establishment

Umehara, Takashi; Tayama, Toru; Akiyama, Isamu; Nagata, Yasushi*; Onodera, Satoru*

JAERI-Review 2004-019, 109 Pages, 2004/08


This report has been written about the outline of the JT-60 related facility, the JT-60 gaseous waste treatment facility, radiation control equipments and a fundamental radiation control form, which are needed to carry out a radiation control by radiation control officer in Naka Fusion Research Establishment. Further, the following items has been arranged to tables; the low and in-house rules of a radiation protection to apply for the JT-60 facilities, specifications of the JT-60, main parameters and performance of the JT-60, a radiation generated by the JT-60 plasma discharge test, an permitted amount of radiation source and nuclear fuel, each performance of the radiation generators, specifications of the air exhaust facility and the radiation control facility. In addition, figures of the control area, system diagrams of the gaseous waste treatment facility and radiation control monitors are attached.

JAEA Reports

Operation, test, research and development of the High Temperature Engineering Test Reactor (HTTR) (FY1999-2001)

Department of HTTR Project

JAERI-Review 2003-013, 98 Pages, 2003/05


The HTTR (High Temperature Engineering Test Reactor) with the thermal power of 30 MW and the reactor outlet coolant temperature of 850/950$$^{circ}$$C is the first high temperature gas-cooled reactor (HTGR) in Japan, which uses coated-particle fuel, graphite for core components, and helium gas for primary coolant. The HTTR, which locates at the south-west area of 5000 m$$^{2}$$ in the Oarai Research Establishment, had been constructed since 1991 before accomplishing the first criticality on November 10, 1998. Rise to power tests of the HTTR started in September, 1999 and the rated thermal power of 30 MW and the reactor outlet coolant temperature of 850$$^{circ}$$C was attained in December 2001. JAERI received the certificate of pre-operation test, that is, the commissioning license for the HTTR in March 2002. This report summarizes operation, tests, maintenance, radiation control, and construction of components and facilities for the HTTR as well as R&Ds on HTGRs from FY1999 to 2001.

JAEA Reports

Safety admimstration division business report; The second quarter of 2001

Kanamori, Masashi

JNC TN8440 2001-023, 110 Pages, 2001/12


The business of the Safety administration Division became a wide range such as the management of a labor safety health, the crisis management, the security and the management of an entrance, and the business of the following concerning the Tokai Works, the protection of nuclear materials, the business of the sanction, the nuclear material safeguards, the transport of nuclear materials and the business of a quality assurance. For the purpose of summarizing these businesses and utilizing the data concerning the businesses, the report about the businesses achievement has been periodically drawn up as quarter news since 2001, when the Safety Administration Division was established. This report describes about the business achievement of the second quarter news from July to September in 2001.

Journal Articles

Radiation control of the large tokamak device (JT-60) facility

Akiyama, Isamu

Hoeikyo Nyusu, (29), p.8 - 9, 2001/10

no abstracts in English

JAEA Reports

Safety administration division business report; The first quarter of 2001

Kanamori, Masashi

JNC TN8440 2001-015, 100 Pages, 2001/09


As a consequence of this reorganization, the business of the Safety Administration Division became a wide range such as the management of a labor safety health, the crisis management, the security and the management of an entrance, the business of the sanction concerning the Tokai Works, the protection of nuclear materials, the nuclear material safeguards, the transport of nuclear materials and the business of a quality assurance. In the respect of the purpose of summarizing these businesses and utilizing the data concerning the businesses, the report about a business achievement was determined to make.

JAEA Reports

Radiation control on wastes recovery work in wastes storage pit

Ito, Yasuhisa; Noda, Kimio; ;

JNC TN8410 2001-018, 67 Pages, 2001/04


There are waste storage pits where non-radioactive wastes generated from plutonium fuel facilities were stored in JNC Tokai Works. But radioactive wastes were found in one of the pit during wastes arrangement works. Therefore we set the pit temporary controlled area and recovered wastes from it. This report describes the radiation control technique of recovery work in detail.

JAEA Reports

Discussion of uncertainties associated with parameters of biosphere model for safety assessment of geologieal disposal through sensitivity analysis

Kato, Tomoko; ; *;

JNC TN8400 2001-014, 212 Pages, 2001/03


Reference Biospheres are regarded as tools which can be used for making reasonable estimates of radiological impacts for the purposes of safety assessment of geological disposal. Moreover, those are available for reducing the uncertainties based on future human environments and lifestyles. On the other hand, it is recognised that the parameter values have some uncertainties derived from experimental or sampling errors. It is possible to estimate the impacts of these uncertainties throughout the model by sensitivity analysis. Thus for this study, to evaluate the impact of the variation of migration conditions and exposure pathways, we changed some of migration and exposure parameters in turn, which were used in the compartment model where the geosphere-biosphere interface is a river in a plain.

JAEA Reports

Biosphere modeling with climate changes for safety assessment of high-level radioactive waste geological isolation

Kato, Tomoko; ; *; ; Ishiguro, Katsuhiko; Ikeda, Takao*; Richard, L.*

JNC TN8400 2001-003, 128 Pages, 2001/03


In the safety assessment of a high-level radioactive waste (HLW) disposal system, it is required to estimate radiological impacts on future human beings arising from potential radionuclide releases from a deep repository into the surface environment. In order to estimate the impacts, a biosphere model is developed by reasonably assuming radionuclide migration processes in the surface environment and relevant human lifestyles. Releases from the repository might not occur for many thousands of years after disposal. Over such timescales, it is anticipated that the considerable climatic change, for example, induced by the next glaciation period expected to occur in around ten thousand years from now, will have a significant influence on the near surface environment and associated human lifestyles. In case of taking these evolution effects into account in modeling, it is reasonable to develop several alternative models on biosphere evolution systems consistent with possible future conditions affected by expected climatic changes. In this study, alternative biosphere models were developed taking effects of possible climatie change into account. In the modeling, different climatic states existing in the world from the present climate condition in Japan are utilized as an analogy. Estimation of net effects of the climatic change on biosphere system was made by comparing these alternative biosphere models with a constant biosphere model consistent with the present climatic state through flux to dose conversion factors derived from each one.

