Defect Structure and Density Decrease in Neutron-Irradiated Quartz

Weissmann, S.; Nakajima, K.

doi:10.1063/1.1729317

Cited by 45 publications

(16 citation statements)

References 5 publications

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“…As shown in the introduction, the integrity of a CBS is normally evaluated by determining the limit of fast neutron fluence and/or gamma-ray dose, which depend on the authorities or countries. Previous studies have suggested that the concrete strength deteriorates above a fast neutron (>0.1 MeV) fluence of 10 19 n/cm 2 under the temperature condition of light water reactors (Hilsdorf et al 1978;Field et al 2015), while the minimum neutron energy that affects α-quartz is 0.01 MeV (Primak 1958;Weissmann and Nakajima 1963;Bykov et al 1981). Further scientific research is needed to confirm this criterion.…”

Section: Integrity Evaluationmentioning

confidence: 97%

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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Section: Integrity Evaluationmentioning

confidence: 97%

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

Maruyama

Haba²,

Sato

et al. 2016

ACT

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“…Numerous groups have studied quartz as an expanding rock mineral (Wittels and Sherrill 1954;Primak et al 1955;Primak 1958;Weissmann and Nakajima 1963;Lell et al 1968;Bykov et al 1981;Inui et al 1990;Eby et al 1992;Bonnet et al 1994;Douillard and Duraud 1996;Bolse 1999;Ewing et al 2000). Yet, the rate of metamictization and the final expansion strain of other rock-forming minerals are also important topics for research.…”

Section: Concretementioning

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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“…(1) can also be interpreted in a slightly modified form, which corresponds, mathematically speaking, to the form adopted by several researchers, e.g., (Larive 1997;Saouma and Perotti 2006), to model the expansion of concrete subjected to alkali-silica reaction (ASR) as a function of time. Substitution of time by the fluence Φ leads to: (Wittels 1957;Primak 1958;Weissmann and Nakajima 1963 As noted by Bykov et al, "the very strong temperature effect in the range of 30 °C to 100 °C and the reduction of this effect at a higher temperature indicates a nonuniformity of distribution of the defects with respect to the energy of activation, in particular, to a reduction of the fraction of defects with an increased energy of activation." Hence, instead of trying to interpret the data with the calibration of an apparent energy activation, temperature effects are analyzed directly on how Zubov's parameters are affected.…”

Section: A Model For the Effects Of Temperature And Neutron Irradiatimentioning

confidence: 93%

Combined Effects of Temperature and Irradiation on Concrete Damage

Pape

Giorla

Sanahuja

2016

ACT

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Aggregate radiation-induced volumetric expansion (RIVE) is a predominant mechanism in the formation of mechanical damage in the hardened cement paste (hcp) of irradiated concrete under fast-neutron flux . Among the operating conditions difference between test reactors and light water reactors (LWRs), the difference of irradiation flux and temperature is significant. While a temperature increase is quite generally associated with a direct, or indirect (e.g., by dehydration) loss of mechanical properties , it causes a partial annealing of irradiation amorphization of α-quartz, hence, reducing RIVE rate. Based on data collected by Bykov et al. (1981), an incremental RIVE model coupling neutron fluence and temperature is developed. The elastic properties and coefficient of thermal expansion (CTE) of irradiated polycrystalline quartz are interpreted through analytical homogenization of experimental data on irradiated α-quartz published by Mayer and Lecomte (1960). The proposed model, implemented in the meso-scale simulation code AMIE, is compared to experimental data obtained on ordinary concrete made of quartz/quartzite aggregate (Dubrovskii et al. 1967). Substantial discrepancy, in terms of damage and volumetric expansion developments, is found when comparing irradiation scenarios assuming constant flux and temperature, as opposed to more realistic test reactor operation conditions.

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Defect Structure and Density Decrease in Neutron-Irradiated Quartz

Cited by 45 publications

References 5 publications

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

Combined Effects of Temperature and Irradiation on Concrete Damage

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