[en] Collection of Lithuanian laws regulating environmental protection in Lithuania is presented. The main of them is the Law on environmental protection of the Republic of Lithuania. This law establish the main rights and duties of legal and natural persons guaranteeing the right of the population of the Republic of Lithuania to healthy and safe environment, harmonic development of the interaction between the society and nature. Among general principles of environment protection, regulation of economic activities and introduction of basis of taxation for environment pollution, the law defines the main requirements for the production and usage of radioactive materials, management of radioactive waste. According to the article 21 usage of radioactive materials for the production of nuclear weapons is prohibited. By the article 23 importation of radioactive waste into the Republic of Lithuania for storage, treatment and disposal is prohibited. Two governmental institutions - Environmental Protection Department and Ministry of Health are responsible for the preparation of regulations for the record-keeping, transportation, storage, disposal of radioactive materials as well as norms of radiation protection. The full text of the Law on taxes on the state natural resources, Law on taxes on environmental pollution are also included in this publication

[en] Data of thermo hydrodynamic calculations in the case of disconnection of main circulating pump in the RBMK-1500 reactor are presented. Analysis was performed using RELAP5 code. It was shown that for the reactor core cooling it is enough to have two circulating pumps

[en] Safety analysis of Ignalina NPP operation in the case when gap closure between graphite - fuel channel occur was performed. The main results of this analysis as well as data of gap measurements during the year 1996 - 1998 are provided

[en] Analysis of steam lines rupture between blocks D and G of Ignalina NPP was performed. Model for evaluation of thermo hydrodynamic parameters was developed. Structural analysis of the shaft building was done as well. State of the art codes such as RELAP5, ALGOR, NEPTUNE were used in these calculations

[en] Analysis of flooding possibilities of premises with safety related equipment of Ignalina NPP was performed. In calculations codes SQUIRT and RELAP5 was used. In most cases it was found that it would be enough time to take corrective measure in the case of flooding accident

[en] Being the operating organisation, the Ignalina NPP, in accordance with the Law on Decommissioning of Ignalina NPP Unit 1, is to work out not only the programme for decommissioning Unit 1 but also the plan of decommissioning work. According to the Law, the final Decommissioning Plan for Ignalina NPP Unit 1 is to be drawn up by 31 March 2002 and submitted to the Government for approval. After the Plan has been approved, the Feasibility Study is to be produced. Another item of great importance in the passed Law is the programme of social guarantees. While there is no programme, the personnel of Ignalina NPP feel uncertain about their future which may adversely affect the preparatory work on Ignalina NPP decommissioning. The Ignalina NPP hope for the support of Western countries in coping with the issues of both decommissioning and social safeguards. The closure of outdated nuclear reactors and the storage of spent nuclear fuel are major challenges of the 21 century that can only be dealt with through international cooperation

[en] Real cooperation of Baltic States in energy sector is lagging behind our common political goals and our numerous declarations. What we have today in the three Baltic states as really useful common installations like common electricity grid, Dispatch Centre in Latvia, were mostly inherited from the Soviet times. Exchange of produced electricity from hydro power plants on the Daugava and Ignalina Nuclear Power Plant during different seasons of the year can be put as a very good example of mutual benefit for the two neighbouring countries and there are more similar examples

[en] The results of application of the calculation method for determination of admixture distribution in the boundary air layer in real time in the Ignalina NPP environment are presented. Results of calculations are presented on maps with geographical co-ordinates. The following has been shown: 1) possibility of estimation of fallout fields with the application of real time meteorological data; 2) continuous measurements of dose rate of the ionizing radiation allow to evaluate the rate of radionuclide emission into the boundary air layer. (author)

[en] A technique and results of application of environmental radioisotopes (tritium and radiocarbon) and stable isotopes (deuterium, oxygen-18 and carbon-13) for evaluation of dynamics and origin od different natural water bodies are considered. Natural waters including the groundwater in three regions of Lithuania: the district of the Ignalina NPP with great system of Quaternary aquifers water, the district of North Lithuania with important water system formed in Devonian rocks and the district of South-eastern Lithuania with the groundwater system feebly protected in landscapes of sandy plain and the water system of deep actively interacting aquifers have been investigated. On the basis of received results the peculiarities of isotopic composition of natural waters in territories under investigation are described and features of their origin, dynamics and mixing are compared. (author))

[en] Peripheral rod withdrawal accident was simulated for the maximum permissible operational power level of Ignalina NPP (i.e. 4200 MW). This condition envelopes the normal operation power range from 1000 MW to 4200 MW during which all process, control and protection functions are available. The results of the performed calculation showed, that in a case of an accidental peripheral rod withdrawal, no safety criteria are exceeded and the fuel integrity is maintained. LAC and LEP systems are capable to deal with the reactivity increase, resulted from continuous single rod withdrawal during reactor operation at full nominal power. (author)