Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 94

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

A Spectroscopic technique for analysis developed in the field of unclear energy

Kusaka, Ryoji

Bunko Kenkyu, 67(6), p.239 - 240, 2018/12

A spectroscopic technique for analysis developed by collaboration between Japan Atomic Energy Agency (JAEA) and Quantum and Radiological Science and Technology (QST) is discussed for readers outside the field of nuclear energy. This paper introduces a quantitative analysis for $$^{107}$$Pd radioisotope contained in a spent nuclear fuel by using laser-induced photoreduction and inductively coupled plasma mass spectrometry (ICP-MS). The importance and problems of quantitative analysis for radioisotopes in spent nuclear fuels are described, and the principle, advantages, and future applications of the spectroscopic technique are discussed.

Journal Articles

Migration behavior of stable and radioactive strontium in natural aquifer

Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Munakata, Masahiro; Matsumoto, Junko; Ogawa, Hiromichi; Bamba, Tsunetaka*; Wang, Z.*; Yang, Y.*; Zhao, Y.*

Proceedings of International Symposium on Radioecology and Environmental Dosimetry, p.179 - 184, 2003/00

Migration behaviors of stable strontium element and radioactive nuclide strontium 90 in natural aquifer were studied by a field test, which was performed in the aquifer loess zone at 30 m under the ground surface of the field test site of China Institute for Radiation Protection. The migration behavior of stable strontium was a little different from that of $$^{90}$$Sr. The difference was evaluated by applying the distribution coefficient considering Sr and coexistent ion concentrations. Migration behavior of radionuclide in natural environment has been generally demonstrated on field tests without radioactive tracers and/or large-scale column tests with radioactive tracers. Such tests seem to be valuable to improve reliability of the migratory evaluation.

JAEA Reports

JAEA Reports

Behavior of carbon-14 in the Tokai reprocessing plant

; ; ;

JNC-TN8410 2001-021, 33 Pages, 2001/09

JNC-TN8410-2001-021.pdf:4.37MB

Carbon-14 released from the nuclear facilities is an important radionuclide for the safety assessment, because it tends to accumulate in environment through food chain and has as a significant impact to personal dose. Carbon-14 has been monitored routinely as one of the main gaseous radionuclides exhausted from the Tokai Reprocessing Plant (TRP) since OCtober of 1991. Furthermore, behavior of carbon-14 in TRP has been investigated through the reprocessing operation and the literature survey. This report describes the result of investigation about the behavior of carbon-14 in TRP as followings. (1)Only a very small amount of carbon-14 in the fuel was liberated into the shear off-gas and most of it was liberated into the dissolver of-gass. Part of the carbon-14 was trapped at the caustic scrubber installed in the of-gas treatment process, and untrapped carbon-14 was released into the environment from the main stack. Amount of carbon-14 released from the main stack was about 4.1$$sim$$6.5GBq every ton of uranium reprocessed. (2)Carbon-14 trapped at the caustic scrubbers installed in the dissolver off-gas and in the vessel off-gas treatment process is transferred to the low active waste vessel. Amount of carbon-14 transferred to the low active waste vessel was about 5.4$$sim$$ 9.6GBq every ton of uranium reprocessed. (3)The total amount of carbon-14 input to TRP was summed up to about 11.9$$sim$$15.5 GBq every ton of uranium reprocessed considering the released amount from the main stack and the trapped amount in the off-gas treatment devices. The amount of nitrogen impurity in the initial fuel was calculated about 15$$sim$$22ppm of uranium metal based on the measured carbon-14. (4)The solution in the low active waste vesselis concentrated at the evaporator.Most of the carbon-14 in the solution was transferred into concentrated solution. (5)Tokai vitrification Demonstration Facility (TVF) started to operate in 1994. Since then, carbon-14 has been measured in the ...

