Comparison of electrical properties of ceramic insulators under gamma ray and ion irradiation

Tanaka, Teruya; Nagayasu, R.; Sato, F.; Muroga, T.; Ikeda, T.; Iida, Toshiyuki

doi:10.1016/j.fusengdes.2005.09.047

Cited by 7 publications

(6 citation statements)

References 14 publications

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“…In the fusion blanket environment, the dose rate will be about 3 orders of magnitude higher than the present experiment [8]. Extrapolation from the present and previous results on the dose rate dependence [5,6] gives the RIC levels between 10 À9 and 10 À7 S/m for the environment. In the case of Y 2 O 3 , which showed the largest RIC, RIC will dominate the insulating performance up to $500°C in the fusion blanket.…”

Section: Discussioncontrasting

confidence: 41%

“…The evaluated radiation induced conductivities (RIC) were 5.1 · 10 À12 S/m for Er 2 O 3 (4.5 Gy/s), 3.0 · 10 À10 S/m for Y 2 O 3 (5.1 Gy/s) and 2.2 · 10 À11 S/m for CaZrO 3 (8.8 Gy/s) at room temperature. The induced currents at room temperature were almost proportional to the bias voltages in both the measurements without and under the irradiation [6]. During heating, the conductivities without irradiation gradually increased with temperature.…”

Section: Methodsmentioning

confidence: 86%

“…Previously, neutron and gamma-ray irradiations using a DT neutron source, a fission reactor and a 60 Co gamma-ray source have been performed on the candidate materials such as Er 2 O 3 , Y 2 O 3 and CaZrO 3 at low temperature (<50°C) [5,6]. The results indicated that degradation of the insulating property due to radiation induced conductivity (RIC) would not prevent the candidate materials from maintaining the required performance (<10 À2 S/m) [7] at high dose rate (several kGy/s) in the fusion blanket [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electrical insulating property of ceramic coating materials in radiation and high-temperature environment

Tanaka

Nagayasu

Sawada

et al. 2007

Journal of Nuclear Materials

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Section: Discussioncontrasting

confidence: 41%

Section: Methodsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrical insulating property of ceramic coating materials in radiation and high-temperature environment

Tanaka

Nagayasu

Sawada

et al. 2007

Journal of Nuclear Materials

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“…This jump in the current value may be attributed to the excess of the free charge carriers released from the formation of free radicals of C-H and O-H groups as a result of a change in the structure, discussed above. Furthermore, the effect of gamma irradiation, over the dose range of interest, may lead to the creation of hole-electron pairs [21] sharing in the increase of the current, in both regions, with the irradiation dose. This increase in the nonlinearity of the I -V curves can be explained by the recombination of the charge carriers and it is also expected that the electric field near the positive electrode may be weakened due to the existence of the space charge [21].…”

Section: Electrical Behaviourmentioning

confidence: 99%

Study on the structure and electrical behaviour of zinc aluminate ceramics irradiated with gamma radiation

All¹,

Fawzy²,

Radwan³

2007

J. Phys. D: Appl. Phys.

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The preparation process of zinc aluminate (ZnAl2 O4) ceramic powder, as well as the sintering temperature have been consequently governed using scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. A broad exothermic peak in the range 223–310 °C is observed due to the crystallization of ZnAl2O4 powder. Then the final resultant powder was irradiated with gamma rays at different doses from 30 to 150 kGy. The effect of gamma irradiation on the structure and the electrical behaviour of ZnAl2O4 ceramics has been obtained. The induced changes in the structure have been studied via SEM, XRD and FTIR spectrometers. The obtained results reveal no changes in the spinel phase of ZnAl2O4, while some displacements of the constituent individual atoms for the irradiated samples are observed. The I–V characteristic curves and the dielectric properties of the prepared ceramic powder have been measured for unirradiated and irradiated samples. These curves exhibit nonlinearity of this type of ceramics, where the dc current gradually increases with the increase in the dose. The irradiation of ZnAl2O4 with gamma radiation was found to increase the nonlinearity of the I–V curves. The dielectric constant and loss were found to decrease as the dose increases. Therefore, the irradiation of ZnAl2O4 with gamma rays can improve its utility as an electronic protector in electrical circuits against sudden overvoltage.

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“…Ceramic material shows good electrical and mechanical properties under irradiation. Many ceramic materials have been used as electrical insulator materials for various diagnostics components [10]- [12], the first wall current break, the RF windows, etc. The ceramic break had been used in KSTAR in-cryostat helium line [13].…”

Section: Introductionmentioning

confidence: 99%

Testing of the Ceramic Insulation Break for Fusion Device

Liu

Pan

et al. 2014

IEEE Trans. Appl. Supercond.

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Large magnet system is an essential component of most current or planned fusion devices. Axial insulation breaks are required in order to electrically isolate the cryogenic distribution system from the potential high voltage of the magnet system and bus bars. The epoxy resin based insulation break could be the weak link in magnet design, due to insulation sensitivity to high irradiation doses. The Al 2 O 3 ceramic material instead of epoxy based material was used to manufacture the insulation break. Kovar alloy which has a similar mean coefficient of thermal expansion with Al 2 O 3 ceramic in the temperature range of 300-1073 K was used as two ends of the insulation breaks. The ceramic tubes and Kovar alloy tubes were vacuum brazed together using silver-based filler at 1073 K. The helium tightness, the insulation resistances and dielectric breakdown were checked at room temperature and LN 2 temperature. Then 2 kN traction and compression were tested at room temperature and LN 2 temperature. The maximum tensile force of 8.62 kN and 8.18 kN were measured at room temperature and LN 2 temperature, respectively. The three point bending test was carried out. The test results of 4.5 kN and 3.6 kN were measured at room temperature and LN 2 temperature, respectively. The 50 thermal shock cycles were performed from 77 K to 300 K to ensure that the ceramic break could operate under rapid temperature change.

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Comparison of electrical properties of ceramic insulators under gamma ray and ion irradiation

Cited by 7 publications

References 14 publications

Electrical insulating property of ceramic coating materials in radiation and high-temperature environment

Electrical insulating property of ceramic coating materials in radiation and high-temperature environment

Study on the structure and electrical behaviour of zinc aluminate ceramics irradiated with gamma radiation

Testing of the Ceramic Insulation Break for Fusion Device

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