Low drift type N thermocouples for nuclear applications

Scervini, M.; Rae, C.M.F.

doi:10.1109/animma.2013.6727899

Cited by 5 publications

(9 citation statements)

References 6 publications

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“…2 [17]: the total drift for the new thermocouple is +38 μV (about +1°C) after 300 h, whilst for Inconel 600 sheathed type N thermocouple the drift is -307 μV (about -8.5°C). to run trials on them as part of an out-of-pile test to be undertaken in 2014 at INL in comparison with other commercial and customized thermocouples [14].…”

Section: Low Drift Cambridge Type N Thermocouplesmentioning

confidence: 99%

“…The use of the Cambridge sheath allows to mitigate the contamination of the type N negative thermoelement, which is known to give the most significant contribution to the total drift between the two thermoelements [17].…”

Section: B Eds Analyses: the Thermoelementsmentioning

confidence: 99%

“…In [17] Mn was also detected, using Wavelength Dispersive X-Ray Spectrometry (WDS), as a contaminant in the thermoelements when the sheath was made of Inconel 600. WDS allows to resolve the K-α x-ray energies of Mn and Cr, whilst with EDS analysis this may not be possible, particularly when the Cr content is high, i.e.…”

Section: B Eds Analyses: the Thermoelementsmentioning

confidence: 99%

“…During the long term out-of-pile test undertaken at INL in 2014 [14] type N thermocouples using a customized sheath developed at the University of Cambridge [17], herein called Cambridge type N thermocouples, were tested along several other commercial and customized type N thermocouples.…”

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confidence: 99%

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Low drift type N thermocouples in out-of-pile advanced gas reactor mock-up test: Metallurgical analysis

Scervini

Palmer

Haggard

et al. 2015

2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and Their Applications (ANIMMA

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Thermocouples are the most commonly used sensors for temperature measurement in nuclear reactors. They are crucial for the control of current nuclear reactors and for the development of GEN IV reactors. In nuclear applications thermocouples are strongly affected by intense neutron fluxes. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time dependent change in composition and, as a consequence, a time dependent drift of the thermocouple signal. Thermocouple drift can be very significant for in-pile temperature measurements and may render the temperature sensors unreliable after exposure to nuclear radiation for relatively short times compared to the life required for temperature sensors in nuclear applications. Previous experiences with type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly type N thermocouples are expected to be only slightly affected by neutron fluxes. Currently the use of Nickel based thermocouples is limited to temperatures lower than 1000°C due to drift related to phenomena other than nuclear irradiation. As part of a collaboration between Idaho National Laboratory (INL) and the University of Cambridge a variety of Type N thermocouples have been exposed at INL in an Advanced Gas Reactor mock-up test at 1150°C for 2000 h, 1200°C for 2000 h, 1250°C for 200 h and 1300°C for 200 h, and later analysed metallurgically at the University of Cambridge.The use of electron microscopy allows to identify the metallurgical changes occurring in the thermocouples during high temperature exposure and correlate the time dependent thermocouple drift with the microscopic changes experienced by the thermoelements of different thermocouple designs.In this paper conventional Inconel 600 sheathed type N thermocouples and a type N using a customized sheath developed at the University of Cambridge have been investigated. The rationale for the superior performance of the type N using a customized sheath developed at the University of Cambridge is explained in comparison with the behavior of conventional type N Inconel600 sheathed thermocouples. I. THERMOCOUPLES FOR NUCLEAR APPLICATIONSHERMOCOUPLES at high temperatures experience drift, a time dependent departure of the thermocouple signal from the real temperature of the environment. Thermocouple drift introduces a time dependent error in the temperature reading of the sensor.Metallurgical modifications occurring along the length of the thermocouple are responsible for drift. In nuclear applications thermocouples experience not only high temperatures, responsible for temperature activated microstructural or compositional changes, but also neutron irradiation, which produces:Atomic displacements generate dislocation loops and voids into the irradiated materials.With sustained irradiation the dislocation loops density increases. Macroscopically the effects are equivalent to cold work: increased hardening, reduced te...

