Repair materials and techniques for concrete structures in nuclear power plants

Krauss, Paul D.; Naus, D.J.

doi:10.1016/s0029-5493(97)00336-1

Cited by 9 publications

(6 citation statements)

References 2 publications

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“…18-20 A survey questionnaire has been sent to U.S. utilities to obtain information related to in-service inspection procedures, incidences of degradation, and repair procedures that have been utilized with respect to the concrete structures. 21 Responses to the survey questionnaire, provided by slightly less than half the commercial nuclear power plants in the U.S., indicated that the majority of problems associated with the concrete structures were the result of design and construction errors, generally initiated during construction, and have been corrected. + This indicates the overall effectiveness of quality control/quality assurance programs at nuclear power plants in ensuring that the factors associated with production of good quality concrete have been adequately addressed (e.g., material selection, batching, mixing, placing, and curing).…”

Section: Figure 22 Concrete Historical Timelinementioning

confidence: 99%

“…223 Guidelines for the repair of reinforced concrete structures have been developed. 21,158,[224][225][226][227][228] A reliability-based methodology has been developed that can be used to facilitate quantitative assessments of current and future structural reliability and performance of reinforced concrete structures in nuclear power plants. 229 The methodology is able to take into account the nature of past and future loads, and randomness in strength and in degradation resulting from environmental factors.…”

Section: Summary and Commentarymentioning

confidence: 99%

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Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

Naus¹

2007

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The objective of this study was to provide a primer on the environmental effects that can affect the durability of nuclear power plant concrete structures.As concrete ages, changes in its properties will occur as a result of continuing microstructural changes (i.e., slow hydration, crystallization of amorphous constituents, and reactions between cement paste and aggregates), as well as environmental influences. These changes do not have to be detrimental to the point that concrete will not be able to meet its performance requirements. Concrete, however, can suffer undesirable changes with time because of improper specifications, a violation of specifications, or adverse performance of its cement paste matrix or aggregate constituents under either physical or chemical attack. Contained in this report is a discussion on concrete durability and the relationship between durability and performance, a review of the historical perspective related to concrete and longevity, a description of the basic materials that comprise reinforced concrete, and information on the environmental factors that can affect the performance of nuclear power plant concrete structures. Commentary is provided on the importance of an aging management program.

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Section: Figure 22 Concrete Historical Timelinementioning

confidence: 99%

Section: Summary and Commentarymentioning

confidence: 99%

Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

Naus¹

2007

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“…The value of rebound of the hammer is recorded and correlated with the supplied standard charts to estimate the strength of the concrete. It is a hand-operated single-piece equipment which measures the surface hardness up to certain depth (Krauss, 1994). The operator places the impact plunger of the hammer against the concrete and then presses the hammer until the hammer releases.…”

Section: Rebound Hammermentioning

confidence: 99%

Damage evaluation of a full-scale RC frame exposed to multiple extreme loads

Kumar

2019

JSFE

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Purpose The occurrence of multiple hazards in extreme conditions is not unknown nowadays, but the sustainability of the reinforced concrete structures under such scenarios form competitive challenges in civil engineering profession. Among all, fire following earthquake (FFE) is categorized under multiple extreme load scenarios which causes sequential damages to the structures. This paper aims to experiment a full-scale RC frame sub-assemblage for the FFE scenario and assess each stage of damage through the nondestructive testing method. Design/methodology/approach Two levels of simulated earthquake damages, i.e. immediate occupancy (IO) level and life safety (LS) level of structural performance were induced to the test frame and then, followed by a realistic compartment fire of 1 h duration. Also, the evaluation of damage to the RC frame after the fire subsequent to the earthquake was carried out by obtaining the ultimate capacity of the frame. Ultrasonic pulse velocity and rebound hammer test were conducted to assess the structural endurance of the damaged frame. Cracks were also marked during mechanical damages to the test frame to study the nature of its propagation. Findings Careful visual inspection during and after the fire test to the test frame were done. To differentiate between concrete chemically affected by the fire or physically damaged is an important issue. In situ inspection and laboratory tests of concrete components have been performed. Concrete from the test frame was localized with thermo-gravimetric analysis. The UPV results exhibited a sharp decrease in the strength of the concrete material which was also confirmed via the DTA, TGA and TG results. It is important to evaluate the residual capacity of the entire structure under the FFE scenario and propose rehabilitation/retrofit schemes for the building structure. Research limitations/implications The heterogeneity in the distribution of the damage has been identified due to variation of fire exposure. The study only highlights the capabilities of the methods for finding the residual capacity of the RC frame sub-assemblage after an occurrence of an FFE. Originality/value It is of find kind of research work on full-scale reinforced concrete building. In this, an attempt has been made for the evaluation of concrete structures affected by an FFE through nondestructive and destructive methods.

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“…Initially, degradation of NPP concrete structures in the U.S. occurred early in their life and has been corrected [37][38][39]. Causes were primarily related either to improper material selection and construction/design deficiencies, or environmental effects.…”

Section: Operating Experiencementioning

confidence: 99%

Overview of activities in the U.S. related to continued service of nuclear power plant concrete structures

Naus

2011

EPJ Web of Conferences

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Abstract. Safety-related nuclear power plant concrete structures are described and commentary on continued service assessments of these structures is provided. In-service inspection and testing requirements in the U.S. are summarized. The license renewal process in the U.S. is outlined and its current status noted. A summary of operating experience related to U.S. nuclear power plant concrete structures is presented. Several candidate areas are identified where additional research would be of benefit to aging management of NPP concrete structures. Finally current ORNL activities related to aging-management of concrete structures are outlined: development of operating experience database, application of structural reliability theory, and compilation of elevated temperature concrete material property data and information.

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Repair materials and techniques for concrete structures in nuclear power plants

Cited by 9 publications

References 2 publications

Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

Damage evaluation of a full-scale RC frame exposed to multiple extreme loads

Overview of activities in the U.S. related to continued service of nuclear power plant concrete structures

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