JAEA Reports

Manufacture history results of an investigation of the bitumen solidification object towards the check of an abandonment object

; ; *

JNC-TN8440 2001-024, 210 Pages, 2001/08

JNC-TN8440-2001-024.pdf:24.99MB

In order to make this book reflect in the investigation which turned the bitumen solidification object to maintenance of the abandonment object technical standard on condition of carrying out subterranean disposal in the future - solidification - it created for the purpose of utilizing as precious sources of information, such as a nuclide inventory in the living body, group-izing of the past campaign required for typical solidification object selection, and information offer at the time of disposal examination. A development operation history collected so that histories including the shift action in an institution of the formation of discharge reduction of the characteristic of solidification object manufacture outlines, such as composition of the process of an institution and a solidification object and a storage actual result, the contents of an examination of the past campaign, and the solidification object manufactured based on topics or radioactive iodine and radioactive carbon etc., such as the past contents of an examination / operation, may grasp comprehensively in creation, and it carried out as the composition stared the trend of future disposal fixedly. It was a period (for 16 years) until an bituminization demonstration facility processing institution will start a cold examination from April (Showa 57), 1982, and it starts a hot examination from May 4, it starts solidification processing technical development operation from october 6 and it results in the fire explosion accident on March 11 (Heisei 9), 1997, and low level radioactivity concentration waste fluid was processed 7,438 m$$^{3}$$, and 29,967 bitumen solidification objects were manufactured. According to the accident, it is necessary to hand it down to future generations with processing technology while the bitumen solidification object manufactured in 15 years although the bituminization demonstration facility processing institution came to close the mission holds information precious ...

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai reprocessing plant FY 2000

Maruo, Yoshihiro; ; Takeishi, Minoru; ; ; Takeyasu, Masanori;

JNC-TN8440 2001-011, 146 Pages, 2001/06

JNC-TN8440-2001-011.pdf:2.98MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during April 2000 to March 2001. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.

JAEA Reports

Evaluation of the analytical errors jn plutonium and uranium isotopic composition analysis based on routine control measurement data (1998/9$$sim$$2000/12)

; ; ; ; ; *; *

JNC-TN8440 2001-005, 33 Pages, 2001/02

JNC-TN8440-2001-005.pdf:1.24MB

Four mass spectrometers are used for plutonium and uranium isotopic composition analysis in the Plutonium Fuel Center. Analytical errors of the analysis was evaluated based on routine control data obtained with measurement of reference materials. It was confirmed that the errors satisfied the International Target Values for safeguard analysis, and the random error of the analysis was improved by changing conventional method to total evaporation method.

JAEA Reports

The Results of the envilonmental monitoring related to the criticality accident in JCO

Shinohara, Kunihiko; ; ; ; ; Kano, Yutaka;

JNC-TN8440 2001-004, 62 Pages, 2001/02

JNC-TN8440-2001-004.pdf:4.17MB

Concerming about the action for the criticality accident in JCO Co., Ltd. (JCO) occurred at 10:35 on 30$$^{th}$$ Sept. 1999, Japan Nuclear Cycle Development Institute(JNC) established "JNC's task force" at 12:35 on the same date in conjuction with Head Office and Tokai Works. And JNC's task force had supported the government of Japan, the local governments and JCO humanly, physically and technically until the jobs of the task force was transferred to "Support Assembly for Countermeasure and Research of JCO Criticality Accident" and routine line on 12$$^{th}$$ Oct. 1999. This report compiled the results of the environmental monitoring performed by JNC based on the request from the government of Japan and the local governments.

JAEA Reports

None

*

JNC-TN1400 2000-007, 100 Pages, 2000/07

JNC-TN1400-2000-007.pdf:4.67MB

no abstracts in English

JAEA Reports

Macroscopically and microscopically research about structure of faults at a repository scale

*; *; Morooka, Koichi*

JNC-TJ8400 2000-043, 171 Pages, 2000/03

JNC-TJ8400-2000-043.pdf:5.27MB

This study is an object to collect and arrange data about the mass transfer path during a natural barrier system by grasping actual rock feature, in order to be useful for a performance assessment of a natural barrier system at geological disposal of HLW. An existence of permeability high large-scale faults extends a large influence over a performance assessment of geological disposal. With "The Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan" which Nuclear Cycle Development Institute (JNC) issued, it is as" A repository would be located at least 100 meters away from major faults and major fracture zones which could adversely affect the stability and performance of the repository" as a Reference Case concept model of a natural barrier system, Then, they are as "in the Reference Case, the transport path consists of the host rock and the downstream fault". It will not be easy to know the distribution of faults in the subsurface deep division without data acquired from many boreholes and underground laboratory. With this study, specific data on the large-scale faults and fracture zones has been collected and arranged by investigating in underground galleries and on the literatures of a post-operated mine site. Based on this result, a consideration on the principal transfer pass at a natural barrier system has been conducted. The contents conducted in this report is the follows. (1)investigation of literature about data of fracture, shear zone, and geology, (2)field investigation of fracture and shear zone in the rock, (3)arrangement of these results, (4)modeling of the major water conductive feature, and (5)evaluation of an assumption which has been introduced in the Second Progress Report issued by JNC.

