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Journal Articles

A Portable radioactive plume monitor using a silicon photodiode

Tamakuma, Yuki*; Yamada, Ryohei; Iwaoka, Kazuki*; Hosoda, Masahiro*; Kuroki, Tomohiro*; Mizuno, Hiroyuki*; Yamada, Koji*; Furukawa, Masahide*; Tokonami, Shinji*

Perspectives in Science (Internet), 12, p.100414_1 - 100414_4, 2019/09

https://doi.org/10.1016/j.pisc.2019.100414

In this study, a portable radioactive plume monitor using a silicon photodiode was developed for the detection of a radioactive plume (e.g. $^{131}$ I, $^{134}$ Cs and $^{137}$ Cs) in an emergency situation. It was found that the background count rate was proportional to ambient dose equivalent rate and the detection limit for the monitor at 20 Sv h $^{-1}$ as an ambient dose equivalent rate was evaluated to be 187 Bq m $^{-3}$ using the ISO11929 method. These results suggest that the detection limit for the system can be decreased effectively by lead shielding with optimized thickness.

Journal Articles

High-sensitivity detection of fissile materials in a waste dram by direct interrogation of 14MeV acc neutrons

Haruyama, Mitsuo; Ara, Katsuyuki*; Takase, Misao*

Nihon Genshiryoku Gakkai-Shi, 43(4), p.397 - 404, 2001/04

https://doi.org/10.3327/jaesj.43.397

Times Cited Count：3 Percentile：27.1(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Development of analytical method for plutonium in high active liquid waste solution by high performance spectrophotometry

Jitsukata, Shu*; *; ; ; Kurosawa, A.

JNC TN8410 2001-002, 66 Pages, 2000/12

JNC-TN8410-2001-002.pdf:2.03MB

It was required from IAEA to determine a small amount of plutonium in the high active liquid waste solutions (HALW) in the tokai reprocessing plant. High performance spectrophotometer (HPSP), which could be obtained lower detection limit than conventional spectrophotometer, is studied to be applied to the inspection and verification analysis by the IAEA. [Cold Test] Neodymium, showing an absorption peak near the absorption wavelength of plutonium (VI), was used as an alternative element to plutonium, in order to review the calculation method of the peak intensity. As a result, the three-point correction method was found to be simple and effective. [Hot Test] Plutonium nitrate solution was used the fundamental test of this method. Since the method is known to be influenced by acidity, suspended sludge and coexistent elements in a sample, each dependency was examined. It was found that measurement results varied about 14% at a nitric acid concentration of 2-4 mol/L. Sludge should be removed by filtration before the measurement. The effect of coexisting elements could be eliminated adjusting the optical balance between reference and sample beam intensity. In the case of measuring a low concentration plutonium solution sample, a ratio of the peak intensity to the background intensity (S/B ratio) is relatively small. Therefore a method should be improved the S/B ratio by analyzing the obtained spectra. Accumulated average method, moving average method and Fourier transform method was tested. The results showed that a combination of the accumulated average method and the moving average method was the optimum method for the purpose. Linearity of the calibration curve was found between 0-11 mgPu/L. Synthetic sample solution, which simulated the actual constituents of the HALW with plutonium showed a good linear relation at 0-11 mgPu/L. The detection limit for plutonium concentration was 0.07 mgPu/L. When the synthetic HALW solution containing plutonium was measured, the de

JAEA Reports

Development of building surfaces contamination measurement technique (Contract research)

Hatakeyama, Mutsuo; Ito, Hirokuni; Yanagihara, Satoshi

JAERI-Tech 2000-056, 38 Pages, 2000/09

JAERI-Tech-2000-056.pdf:5.23MB

no abstracts in English

JAEA Reports

Experimental investigation of activities and tolerance of denitrifying bacteria under alkaline and reducing condition

Mine, Tatsuya*; Mihara, Morihiro;

JNC TN8430 2000-009, 35 Pages, 2000/07

JNC-TN8430-2000-009.pdf:0.88MB

In the geological disposal system of TRU wastes, nitrogen generation by denitrifying bacteria could provide significant impact on the assessment of this system, because nitrate contained in process concentrated liquid waste might be electron acceptor for denitrifying bacteria. In this study, the activities and tolerance of denitrifying bacteria under disposal condition were investigated. pseudomonas denitrificans as denitrifying bacteria was used. The results showed that Pseudomonas denitrificans had activity under reducing condition, but under high pH condition (PH9.5), the activity of Pseudomonas denitrificans was not detected. It is possible that the activity of Pseudomonas denitrificans would be low under disposal condition.

