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Journal Articles

Development of remote sensing technique using radiation resistant optical fibers under high-radiation environment

Ito, Chikara; Naito, Hiroyuki; Ishikawa, Takashi; Ito, Keisuke; Wakaida, Ikuo

JPS Conference Proceedings (Internet), 24, p.011038_1 - 011038_6, 2019/01

https://doi.org/10.7566/JPSCP.24.011038

A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels at the Fukushima Daiichi Nuclear Power Station. The tentative dose rate in the reactor pressure vessels is assumed to be up to 1 kGy/h. We developed a radiation resistant optical fiber consisting of a 1000 ppm hydroxyl doped pure silica core and 4 % fluorine doped pure silica cladding. We attempted to apply the optical fiber to remote imaging technique by means of fiberscope. The number of core image fibers was increased from 2000 to 22000 for practical use. The transmissive rate of infrared images was not affected after irradiation of 1 MGy. No change in the spatial resolution of the view scope by means of image fiber was noted between pre- and post-irradiation. We confirmed the applicability of the probing system, which consists of a view scope using radiation-resistant optical fibers.

Journal Articles

Development of a water purifier for radioactive cesium removal from contaminated natural water by radiation-induced graft polymerization

Seko, Noriaki*; Hoshina, Hiroyuki*; Kasai, Noboru*; Shibata, Takuya; Saiki, Seiichi*; Ueki, Yuji*

Radiation Physics and Chemistry, 143, p.33 - 37, 2018/02

https://doi.org/10.1016/j.radphyschem.2017.09.007

Times Cited Count：16 Percentile：85.18(Chemistry, Physical)

Journal Articles

Adsorption efficiency of a new adsorbent towards uranium and vanadium ions at low concentrations

Kavakli, P. A.*; Seko, Noriaki; Tamada, Masao; Gven, O.*

Separation Science and Technology, 39(7), p.1631 - 1643, 2005/00

https://doi.org/10.1081/SS-120030785

Times Cited Count：58 Percentile：84.37(Chemistry, Multidisciplinary)

A new type of fibrous adsorbent with excess amidoxime groups was synthesized by radiation-induced graft polymerization. Glycidyl methacrylate (GMA) was first radiation-grafted on polyethylene-coated polypropylene nonwoven fabrics and chemically modified with 3,30-iminodipropionitrile [NH (-CH $_{2}$ -CH $_{2}$ -CN) $_{2}$ ] (IDPN), which was further reacted with hydroxylamine to obtain graft chains containing two amidoxime groups per graft repeating units. The adsorption properties of this new adsorbent for uranium (U), vanadium (V), lead (Pb), copper (Cu), and cobalt (Co) ions at low concentrations (3.3-1000 ppb).

Journal Articles

Rapid removal of arsenic(V) by zirconium(IV) loaded phosphoric chelate adsorbent synthesized by radiation induced graft polymerization

Seko, Noriaki; Basuki, F.*; Tamada, Masao; Yoshii, Fumio

Reactive and Functional Polymers, 59(3), p.235 - 241, 2004/07

https://doi.org/10.1016/j.reactfunctpolym.2004.02.003

Times Cited Count：52 Percentile：82.13(Chemistry, Applied)

Fibrous arsenic(As) adsorbent was synthesized by loading zirconium(Zr) on fibrous phosphoric adsorbent which was directly synthesized by radiation-induced grafting of 2-hydroxyethyl methacrylate phosphoric acid on polyethylene-coated polypropylene nonwoven fabric. Zirconium reacted with phosphoric acid grafted in the polyethylene layer. Zirconium density of the resulting adsorbent was 4.1 mmol/g. The breakthrough curve of As(V) adsorption was independent of the flow rate up to 1300 h $^{-1}$ in space velocity. The total capacity of As(V) was 2.0 mmol/ g-adsorbent at pH of 2. The adsorbed Zr(IV) could be evaluated by 0.4 M sodium hydroxide solution because no Zr(IV) could be found in the eluted solution. Anions of chloride and nitrate interfered the breakthrough capacity.

Journal Articles

Irradiation Assisted Stress Corrosion Cracking (IASCC)

Tsukada, Takashi

Zairyo To Kankyo, 52(2), p.66 - 72, 2003/02

http://joi.jlc.jst.go.jp/JST.Journalarchive/jcorr1991/52.66

Irradiation assisted stress corrosion cracking (IASCC) is a potential failure mode suffered by the core-components of austenitic stainless steels in the aged light-water reactor (LWR), which is the intergranular type cracking caused by synergistic effects of neutron/gamma radiation and chemical environment. Effects of radiation on the materials and high-temperature water are discussed in this paper to understand IASCC phenomenon from a mechanistic viewpoint. It is essential to elucidate the radiation-induced microcompositional and microstructural changes in the alloy for mechanistic and predictive investigations of IASCC. Although grain boundary segregations of alloying and impurity elements are significant factors affecting IASCC, it has been considered that the radiation-induced microstructural and mechanical changes of materials play critical roles in IASCC. For mechanistic understanding of IASCC, further fundamental research works with experimental and theoretical approaches are needed. Efforts directed to the researches at the Japan Atomic Energy Research Institute are also described.

Journal Articles

Radiation-induced reactions the lowest excited states in cinnamic acid crystals

Maekawa, Yasunari; Inaba, Tomonori; Hobo, Hiroki; Narita, Tadashi*; Koshikawa, Hiroshi; Moon, S.; Kato, Jun; Yoshida, Masaru

Chemical Communications, (18), p.2088 - 2089, 2002/09

Radiation-induced reactions of cinnamic acid derivatives have been examined and compared them with photoreactions in the crystalline states; all the reaction products were exactly the same as those of the photoreactions, indicating that the reactions proceed only via the lowest excited state to give [2+2]cycloadducts, E/Z isomerization products, or starting molecules.

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