Authors & Affiliations

Sobolev A.V.
Obninsk Institute for Nuclear Power Engineering, National research Nuclear University “MEPhI”, Obninsk, Russia

Sobolev A.V. – Senior Lecturer, Department of Nuclear Physics and Technology, Obninsk Institute for Nuclear Power Engineering, National research Nuclear University “MEPhI”. Contacts: 1, Studgorodok, Obninsk, Kaluga region, Russia, 249030. Tel.: +7(910) 709-13-99; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

Abstract

The paper presents the results of estimating the distribution parameters of accidental streams of accidents at NPPs in Russia, based on the operational experience data for 2013–2014. Weibull-Gnedenko distribution is used as the law of random time distribution between incidents. The latter is also known as the distribution of extreme parameters, i.e. distribution of a random flow of events among the reasons for which there are dominant.
Simple engineering relations are given that allow us to calculate the estimates of the Weibull distribution parameters from statistical parameters calculated from the analysis of the Russian NPPs operating experience. In particular, these relations can be considered as a method for obtaining estimates of the Weibull distribution parameters from the results of statistical data quantitative analysis.
Since the author took part in the work on obtaining estimates of the accidental streams distribution parameters of incidents on the power units of Russia's NPPs from the experience of exploitation from 1995 to 2007, the question is raised about the relevance of the estimates obtained 10 years ago. The prerequisites for changing the parameters of incidents accidental streams at the power units in Russia and the prerequisites to the absence of their changes are considered. Analysis of the change dynamics in incidents accidental streams on the power units of nuclear power plants in Russia will allow, roughly, to assess the relevance of the earlier work results on obtaining quantitative estimates of equipment reliability indicators and nuclear power plants personnel. An important issue in the presence of a change is the definition of these changes trend.
A comparative analysis of the estimates obtained from the operational experience data for 2013–2014 is made with estimates based on operational experience from 1995 to 2007. Comparative analysis showed a weak tendency to shift the estimates of the random flows parameters of accidents at nuclear power plants in Russia from a region with a youthful intensity, into a region with constant intensity (the stage of normal operation).
In general, the results of the comparative analysis have shown the relevance for today of data with the distribution parameters estimates of accidental flows of accidents at power units of Russian NPPs, obtained from the experience of exploitation for 1995–2007.

Keywords
random flow of accidents, NPP powerunit, Weibull distribution, operating experience, statistical value

Article Text (PDF, in Russian)

References

UDC 621.039.58

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2017, issue 4, 4:6