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Tanigawa, Masafumi; Nakamura, Daishi; Asakawa, Naoya*; Seya, Kazuhito*; Omori, Fumio*; Koiso, Katsuya*; Horigome, Kazushi; Shimizu, Yasuyuki
JAEA-Technology 2024-001, 37 Pages, 2024/05
JAEA-Technology-2024-001.pdf:2.32MB
At plutonium conversion development facility, the neutralization sedimentation and the coagulation sedimentation (sludge) items are stored in a polyethylene container packed in the plastic bag. The neutralization sedimentation items and the coagulation sedimentation items are stored in the globe box and storage room in the facility, respectively. Some sludge items generate gases, that swelled the plastic bag. We should ensure whether the bag swelling by visual confirmation. When the swelling is confirmed, those containers are transferred to the glove box to exchange the plastic bag for new one. By keeping the above procedure, those items were stored safely in the facility since its founding. The stabilization work for enhance the safe storage was planned to reduce the gas generation of the sludge items caused by the radiolysis of water. Those sludge items have the containing a sodium nitrate that has moisture-absorption characteristic. Therefore, the stabilization method aimed to remove the sodium nitrate from the items. The work was conducted from August 2018 to August 2022. The sodium concentration in items were reduced to 3 wt% or lower. Each stabilized sludge item packed in plastic bag were confirmed its swelling for over one year in the storage place. No gas generation from all item has been observed for more than the one year. And while both the neutralization and the coagulation sedimentation items were stored they were not the increasing of the moisture in the items. As a result, those items were evaluated that will not generate gases any more and confirmed to be stabilized after this treatment. Then, those neutralization sedimentation items were stored in powder cans and transferred to powder storage room as a retained waste. Based on the above results, risks of the gas generation from sludge items were decreased enough. Therefore, the safety of the stored sludge item was improved and confirmed.
Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05
High level liquid waste generated from reprocessing of spent nuclear fuel is possible to form precipitations so called as sludge. The sludge will significantly influence on extraction chromatography technology for trivalent minor actinide (MA(III)) recovery. Applicability of a pre-column as a filter for removal of the sludge was experimentally evaluated. In this study, remote handling media exchanging experiments were carried out, and a concept of the pre-column system was proposed based on the results. The media of the pre-column was porous silica particle. Since the media formed block, it interfered water current on ejecting porous silica particle. It was better on trickling basis and using upper outlet than other system, but the operation to control the media block behavior and optimization of water flow is needed.
Arai, Takahiro*; Ito, Daiyu*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
Chemical Engineering & Technology, 41(6), p.1199 - 1204, 2018/06
Times Cited Count：4 Percentile：14.58(Engineering, Chemical)In reprocessing process, spent nuclear fuel is dissolved by HNO
. Mo and Zr in the acidic solution react to form zirconium molybdate hydrate (ZMH). ZMH adheres to the inner-surface of reprocessing equipment, giving a great influence on stable operation. Conventional anti-encrustation is achieved by cleaning the surface of the reprocessing equipment by high pressure water and dissolving wall deposits by acid or alkaline solution. However, the former increases radioactive waste volume, and the latter contributes to corrosion of the metal surface. In this study, encrustation mechanism of ZMH crystal was investigated based on the deposited mass on the solid surface. Observing the deposition process, it was clarified that ZMH fine crystal growth is accelerated and agglomerated, followed by the rapid deposition. Total deposited mass decreased not only by lowering initial ratio of Mo and Zr concentration under the range of 1.0 
Mo/Zr 2.0, but also by lowering HNO concentration.
Takeuchi, Masayuki; Aihara, Haruka; Nakahara, Masaumi; Tanaka, Kotaro*
Procedia Chemistry, 21, p.182 - 189, 2016/12
Times Cited Count：2 Percentile：79.33(Chemistry, Inorganic & Nuclear)A simulation technology with electrolyte thermodynamic model has been developed to evaluate the precipitation behavior in reprocessing solution based on nitric acid solution. The simulation results were compared with the experiment data from non-radioactive simulated HLLW with ten elements and Pu-Zr-Mo solution, and the reliability of the thermodynamic model was verified. Most of the precipitation species was zirconium molybdate hydrate from the both data. It is demonstrated that the chemical species and amount of the precipitation calculated by thermodynamic model reflected well that of experiments. This study has shown the thermodynamic simulation model is one of the useful tools to estimate the behavior of precipitation from the reprocessing solution.
