High level gamma and neutron irradiation of silica optical fibers in CEA OSIRIS nuclear reactor

Cheymol, G.; Long, Mark D.; Villard,; Brichard,

doi:10.1109/radecs.2007.5205466

Cited by 7 publications

(8 citation statements)

References 4 publications

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“…A SM fibre drawn by FORC ended with approximately the same attenuation while PBG fibre showed much lower loss before failing suddenly during the last reactor cycle. The detailed results can be found in [11].…”

Section: Ria In Fibres-choice Of the Wavelength Rangementioning

confidence: 99%

Fabry Perot sensor for in-pile nuclear reactor metrology

Cheymol

Aubisse

Brichard

et al. 2008

Optical Sensors 2008

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Optical fibre sensors are attractive devices that can bring substantial advantages over conventional sensing approaches for fission Material Testing Reactors (MTRs), such as high accuracy capabilities with limited intrusiveness and the ability to withstand high temperature. In the framework of the Joint Instrumentation laboratory (JIL), CEA and SCK CEN have joined their resources to develop, in particular, an OFS prototype with the aim to measure dimensional changes on nuclear materials irradiated in MTRs. We briefly present the objectives and the workplan of that project, in which the first phase addressed an analysis of the different measurement systems considered towards the specific environmental conditions encountered in a fission reactor. Among them, radiation is responsible for the biggest error source through the density change of silica glass due to neutron-induced compaction. The analysis has leaded us to focus mainly on an Extrinsic Fabry Perot design based on low coherence interferometry. We present the adapted schemes designed to avoid the consequences of the silica compaction. As part of the current development, we present the results of experiments that allow appreciating the variation with different parameters of the response, especially the modulation of the signal returned. That permits to set partially the design and brings some tolerances data. A home made signal conditioning allows to extract the cavity length and then the change in the dimension of the sample to test.

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Section: Ria In Fibres-choice Of the Wavelength Rangementioning

confidence: 99%

Fabry Perot sensor for in-pile nuclear reactor metrology

Cheymol

Aubisse

Brichard

et al. 2008

Optical Sensors 2008

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“…RIA was still increasing at the end of the experiment but at much lower rate than during the first 10 days. The detailed results can be found in [4]. It is important to consider also the spectrum profile of the RIA (see figure 1): it shows clearly a lower RIA in the preferable wavelength range between 0.8 and 1.2 µm.…”

Section: Fibre Optic and High Level Of Radiationmentioning

confidence: 99%

Fibre optic extensometer for high radiation and high temperature nuclear applications

Cheymol¹,

Villard²,

Gusarov³

et al. 2011

2011 2nd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications

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In the framework of the Joint Instrumentation Laboratory (LCI), gathering resources from SCK-CEN (Belgium) and CEA (France), we are developing an optical sensor in order to accurately measure radiation-induced elongation of material placed in the core of a Material Testing Reactor (MTR). This extensometer displays common advantages of Fibre Optic (FO) sensors: high resolution, easy remote sensing and multiplexing, and also compact size which is of particular interest for in pile experiments with little room available. In addition, light weight reduces gamma heating hence limiting the thermal effect. In accordance with the specifications, the sensor has preferably two fixing points defining a gauge length of 10 to 15 mm (as a minimum). The diameter is less than 2 mm. Intense gamma and neutron irradiation as well as high temperatures are the most difficult environment conditions to withstand. Reactor radiation produces huge losses in common optical fibre. The losses can be limited by selecting the fibres (mainly with high purity silica core), the wavelength range (800 -1200nm), and a measurement based on interferometry (largely insensitive to losses in the fibre thanks to the wavelength encoding of the useful signal). Heavy neutron -mainly-and gamma flux such as in MTR, also produce compaction of silica, resulting in a significant drift and preventing the use of commercial FO sensors in such environment. Knowing this issue we revised the basic scheme of Extrinsic Fabry Perot Interferometer (EFPI) in order to limit the effects of compaction. A first sensor prototype fixed on a stainless steel support was tested in the Smirnof test facility in the BR2 MTR in Mol (Belgium). The support was subject to a constant mechanical and thermal stress, and his dimensions were not supposed to vary. This test showed a very low drift of the revisited EPFI design under high irradiation field in comparison with a commercial EFPI. This result has to be confirmed with second generation sensors with an increased robustness. The other difficulty to face is high temperature. Fibre optics with metal coating allows safe operation under temperatures up to 400°C and even higher. But differential dilatation between silica and typical metallic material produces differential elongation in the range of 0.5 10-2 i.e 5000µε for an increase in temperature of 300-400°C. Such large elongation has to be considered carefully in the sensor design and its fixing on the sample. Laboratory tests with a second generation of adapted sensors demonstrated their

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“…Fluctuations of the source and the level of radio-luminescence have been considered. A more precise description of the experience can be found in [15].…”

Section: A Irradiation At Extreme Total Dose -Fibers and Setupmentioning

confidence: 99%

Fibre optics for metrology in nuclear research reactors applications to dimensional measurements

Cheymol

Brichard

Villard

2009

2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications

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In-situ measurement is a key issue for advanced irradiation programs in nuclear research reactors, especially in Material Testing Reactors (MTR). In that prospect, Optical Fibre Sensors (OFS) can feature unique intrinsic properties that bring substantial advantages over conventional sensing approaches. One of the objectives of the Joint Instrumentation Laboratory (JIL), gathering SCKCEN (Belgium) and CEA (France) resources and know-how, is to develop Optical Fibre Sensors (OFS) for metrology under high radiation. A preliminary condition to the development of OFS is to ensure that the Radiation Induced Absorption (RIA) of the light in the fibre does not exceed a pre-defined threshold. We report the results of a long lasting irradiation experiment, at higher dose than previously reported: up to a fast neutron fluence of 10 20 n/cm 2 and an ionising dose of 16 GGy, carried out on various fibres, including hollow core photonic band gap (PBG) fibres, singlemode (SM) and multimode (MM) fibres. If we consider that RIA measurements losses < 10 dB are acceptable for the development of OFS in harsh environments such as MTRs, it can be stated that multimode and single mode fibres exist that fulfill this criteria, as far as the most favourable spectral region, in the 800 to 1100/1200 nm wavelength range is considered. Possible applications of OFS sensors in the vicinity of research reactors core are presented. We focus then on the project of dimensional measurement, based mainly on low coherence interferometry with an Extrinsic Fabry Perot. We report some first irradiation experiments on commercial sensors, then we present the adapted schemes designed to avoid the consequences of the radiation induced silica compaction. On that basis, we have set the configuration, built some first prototypes in metallic capillaries and we have worked on the anchoring of the sensor on a sample. We present the prototypes developed and the first results of testing accuracy. The irradiation of some sensors anchored on a stainless steel plate is planed in 2009 in the BR2 reactor facility of SCKCEN in Mol/Belgium using a dedicated irradiation rig. The purpose of this experiment will be to assess, in a first step, the

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High level gamma and neutron irradiation of silica optical fibers in CEA OSIRIS nuclear reactor

Abstract: In the final objective of elaborating an optical

Cited by 7 publications

References 4 publications

Fabry Perot sensor for in-pile nuclear reactor metrology

Fabry Perot sensor for in-pile nuclear reactor metrology

Fibre optic extensometer for high radiation and high temperature nuclear applications

Fibre optics for metrology in nuclear research reactors applications to dimensional measurements

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