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

Sneve, Malgorzata; Shandala, N. K.; Киселев, С. М.; Simakov, A.V.; Титов, А. В.; Seregin, V. A.; Kryuchkov, Victor; Shcheblanov, V. U.; Bogdanova, L. S.; Grachev, M.I.; Smith, Graham M.

doi:10.1088/0952-4746/35/3/571

Cited by 9 publications

(8 citation statements)

References 4 publications

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“…In 2002, at the moment of the remediation beginning, almost all buildings and constructions of the facility were in emergency conditions, under degradation and continuously contaminated the environment [27]. The remediation of the facility continues today, the appropriate infrastructure is created for removal of SNF and radioactive waste (RW) [3,28].…”

Section: Results For the Andreeva Bay Nwc Sevrao Technical Sitementioning

confidence: 99%

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

Chizhov

Sneve

et al. 2019

J. Radiol. Prot.

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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. The method makes it possible to estimate SCD with reasonable accuracy without increasing the number of measurements, and thus avoid additional occupational exposure and the use of additional resources. SCD and ADER as spatial variables have different support of measurement data. For ADER, measured at a height of 1 m, the support of measurement data can be taken to be a circle in the centre of which a gamma-ray detector is located, with a radius of several tens of meters. In contrast, SCD has the support of measurement data, close to the overall dimensions of the beta detector (100 cm2). To solve the problem of SCD calculation on the basis of ADER measurements, the method of conversion coefficients (MCC) is usually applied, based on the use of conversion factors; however, this method provides an adequate estimate only under conditions of an SCD with low gradient over the surface. The method proposed in this article is applicable for an arbitrary distribution of SCD, and designed to deal with heterogeneous contamination patterns. The developed method is based on the numerical solution of the Fredholm equation of the first kind. The measurement data always contain an error, therefore, the task of the SCD calculation is an ill-posed problem, and the Tikhonov regularisation method (ridge regression) was used to solve it. The article presents the method developed and examples of use. Validation of the method was performed using 38 measurements of the radioactive contamination from 137Cs in soil. It is shown that the method proposed in the article demonstrates a significant superiority in comparison with the MCC method, because it allows more accurate localisation of areas contaminated with radionuclides and is applicable for an arbitrary distribution of SCD.

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Section: Results For the Andreeva Bay Nwc Sevrao Technical Sitementioning

confidence: 99%

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

Chizhov

Sneve

et al. 2019

J. Radiol. Prot.

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“…A significant reduction of the ADER integral on the technical site was achieved by the personnel, who obtained insignificant individual and collective doses at that time. According to publication [38], the average individual dose in the period from 2008-2012 did not exceed 1.2 mSv, and the annual collective dose was not higher than 110 mSv•person. In the following years, the picture of occupational exposure did not change.…”

Section: Discussionmentioning

confidence: 99%

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

Chizhov

Sneve²,

Shandala³

et al. 2018

J. Radiol. Prot.

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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. The analysis of aggregated indicators and data mining were used. The article suggests the best number and location of checkpoints needed to ensure sufficient accuracy of the radiation situation description. The fractal properties of the radiation field are studied using the Hurst index. The relationship between checkpoints was assessed using the method of searching for checkpoint communities. The decrease in the integral of the ambient dose equivalent rate (ADER) at the technical site was evaluated by the method of time series decomposition. Three components of time series were identified: trend, seasonal and residual. The trend of the ADER integral over the technical site is a monotonic decreasing function, where the initial and final values differ tenfold. Taking into account that 137Cs dominates the radiation situation on-site, it is clear that the ADER due to the radionuclide decay will have decreased by 1.4 times. It is estimated that only a small proportion of 137Cs has migrated off-site. Therefore, approximately a sevenfold decrease in dose rate is mainly due to remediation activities of personnel. During the year, the seasonal component varies the ADER integral by a factor of two, due to snowfall. The residual component reflects the uncertainty of the ADER integral calculation and phases of active SNF and RW management. The methods developed are used to support the optimization of remediation work as well as regulatory supervision of occupational radiation protection.

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“…Проведение РГМ планируется и осуществляется с учетом разработанной Госкорпорацией «Росатом» стратегии реабилитации площадок и особенностей применяемых технологий, используемых на каждом этапе реабилитации объектов наследия. Результаты многолетних радиационно-гигиенических исследований на площадках наследия подробно изложены в ряде отечественных и зарубежных публикаций [2][3][4][5][6][7][8][9][10][11][12][13]. Накопленный опыт в этой области позволяет отметить ряд характерных особенностей состояния загрязнения технических площадок и прилегающих территорий и определить приоритеты в надзорной деятельности в будущем.…”

Section: радиационно-гигиенический мониторинг на территориях расположunclassified

“…Эффективность этой деятельности подтверждается результатами РГМ, позволившими охарактеризовать изменение радиационной обстановки положительной динамикой уменьшением мощности дозы гамма-излучения на промплощадках объектов наследия [2].…”

Section: оценка радиоактивного загрязнения площадок ядерного наследияunclassified

Scientific and practical experience of supervisory activities in the field of the public and environmental protection at the Russian nuclear legacy sites

Shandala

Киселев

Титов

2019

Radiac. gig. (2008)

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Today, Russia is implementing a national program for the remediation of legacy sites, resulting from the activities of the nuclear industry, the use of nuclear energy for military purposes, and due to radiation accidents and emergencies. Main priority is given to the health care provision issues of the workers and the population living in the vicinity of the targeted facilities. These tasks are under the regulatory responsibility of the FMBA of Russia. Since the beginning of the development of the nuclear industry in the country, the Institute of Biophysics, technical supporting organization of the FMBA of Russia (now the State Research Center – Burnasyan Federal Medical Biophysical Center Federal Medical Biological Agency (SRC-FMBC)), has been a leading institute in the scientific and methodological support of public radiation safety in the vicinity of radiation hazardous facilities serviced by the FMBA of Russia. In this regard, radiation-hygienic monitoring has always served as the main regulatory tool for more than 60 years. The paper describes the results of long-term monitoring (2005-2018) at the former coastal technical bases of the Russian Navy ( now – sites for temporary storage of SNF and RW in the Russian Northwest and Far East (nuclear legacy sites); sites of the uranium mining and milling facilities: Priargun Mountain Chemical Association and former Production Association “Almaz” (Lermontov, Stavropol Krai); and at uranium legacy sites of the Central Asia (Republic of Tajikistan and Kyrgyz Republic). The peculiarities of radiation situation at the sites are discussed, current challenges identified, and further regulatory improvements presented based on the gained experience.

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

Cited by 9 publications

References 4 publications

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

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

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

Scientific and practical experience of supervisory activities in the field of the public and environmental protection at the Russian nuclear legacy sites

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