Further development and application of a method for assessing radionuclide surface activity distribution and source location based on measurements of ambient dose equivalent rate. Examples for Andreeva Bay, Chernobyl NPP and Istiklol.

A method for reconstructing surface activity density (SAD) maps based on the solution of the Fredholm equation has been developed and applied. The construction of SAD maps was carried out for the site of the temporary storage (STS) of spent fuel and radioactive waste (RW) in Andreeva Bay using the results of measuring campaign in 2001-2002 and for the sheltering construction of the solid RW using the results of measurements in 2021. The Fredholm equation was solved in two versions: under conditions of a barrier-free environment and taking into account buildings and structures located on the industrial site of the STS Andreeva Bay.

Further development and application of a method for assessing radionuclide surface activity distribution and source location based on measurements of ambient dose equivalent rate.

A method has been developed for solving the Fredholm equation in the barrier geometry for reconstructing the surface activity density (SAD) from the results of measuring the ambient dose equivalent rate (ADER). Inclusion of the barrier geometry means that the method takes into account the shielding effect of buildings and structures on the contaminated site. The method was based on the representation of the industrial site, buildings and radiation fields in the form of a raster and the use of the visibility matrix (VM) of raster cells to describe the barrier geometry.

Cytogenetic analysis (buccal micronucleus cytome assay) of radioactive waste management workers.

The Russian Federation is implementing a program for dismantling nuclear-powered submarines and nuclear service vessels decommissioned from the Navy. Program personnel may be exposed to mutagenic and carcinogenic factors, including ionizing radiation. Improved preclinical health diagnostics are desirable, for timely identification of health effects, optimization of preventive measures, and medical interventions.

Radiation survey and environmental impact assessment at the site of temporary storage at Andreeva Bay (16 years of studies).

The site of temporary storage for spent fuel and radioactive waste at Andreeva Bay is a largest nuclear legacy site in the Russian Northwest. The radiation situation within the industrial site and in the surrounding health protection zone (HPZ) is characterised by significant local contamination of the topsoil, which is a source of environmental contamination and potential spread of radioactivity within and outside the HPZ, including the adjacent marine environment. The highest levels of radioactive contamination of soil due to manmade radionuclides have been registered around the spent nuclear fuel storage facilities, where the specific activity of Cs-137 reaches 5 × 10Bq kg, and that of Sr-90, 5.

Comprehensive environmental monitoring during remediation of a nuclear legacy site in the Far East of Russia.

In compliance with the fundamentals of the government's policy on nuclear and radiation safety, Russia is continuing to implement its national program for decommissioning its nuclear legacy. Under this program, the State Atomic Energy Corporation, 'Rosatom', is carrying out decommissioning and remediation of the Navy's former shore technical bases (STBs) in the Russian Far East. Along with the 'old problems' accumulated during the operation of STBs in the past, new challenges arise because of the planned intensification of radioactive waste (RW) management on the site in the nearest future.

Topographical classification of dose distributions: implications for control for worker exposure.

This paper deals with classification of dose distributions of nuclear workers based on antikurtosis (Q) and entropy coefficients (K) and their relationship presented in QK-diagrams. It is shown that determination of the most appropriate distribution to adopt, for a specific data set of a wide range of input data, requires building and analysing QK-diagrams for distributions of logarithms of individual doses. Actual dose distributions for emergency and occupational exposure situations were then considered, as well as doses for one day of work during clean-up and routine activities.

The development and application of a method for assessing radionuclide surface contamination density based on measurements of ambient dose equivalent rate.

This article presents a method for assessing the radionuclide surface contamination density (SCD) on open sites and in premises of a radiation hazardous facility based on measurements of the ambient dose equivalent rate (ADER). The method is intended for use at the initial stage of the assessment of the radiation environment at facilities. The assessed SCD at a given location on the surface can differ from the directly measured SCD at that location, since sources located on the surface and distributed by the depth contribute to the ADER value.

Radiation situation dynamics at the Andreeva Bay site for temporary storage of spent nuclear fuel and radioactive waste over the period 2002-2016.

The Coastal Technical Base (CTB) №569 at Andreeva Bay was established in the early 1960s and intended for the refueling of nuclear submarine reactors and temporary storage of spent nuclear fuel (SNF) and radioactive waste (RW). In 2001, the base was transferred to the Russian Ministry for Atomic Energy and the site remediation began. The paper describes in detail the radiation situation change at the technical site in Andreeva Bay from 2002-2016, the period of preparation for the most critical phase of remedial work: removal of spent fuel assemblies.

NORWEGIAN-RUSSIAN COOPERATION IN NUCLEAR LEGACY REGULATION: CONTINUING EXPERIENCE AND LESSONS.