JAEA Reports

Measurement of U and Pu concentration by X-ray fluorescence spectrometry using vertical irradiation system.

; ; ; Ikeda, Hisashi ; Jitsukata, Shu*; *

JNC TN8410 2000-022, 55 Pages, 2000/05

JNC-TN8410-2000-022.pdf:1.57MB

Measurement of U and Pu concentrations by wavelength dispersion type X-ray fluorescence spectrometry was studied. Sample holder was installed inside of glove box and other instruments, X-ray tube, monochromator and detectors were set out side of the glove box. X-rays was irradiated to sample though Be window. Fluorescent X-rays form sample were also passing though the same Be window and detected outside. Analytical conditions were optimized as follows. Sample thickness is 8 mm, which is 3ml of sample volume by the sample holder. Voltage and eurrent for X-ray tube is 50kV and 40 mA, respectively. Measurement was done twice, 60 seconds each, and averaged X-ray intensity was used to calculate elemental concentrations. Matrix correction was necessary to measure U and Pu concentration within 10% accuracy. Detection limits were calculated to 0.4 mg/L for U and 0.7mg/L for Pu. Calibration curve was liner up to 9 g/L fbr U and Pu. Two calculation methods, calibration curve method and standard addition method, were studied to measure Pu concentration in organic solution. Detection limit was 5.3 mg/L and 0.2 mg/L, respectively.

Journal Articles

Improvement of tritium accountancy technology for the ITER fuel cycle safety enchancement

Ohira, Shigeru; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Tadokoro, Takahiro*; Nakamura, H.*; Ito, Takeshi*; Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; et al.

Nuclear Fusion, 40(3Y), p.519 - 525, 2000/03

https://doi.org/10.1088/0029-5515/40/3Y/312

Times Cited Count：24 Percentile：59.01(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

QA issues for site hydrochemical data used for groundwater evolution models

Sasamoto, Hiroshi; Yui, Mikazu; Savage, D.*; Bille, B.*

JNC TN8400 99-025, 32 Pages, 1999/06

JNC-TN8400-99-025.pdf:1.94MB

Groundwater data used for modelling site or repository evolution need to be assessed for their quality and whether they are "fit for purpose", prior to utilization. This report discuss factors and issues which impinge upon the quality of such data. It is recommended that geochemical modelleres : (1)are aware of how groundwater samples were collected, whether during drilling, during hydraulic testing, or thereafter, by in-situ measurement, pumped from boreholes, or by pressurised sampler ; (2)are aware of what procedures (if any) were used to "correct" samples for drill fluid contamination and what errors were associated with those methods ; (3)are aware of whether samples were subject to de-pressurisation during sampling, and whether geochemical modelling techniques were applied to correct the compositions of samples for that process ; (4)request different measures of redox activity (e.g., electrode measurements of Eh, concentrations of different redox-sensitive aqueous species) to be applied to key groundwater samples to investigate the extent of redox equilibrium ; (5)are aware of how groundwater samples were filtered and preserved for off-site analysis ; (6)ensure that adequate methods of groundwater filtration ( 0.1m) and chemical analysis are applied to ensure accurate and reproducible analyses for dissolved aluminum at low levels of concentration (generally less than 0.2 mg/L) ; (7)are aware of elemental errors and detection limits in chemical analysis of groundwater samples and assess the quality of groundwater analyses via ion exchange balances and via a comparison of measured and calculated values for total dissolved solids contents. (8)ensure that detailed mineralogical analysis is carried out on rock samples from locations where key groundwater samples have been extracted.