JAEA Reports

Measurement of neutron capture cross sections of Tc-99

*

JNC-TJ9400 2000-008, 61 Pages, 2000/02

JNC-TJ9400-2000-008.pdf:2.5MB

For studies on nuclear transmutation of long-lived fission products (LLFPs) in a fast reactor, detailed characteristics of reactor core such as transmutation performance have to be investigated, so accurate neutron cross section data of LLFPs become necessary. Therefore, the keV-neutron capture cross sections of Tc-99, which is one of important LLFPs, were measured in the present study to obtain the accurate data. The measurement was relative to the standard capture cross sections of Au-197. A neutron time-of-flight method was adopted with a ns-pulsed neutron source by a Pelletron accelerator and a large anti-Compton NaI(TI) gamma-ray detector. As a result, the capture cross sections of Tc-99 were obtained with the error of about 5 % in the incident neutlon energy region of 10 to 600 keV. The present data were compared with other experimental data and the evaluated values of JENDL-3.2, and it was found that the evaluations of JENDL-3.2 were 15-20 % smaller than the present measurements.

JAEA Reports

Study on the nuclide behavior in nuclear fuel recycling system

Fujii, Toshiyuki*; *

JNC-TJ9400 2000-003, 36 Pages, 2000/02

JNC-TJ9400-2000-003.pdf:1.36MB

For establishing a recycling system based on low-decontamination, the distribution behaviors of radionuclides in the process are essential information for the design of the system. Molybdenum and palladium are less radioactive fission products, but attention should be paid to them because they are likely to extremely affect the performance of the recycled fuels. In this context, in this study, the extraction behaviors of molybdenum and palladium under conditions of PUREX and TRUEX extraction process were experimentally studied, and their chemical mechanisms were discussed. In cojunction with the extraction experiments, absorption spectrometry was applied to identify the related species and the extraction mechanism. As a result, knowledge for the distribution characteristics of molybdenum and palladium in PUREX and TRUEX process was reinforced.

JAEA Reports

Improvement of biosphere model for performance assessment of geological disposal system (III)

Ikeda, Takao*; Yoshida, Hideji*; *

JNC-TJ8400 2000-046, 264 Pages, 2000/02

JNC-TJ8400-2000-046.pdf:6.73MB

This report contains discussions about methodology for the selection of parameter values, stochastic approach for the biosphere assessment and biosphere modelling for marine discharge case are described. Regarding the methodology for the selection of parameter values, important aspects for the data selection were discussed, and data selection protocol was developed. Regarding the stochastic approach for the biosphere assessment, it is confirmed that Straightforward Monte Carlo Method and Latin Hypercube Sampling Method are the most adequate based on a literature survey. Then stochastic assessment by using biosphere model that was developed in the second progress report was carried out to check the sensitivity of parameter values. Finally, availability of several kind of assessment models for marine discharge case were discussed. It was confirmed that Multiple Compartment Model was the most applicable. Assessment using Multiple Compartment Model was carried out. The results were compared with those derived by numerical model. As a result, the difference between two models were small enough.

JAEA Reports

None

Ikeda, Takao*; Yoshida, Hideji*; *

JNC-TJ8400 2000-045, 134 Pages, 2000/02

JNC-TJ8400-2000-045.pdf:4.12MB

None

JAEA Reports

Study on microbial transport and adsorption behavior on engineering barrier for geological disposal of radioactive wastes

Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*

JNC-TJ8400 2000-030, 54 Pages, 2000/02

JNC-TJ8400-2000-030.pdf:1.69MB

It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh= -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH=3$$sim$$6, but the other of Kd value is about 400,000 ml/g on pH=13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.

