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 The problem is the outdated material base, but although it is outdated, […]
Latest Articles
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 in a future large study […]
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 (base year) to 2050. Two […]
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 replied to a set of […]
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 scope and the deadline of […]
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 and horizontal) of disposal canisters. […]
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 fully acceptable. The stopping of […]
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. Analyses are performed with varied […]
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. The uncertainties in some parameters […]
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 the content of “Regulation on […]
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 in the axial profile of […]
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 the accident sequences and determination […]
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 plants that do not require […]
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 the results and adjustment of […]
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 safety assessment, specific consideration were […]