BgNS TRANSACTIONS – Science and technology journal of the Bulgarian nuclear society


BgNS TRANSACTIONS is published in one volume (two issues) per year and scientific and technological papers, communications, and information in the following areas of nuclear science and technology are accepted:

  • NPP Planning, Regulation, and Economics
  • Nuclear Physics and Technology
  • Nuclear Safety and System Reliability
  • Radiation Protection and Dosimetry
  • Radioactive Waste and Spent Nuclear Fuel
  • Nuclear Methods and Instruments
  • Radioecology

ISSN: 2603-5480 (online)
ISSN: 2603-5553 (print)
The Journal is abstracted in INIS (the IAEA International Nuclear Information System) and National Reference List of contemporary Bulgarian scientific publications


Assoc. prof. PhD. Tzvetana Nonova (INRNE, Bulgarian Academy of Sciences)


Assoc. prof. DSc PhD Pavlin Groudev (INRNE, Bulgarian Academy of Sciences)
Assoc. prof. PhD Lyudmil Tsankov (Sofia University St. Kliment Ohridski)
Assoc. prof. PhD Kalin Filipov (Technical University of Sofia)
Assoc. prof. PhD Maria Manolova (INRNE, Bulgarian Academy of Sciences)
Assoc. prof. PhD Boris Kalchev


Latest Articles

Nuclear Physics in the Activity of Vasil Levski National Military University – N. Dolchinkov

The training in nuclear physics and related disciplines is embedded in the curricula of cadets and students in the specialties ZNI and ZNBAK. The trainees have the opportunity to get acquainted in person with the activities of Kozloduy NPP and INRNE at BAS. The problem is the outdated material base, ...
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Radionuclide Content in Black Sea Sediments from Varna Bay at the Northern Bulgarian Coast – Tz. Nonova, K. Slavova, I. Genov, L. Dobrev, V. Doncheva, O. Hristova, B. Dzhurova

This work presents data on the accumulation of technogenic 137Cs and natural radionuclides of the 238U and 232Th series (238U, 226Ra, 232Th) and 40K in Black Sea sediments collected from Varna bay at the Northern Bulgarian Black Sea coast. The aim of the study is to be the first step ...
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Long Term Electricity Supply System Planning Including Nuclear Power Option – S. Nikolova-Poceva, A. Chaushevski

This paper presents alternatives for expansion of the Macedonian electricity supply system. MESSAGE tool is used for modeling the analyzed system, for developing the scenarios, to analyze cost optimal energy pathways and to determine the optimal electricity generation technology mix. The time horizon for the case study is from 2020 ...
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Survey of Public Attitudes and Availability of Radiophobia in Bulgaria in the Context of Development of the Nuclear Energy Sector – V. Valcheva, D. Zgureva

This article represents a brief overview of the results of the survey among adult citizens of the Republic of Bulgaria. The method of the sampling is a quota based on the characteristics of age, sex, education and the type of the settlement. The citizens from different social and demographic groups ...
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Method for Categorization of the Deviations Identified during the Periodic Safety Review (PSR) of Units 5 and 6 at Kozloduy NPP – E. Kichev

The purpose of the presented method is to be applied for categorization in terms of safety of the findings (negative as deviations and positive as strengths) identified during the Periodic Safety Review (PSR) of units 5 and 6 at Kozloduy NPP. Such categorization is the main argument of fixing the ...
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Determination of Disposal Density of VVER-1200 Spent Fuel Loaded Canisters in Horizontal Geological Disposal – G. Özesme, B. Bulut Acar

Geological disposal is a widely accepted method for permanent disposal of spent nuclear fuel and high-level waste. There are various geological disposal concepts under development in many countries and these concepts have differences mainly in the geometry and material of disposal canisters, geological formations of host rock and orientation (vertical ...
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Double Expert Methodology of NPP Power Equipment Inspection to Increase the Exploitation Lifetime – I.A. Aretinskaya, O.A. Chulkin, V.N. Kolykhanov, A.N. Kharabet, O.E. Zoteev, V.O. Zoteev

The problem of the lifetime extension of NPP power equipment is actual at present time. In our previous research, we were applying fuzzy sets and fuzzy algorithm methods that yielded positive results for solving this problem. The practice has shown that a forecast tool, based on stochastic theory, cannot be ...
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Aircraft Crash as an External Hazard to a Nuclear Installation (NPP) – Svetlin Filipov, Milko Miloshev

The paper presents the baseline in the external hazards assessment for a NPP with respect to the aircraft crash. Methodology for performing assessment of the capacity of safety important facilities in case of an aircraft crash is described. The main stages of the process of assessment are identified and noted ...
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Application of the ASTECv2.1.1.6 Severe Accident Computer Code and SUNSET Tool for Uncertainty and Sensitivity Analyses on MCCI VVER1000 Test Case – R. Gencheva, A. Stefanova, P. Petrova, P. Groudev

