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Journal Articles

Measurement, monitoring and prevention of environmental contamination with radioactive substances

Matsuzuru, Hideo

Nippon Gakujutsu Kaigi Kohaishita Seikatsu Kankyo No Sentan Gijutsu Ni Yoru Kaifuku Kenkyu Renrakukai Iinkai Shimpojiumu "Hoshasei Busshitsu Ni Yoru Kankyo Osen No Yobo Ni Mukete", p.53 - 62, 2002/00

no abstracts in English

JAEA Reports

JCO criticality accident termination operation

Kanamori, Masashi

JNC-TN8440 2001-018, 50 Pages, 2001/12

JNC-TN8440-2001-018.pdf:1.31MB

On September 30 at around 10:35 AM, criticality accident occurred at the JCO's conversion building in Tokai-mura. Since criticality accident had not been anticipated, neither devices for termination of criticality accident nor neutron detectors were available. Immediately after the information of the accident, our emergency staff(Japan Nuclear cycle development institute staff) went to JCO site, to measure the intensity of neutrons and gammas. There were four main tasks, first one was to measure the radiation intensity, second one was to terminate the criticality accident, third one is to alert the residents surrounding the JCO site, fourth one is to evacuate the employees in the site. These tasks were successfully performed until October 1. This paper describes about how these operations were performed by the relevant staffs.

Journal Articles

Study on the measurements and evaluation of environmental external exposure after the nuclear accident

Sakamoto, Ryuichi; Saito, Kimiaki; Tsutsumi, Masahiro; Nagaoka, Toshi

Hoken Butsuri, 36(4), p.297 - 307, 2001/12

There are many factors which affect external exposure in contaminated area: distributions of fallout, compositions of radioactive nuclides, soil conditions, depth profile of radioactivity in soil, rain fall, snow cover, radioactive decay, shielding effects of houses and other structures, de-contamination measures, and the 'occupancy factor' which accounts for the fraction of time that inhabitants spend in different locations. In this study, several important issues concerning these factors have been investigated using field measurements and computational simulations since 1992 in the Chernobyl area. The objectives of the study were: 1) The development of a mobile survey method to collect radiation data of the contaminated area over a wide area in a short time; 2) The verification of a method to infer external doses to the population; 3) The provision of basic data used for the evaluation of external dose due to gamma ray using a Monte Carlo simulation method. 4) Characteristics of the radiation fields in contaminated area. In this report, the results were summerized.

JAEA Reports

Annual report on the effluent control of Tokai Works FY 2001

Shinohara, Kunihiko; Takeishi, Minoru; ; ; Mizutani, Tomoko

JNC-TN8440 2001-019, 141 Pages, 2001/11

JNC-TN8440-2001-019.pdf:12.69MB

This report was written about the effluent control in JNC Tokai Works from 1$$^{st}$$ April 2000 to 31$$^{st}$$ March 2001. In this period, the quantities and concentrations of retroactivities in liquid waste from Tokai Works were under the discharge limits of "Safety Regulations for the Tokai Reprocessing Plant", "Safety Regulations for the Tokai Reprocessing Plant" and regulations of government.

JAEA Reports

The calculation and estimation of wastes generated by decommissioning of nuclear facilities

; ; ; Takeda, Seiichiro

JNC-TN8420 2001-008, 134 Pages, 2001/07

JNC-TN8420-2001-008.pdf:4.4MB

This investigation was conducted as a part of planning the low-level radioactive waste management program (LLW management program). The aim of this investigation was contributed to compile the radioactive waste database of JNC's LLW management program. All nuclear facilities of the Tokai works and Ningyo-toge Environmental Engineering Center were investigated in this work. The wastes generated by the decomissioning of each nuclear facility were classified into radioactive waste and others (exempt waste and non-radioactive waste), and the amount of the wastes was estimated. The estimated amounts of radioactive wastes generated by decomissioning of the nuclear facilities are as follows. (1)Tokai works. The amount of waste generated by decommissioning of nuclear facilities of the Tokai works is about 1,079,100 ton. The amount of radioactive waste is about 15,400 ton. The amount of exempt waste and non-radioactive waste is about 1,063,700 ton. (2)Ningyo-toge Environmental Engineering Center. The amount of waste generated by decommissioning of nuclear facilities of Ningyo-toge Environmental Engineering Center is about 112,500 ton. The amount of radioactive waste is about 7,800 ton. The amount of exempt waste and non-radioactive waste is about 104,700 ton.

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

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

Maruo, Yoshihiro; ; ;

JNC-TN8440 2001-001, 135 Pages, 2000/12

JNC-TN8440-2001-001.pdf:4.61MB

None

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai reprocessing plant FY 1999

; Shinohara, Kunihiko; ; ; ; Takeyasu, Masanori;

JNC-TN8440 2000-007, 141 Pages, 2000/06

JNC-TN8440-2000-007.pdf:3.02MB

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 1999 to March 2000. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.