Safe management of nuclear legacies arising from past activities is a critical issue in maintaining confidence for the continuing and future use of radioactive materials. Effective and efficient regulatory supervision of nuclear legacy management is a critical part of that process. The Norwegian Radiation Protection Authority plays an active role in bilateral regulatory cooperation projects with sister authorities in the Russian Federation, as part of Norway's Plan of Action to improve radiation and nuclear safety.

[RADIATION HYGIENIC MONITORING AT THE AREA OF THE LOCATION OF THE FAR EASTERN CENTER FOR RADIOACTIVE WASTE MANAGEMENT (FEC "DALRAO"--BRANCH OF FSUE "ROSRAO")].

Intensification ofactivities in the field of spent nuclear fuel (SNF) and radioactive waste (RW) management in the Far East region of Russia assumes an increase of the environmental load on the territories adjacent to the enterprise and settlements. To ensure radiation safety during works on SNF and radioactive waste management in the standard mode of operation and during the rehabilitation works in the contaminated territories, there is need for the optimization of the existing system of radiation-hygienic monitoring, aimed at the implementation of complex dynamic observation of parameters of radiation-hygienic situation and radiation amount of the population living in the vicinity of the Far Eastern Center for Radioactive Waste Management (FEC "DALRAO"). To solve this problem there is required a significant amount of total and enough structured information on the character of the formation of the radiation situation, the potential ways of the spread of man-made pollution to the surrounding area, determining the radiation load on the population living in the vicinity of the object.

[RADIATION SAFETY DURING REMEDIATION OF THE "SEVRAO" FACILITIES].

Within a framework of national program on elimination of nuclear legacy, State Corporation "Rosatom" is working on rehabilitation at the temporary waste storage facility at Andreeva Bay (Northwest Center for radioactive waste "SEVRAO"--the branch of "RosRAO"), located in the North-West of Russia. In the article there is presented an analysis of the current state of supervision for radiation safety of personnel and population in the context of readiness of the regulator to the implementation of an effective oversight of radiation safety in the process of radiation-hazardous work. Presented in the article results of radiation-hygienic monitoring are an informative indicator of the effectiveness of realized rehabilitation measures and characterize the radiation environment in the surveillance zone as a normal, without the tendency to its deterioration.

Radiation safety during remediation of the SevRAO facilities: 10 years of regulatory experience.

In compliance with the fundamentals of the government's policy in the field of nuclear and radiation safety approved by the President of the Russian Federation, Russia has developed a national program for decommissioning of its nuclear legacy. Under this program, the State Atomic Energy Corporation 'Rosatom' is carrying out remediation of a Site for Temporary Storage of spent nuclear fuel (SNF) and radioactive waste (RW) at Andreeva Bay located in Northwest Russia. The short term plan includes implementation of the most critical stage of remediation, which involves the recovery of SNF from what have historically been poorly maintained storage facilities.

[Substantiation of a complex of radiation-hygienic approaches to the management of very low-level waste].

In the article there are presented materials on radiation-hygienic approaches to the treatment of very low level radioactive waste (VLLW) and industrial waste containing radionuclides. There is done detailed information on radiation-hygienic principles and criteria for the assurance ofradiation safety in the collection, transportation, storage and processing of VLLW as a category of radioactive waste..

[Radio-ecological situation in the area of JSC "Priargunsky Production Mining and Chemical Association"].

In order to assess the radioecological situation created in the area of the location of diversified uranium mining enterprise "Priargunsky Production Mining and Chemical Association" (PIMCU) there was investigated the radioactivity of a number of the compartments of environment, both at the industrial site and beyond it, as well as the volume activity of radon inside the ground and working premises. Radioecological situation in the vicinity of the uranium mines was performed in comparison with the background (fixed reference, control) district, where there is no uranium mining. Performed studies have shown the significant excess content of 226Ra, 232Th, 210Pb, 222Rn in soil, water open water bodies and local foods near uranium mines compared to areas outside the zone of influence of uranium mining that allows to make a conclusion about the significant technogenic pollution of local areas of the plant and adjoining territory.

3D simulation as a tool for improving the safety culture during remediation work at Andreeva Bay.

Andreeva Bay in northwest Russia hosts one of the former coastal technical bases of the Northern Fleet. Currently, this base is designated as the Andreeva Bay branch of Northwest Center for Radioactive Waste Management (SevRAO) and is a site of temporary storage (STS) for spent nuclear fuel (SNF) and other radiological waste generated during the operation and decommissioning of nuclear submarines and ships. According to an integrated expert evaluation, this site is the most dangerous nuclear facility in northwest Russia.

[Regulatory supervision and radiation survey in the area of location of former military technical bases].

