A technique for detection of fuel failures by the activity of XE radionuclides during WWER reactor operation
Fuel failures during operation of Nuclear Power Plants (NPPs) may lead to substantial economic losses. Negative effects of reactor operation with leaking fuel in the core may be reduced if fuel failures are detected in timely manner.
Currently, the value of the ratio of normalized release rates for 131I and 134I is used for detecting fuel failures during steady state operation of WWER reactors. However, unequivocally establishing fuel failure based on the activity of iodine radionuclides is not possible in all possible cases. Such situation may occur in the case of small defects of fuel cladding of the leaking fuel rod or under high fuel burnup if the defect is overlapped by the surface of the fuel pellet. If such case fuel holdups can make the dominant contribution in iodine radionuclide activity, and the fuel cladding failure may be indistinguishable against the background activity level.
The technique for detection of fuel failures at WWER reactors by activity of radioactive noble gases in the primary coolant is suggested in the present paper. It is shown that radioactive noble gases may serve as the indicator of fuel failures more sensitive than the activity of reference iodine radionuclides. The suggested criterion for detection of fuel failures is based on monitoring the ratio between 133Xe and 135Xe activities. Some examples of practical applications of the developed methodology are given.
- Shumkova N. Yu., Bykov O.V., Belousova L.P. Ukrainian WWER-type NPP units. Results of cladding tightness inspection. IAEA-TECDOC-1345, 2003, pp. 77-86.
- Burman D.L. Development of a coolant activity evaluation model & related application experience. Proc. Int. Top. Mtg «LWR Fuel Performance».Paris, 1991, v. 1, p. 363.
- Beyer C.E. An analytical model for estimating the number and size of defected fuel rods in an operating reactor. Proc. Int. Top. Mtg «LWR Fuel Performance». Paris, 1991, v. 2, p. 437.
- Parrat D., Genin G.B., Musante Y., Petit C., Harrer J. Failed rod diagnosis and primary circuit contamination level determination, thanks to the DIADEME code. IAEATECDOC1345, 2003, pp. 265-276.
- El-Jaby A., Lewis B.J., Thompson W.T., Iglesias F. and Ip M. A General Model for Predicting Coolant Activity Behaviour for Fuel-failure Monitoring Analysis. J. Nucl. Mater., 2010, v. 399, pp. 87-100.
- Likhanski V., Evdokimov I., Khoruzhii O., Sorokin A., Novikov V. 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.
- Oliver Lena, Svensson Peter, Bishop Kendal, Westinghouse O.P. Fission product analysis using the FPA code. Proc. Int. Westhinghouse Electric Sweden AB, 2017, pp. 2-3.
- Slavyagin P., Lusanova L., Miglo V. Fuel failure diagnostics in normal operation of nuclear power plants with WWER-type reactors. IAEATECDOC1345, 2003, pp. 303-315.
- RD JeO 126.96.36.199.0521-2009 «Sborki teplovydeljajushhie jadernyh reaktorov tipa VVJeR-1000. Tipovaja metodika kontrolya germetichnosti obolochek teplovydelyayushhih elementov» s Izm. №2. Moscow. AO «Koncern Rosjenergoatom» Publ., 2016, pp. 28-34 (in Russian).
- Review of fuel failures in water cooled reactors in 2006-2015. The IAEA nuclear energy series, 2018, pp. 43-45.
- 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. IAEATECDOC1345, 2003, pp. 326-337.
- Wise C. The transport of short-lived fission products close to the fuel surface. J. Nucl. Mater. 1988, v. 152, pp. 102-113.
- White R.J. The fractal nature of the surface of uranium dioxide: a resolution of short-lived/stable 1. gas release dichotomy. J. Nucl. Mater. 2001, v. 295, pp. 133-148.
- Olander D.R. Fundamental aspects of nuclear reactor fuel elements. Berkeley. Department of nuclear engineering University of California, 1976, 624 p.
- Wise C. Recoil release of fission products from nuclear fuel. J. Nucl. Mater. 1985, v. 136, pp. 30-47.
- Turnbull J.A. and Friskney C.A. The diffusion coefficients of gaseous and volatile species during the irradiation of uranium dioxide. J. Nucl. Mater. 1982, v. 107, pp. 168-184.
- Rossiter G., White R. The Fission Gas Diffusion Coefficient in Irradiated Oxide Fuel: An Analysis of Current Experimental Data. Proc. Enlarged Halden Programme Group Meeting, Storefjell, 2002.
- Tasaka Kanj, Katakura Junichi, Ihara Hitosh, Yoshida Tadashi, Iijima Shungo, Nakashima Ryuzo, Nakagawa Tsuneo, Takano Hideki JNDC nuclear data library of fission products; version 2. JAERI. 1990, no. 1320, pp. 92-96.