O. V. Mykhailov
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, 36a, Kirova St., Chornobyl, 07270, Ukraine
https://orcid.org/0000-0002-9344-3550
M. I. Pavliuchenko
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, 36a, Kirova St., Chornobyl, 07270, Ukraine
https://orcid.org/0000-0003-1291-1154
А. О. Doroshenko
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, 36a, Kirova St., Chornobyl, 07270, Ukraine
https://orcid.org/0000-0001-6285-2610
DOI: doi.org/10.31717/2311-8253.26.2.6
Abstract
The paper presents the results of systematization and analysis of measurements of relative humidity (RH) and neutron flux density (NFD) in the premises of New Safe Confinement (NSC) and Shelter Object (SO) complex in the period from September 2022 to December 2025. After the NSC arch was installed in its design position (November 2016), in accordance with the Fuel-Containing Materials (FCM) Monitoring Program (2018), studies of dynamics of temperature, RH, speed and direction of airflows in the SO premises are being carried out. The main goal of such studies is to obtain information about microclimate changes in the NSC space and to assess its impact on nuclear and radiation state of the FCM, to develop and to implement corrective measures for ventilation systems operation. This work is aimed to search and mathematically substantiate the presence or absence of relation between RH and NFD in the SO premises, where FCM clusters are located, according to the monitoring data of 2022−2025. The RH measurements in the SO premises were carried out using autonomous weather stations of PCE FWS type and loggers of RC‑4HC type. The NFD values in RH in the SO premises were obtained using the measurement of channels of Nuclear Safety Monitoring System and Expert Research System. It was established that the average monthly RH values in the SO premises, which are located within the building elevations of 0.00−9.00, in axes 44−48, rows K–L, have synchronous seasonal fluctuations and very significant Pearson linear correlation coefficient (r > 0.9). It is shown that RH decrease is accompanied by increase in NFD in the controlled premises and vice versa. According to the results of cross-correlation analysis, it was found that in that place may occur a moderate to high degree of correlation between the time series of average monthly values of
RH and NFD, provided that their calendar is shifted by a time lag of three weeks to two calendar months.
Keywords: Shelter Object, fuel-containing materials, relative air humidity, neutron flux density, correlation coefficient, time lag.
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