Study on Environmental and Mechanical Properties of Irradiated Concrete

Kakizaki, Masayoshi; Idei, Yoshio; Sukegawa, Takenori; Akutsu, Youichi; Hatano, Hiroaki; Kurioka, Hitoshi

doi:10.3130/aijs.61.1_10

Cited by 6 publications

(5 citation statements)

References 1 publication

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“…The planar and elevational sections of the target CBS are shown in Fig. 7 (Kakizaki et al 1996). As can be seen from the figure, the thickness of CBS is 1500-3000 mm.…”

Section: Impact Of Neutronsmentioning

confidence: 76%

“…8. The calculation conditions have been validated by the 152 Eu activity that was experimentally obtained at the decommissioning process (Kakizaki et al 1996). The typical calculation results of neutron and gamma-ray spectra at the full-power reactor condition at the surface of the CBS are shown in Fig.…”

Section: Settingmentioning

confidence: 99%

“…Table 3 Chemical composition of cement (Idei et al 1990 Table 4 Physical properties of cement (Idei et al 1990). Kakizaki et al 1996). The planar and elevational sections of the target CBS are shown in Fig.…”

Section: Impact Of Neutronsmentioning

confidence: 99%

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A Numerical Model for Concrete Strength Change under Neutron and Gamma-ray Irradiation

Maruyama

Haba²,

Sato

et al. 2016

ACT

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For performance evaluation of existing reinforced concrete members under irradiation conditions, a numerical code called "DEVICE" (Damage EValuation for Irradiated ConcretE), which takes into account the heat, moisture, and radiation transport coupled with cement hydration, is proposed. This code is composed of the established computational cement-based material (CCBM) model and the one-dimensional deterministic transport Sn code "ANISN". In the proposed model, temperature-dependent irradiation-induced expansion of aggregate minerals and resultant strength deterioration of concrete are introduced. Currently, the knowledge and modeling of irradiation-induced expansion of aggregate mineral is limited only for α-quartz. DEVICE was used for evaluating the strength distribution of the decommissioned plant Japan Power Demonstration Reactor (JPDR). Compressive strength distribution in a concrete biological shielding (CBS) wall of the JPDR was obtained by core sampling, and the compressive loading test results were compared with the calculation results. This comparison proved the practicality potential of DEVICE to predict the concrete strength distribution in a CBS. In addition, concrete strength change and its distribution in a CBS of an anonymous two-loop pressurized water reactor was simulated by DEVICE. The contributing factors for the change in the distribution of concrete strength at the inner surface of the CBS are discussed. Furthermore, the ways of integrity evaluation other than the existing allowable fast neutron fluence method are proposed and discussed as follows: 1) mineral composition-based allowable fast neutron fluence; 2) strength prediction at the inner surface based on the expansion of mineral composition of aggregates and the lower limit curve of the ratio of compressive strength of the specimen after irradiation (Fc) to that of the reference specimen (Fco) as a function of concrete expansion; and 3) direct numerical calculation for seismic performance by considering irradiation-induced volume expansion and degradation of concrete.

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“…The planar and elevational sections of the target CBS are shown in Fig. 7 (Kakizaki et al 1996). As can be seen from the figure, the thickness of CBS is 1500-3000 mm.…”

Section: Impact Of Neutronsmentioning

confidence: 76%

Section: Settingmentioning

confidence: 99%

See 1 more Smart Citation

A Numerical Model for Concrete Strength Change under Neutron and Gamma-ray Irradiation

Maruyama

Haba²,

Sato

et al. 2016

ACT

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“…The gray areas indicate the place of core sampling whose data are used in this study. After (Kakizaki et al 1996, Maruyama et al 2016a. Fig.…”

Section: ~10 × 10mentioning

confidence: 99%

Development of Soundness Assessment Procedure for Concrete Members Affected by Neutron and Gamma-Ray Irradiation