Activities related to the rehabilitation of areas and facilities of the temporary storage of spent nuclear fuel and radioactive waste (SNF and RW) at Andreeva Bay and Gremikha on the Kola Peninsula and in the Primorsky Krai in the Russian Far East is an important component of the regulatory functions of the Federal Medical biological Agency (FMBA of Russia). Technical support to the FMBA of Russia in this activity is provided by A.L Burnazyan Federal Medical Biophysical Center Main research interests include evaluation of radiological threats to determine the priority directions of regulation, a detailed analysis of the radiation situation at areas, territories and in vicinity of temporary waste storage facilities, radiation control and environmental monitoring, the development of digital maps and geoinformation systems, project expertise in the field of rehabilitation of PVC including the management of SNF and RW Implementation of these natural, practical and theoretical works is completed by development a set of regulatory documents ensuring adherence to radiation safety for the stuff population and the environment, and the also documents governing the management of SNF and RW waste in the territories of PVC.

Radio-ecological characterization and radiological assessment in support of regulatory supervision of legacy sites in northwest Russia.

The Norwegian Radiation Protection Authority has been implementing a regulatory cooperation program in the Russian Federation for over 10 years, as part of the Norwegian government's Plan of Action for enhancing nuclear and radiation safety in northwest Russia. The overall long-term objective has been the enhancement of safety culture and includes a special focus on regulatory supervision of nuclear legacy sites. The initial project outputs included appropriate regulatory threat assessments, to determine the hazardous situations and activities which are most in need of enhanced regulatory supervision.

[Ecological and economic approaches to removing radioactively dangerous objects from service].

The paper considers major ecological and economic problems when removing radiation dangerous objects from service and rehabilitating the areas, which require their solution: the absence of specific guidelines for ranking the contaminated lands exposed to radioactive and chemical pollution from the potential risk to the population and environment; no clear criteria for ceasing area rehabilitation works; radiation exposure levels for the population living in the areas after rehabilitation; allowable levels of residual specific activity, and levels of heavy metals in soil, surface and underground water and bed sediment. The cost such works is the most important and decisive problem. A decision-making algorithm consisting of three main blocks: organizational-technical, engineering, geological and medicoecological measures is proposed to solve managerial, economic, and scientific problems.

[Radioecological approaches to ranking radiation dangerous objects].

The paper gives complex criteria for evaluating the hazard of radiation dangerous objects (RDO). The proposed criteria include the following indicators: the ratio of the cumulative activity of radioactive waste to a hazard factor (D value) or to the allowable level of i-radionuclide in the storage; the power of an effective gamma-radiation dose; the rate of radionuclide migration; the doses of human radiation. A scoring system for the hazard of RDO from the above indicators is given.

Independent regulatory examination of radiation situation in the areas of spent nuclear fuel and radioactive wastes storage in the Russian far east.

This paper describes the findings of the radiation situation analysis on-site near Sysoeva and Razbojnik Bays. The results of radiation monitoring performed by radiological laboratory of DalRAO and studies performed by the experts from the Burnasyan Federal Medical Biophysical Centre have been used in the course of analysis. On the industrial sites, gamma dose rate reaches 60 µSv h(-1), and the specific activities of man-made radionuclides in soil reach 2.

Regulatory supervision of sites for spent fuel and radioactive waste storage in the Russian northwest.

In the 1960s two technical bases for the Northern Fleet were created in the Russian northwest at Andreeva Bay in the Kola Peninsula and Gremikha village on the coast of the Barents Sea. They maintained nuclear submarines, receiving and storing radioactive waste and spent nuclear fuel. No further waste was received after 1985, and the technical bases have since been re-categorised as temporary storage sites.

Radiological criteria for the remediation of sites for spent fuel and radioactive waste storage in the Russian Northwest.

In the 1960s, two technical bases of the Northern Fleet were created in Northwest Russia, at Andreeva Bay in the Kola Peninsula and Gremikha village on the coast of the Barents Sea. They maintained nuclear submarines, performing receipt and storage of radioactive waste and spent nuclear fuel, and are now designated sites of temporary storage (STSs). An analysis of the radiation situation at these sites demonstrates that substantial long-term remediation work will be required after the removal of the waste and spent nuclear fuel.

Scope of radiological protection control measures.

In this report, the Commission recommends approaches to national authorities for their definition of the scope of radiological protection control measures through regulations, by using its principles of justification and optimisation. The report provides advice for deciding the radiation exposure situations that should be covered by the relevant regulations because their regulatory control can be justified, and, conversely, those that may be considered for exclusion from the regulations because their regulatory control is deemed to be unamenable and unjustified. It also provides advice on the situations resulting from regulated circumstances but which may be considered by regulators for exemption from complying with specific requirements because the application of these requirements is unwarranted and exemption is the optimum option.

[Results of radiation monitoring in Moscow region over 1957-2005].

The article contains data on radiation situation in Moscow region, characteristics of overall beta-activity of ambient air, fall-out density, radionuclide contents of foods. Radionuclides content of environment appeared to decrease by 2-3 orders. Individual doses of internal irradiation for Moscow population are 100 times lower than the levels legally set for technogenic sources.