Li, Z.*; Onuki, Toshihiko; Ikeda, Ko*
Materials, 9(8), p.633_1 - 633_17, 2016/08
Times Cited Count：31 Percentile：75.98(Chemistry, Physical)Geopolymer samples were prepared at room temperature using paper sludge ashes and immobilization of Sr and Cs in these samples were evaluated by short-term leaching test. The prepared geopolymer samples were semi-crystalline and porous. For the leaching test, the geopolymer samples containing 1 weight % of strontium nitrate or cesium nitrate were prepared, crushed to be finer than 4 mm in size, and immersed in a phthalic salt buffer (pH4) for 6 h. About 0.2% of Sr and 1.3% of Cs were leached from the geopolymer samples.
Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Okamura, Nobuo; Koizumi, Kenji
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05
Seko, Noriaki; Tamada, Masao; Yoshii, Fumio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.340 - 345, 2004/12
Fibrous adsorbents having chelate agent such as amidoxime (AN/MAA-ad), iminodiacetic acid (IDA-ad), and phosphoric acid (HMPA-ad) were prepared by radiation-induced graft polymerization. AN/MAA-ad was synthesized by co-grafting of acrylonitrile and methacrylic acid. Then the introduced functional group of CN was converted to the amidoxime with chemical treatment. Grafting of glycidyl methacrylate and chemically introducing the IDA group synthesized IDA-ad. HMPA-ad was directly synthesized by grafting of phosphoric acid monomer. The densities of the chelate agency were 3.5 mol/kg for AN/MAA-ad, 2.0 mol/kg for IDA-ad and 2.0 mol/kg for HMPA-ad after the grafting time of 2, 1.5 and 8 hours, respectively. HMPA-ad had 200 times higher distribution coefficient for uranium than that of a commercial adsorbent (Diaion-PK216) at pH 0.5. The distribution coefficient for AN/MAA-ad became 500 times higher than that of Diaion-CR11 more than pH 8. These chelate adsorbents are promising materials for removal of uranium from acid or alkali treated waste sludge contaminated uranium.
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
; ; Kawata, Tomio
PNC TN8410 92-012, 47 Pages, 1991/12
[Purpose] We confirmed that modified (6000rpm type) centrifugal clarifier arose the unstable vibration during the reduction of rotating speed under the condition of bearing undissolved residue after the clarification operation. This report describes the cause of unstable vibration that arise in the clarification body set on the rack which induced resonance vibration and the measurement results of vibration characteristic after taking countermeasure for vibration decrease. [Method] It was considered that the causes of the unstable vibration were following; (1)Unbalance between damping force of the lower bearing damper and the vibration force arisen by the rotational bowl (2)Effect of feed condition (3)Effect of self-excited vibration of the free liquid surface (4)Effect of frame strength The test has been conducted to make quantitative measure of vibration characteristic (amplitude of the rotational bowl and shaft) by changing the load in the rotational bowl. We also conducted the test to reconfirm the effect of the circumferential baffle plate which has shown the most effective effect to the vibration decrease in the preceding report. [Results] The effects of the circumferential baffle plate placed on the inside wall of the rotational bowl are shown as follows; (1)The unstable vibration during the reduction of rotating speed has been suppressed By this result, we verified that the vibration on the free liquid surface in the rotational bowl caused the vibration for the bowl without the circumferential baffle plate. (2)It was able to run the clarification operation in the standard condition(100
/h 
6h) for the rotational speed ranging from 4000 to 6000rpm. [Conclusion] By the results of this test and of the preceding report, the feed condition and the condition of setting the circumferential baffle plate are showed in the following, considering the aspects of rotational stability. (1)Condition of feed nozzle - feed 55㎜ in height from the lower ...
; Machi, Sueo
Mizu, 29(1), p.25 - 28, 1986/00
no abstracts in English
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Solid Wastes by Microwave Heating; ; ; ; ; ; ;
JAERI-M 84-001, 76 Pages, 1984/02
no abstracts in English
; ; ;
Journal of Nuclear Science and Technology, 19(5), p.410 - 418, 1982/00
Times Cited Count：3 Percentile：40.62(Nuclear Science & Technology)no abstracts in English
; ; ; ;
JAERI-M 7373, 25 Pages, 1977/11
no abstracts in English
; ;
Journal of Nuclear Science and Technology, 14(2), p.125 - 130, 1977/02
no abstracts in English
; ; Morishita, Satoru; Wadachi, Yoshiki
Nihon Genshiryoku Gakkai-Shi, 17(1), p.27 - 30, 1975/01
no abstracts in English
Machi, Sueo
Shosha, 1975(22), p.3 - 10, 1975/00
no abstracts in English
Segawa, Takeshi*; Hoshino, Tadaya*; ; ; ; ;
PNC TN841 74-14, 48 Pages, 1974/06
no abstracts in English
