Long term remote reactor power and fuel composition monitoring using antineutrinos
Antineutrino detection was carried out at a distance of 11–13 meters from the reactor core using a compact (1 m³ of active volume) segmented polystyrene scintillator detector. In their work, the authors demonstrated that antineutrino data can be used to continuously monitor changes in the thermal power of a VVER-1000 reactor with an accuracy of 1.0% over a weekly measurement interval across several fuel campaigns. Based on changes in the energy spectrum of the antineutrino signal, an independent method successfully extracted information about temporal changes in the ratio of fissile uranium and plutonium isotopes. This revealed a decrease in the contribution of ²³⁵U and an increase in the proportion of ²³⁹Pu over the course of a one-and-a-half-year fuel campaign. This result correlates well (differing by no more than three percent) with another measurement result obtained using the standard methodology currently employed in the nuclear industry. The obtained data confirm the ability of compact antineutrino detectors not only to monitor the power of a nuclear reactor but also to track changes in the fuel composition without the need for direct access to the core. The methodology described in the publication can be used for tasks of remote reactor diagnostics and nuclear safety assurance. The DANSS measuring setup has proven to be a reliable tool capable of stable and precise operation under the conditions of an operational NPP for a long period.
The shares of ²³⁵U and ²³⁹Pu in the reactor fuel fission reactions, extracted from the measured antineutrino spectra (colored points), compared with the data from the standard methodology provided by the NPP staff (lines). Information for three fuel campaigns of the 4th power unit of the Kalinin NPP is presented: 6, 7, 8 (a, b, c). The calculations used two models of reactor antineutrino spectra: the Kurchatov Institute (KI) model and the Huber-Mueller (HM) model.
Work is currently underway on a deep modernization of the setup. The next version of the detector, DANSS-2, with an increased volume and significantly improved energy resolution, is being developed.
The author list includes staff members from the JINR Laboratory of Nuclear Problems:
V. Belov, A. Bystryakov, I. Zhitnikov, D. Zinatulina, S. Kazartsev, A. Kuznetsov, D. Medvedev, D. Ponomarev, I. Rozova, N. Rumyantseva, A. Salamatin, D. Filosofov, M. Fomina, E. Shevchik, M. Shirchenko, E. Yakushev.
The article is available at the link: Long term remote reactor power and fuel composition monitoring using antineutrinos - ScienceDirect