This article concerns an uncertainty and sensitivity investigation of certain parameters in the molten corium concrete interaction (MCCI) test case for VVER1000. It has been used the MEDICIS/ASTECv2.1.1.6 severe accident computer code to describe the basic parameters behaviour and the main phenomena arising during the MCCI in VVER1000 reactor design ...
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DEC (Design Extension Conditions) Analyses in Kozloduy NPP – Krasen Rashkov

It is clear from the IAEA publication – Safety of Nuclear Power Plants: Design, SSR-2/1 (Rev. 1) that the classification of the initiating events for safety analyses is changing. New groups appear, using a new term – design extension conditions (DEC). In 2016 Bulgarian Nuclear Regulatory Agency (BNRA) substantially changed ...
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Evaluation of the Neutron Flux Distribution in Two-Zone Reactor – V. Kolykhanov, I. Kozlov, D. Polehenkyi, H. Kulyk

The distribution of heat release in the reactor core is important for reliable and safe operation of NPPs. During reactor campaign, the core composition changes due to fuel burnup and this leads to a change in the neutron flux distribution in the core volume. A numerical analysis of the change ...
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Determination of the LB LOCA Ranges in the Containment for the Purposes of PSA Level 1 for KNPP – E. Borisov, B. Marinova

In this paper a short description for specific application of the RELAP5/MOD3.3 Patch 5 for Kozloduy NPP (KNPP) safety analyses is presented. More specifically, results from determination of the LB LOCA ranges in the containment are discussed. The analyses are part of the supporting activities related to the modelling of ...
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Conditions for Prevention of Water Hammers at Start-Up of Emergency Feed-Pumps with a Steam-Driver of Nuclear Power Plants – V. Skalozubov, D. Pirkovskiy, N. Bilous, I. Kozlov, V. Kolyhanov, O. Sedova

The initial event of severe accidents and devastating explosions at Fukushima-Daiichi NPP in 2011 was the complete loss of long-term power supply due to the combined effects of beyond-design tsunamis and an earthquake. Lessons from the Fukushima accident identified the need for further development of safety systems for nuclear power ...
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Nb-93m Activation Cross Section Libraries Investigation – M. Mitev, D. Dimitrov, M. Manolova

The isotope 93mNb is suitable for a test element in the development of principally new approaches in the radiochemistry. In order to correctly evaluate the measurements a suitable experimental setup has to be assured through preliminary calculation of the expected induced activity. These calculations also provide ground for evaluation of ...
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Extension of the Lifetime of the Existing NPPs – M. Manolov

This paper presents the activities undertaken by Kozloduy NPP to operate the units 5 and 6 beyond an established time frame defined by the licence and the original plant design – so called Long Term Operation /LTO/ which should be justified by safety assessment. Among the topics covered by the ...
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Specific Aspects of the Emergency Arrangements when Establishing ERO – S. Filipov

Considering the requirement for the adequate emergency arrangements and accident management, some areas in this field are still blank or not well addressed. Among all the factors which play role during accident management and emergency activities, there is one which is a kind of underestimated in most of the emergency ...
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Innovative Approaches for Nuclear Knowledge Transition within the European Union – M. Krusteva

The consequences of the three major accidents in nuclear energy, and in particular that of the Chernobyl nuclear power plant in terms of their impact on nuclear energy regulation and the availability of staff for the nuclear energy are discussed in this paper. The lack of common standards for evaluation ...
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Challenges for Introducing Nuclear Energy Program in Small Embarking Country – A. Causevski, S. Nikolova-Poceva, N. Popov, P. Groudev, N. Zaharieva

Nuclear Energy Program (NEP) for each country, especially for newcomer countries is a long-term process with lot of challenges for the political establishment of the country, as well as for the institutions and all involved stakeholders. According the IAEA recommendations, the process can be divided in 3 continuous phases. The ...
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Modeling and Analysis of Portable Diesel-Pump Mitigation Strategy Implemented as a Post-Fukushima Safety Measure – B. Kuzmanov

In accident situations involving Beyond-Design-Basis External Events (BDBEE) taking place in a nuclear power station, there is a necessity for an external portable pump equipment to be delivered on site, in order to avoid fuel melting and to preserve the containment building integrity. It can thus be guaranteed the long-term ...
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Radiological Analysis of Spent Fuel Transportation Container – A. Yordanov

The transportation of Kozloduy NPP’s WWER-1000 spent nuclear fuel requires design and validation of a special transport equipment. The exploitation of such equipment requires the fulfillment of IAEA Safety Standards Series Safety Guide No. NS-G-1.4 recommendations and compliance with the Bulgarian legislation, which states that the maximal dose rate at ...
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Analysis of the Containment Phenomena, Including Thermal-Hydraulic Processes and Fission Products Behaviour after Inadvertent Withdrawal of the Regulating Control Rod Group During Full-Power Operation – V. Saraeva, N. Rijova

The inadvertent withdrawal of the regulating control rod group during full-power operation leads to an increase in the reactor power and thus to an increase in the primary circuit temperature and pressure. The fuel assemblies with the highest power peaking factors reach the state of boiling crisis and may be ...
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