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Temperature of Water-cooled Reactor


Methodological Security of Temperature Measurement and Diagnostics within Power Water-moderated Water-cooled Reactor (PWR) Type on Base of Analysis of Influence Functions for Measuring Means.

Tech Area / Field

  • FIR-INS/Nuclear Instrumentation/Fission Reactors

3 Approved without Funding

Registration date

Leading Institute
NPO Lutch, Russia, Moscow reg., Podolsk

Supporting institutes

  • FEI (IPPE), Russia, Kaluga reg., Obninsk\nOKB Gidropress, Russia, Moscow reg., Podolsk\nMIFI, Russia, Moscow


  • Imatran Voima (IVO), Finland, Helsinki\nSCK-CEN, Belgium, Mol

Project summary

In connection with growing attention to the nuclear power plant's safety, International Atomic energy Agency (IAEA) have specified a complex of non-trivial tasks for in-pile thermometry of PWR fuel elements in works dedicated to the atomic power station's safety. A key problem here lies in authenticity of estimating the thermocouple-based thermometry errors, which can tens times exceed permissible levels. Methods and means of the classical metrology for the in-pile thermometry do not guarantee a required accuracy of these estimates because of inadequate considering the affecting factors, the basic of which is nuclear radiation and unknown magnitude contact heat resistance between a sensor and an object under thermometry. On this reason, the in-pile thermometry is, in its essence, "blind" in viewing the temperature error of any dangerous level. It is required urgent and radical updating the metrologica! security of in-pile temperature measurements.

A base to meet the above task, is built at RI SIA "Lutch", where problems of temperature measurements within high flux (~ 3ґ1015nґcm-2ґs-1) reactors for nuclear-powered jet engines, provoked conducting a close-type unity of thorough metrological studies, development new procedures and means for their actualization, including in-pile tests of lightguides, and building a pyrometer based on fiber optics. Perfecting and improving the available procedures, technical means, creation of novelty before building the "state-of-art" metrology for the in-pile thermometry, constitute the suggested project contents.

The project objective: improvement of temperature-related safety of atomic piles.

The technical approach is based on calculational/experimental methods for estimates of instrument-induced and procedure-induced errors in measuring temperature of fuel, coolant, fuel element's cladding, with the aid of thermocouples in reactor different operation modes.The procedure-induced errors estimation is based on delta-pulse thermal sounding of thermocouples with registration of transient pulse characteristics and processing them using dedicated algorithms. This ensures adequate accounting of factors affecting the operating signal and, respectively, the highest accuracy for the errors estimate.

The instrument-induced errors are described through a calculational non-linear model, built on the base of experimental data and taking into consideration the influence of slow, fast neutrons and temperature under irradiation

Expected results

- a unity of models and procedures for more accurate estimate of instrumental/procedural errors in the in-pile thermometry;
- active prototype of the recorder for transient parameters and related documentation pack;
- multi-channel fast-response pyrometer (with) related documentation pack), equipped with irradiation-resistant lightguides.

An available information promises hopes for agreement to participate in the project from the side of Dr. Harry Tyomisto (IVO INTERNATIONAL LTD, Rajatorpantie 8, Vantaa 01 019 IVO, Finland), as well as employees of "Analysis and Measurement Services Corporation" - Mr. H.M.Hashemian and Mr. K.M.Knoxville, Tennassee 37923-4599 (615) 691-1756 - within the scope of information/instrumentation-related assistance and infusion of results into practice.


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