Maruyama

Kontani

Takizawa

et al. 2017

ACT

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In 2008, Nuclear and Industrial Safety Agency (NISA) (currently integrated to the Nuclear Regulatory Authority) launched a project to develop a soundness assessment method for concrete members subject to a radiation environment. Presently, the soundness of concrete members subject to radiation is evaluated based on whether the predicted fast neutron fluence and gamma-ray dose values are lower than specific reference values in Japan, which are 1×10 20 n/cm 2 and 2×10 5 kGy, respectively. These reference values were determined based on report by Hilsdorf et al. This project begins by reviewing Hilsdorf et al.'s report, and we find that the scientific evidence for the current reference values is weak. We thus conclude that new experimental research is required to assess the current reference values and to propose a new alternative soundness assessment procedure if needed. We quantitatively evaluated the influence of neutrons, gammarays, and the resultant heating and drying processes on the strength of concrete as well as their underlying mechanisms. The irradiation experiments confirmed the degradation mechanism of concrete due to neutron irradiation. The main reason for this degradation is the metamictization of rock-forming minerals, which, in turn, leads to aggregate expansion. Due to aggregate expansion, cracks around aggregates form, which reduce the compressive strength and Young's modulus of concrete. Among the rock-forming minerals, α-quartz is the most sensitive to neutron radiation.60 Co gamma-ray irradiation experiments demonstrated that concrete strength increased as the gamma-ray dose and gammaray flux does not have a dose-rate impact on the first radiolysis of evaporable water in cement paste within the present study. The effect of gamma-ray irradiation on the properties of concrete is equivalent to that of heating and drying. Concrete strength alteration due to heating and drying is attributed to the colloidal and porous nature of hardened cement paste and crack formation around the aggregate due to a mismatch in the volume changes of the mortar and aggregate. In addition, a numerical analysis code called DEVICE (Damage EValuation for Irradiated ConcretE) is developed to harness knowledge obtained from concrete samples to predict the distribution of the physical properties in concrete members and their changes over time. From these fundamental studies, we propose a new soundness assessment procedure for concrete members subject to radiation. We also recommend a new radiation-induced strength-degradation reference value of 1×10 19 n/cm 2 for fast neutron.

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“…-rays do not affect the nature of concrete up to a dose of 10 10 Gy. [3][4][5][6][7][8] Irradiation of fast neutrons at a dose of more than $5 Â 10 19 n/cm 2 causes the deterioration of concrete due to the expansion of aggregates and the shrinkage of cement paste. 3,4) The degree of expansion strongly depends on the types of aggregate and cement, and is highest for concrete composed of portland cement and silica-rich aggregates.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nuclear Radiation on Alkali-Silica Reaction of Concrete

Ichikawa

Kimura

2007

Journal of Nuclear Science and Technology

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The effect of electron beam-irradiation on the reactivity of plagioclase, one of the major minerals composing volcanic rocks, to alkali has been examined to clarify whether nuclear radiations accelerate the alkali-silica reaction of concrete containing volcanic rocks as aggregates. Irradiation of plagioclase with a 30 keV electron beam at a dose of more than 0:9 Â 10 8 Gy converts a crystalline plagioclase to an amorphous one that is 35 times more reactive to alkali than the crystal. The high reactivity of the irradiated plagioclase indicates that the deterioration of concrete by alkali-silica reaction is possible to be induced by nuclear radiations even when the aggregates are inert to alkali before the irradiation.

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Study on Environmental and Mechanical Properties of Irradiated Concrete

Cited by 6 publications

References 1 publication

A Numerical Model for Concrete Strength Change under Neutron and Gamma-ray Irradiation

A Numerical Model for Concrete Strength Change under Neutron and Gamma-ray Irradiation

Development of Soundness Assessment Procedure for Concrete Members Affected by Neutron and Gamma-Ray Irradiation

Effect of Nuclear Radiation on Alkali-Silica Reaction of Concrete

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