Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Increasing the Efficiency of the Fuel Cladding Failure Detection System with Respect to Gas in Liquid-Metal Fast Breeder Reactors

9/23/2022 2022 - #03 Global safety, reliability and diagnostics of nuclear power installations

Kudryaev A.A. Lukyanov D.A. Guryev S.A. Steporzhinskaya M.I.

DOI: https://doi.org/10.26583/npe.2022.3.08

UDC: 621.039.564.5

The article discusses technical means, methods and algorithms of modern gas systems for detecting fuel cladding failures in liquid-metal fast breeder reactors (LMFBRs). These systems provide fuel cladding failure detection from the initial stage (gas leakage) to the further stages of defect development accompanied by the release of gaseous nuclear fuel fission fragments from the fuel cladding.

A typical gas system includes a loop through which the reactor cover gas circulates. The loop is equipped with units for measuring the total gas volumetric activity and spectrometric units for measuring the volumetric gamma-activity of reference noble gases. Modern gamma-spectrometers actually provide high measurement accuracy, but the exposure time is about 1 hour. Thus, the control of warning and emergency settings during the fuel cladding failure detection is provided by specialized detection blocks that work more quickly.

The developed gas-monitoring unit is based on an ionization chamber. It works in continuous mode and provides measurement of the total volumetric beta activity of the gaseous medium from 1.0⋅102 to 1.0⋅108 MBq/m3 for the entire range of expected energies of detected beta particles. It is shown that the specialized gas-monitoring unit is highly efficient for measuring the total volumetric activity of radioactive noble gases in the LMFBRs. According to the results of a comprehensive analysis of volumetric measurements of beta and gamma activity, the proposed methods and algorithms make it possible:

– to detect gas depressurization of fuel elements at an early stage of its occurrence;

– to evaluate (based on the results of remote measurements) the total volumetric activity of noble radionuclides in the reactor; and

– to determine the sensitivity of ionization chambers to beta particles.

The considered detection unit, methods and algorithms for increasing the efficiency of the gas systems for detecting fuel cladding failures are designed for use in power units and fast neutron research reactors of the BN, MBIR and BREST types.

References

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LMFBR fuel cladding failure detection systems measurement of volumetric activity of inert gases

Link for citing the article: Kudryaev A.A., Lukyanov D.A., Guryev S.A., Steporzhinskaya M.I. Increasing the Efficiency of the Fuel Cladding Failure Detection System with Respect to Gas in Liquid-Metal Fast Breeder Reactors. Izvestiya vuzov. Yadernaya Energetika. 2022, no. 3, pp. 84-94; DOI: https://doi.org/10.26583/npe.2022.3.08 (in Russian).

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