Izvestiya vuzov. Yadernaya Energetika

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

Development of a criterion to record the facts of fuel carryover from leaking fuel elements during VVER reactor operation

9/16/2020 2020 - #03 Nuclear power plants

Evdokimov I.A. Khromov A.G. Kalinichev P.M. Likhanskij V.V. Kovalishin A.A. Laletin M.N.

DOI: https://doi.org/10.26583/npe.2020.3.05

UDC: 621.039.548

Operation of nuclear fuel at an NPP involves the potential of a fuel cladding failure. One of the possible and gravest consequences of a fuel failure is the fuel composition being washed out from the leaking fuel element and entering the coolant.

Reliable detection of the fuel carryover in the course of the fuel life is important for the further handling of the failed fuel assembly. The fuel carryover can be detected as part of the fuel cladding integrity inspection during the reactor operation. For this purpose, activity of 134I is traditionally used in VVER reactors. In practice, however, the activity of 134I is capable to increase in the course of the fuel lifetime even in the event when there are no fuel failure and the only source of the fission product escape are fuel deposits in the core.

A criterion has been proposed which makes it possible to distinguish cases when the growth in the activity of short-lived radionuclides is the result of the fission product escape from fuel deposits or the fuel composition carryover from the failed fuel elements during VVER reactor operation. Examples are provided of the developed criterion practical application at effective NPPs.

The reported study was funded by RFBR, Project No. 20-38-90081.

References

  1. Ingemansson T., Rudling P., Lundgren K. Assessment Of Fuel Washout In LWRs – New Methodologies. Proc. Int. Meet. on LWR Fuel Performance, Orlando, Florida, September 19’22. 2004, paper 1002.
  2. RD EO 1.1.2.10.0521-2009 Fuel Assemblies of VVER’1000 Nuclear Reactors. Typical Cladding Failure Control Methods (as amended №2). Moscow. Kontsern Rosenergoatom Publ., 2016, pp. 61-63 (in Russian).
  3. Shestakov Yu. M., Semenovykh A.S.Problems and Perspectives of Moving Toward Zero Fuel Failures and Mitigation of Fuel Failure Consequences at NPPs with VVER Reactors in Russia. The XIth Int. Conf. «WWER Fuel Performance, Modeling and Experimental Support». Bulgaria, Varna, September 26 – October 03, 2015.
  4. Povarov V.P., Tereshchenko A.B., Kravchenko Yu.N., Pozychanyuk I.V., Gorobtsov L.I., Golubev Ye.I., Bykov V.I., Likhansky V.V., Yevdokimov I.A., Zborovsky V.G., Sorokin A.A. Development and application of modern methods to inspect the integrity and assess the state of fuel at Novovoronezh NPP. Teploenergetika. 2014, no.2, pp. 54-64 (in Russian).
  5. Alvarez L., Daniels T. et al. Review of fuel failures in water cooled reactors. IAEA Nuclear Energy Series No.NF’T’2.1. IAEA, Vienna, 2010, p. 157.
  6. Parrat D., Genin G.B., Musante Y, Petit C., Harrer M. Failed rod diagnosis and primary circuit contamination level determination, thanks to the DIADEME code. IAEA’TECDOC’1345, 2003, pp. 265-276.
  7. El-Jaby A., Lewis J. et al. A General Model for Predicting Coolant Activity Behaviour for Fuel-failure Monitoring Analysis. J. Nucl. Mater., 2010, v. 399, pp. 87-100.
  8. Likhanskii V., Evdokimov I. et al. Modelling of Fission Product Release from Defective Fuel under WWER Operation Conditions and in Leakage Tests During Refuelling. Proc. Int. Top. Mtg LWR Fuel Performance, Florida, 2004., pp.798-812.
  9. Oliver Lena, Svensson Peter et al. Fission Product Analysis using the FPA Code. Proc. Int. Westhinghouse Electric Sweden AB. 2017, pp. 2-3.
  10. Slavyagin P., Lusanova L., Miglo V. Fuel Failure Diagnostics in Normal Operation of Nuclear Power Plants with WWER-type Reactors. IAEA’TECDOC’1345, 2003, pp. 303-315.
  11. Lewis B.J., Chan P.K., El-Jaby A., Iglesias F.C., Fitchett A. Fission Product Release Modeling for Application of Fuel-failure Monitoring and Detection – An Overview. Journal of Nuclear Materials. 2017, v. 489, pp. 64-83.
  12. Galanin A.D. Introduction to the Theory of Thermal’Neutron Reactors. Moscow. Energoatomizdat Publ., 1989, pp. 209-217 (in Russian).
  13. Slavyagin P., Lusanova L., Miglo V. Regulation of the Fission Product Activity in the Primary Coolant and Assessment of Defective Fuel Rod Characteristics in Steady State WWER-type Reactor Operation. IAEA’TECDOC’1345, 2003, pp. 326-337.
  14. Kalinichev P.M., Evdokimov I.A., Likhanskii V.V. Methodology for Identifying Fuel Failures by the Activity of Xe Radionuclides During VVER Reactor Operation. Izvestiya vuzov. Yadernaya Energetika. 2018, no.2, pp. 10-113; DOI: 10.26583/npe.2018.2.10 (in Russian).
  15. Nikitin O.N. Regularities in changes of the microstructure and the xenon distribution in UO2 with a high burn’up in the VVER reactor conditions. Cand. Sci. (Phys.-Math.) Diss. Dimitrovgrad. OAO «GNC NIAR» Publ., 2010 (in Russian).
  16. Kryukov F.N. Electron’probe X’ray spectral microanalysis of fuel compositions and fuel claddings in nuclear reactors. Dr. Sci. (Phys.-Math.) Diss. Dimitrovgrad. OAO «GNC NIAR» Publ., 2006 (in Russian).

VVER fuel element fuel failure fission products methodology coolant activity iodine radionuclides fuel carryover