Distribution of tritium and its compounds in the environment under normal conditions of operating of Kalininskaya nuclear power plant

Tritium is one of the most important dose-forming radionuclides that determine the radiation situation in the area where nuclear fuel cycle enterprises are located. At the same time, it is not possible to catch the tritium formed during the operation of a nuclear power plant using modern, efficient and cheap technologies. This causes an increase in its concentration in environmental objects and an increase in the contribution of technogenic tritium to the radiation load of the population. Therefore, the task of monitoring the formation of tritium during the operation of nuclear power plants, the content of tritium in emissions and discharges of nuclear power plants, as well as the distribution of this radionuclide in the environment is especially urgent today. The study aims to analyze the environmental pollution due to emissions and discharges of tritium from the Kalininskaya nuclear power plant, the process of spreading tritium by air, as well as the accumulation of this radionuclide in water bodies, soil and food products grown in the area of the nuclear power plant. The following methods, developed by the specialists of the Burnasyan Federal Medical Biophysical Center were used during the research: 1) "Method for determining the volumetric activity of organic and inorganic tritium compounds in water bodies by liquid scintillation spectrometry". 2) "Methodology for determining the concentration of organic and inorganic tritium compounds in the air of the environment and industrial premises". 3) "The method for determining the specific activity of tritium compounds in soil and vegetation" was developed and tested in the course of field studies at the Kalinin NPP. As a sample preparation we used the method based on burning a selected sample in a specialized Pyrolyser-6 Trio oven. All prepared counting samples were measured by liquid scintillation spectrometry on a counter Tri-Carb 3180TR/SL. On the basis of an integrated approach to assessing the content of tritium and its compounds in air, water, soil and food, an analysis of the formation of environmental pollution due to emissions and discharges of tritium from the Kalinin NPP was carried out. It is shown that the transport of emissions from the NPP by air and the wind direction prevailing in the territory of the NPP location have a significant importance in the formation of the contribution to the ingress of tritium into foodstuffs. The necessity of taking into account the ingress of tritium and its compounds with nuclear plant emissions into the environment in the task of optimization of radiation protection of the population under conditions of normal operation of NPP is shown.

Radiation resistance of organic compounds for LRW solidification

Experiments were carried out to determine the radiation resistance of a bitumen compound produced based on genuine cubic residue from the Kalinin NPP using bitumen grades BND 60/90 and BND 90/130, polymer compounds based on spent ion exchange resins and spent inorganic sorbents. It was found that at an irradiation dose of 1·106 Gy, the volume of the bitumen compound increases to no more than 10 vol. %, which complies with the NP-019-15 requirements. The polymer compound based on spent ion-exchange resins from the testing of a pilot plant for resin conditioning directly in a disposal container by dewatering and impregnation with an epoxy binder, meets the

Investigation of the impact of steady-state VVER-1000 (1200) core characteristics on the reactor stability with respect to xenon oscillations

The article presents a method for obtaining an analytical expression for the criterion of stability of a VVER-1000 (1200) reactor with respect to xenon oscillations of the local power in the core, containing an explicit dependence of the criterion ratio coefficients on the arbitrary axial neutron field distribution in steady states of the core. Based on the data of numerical experiments using a full-scale model of the Kalinin NPP power units, the authors present the results of checking the validity of this expression for the reactor stability criterion with respect to xenon oscillations for different NPPs with VVER-1000 (1200) reactors.

Microelements speciations in bottom sediments of Udomlya and Pes’vo lakes

Microelements in bottom sediments may enter different compounds; however, of greatest interest are their mobile forms as the most bioavailable. The microelements speciation in the pore water and solid phase of bottom sediments were studied in the cooling reservoir of the Kalinin NPP (lakes Udomlya and Pesvo).

RADIATION-HYGIENIC ASPECTS OF REPRODUCTIVE HEALTH IN MALES OF THE STAFF OF THE NUCLEAR POWER PLANT

The aim of this study was a retrospective evaluation of the reproductive health of the male staff of the Kalinin and Kursk nuclear power plant (NPP). Material and Methods. Fertility indices were used for the evaluation of the reproductive health status (ability to have children) and the health status of their offspring. For the assessment of the fertility there were used data concerning the marital status, childbirths and radiation doses received by males, obtained from the questionnaires, developed as part of this study. The data about the health of newborns was obtained from information copied from the individual cards of pregnant history cases and infant history case. In total, in the study there was analyzed data on the marital status of 679 men from Kalinin and 631 men from Kursk NPP, as well as data on the 735 and 813 newborn in the families of staff of the Kalinin and Kursk NPP, and data on 1438 and 1284 pregnant women respectively. As control groups there were used data about health of newborns and pregnant women of cities of Udomlya and Kurchatov. The combined groups included 1549 newborns and of 2718 pregnant women. Results. Infertile marriages due to the male infertility accounted for 7.3% of the Kalinin NPP personnel, and 2.5% -of Kursk NPP personnel. The incidence and complication rates of the pregnancy in families of Kalinin and Kursk NPP staff are comparable with those in the control group of pregnant women and were 75.7%, 61.6% and 71.0%, respectively. Adverse pregnancy outcomes (spontaneous abortions and early neonatal death of the newborn) were recorded in 6.9%, 0.1% in the families of the personnel of the Kalinin NPP and 8.9%, 0.2% in the families of the personnel Kursk of the NPP complying with the control values of 7.6% 0.2%, respectively. The frequency of the birth of the health child corresponds to control values as 73.6% of the families of the personnel of the Kalinin NPP, amounting to 65.3% in the families of the personnel of the Kursk NPP and 69.7% in the control group. The relative risk of birth of a child with congenital malformations RR = 0,84 in the families of staff at Kalinin NPP and RR = 1.0 - at Kursk NPP. Conclusion. No impact of occupational exposure on the reproductive health was revealed for the male staff both at Kalinin and Kursk NPP.

Hidden Anomalies Detection in Large Arrays of Nuclear Power Plant Operating Data

In this paper, it is investigated nuclear power plant operating data which was obtained from reactor main coolant pumps (MCP) of the third isolated generating plant of Kalinin NPP. It is necessary permanent monitoring for state of all pump components since breakdown of a reactor coolant pump leads to substantial economic losses. It is installed over 50 sensors of different control systems at the every MCP. Received data is stored but it is not analysed for the purpose of discovering joint dependencies between equipment pieces and unobvious, hidden trends of accident propagation. In this work, it was proposed techniques for detection of hidden anomalies and MCP operating regularity based on factor analysis, clustering and linear regression models. It was written a Python script which automates necessary calculations.