Management and Safety of Existing Concrete Structures via Optical Fiber Distributed Sensing

2014 ◽  
pp. 217-246 ◽  
Author(s):  
Joan R. Casas ◽  
Sergi Villalba ◽  
Vicens Villalba
Keyword(s):  
Optical Fiber ◽  
Concrete Structures ◽  
Distributed Sensing

scholarly journals Sol-Gel Coating Membranes for Optical Fiber Sensors for Concrete Structures Monitoring

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1245
Author(s):  
Bárbara R. Gomes ◽  
Rui Araújo ◽  
Tatiana Sousa ◽  
Rita B. Figueira
Keyword(s):  
Optical Fiber ◽  
Sol Gel ◽  
Concrete Structures ◽  
Optical Fiber Sensors ◽  
Rational Approach ◽  
Simple Method ◽  
Fiber Sensors ◽  
Chemical Reagents ◽  
Current State ◽  
Gel Membranes

The use of advanced sensing devices for concrete and reinforced concrete structures (RCS) is considered a rational approach for the assessment of repair options and scheduling of inspection and maintenance strategies. The immediate benefits are cost reduction and a reliable prevention of unpredictable events. The use of optical fiber sensors (OFS) for such purposes has increased considerably in the last few years due to their intrinsic advantages. In most of the OFS, the chemical transducer consists of immobilized chemical reagents placed in the sensing region of the optical sensor by direct deposition or by encapsulation in a polymeric matrix. The choice of the support matrix impacts directly on the performance of the OFS. In the last two decades, the development of OFS functionalized with organic–inorganic hybrid (OIH) sol–gel membranes have been reported. Sol–gel route is considered a simple method that offers several advantages when compared to traditional synthesis processes, allowing to obtain versatile materials with unique chemical and physical properties, and is particularly valuable in the design of OIH materials. This review will provide an update of the current state-of-the-art of the OFS based on OIH sol-gel materials for concrete and RCS since 2016 until mid-2021. The main achievements in the synthesis of OIH membranes for deposition on OFS will be discussed. The challenges and future directions in this field will also be considered, as well as the main limitations of OFS for RCS monitoring.

Flight demonstration of aircraft wing monitoring using optical fiber distributed sensing system

2019 ◽  
Vol 28 (5) ◽  
pp. 055007 ◽  
Author(s):  
Daichi Wada ◽  
Hirotaka Igawa ◽  
Masato Tamayama ◽  
Tokio Kasai ◽  
Hitoshi Arizono ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Distributed Sensing ◽  
Aircraft Wing ◽  
Sensing System

scholarly journals Tests under irradiation of optical fibers and cables devoted to corium monitoring in case of severe accident in a Nuclear Power Plant

2020 ◽  
Vol 225 ◽  
pp. 08006
Author(s):  
G. Cheymol ◽  
L. Maurin ◽  
L. Remy ◽  
V. Arounassalame ◽  
H. Maskrot ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Nuclear Power ◽  
Carbon Coating ◽  
Hydrogen Diffusion ◽  
Coating Layer ◽  
Distributed Sensing ◽  
Severe Accident ◽  
Normal Operation ◽  
The Status

The DISCOMS project, which stands for “DIstributed Sensing for COrium Monitoring and Safety”, considers the potential of distributed sensing technologies, based on remote instrumentations and Optical Fiber Sensing cables embedded into the concrete floor under the reactor vessel, to monitor the status of this third barrier of confinement. This paper focuses on the selection and testing of singlemode (SM) optical fibers with limited RIA (Radiation Induced Attenuation) to be compliant with remote distributed instruments optical budgets, the ionizing radiation doses to sustain, and their reduction provided by the concrete basemat shielding. The tests aimed at exposing these fibers and the corresponding sensitive optical cables, to the irradiation doses expected during the normal operation of the reactor (up to 60 years for the European Pressurized Reactor), followed by a severe accident. Several gamma and mixed (neutron-gamma) irradiations were performed at CEA Saclay facilities: POSÉÏDON irradiator and ISIS reactor, up to a gamma cumulated dose of about 2 MGy and fast neutron fluence (E > 1 MeV) of 6 x 1015 n/cm2. The first gamma test permitted to assess the RIA at various optical wavelengths, and to select three radiation tolerant singlemode fibers (RIA < 5 dB/100 m, at 1550 nm operating wavelength). The second one was performed on voluminous strands of sensitive cables encapsulating the selected optical fibers, up to approximately the same accumulated dose, at two temperatures: 30°C and 80°C. A significant increase of the RIA, without any saturation tendency, appeared for fibers inserted into cables, correlated with the increase of the hydroxyl attenuation peak at 1380 nm. Molecular hydrogen generated by the radiolysis of compounds of the cable is at the origin of this phenomenon. A third gamma irradiation run permitted to measure the radiolytic hydrogen production yield of some compounds of a dedicated temperature cable sample. The efficiency of a carbon coating layer over the silica cladding, acting as a barrier against hydrogen diffusion, was also successfully confirmed. Finally, the efficiency of this carbon coating layer has also been tested under neutron irradiation, then qualified as a protection barrier against hydrogen diffusion in the optical fiber cores.

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