Entity

Time filter

Source Type

Kozloduy, Bulgaria

Popov L.,Kozloduy NPP
Journal of Radioanalytical and Nuclear Chemistry | Year: 2016

An alternative method for determination of Pu isotopes in various environmental samples has been developed. The separation of Pu is attained by two stage solvent extraction with triisooctylamine/xylene in hydrochloric acid and nitric acid [Pu is converted to Pu4+ by the redox system Fe3+/(NO3)−/(SO3)2−] media. The analytical method has been successfully applied for the determination of Pu isotopes in surface air in a 100 km area around the Kozloduy Nuclear Power Plant in Bulgaria and in surface water of the Danube River. The analytical quality was checked by analyzing reference materials from IAEA (Soil-6, IAEA-375, IAEA-384) and NPL (AL-2008, AL-2009, AL-2010, AL-2011). © 2016 Akadémiai Kiadó, Budapest, Hungary Source


Novel and robust method for determination of uranium isotopes in various environmental materials is presented. The method is based on total decomposition of the solid materials by the use of closed vessels microwave acid digestion systems and pre concentration of uranium from the liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid-liquid extraction with triisooctylamine/xylene in sulfuric and consecutively in hydrochloric acid media. Purified uranium is electrodeposited on a stainless steel disks and then measured by alpha spectrometry. The critical steps in the method were examined. The analytical method has been successfully applied to the determination of uranium isotopes in mineral and tap waters, as well as in soils from Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices. © 2013 Akadémiai Kiadó, Budapest, Hungary. Source


Popov L.,Kozloduy NPP
Journal of Radioanalytical and Nuclear Chemistry | Year: 2012

Methods for routine assessment of 3H and 14C content in gaseous releases from ventilation stacks of Kozloduy Nuclear Power Plant (Bulgaria) were developed. Technique for correction of incomplete desorption of tritium from exposed silica gel was proposed. The distribution and the concentrations of both nuclides in various chemical forms were constantly monitored for a period of 1 year. The results for annual normalized gaseous discharges were assessed for the fifth unit at 173 GBq/(GW.a)for 3H and 369 GBq/(GW.a) for 14C, while for the sixth unit - 3H -98 GBq/(GW.a) and 14C -289 GBq/(GW.a). © 2012 Akadémiai Kiadó, Budapest, Hungary. Source


Alternative method for determination of uranium isotopes in various environmental samples is presented. The method is based on total decomposition of the solid materials and preconcentration of liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid-liquid extraction with triisooctylamine/xylene in hydrochloric media. After the additional removal of stable iron by extraction with diisopropyl ether, purified uranium is electrodeposited on stainless steel disks and measured by alpha spectrometry. The analytical method has been successfully applied to the determination of uranium isotopes in water and bottom sediments from the rivers Danube, Ogosta and Tzibritza in Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices. © 2012 Elsevier Ltd. Source


Groudev P.,Bulgarian Academy of Science | Stefanova A.,Bulgarian Academy of Science | Manolov M.,Kozloduy NPP
Annals of Nuclear Energy | Year: 2011

This paper presents the thermal-hydraulic investigation "Primary to secondary leakage at low power" for analytical validation of Symptom Based Emergency Operating Procedures (SBEOPs) at low power for VVER440/V230 units 3 and 4 at Kozloduy NPP. The main purpose of this analysis is to provide the response of monitored plant parameters to identify symptoms available to the operators and define timing for reaching the following stages during the development of processes in the reactor system, after primary to secondary leakage:Reaching the saturated temperature at the outlet of the assembly.Beginning of reactor core uncovery.Define the time for reaching maximum level in the damaged SG.Termination of natural circulation after decreasing of water level in reactor vessel below the hot nozzles.Defining the time for opening SVs of damaged SG.Define the CSF status and the time of loss of Critical Safety Functions. The thermal-hydraulic analysis for analytical validation of Symptom Based Emergency Operating Procedures (SBEOPs) at low power of reactor for VVER440/V230 units 3 and 4 at Kozloduy NPP is performed with RELAP5/MOD3.2 computer code. The RELAP5/MOD3.2 model of Kozloduy NPP VVER-1000 for investigation of operational occurrences, abnormal events, and design basis scenarios have been developed and validated in the Institute for Nuclear Research and Nuclear Energy - Bulgarian Academy of Sciences (INRNE-BAS) Sofia, and Kozloduy NPP. The model provides a significant analytical capability for the specialists working in the field of NPP safety. © 2010 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations