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JAEA Reports

Involvement in IAEA ENVIRONET and research on overseas reference cases regarding environmental remediation of closed uranium mine

Saito, Hiroshi

JAEA-Review 2016-009, 80 Pages, 2016/07

JAEA-Review-2016-009.pdf:8.28MB

Environmental remediation has been conducted in closed Ningyo-toge Uranium Mine, after decades of mine-related activities. During the remediation, whole procedure, priority, necessary investigations and specific methods have been examined, and issues are clarified which should be solved in the future. For that, it has been recommended that opinions are exchanged among specialists in related fields overseas, and information and their experience are referred. As part of the activities, Ningyo-toge Environmental Engineering Center has been involved continuously in IAEA ENVIRONET, multinational network for environmental remediation. Also, bonds are tightened among participants and IAEA by exchanging opinions and sharing the issues. In parallel, literature survey has been conducted to supplement the information obtained through ENVIRONET and to clarify additionally-required information and targeted sites. The expected information are obtained from the site-visits and now being organized.

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

ComparaUve analyses on nuclear charaderistics of water-cooled breeder cores

; Sato, Wakaei*;

JNC-TN9400 2000-037, 87 Pages, 2000/03

JNC-TN9400-2000-037.pdf:3.48MB

ln order to compare the nuclear characteristics of water-cooled bleeder cores with that of LMFBR, MOX fuel cell models are established for boiling and non-boiling LWR, non-boiling HWR and sodium-cooled reactor. Frst, the comarison is made between the heterogeneous cell calculation results by SRAC and those by SLAROM. The results show some differences as for neutron energy spectrum, one-grouped cross section and conversion ratio due to the different grouped cross section library (both are based on JENDL-3.2, though) used for each code, however, the difference is acceptably small for grasping the basic characteristics of the above-mentioned cores. Second, using the SLAROM code, main core parameters such as mean neutron energy, ratio of fast neutron and $$eta$$-value, are analyzed. The comparison between the cores show that softened neutron spectrum by the scattering effect of hydrogen or heavy hydrogen increase the contribution of nuclear reaction (especially for neutron capture reaction rather than fission reaction) in lower energy region comparing with LMFBR. ln order to overcome the effect, tighter lattice than LMFBR is necessary for water-cooled cores to realize the breeding of fissile nuclides. Third, effects of Pu isotopic composition on the breeding ratio are evaluated using SRAC burnup calculation. From the results, it is confirmed that degraded Pu (larger ratio of Pu-240) show the larger breeding ratio. At last, sensitivity analyses are made for k-effective and main reaction ratios. As for k-effective, using a temporary covariance data of JENDL-3.2, uncertainty resulting from the cross sections' error is analyzed for a boiling LWR and a sodium-cooled reactor. The boiling LWR core shows larger sensitivity in lower energy region than the sodium-cooled reactor (especially for the energy region lower than 1kev), And, 18-group analysis that is considered acceptably good for LMFBR analysis, should not be enough for accurate sensitivity estimation of ...

JAEA Reports

A feasibility study of the particle interaction method for the flow regimes with the chemical reaction; (Report under the contract between JNC and Toshiba Corporation)

Shirakawa, Noriyuki*; *; *; *

JNC-TJ9440 2000-008, 47 Pages, 2000/03

JNC-TJ9440-2000-008.pdf:1.96MB

The numerical thermohydraulic analysis of a LMFR component should involve its whole boundaly in order to evaluate the effect of chemical reaction within it. Therefore, it becomes difficult mainly due to computing time to adopt microscopic approach for the chemical reaction directly. Thus, the thermohydraulic code is required to model the chemically reactive fluid dynamics with constitutive correlations. The reaction rate denpends on the binary contact areas between components such as continuous liquids, droplets, solid particles, and bubbles. The contact areas change sharply according to the interface state between components. Since no experiments to study the jet flow with sodium-water chemical reaction have been done, the goal of this study is to obtain the knowledge of flow regimes and contact areas by analyzing the fluid dynamics of multi-pahse and reactive components mechanistically with the particle interaction method. For the first stage of the study, the applicability of this method to the nalysis of a liquid jet into the other liquid pool was investigated. Based on the literatures, we investigated the jet flow mechanisms and analyzed the experiment of a water jet into a gasoline pool. We also analyzed SWAT3/Run19 test, the jet flow in a rod bundle, to study the applicability of the method to a complicated boundary without a chemical reaction model. The calculated fluid dynamics was in good agreement with the experiment. Furthermore, we studied and formulated the paths of phase change and chemical reaction, and conceptually designed the adopting the heat-transfer-limited phase change model and the synthesizd reaction model with a water-hydrogen conversion ratio.

JAEA Reports

Investigation of utilizing plutonium as mixed oxide fuel (5); BWR for next generation

*; *; *; *

JNC-TJ9440 2000-007, 43 Pages, 2000/03

JNC-TJ9440-2000-007.pdf:1.73MB

Planning of the plutonium utihzation in the Light water thermal reactor has been investigated to evaluate scenario for FBR development. Plans for MOX fuel utilization in the ABWR including Ooma plant are studied, and information of high burnup fuels for a future BWR is summarized based on public documents. Nuclear compositions of the present burnup fuel (45,000MWd/t) and a high burnup fue (60,000MWd/t) have been evaluated using an open code: SRAC. Results of the study are follows; (1)Surveying the status of MOX fuel utilization. The status of MOX and UO$$_{2}$$ fuel utilization in the present BWR and future BWR have been summarized based on public documents. (2)Evaluation of spent MOX and UO$$_{2}$$ fuel composition. Nuclear compositions of spent MOX and UO$$_{2}$$ fuels at 45,000MWd/t and 60,000MWd/t burnup have been evaluated and summarized for recycle scenarios by FBR.

JAEA Reports

None

*; *

JNC-TJ8420 2000-010, 171 Pages, 2000/03

JNC-TJ8420-2000-010.pdf:5.34MB

no abstracts in English

JAEA Reports

None

Toida, Masaru*; Shiogama, Yukihiro*; Atsumi, Hiroyuki; Masumoto, Kazuhiko*; *; Abe, Yasunori*; *

JNC-TJ7440 2000-006, 137 Pages, 2000/02

JNC-TJ7440-2000-006.pdf:3.55MB

no abstracts in English

JAEA Reports

Literature survey of redox reactions in the new field

*; Sasamoto, Hiroshi; *; Inagaki, Manabu*; Yui, Mikazu

JNC-TN8400 2000-007, 32 Pages, 2000/01

JNC-TN8400-2000-007.pdf:0.69MB

This report presents a summary of literature survey about geochemical reactions which are important to evaluate the redox conditions in the near field rock mass and buffer. The results of literature survey are summarized as follows; (1)Minerals including ferrous iron and organic materials in the rock mass are important reductants. Initial stage after closure of repository, oxygen will be consumed by pyrite, because the reaction rate between pyrite and oxygen is relatively fast. (2)It is possible to estimate the redox capacity for reductants by rock (mineral)-water iteraction experiment in a laboratory. And it is expected that the ferrous iron-rich rock and higher porosity rock may have bigger redox capacity. (3)It is possible to estimate the oxygen consumption rate by reductants such as minerals including ferrous iron. The rate law and rate constant for the oxidation reaction of ferrous iron in the solution are also determined. As a conclusion, it seems that we can evaluate kinetically the evolution of geochemical conditions in the near field rock mass and buffer by excavation of drifts, based on data derived from these existing literatures.

JAEA Reports

Data collection by literature survey on rock physical properties in Japan (II)

Sato, Toshinori; ; Fujita, Tomoo; Hasegawa, Hiroshi

JNC-TN7400 99-011, 36 Pages, 1999/12

JNC-TN7400-99-011.pdf:1.55MB

In order to understand the general thermal and mechanical properties of rock masses and initial stress of rock at depth, data were compiled from the published literature in Japan and collected from investigations carried out at Kamaishi mine and Tono mine. Statistical examinations derived the ranges, means and medians of the mechanical properties for the different rock types. It was confirmed that the correlations between the mechanical properties were in agreement with correlations determined previously in other similar surveys. The unconfined compressive strength of Neogene sedimentary rocks showed a tendency to increase with increasing depth ($$geq$$ 500 m). An examination of the measured initial stress data collected through literature surveys showed that the vertical stress can be approximated by the extent of gravitational loading at a particular point. There is an approximately linear relationship between the average stress in a horizontal plane and the depth. The lateral pressure coefficient tends to have a high value and large range at shallow depths, but tends towards $$<$$ 1 with increasing depth.

JAEA Reports

Fracture characteristics in Japanese rock

Ijiri, Yuji; ;

JNC-TN8400 99-091, 69 Pages, 1999/11

JNC-TN8400-99-091.pdf:2.83MB

It is crucial for the performance assessment of geosphere to evaluate the characteristics of fractures that can be dominant radionuclide migration pathways from a repository to biosphere. This report summarizes the charactelistics of fractures obtained from broad literature surveys and the fields surveys at the Kamaishi mine in northern Japan and at outcrops and galleries throughout the country. The characteristics of fractures described in this report are fracture orientation, fracture shape, fracture frequency, fracture distribution in space, transmissivity of fracture, fracture aperture, fracture fillings, alteration halo along fracture, flow-wetted surface area in fracture, and the correlation among these characteristics. Since granitic rock is considered the archetype fractured media, a large amount of fracture data is available in literature. In addition, granitic rock has been treated as a potential host rock in many overseas programs, and has JNC performed a number of field observations and experiments in granodiorite at the Kamaishi mine. Therefore, the characteristics of fractures in granitic rock are qualitatively and quantitatively clarified to some extent in this report, while the characteristics of fractures in another rock types are not clarified.

JAEA Reports

Diffusivity Database (DDB) for Major Rocks; Database for the Second Progress Report

Sato, Haruo

JNC-TN8400 99-065, 379 Pages, 1999/10

JNC-TN8400-99-065.pdf:10.01MB

A database for diffusivity for a data setting of effective diffusion coefficients in rock matrices in the second progress report, was developed. In this database, 3 kinds of diffusion coefficients: effective diffusion coefficient (De), apparent diffusion coefficient (Da) and free water diffusion coefficient (Do) were treated. The database, based on literatures published between 1980 and 1998, was developed considering the following points. (1)Since Japanese geological environment is focused in the second progress report, data for diffusion are collected focused on Japanese major rocks. (2)Although 22 elements are considered to be important in performance assessment for geological disposal, all elements and aquatic tracers are treated in this database development considering general purpose. (3)Since limestone, which belongs to sedimentary rock, can become one of the natural resources and is inappropriate as a host rock, it is omitted in this database development. Rock was categorized into 4 kinds of rocks; acid crystalline rock, alkaline crystalline rock, scdimentaly rock (argillaceous/tuffaceous rock) and sedimentary rock (psammitic rock/sandy stone) from the viewpoint of geology and mass transport. In addition, rocks around neutrality among crystalline rock were categorized into the alkaline crystalline rock in this database. The database is composed of sub-databases for 4 kinds of rocks. Furthermore, the sub-databases for 4 kinds of the rocks are composed of databases to individual elements, in which totally, 24 items such as species, rock name, diffusion coefficients (De, Da, Do), obtained conditions (method, porewater, pH, Eh, temperature, atmosphere, etc.), etc. are input. As a result of literature survey, for De values for acid crystalline rock, totally, 207 data for 18 elements and one tracer (hydrocarbon) have been reported and all data were for granitic rocks such as granite, granodiorite and biotitic granite. For alkaline crystallinc rock, ...

JAEA Reports

None

*; *; *; *

JNC-TJ1420 2000-003, 1020 Pages, 1999/03

JNC-TJ1420-2000-003.pdf:110.99MB

no abstracts in English

JAEA Reports

None

PNC-TJ1309 98-001, 161 Pages, 1998/02

PNC-TJ1309-98-001.pdf:5.01MB

no abstracts in English

JAEA Reports

None

; *

PNC-TN8420 97-013, 24 Pages, 1997/10

PNC-TN8420-97-013.pdf:1.24MB

None

JAEA Reports

None

PNC-TJ1533 97-003, 89 Pages, 1997/03

PNC-TJ1533-97-003.pdf:2.93MB

None

JAEA Reports

None

PNC-TJ1647 97-001, 131 Pages, 1997/02

PNC-TJ1647-97-001.pdf:2.29MB

no abstracts in English

JAEA Reports

None

Homma, Shunji*; Tajima, Yasunori*; Koga, Jiro*; Matsumoto, Shiro*

PNC-TJ1609 97-001, 47 Pages, 1997/02

PNC-TJ1609-97-001.pdf:2.11MB

no abstracts in English

JAEA Reports

None

PNC-TJ1621 96-001, 80 Pages, 1996/03

PNC-TJ1621-96-001.pdf:2.34MB

no abstracts in English

JAEA Reports

None

PNC-TJ1533 96-004, 106 Pages, 1996/03

PNC-TJ1533-96-004.pdf:3.43MB

no abstracts in English

JAEA Reports

None

*; *; *

PNC-TJ1645 96-001, 57 Pages, 1996/02

PNC-TJ1645-96-001.pdf:2.0MB

no abstracts in English

40 (Records 1-20 displayed on this page)