A.M. Zagrebayev - Dr.Sc. (Phys.-Math.), Professor, Department of Cybernetic, National Research Nuclear University MEPhI (Moscow). E-mail: AMZagrebayev@mephi.ru N.V. Ovsyannikova - Dr.Sc. (Phys.-Math.), Associate Professor, Department of Mathematical Software Systems, National Research Nuclear University MEPhI (Moscow). E-mail: NVOvsyannikova@mephi.ru R.N. Ramazanov - Post-graduate Student, Department of Cybernetic, National Research Nuclear University MEPhI (Moscow). E-mail: temy@gmx.com

© Authors, 2015 © Radiotekhnika, 2015 The safe operation of a nuclear reactor requires the constant monitoring of the reactor core state. One important task is the control of neutrons flux density. This article represents the technique for the restoration of axial neutron flux sensor lost read-ings in the core of a nuclear reactor. Earlier research has shown that the coefficients of the harmonic functions approximating the neutron flux are correlated. There exists the set of special functions, which approximate the flux with uncorrelated coefficients. Approximation is suggested to be made as an expansion to the series of functions, adjusted in a certain way. For this research the experimental data derived from operating reactors has been used. The data used in the research was derived for the period from June 9 to August 17, 2011 of 4 measuring channels of unit 1 Tianwan NPP (VVER-1000) and also got from the archive of unit 1 Smolensk NPP (RBMK-1000) for the period from March 15 to April 20, 2013. According to the present reactor operating rules, when two sensors fail, the collection of data is banned. The proposed tech-nique enables to use accumulated data from an archive to restore the neutron field even after a serious loss of measurement information. The simulation results show that by using the archive data of 100 readings, lost reading may be recovered by special functions with an accuracy of about 2.5%.

 

1. Zagrebaev A.M., Nasonova V.A., Ovsjannikova N.V.Matematicheskoe modelirovanie jadernogo reaktora pri sluchajjnykh vozmushhenijakh tekhnologicheskikh parametrov: Monografija. M.: NIJAU MIFI. 2011. 180 s.
2. Zagrebaev A.M. Vosstanovlenie aksialnogo raspredelenija polja nejjtronov pri chastichnojj potere izmeritelnojj informacii // Bezopasnost informacionnykh tekhnologijj. 2005. № 1. S. 43-46.
3. Kostanbaev S.V. Raschetno-izmeritelnyjj kompleks kontrolja raskhoda teplonositelja v kanale reaktora RBMK po informacii o navedennojj aktivnosti: Diss. - kand. tekhn. nauk (05.14.03 - jadernye ehnergeticheskie ustanovki, vkljuchaja proektirovanie, ehkspluataciju i vyvod iz ehkspluatacii). M.: NIJAU MIFI. 2010. 150 s.
4. Pugachev V.S. Teorija sluchajjnykh funkcijj i ee primenenie k zadacham avtomaticheskogo upravlenija. M.: Fizmatgiz. 1960. 883 s.