JAEA Reports

Study on microbial transport and adsorption behavior on engineering barrier for geological disposal of radioactive wastes

Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*

JNC-TJ8400 2000-029, 36 Pages, 2000/02

JNC-TJ8400-2000-029.pdf:1.28MB

It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh = -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH = 3$$sim$$6, but the other of Kd value is about 400,000 ml/g on pH = 13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.

JAEA Reports

Study on migration behavior of radionuclides in engineered clay barrier (II)

*; *; *

JNC-TJ8400 2000-018, 79 Pages, 2000/02

JNC-TJ8400-2000-018.pdf:2.09MB

As a basic research for geological disposal of high-level radioactive wastes, diffusion behavior of radionuclides and corrosion behavior of overpack materials in clay buffer materials (bentonite) were studied. In the study on the diffusion behavior of radionuclides, basal spacing and water content were determined for water saturated, compacted Na-montmorillonite that is major clay mineral of bentonite. The apparent diffusion coefficients of Na$$^{+}$$, Sr$$^{2+}$$, Cs$$^{+}$$ and Cl$$^{-}$$ ions and their activation energies were also determined at different dry densities of montmorillonite. For all kinds of ions, the activation energies were found to increase as the dry density increased. These findings suggest that the diffusion mechanism of ions in compacted montmorillonite changed with increasing dry density. As a reasonable explanation for the changes in the activation energy, we proposed a multiprocess diffusion model, in which predominant diffusion process is considered to change from pore water diffusion to interlayer diffusion via surface diffusion when the dry density increases. The Na-montmorillonite is expected to alter by the ion exchange with Ca$$^{2+}$$ ions, which could be introduced from groundwater and/or cementitious materials in a repository. The apparent diffusion coefficients of Na$$^{+}$$ and Cs$$^{+}$$ ions and their activation energies were studied for Na/Ca montmorillonite mixtures in order to know the effect of this kind of alteration on the diffusion behavior of ions. It was found that the alteration of montmorillonite affected diffusion coefficients and the activation energies for both kinds of cations. These effects cannot be explained only by the pore water diffusion. The multiprocess diffusion model proposed in this study is suggested as the most reasonable explanation for the effects. The oxidation behavior of pyrite in bentonite during drying process was studied for understanding corrosion behavior of overpack materials in bentonite. There ...

JAEA Reports

Distribution of actinide elements among various environmental factors (II)

Kudo, Akira*; *

JNC-TJ8400 2000-010, 67 Pages, 2000/02

JNC-TJ8400-2000-010.pdf:2.17MB

The first and second environmental releases of man-made $$^{239+240}$$Pu came from nuclear explosions at Alamagordo and Nagasaki in 1945. The release at Nagasaki was more serious than at Alamagordo, because it happened in an area with a high population density. Unfissioned $$^{239+240}$$Pu and various fission products have been interacting here with various environmental materials (soils, sediments, and plants) under wet and temperature conditions for more than 45 years. To assess the environmental mobility of $$^{239+240}$$Pu, the distributions of radionuclides from this release were investigated at Nishiyama where heavy black rain containing unfissioned plutonium and fission products fell 30 minutes after the nuclear explosion. The vertical distributions of $$^{137}$$Cs and $$^{239+240}$$Pu were determined in unsaturated soil cores up to 450cm deep. Most radionuclides were found in the soil column 30cm from the ground surface. However, $$^{239+240}$$Pu were detected in the groundwater as well below a depth of 200cm. No $$^{137}$$Cs was found below 40cm from the ground surface or in groundwater. These observations reveal that about 3% of the total $$^{239+240}$$Pu have been migrating in the soil at a faster rate than the remaining $$^{239+240}$$Pu. Sharp peak of $$^{137}$$Cs and $$^{239+240}$$Pu, indicating heavy deposition from the Nagasaki local fallout of 1945, were found in sediment cores collected from the Nishiyama reservoir. $$^{239+240}$$Pu peaks were unexpectedly discovered in pre-1945 sediment core sections. NO $$^{137}$$Cs was found. By contrast to the distribution in sediment cores, $$^{137}$$Cs in tree rings had spread by diffusion from the bark to the center of the tree without holding a fallout deposition record. Most of the $$^{239+240}$$Pu was distributed in the tree rings following a similar deposition record to that found in sediment cores. Furthermore, a very small amount of $$^{239+240}$$Pu (about 1%) was found unexpectedly in pre-1945 tree rings. The only reasonable ...