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Section: Low Drift Cambridge Type N Thermocouplesmentioning

confidence: 99%

Section: B Eds Analyses: the Thermoelementsmentioning

confidence: 99%

Section: B Eds Analyses: the Thermoelementsmentioning

confidence: 99%

mentioning

confidence: 99%

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Low drift type N thermocouples in out-of-pile advanced gas reactor mock-up test: Metallurgical analysis

Scervini

Palmer

Haggard

et al. 2015

2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and Their Applications (ANIMMA

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“…Increasing dislocation loops densities means changing the mechanical properties of the metallic alloys: increased hardening, reduced tenacity, increased brittleness and brittle-ductile transition temperature, reduced ductility and creep failure times [111]. The resulting additional drift of the thermocouples has to be taken in consideration for fast neutrons reactors.…”

Section: Reducing the Drift Of N Type Thermocouples With The Cambridgmentioning

confidence: 99%

Nuclear instrumentation and measurement: a review based on the ANIMMA conferences

Giot

Vermeeren

Lyoussi

et al. 2017

EPJ Nuclear Sci. Technol.

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Abstract. The ANIMMA conferences offer a unique opportunity to discover research carried out in all fields of nuclear measurements and instrumentation with applications extending from fundamental physics to fission and fusion reactors, medical imaging, environmental protection and homeland security. After four successful editions of the Conference, it was decided to prepare a review based to a large extent but not exclusively on the papers presented during the first four editions of the conference. This review is organized according to the measurement methodologies: neutronic, photonic, thermal, acoustic and optical measurements, as well as medical imaging and specific challenges linked to data acquisition and electronic hardening. The paper describes the main challenges justifying research in these different areas, and summarizes the recent progress reported. It offers researchers and engineers a way to quickly and efficiently access knowledge in highly specialized areas.

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Performance of Custom-Made Very High Temperature Thermocouples in the Advanced Gas Reactor Experiment AGR-5/6/7 during Irradiation in the Advanced Test Reactor

et al. 2020

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The Advanced Gas Reactor-5/6/7 (AGR-5/6/7) experiment is the fourth and final experiment in the AGR experiment series and will serve as the formal fuel qualification test for the TRISO fuels under development by the U.S. Department of Energy. Certain locations in this experiment reach temperatures higher than any of the previous AGR tests, up to 1500°C. Such extreme temperatures create unique challenges for thermocouple-based temperature measurements. High-temperature platinum-rhodium thermocouples (Types S, R, and B)and tungsten-rhenium thermocouples (Type C) suffer rapiddecalibration due to transmutation of the thermoelements fromneutron absorption. For lower temperature applications, previousexperience with Type K thermocouples in nuclear reactors haveshown that they are affected by neutron irradiation only to alimited extent. Similarly, Type N thermocouples, which are morestable than Type K at high temperatures, are only slightly affectedby neutron fluence. Until recently, the use of these nickel-basedthermocouples was limited when the temperature exceeds 1050°Cdue to drift related to phenomena other than nuclear irradiation.Recognizing the limitations of existing thermometery to measuresuch high temperatures, the sponsor of the AGR-5/6/7 experimentsupported a development and testing program for thermocouplescapable of low drift operation at temperatures above 1100°C. High Temperature Irradiation Resistant Thermocouples (HTIR-TCs)based on molybdenum/niobium thermoelements have been underdevelopment at Idaho National Laboratory (INL) since circa 2004. A step change in accuracy and long-term stability of thisthermocouple type has been achieved as part of the AGR-5/6/7thermometry development program. Additionally, long-termtesting (9000+ hrs) at 1250°C of the Type N thermocouplesutilizing a customized sheath developed at the University ofCambridge has been completed with low drift results. Both theimproved HTIR and the Cambridge Type N thermocouple typeshave been incorporated into the AGR-5/6/7 test, which beganirradiation in February 2018 in INL’s Advanced

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Low drift type N thermocouples for nuclear applications

Cited by 5 publications

References 6 publications

Low drift type N thermocouples in out-of-pile advanced gas reactor mock-up test: Metallurgical analysis

Low drift type N thermocouples in out-of-pile advanced gas reactor mock-up test: Metallurgical analysis

Nuclear instrumentation and measurement: a review based on the ANIMMA conferences

Performance of Custom-Made Very High Temperature Thermocouples in the Advanced Gas Reactor Experiment AGR-5/6/7 during Irradiation in the Advanced Test Reactor

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