JAEA Reports

Reliability evaluation for radionuclide transport analysis code MATRICS

*; Ijiri, Yuji*; *; *

JNC-TN8400 2000-021, 66 Pages, 2000/04

JNC-TN8400-2000-021.pdf:1.74MB

A reliability evaluation for radionuclide transport analysis code, MATRICS, used in radionuclide transport analysis in the natural barrier system PA in H12 report has been carried out. Sensitivity analysis to radionuclide transport parameter in MATRICS and analytical solution has been performed, and the results of each analysis have been compared. Additionally sensitivity analysis using Talbot Method, Crump method and Hosono method has been carried out, and the results of each inverse Laplace transform method has been compared. The conclusions obtained from the results of the evaluation are summarized as follows, (1)In case of the infinite matrix diffusion distance, an error among the results of each calculation is maximum about 0.4% in the range of Pe number from 1.0 to 100. And, an error among the results of each calculation is maximum about 5.5% in the range of transmissivity from 1.0$$times$$10$$^{-10}$$ to 1.0$$times$$10$$^{-5}$$(m$$^{2}$$/s). (2)In case of the finite matrix diffusion distance (0.03$$sim$$1.0(m)), an error among the results of each calculation is maximum about 0.7% in the range of Pe number from 1.0 to 100. And, an error among the results of each calculation is maximum about 2.4% in the range of transmissivity from 1.0$$times$$10$$^{-10}$$ to 1.0$$times$$10$$^{-5}$$(m$$^{2}$$/s). 3)By comparing Talbot method with other inverse Laplace transform method, Talbot method is confirmed to give similar results with other inverse Laplace transform method in the range of Pe number from 5.0$$times$$10$$^{-1}$$ to 2.0$$times$$10$$^{3}$$, and that of transmissivity below 1.0$$times$$10$$^{-7}$$(m$$^{2}$$/s). Therefore, it is concluded that the reliability of MATRICS are confirmed by conducting sensitivity analysis in the range of Pe number and transmissivity coefficient used in H12 report.

JAEA Reports

Study on solubility of transuranium elements, II

Moriyama, Hirotake*

JNC-TJ8400 2000-050, 47 Pages, 2000/03

JNC-TJ8400-2000-050.pdf:1.49MB

In support of the safety assessment of geologic disposal of high levcl radioactive wastes, the solubility of transuranium elements was studied. The solubility of PuO$$_{2}$$$$cdot$$xH$$_{2}$$O was measured undcr a reducing condition, and the solubility product K$$^{0}_{sp}$$ and the stability constant $$beta$$$$_{4}$$ of Pu(OH)$$_{4}$$ were obtained. The obtained K$$^{0}_{sp}$$ value was found to be much smaller than that predicted by Rai et al. from its dependence on ionic radius. Also, the solubility of PuO$$_{3}$$3 $$cdot$$ xH$$_{2}$$O was measured under an oxidizing condition and the solubility product K$$^{0}_{sp}$$ was obtained. In the analysis of hydrolysis constants of actinide ions, it was found that the systematic trend of the hydrolysis constants was well explained by the hard sphere model considering the effective charges of actinide ions.

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

None

*; *

JNC-TJ7440 2000-005, 45 Pages, 2000/03

JNC-TJ7440-2000-005.pdf:2.72MB

no abstracts in English

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

Influence of naturally-occurring heterogeneous complex-forming materials on the migration behavior of actinides in the geosphere (III)

Tochiyama, Osamu*

JNC-TJ8400 2000-044, 53 Pages, 2000/02

JNC-TJ8400-2000-044.pdf:1.41MB

To estimate the polyelectrolyte effect and the effect of the heterogeneous composition of humic acids, the complex formation constants of Eu(III) and Ca(II) with Aldrich humic acid and polyacrylic acid were obtained, for Eu(10$$^{-8}$$ to 10$$^{-5}$$ M) by solvent extraction with TTA and TBP in xylene, for Ca (10$$^{-10}$$M) with TTA and TOPO in cyclohexane and for Ca(10$$^{-4}$$M) by using ion-selective electrode. By defining the apparent formation as $$beta_{alpha}$$ = [MR$$_{m}$$]/([M][R]), where [R] denotes the concentration of dissociated functional group, [M] and [MR$$_{m}$$] denote the concentration of free and bound metal ion and pcH is defined as-log[H], the values of log$$beta_{alpha}$$ have been obtained at pcH 4.8 - 5.5 in 0.1 - 1.0M NaClO$$_{4}$$ and NaCl. Log$$beta_{alpha}$$ of Eu-humate varied from 5.0 to 9.3 and that of Ca-humate from 2.0 to 3.4..For both humate and polyacrylate, log$$beta_{alpha}$$ increased with pcH or with the degree of dissociation. The increase in the ionic strength O.1 to 1.0 M decreased the log$$beta_{alpha}$$, the decrease in log$$beta_{alpha}$$ of Eu(III)-humate is 1.6, that of Eu(III), polyacrylate 0.7, that of Ca(II)-humate 1.9 and that of Ca(II)-polyacrylate 1.2. While the increase in the metal ion produced no effect on log$$beta_{alpha}$$ of polyacrylate, log$$beta_{alpha}$$ of humate decreased. Depending on the concentration of Eu(III), the coexistence of Ca(II) reduced log $$beta_{alpha}$$ of humate by 0 to 0.8. The dependence of log$$beta_{alpha}$$ of humate on the metal ion concentration suggests the coexistence of strong and weak binding sites in the hmnic acid.

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

None

*

JNC-TJ7420 2000-001, 14 Pages, 2000/02

JNC-TJ7420-2000-001.pdf:0.27MB

no abstracts in English

JAEA Reports

Working Programme for MIU-4 Boreholo Investigations

; ; Metcalf; ; ; ; Takeuchi, Shinji

JNC-TN7410 99-007, 44 Pages, 1999/08

JNC-TN7410-99-007.pdf:2.59MB

JAEA Reports

None

Iida, Takao*

JNC-TJ6400 2000-008, 58 Pages, 1999/03

JNC-TJ6400-2000-008.pdf:1.9MB

None

72 (Records 1-20 displayed on this page)