JAEA Reports

Certification of reliability of nuclide migration data

Ueda, Shinzo*; *; *; *

JNC-TJ8400 2000-002, 316 Pages, 2000/02

JNC-TJ8400-2000-002.pdf:14.28MB

Japan Nuclear Cycle Development Institute (JNC) have been setting migration parameters and developing its database for the 2nd Progress Report of HLW Geological Disposal (H12 Report). In this study, experimentswere carried out to certify the reliability of parameters and scenario, and examination was carried out to survey procedures of quality management. The main contents are as follows. (1)Data acquisition for certification of migration parameters. The effect of NH$$_{3}$$ complex of Pd on distribution coefficients (Kd) of Pd on both bentonite and rocks, and the effect of sulfate and carbonate complexes of Am on Kds of Am on bentonite are investigated. Kds of Pd depended on NH$$_{4}^{+}$$ concentration in aqueous. The dependence varied with pH. Effects of sulfate and carbonate complexes on Kds of Am were not remarkable. Apparent diffusivities of Cs in bentonite saturated by saline water were measured. It was confirmed that the apparent diffusivities of Cs in saline water were similar to those in pure water. (2)Evaluation of colloidal effect on nuclide migration. An evaluation of validity of analytical model (Hwang's model) for nuclide migration under existence of colloids and investigation of characterization of colloids in groundwater were carried out. As the results, it was indicated that the Hwang's model was appropriate, and it was found that samplingtechnique influenced concentration and size distribution of colloids. (3)Influence of organic substances on solubility. Solubility of Th was measured under the condition with humic acid and carbonate. It increased roughly in proportion to the concentration of humic acid. And it was remarkably high under the condition with carbonate. It was confirmed that Th solubility data set in H12 report was conservative, even though humic acid existed in groundwater. (4)Use of Mechanistic Models for Safety Assessment. The integrated sorption/diffusion model has been used to calculate K$$_{d}$$, D$$_{a}$$ and D$$_{e}$$ values ...

JAEA Reports

Tests on decisive proof for the incinerating and melting facility using the in-can type high frequency induction heating

; ; ; ;

JNC-TN9410 2000-002, 149 Pages, 1999/12

JNC-TN9410-2000-002.pdf:23.51MB

LEDF (Large Equipment Dismantling Facility) is the solid waste processing technology development facility that carries out high-volume reduction and low dosage processing. The high-volume reduction processing of the high dose $$alpha$$-waste configured with combustible waste, pvc & rubber, spent ion exchange resin, and noncombustible waste have been planned the incinerating and melting facility using the in-can type high frequency induction heating in LEDF. This test is intended to clarify the design data. It was confirmed that the incinerating and melting performance, molten solid properties and exhaust gas processing performance with pilot testing equipment and bench scale equipment. The result of this test are as follows. (1)Processing speed is 6.7kg/h for the combustible waste, 13.0kg/h for the ion exchange resin, and 30.0kg/h for the noncombustible waste. For above optimum processing conditions are as follows. (a)Operating temperature is 1000$$^{circ}$$C for the combustible waste, 1300$$^{circ}$$C for the ion exchange resin, 1500$$^{circ}$$C for the noncombustible waste. (b)Air flow is 90Nm$$^{3}$$/h. Air temperature is 300$$^{circ}$$C. Air velocity is 20m/s. (2)Incineration time per day is 5h. Warm-up time and incineration time from the stop of waste charging is 0.5h. Melting time per day is 5h inconsideration of heating hold time of incinerated ash and melting of quartz. Warm-up time is 0.5h. (3)The system decontamination factor in Co, Cs and Ce with pilot testing equipment is 10$$^{5}$$ or more. (4)Design data of the iron doped silica gel judged to be have a applicability as RuO$$_{4}$$ gas absorber is as follows. (a)Its diameter distribute in the range of 0.8-1.7mm. (b)To have a decontamination factor of 10$$^{3}$$ can achieve for retention time of 3 seconds and its life time is about 1 year. (5)In terms of the distribution of the nuclear species in molten solid is evenly distributed. It was also confirmed that the distribution of main elements in ceramic layer is ...

94 (Records 1-20 displayed on this page)