JAEA Reports

Radiation monitoring for the HTTR rise-to-power test (1) and (2)'

Nakazawa, Takashi; Yoshino, Toshiaki; Yasu, Katsuji; Ashikagaya, Yoshinobu; Kikuchi, Hisaki

JAERI-Tech 2001-001, 101 Pages, 2001/02


no abstracts in English

JAEA Reports

Improvement of the technique for stack monitoring based on behavior analysis of natural radio-nuclides; The technique for reducing the value of the exhaust monitor's background

Izaki, Kenji; Noda, Kimio; ; Kashimuta, Yoshio*

JNC TN8410 2001-005, 30 Pages, 2001/01


Stack monitoring is the most important work in radiation control works. Exhaust monitors used for stack monitoring have the background (which is the counts by natural radio-nuclides) on normal condition, and the values of the background vary with the facilities. Therefore, if the value of background is high, it is difficult to estimate rapidly the radioactive concentration in the exhaust. In order to estimate rapidly the radioactive concentration in exhaust, we analyzed the behavior of natural radioactivity in the facilities and examine the technique fo reducing the value of the background. As a result of the examination, we found that it is possible to estimate rapidly if we change over the monitoring point to immediately after the HEPA filters on the exhaust duct. In this reports, the analyzed results of behavior of natural radio-nuclides in the facilities and the technique for reducing the values of the background are described. To reduce the value of the background has a major effect on not only rapidly estimating the radioactive density in the exhaust but also finding the unusual things on stack monitoring.

JAEA Reports

Some experiences of radiation protection activities in nuclear emergency

Noda, Kimio; Shinohara, Kunihiko; Kanamori, Masashi

JNC TN8410 2001-010, 35 Pages, 2000/10


We, the radiation control section of JNC have had two important experiences on the JCO critical accident and the JNC fire-explosion accident. Especially, at the critical accident in JCO, it was essential to take an action on the radiation protection activities for the evacuated neighboring inhabitants to the safety area. During the accident, we carried out the radiation protection activities, at the beginning of the accident, environmental monitoring of the surrounding area. Especially for the JCO accident, we took an action to terminate criticality, radiation shielding and monitoring, environmental monitoring, radiation survey of the residents, radiation monitoring of exhaust air.

JAEA Reports

Demonstration study on shielding safety analysis code (VII)


JNC TJ8400 2000-053, 41 Pages, 2000/02


Dose evaluation for direct radiation and skyshine from nuclear fuel facilities is one of the environment evaluation items. This evaluation is carried out by using some shielding calculation codes. Because of extremely few benchmark data of skyshine, the calculation has to be performed very conservatively. Therefore, the benchmark data of skyshine and the well-investigated code for skyshine would be necessary to carry out the rational evaluation of nuclear facilities. The purpose of this study is to obtain the benchmark data of skyshine and to investigate the calculation code for skyshine. In this fiscal year, the followings are investigated; (1)To improve the detection sensitivity of pulsed neutron measurement, two neutron detectors and some electronic circuits are added to the system constructed last year. (2)To estimate the neutron dose at the distant point from the facility instead of the commercialized rem-counter, a $$^{3}$$He detector with paraffin moderator is equipped to the system. (3)Using the new detection system, the skyshine of neutrons from 45Mev LINAC facility was measured in the distance up to 300m. The results show that the time structure of pulsed neutrons almost disappears at the further points than 150m. (4)In the distance from 90m to 300m ordinal total counting method without gate pulse are applied to detect the neutrons. (5)The experimental results of space dependency up to 300m is fitted fairly well by the Gui's response function.

JAEA Reports

Report of radiation exposure control on the 12th periodic inspection at experimental fast reactor JOYO

; Kano, Yutaka; ; Shindo, Katsutoshi

JNC TN9410 2000-001, 20 Pages, 1999/12


The 12th periodic inspection had been executed at the experimental fast reactor JOYO from February 24,1998 to June 28,1999. This inspection had been extended about three months because it was addtion to the work for the safety countermeasure. The result of collective dose equivalent was 263.92 man*mSv, whereas, the expected collective dose equivalent was about 407 man*mSv in the whole period of this inspection. It was confirmed that this inspection was carried out with the suitable radiation protection programmes. In this report, provided in 12th periodic inspection, were described with taking the results of the past periodic inspections into consideration.

JAEA Reports


JNC TN1400 99-016, 171 Pages, 1999/08


no abstracts in English

JAEA Reports


; ; Shimizu, Kazuhiko; Miyahara, Kaname; ; Hasegawa, Hiroshi; Iwasa, Kengo

JNC TN1400 99-008, 656 Pages, 1999/04



JAEA Reports


; ; ; ; ; ;

PNC TN8440 98-025, 111 Pages, 1998/07



JAEA Reports


PNC TN8440 98-045, 118 Pages, 1998/06



132 (Records 1-20 displayed on this page)