YUGOSLAV NUCLEAR PROGRAM IN THE RECENTLY ESTABLISHED CIRCUMSTANCES
by Milena MATAUŠEK, Dušan SPASOJEVIĆ

Abstract: The main aim of the present paper is to provide the basic elements needed for formulating the Yugoslav nuclear program in the recently established circumstances. First, a summary of the purposes, contents and results of the former Yugoslav nuclear programs is given. Our present activities in the field of nuclear sciences and technologies are presented. New circumstances relevant for the use of nuclear energy, both in the world and in our country, are analyzed. The conclusions concerning the future nuclear program are drown.

Key words: nuclear program, nuclear energy, nuclear safety, research nuclear reactors

Note: Full text published in Serbian

CHARACTERISTICS OF SPATIOTEMPORAL INTERMITTENCY IN TWO PHASE FLOWS
by Milan RAJKOVIĆ, Jovica RIZNIĆ, Mamoru ISHII

Abstract: The characteristics of temporal and spatiotemporal intermittent, or slug flow, in two phase flashing flows are analyzed in the context of intermittency transition to chaos. Particularly, the possibility of occurrence of generic intermittency routes (Types I, II and III) is investigated in the presence of density wave instability in the system and conclusive evidence for the occurrence of Types I and III is presented. Particularly important is the prediction of the mean slug length and the slug length distribution since the slug flow represents an unfavorable flow regime for gas- liquid transportation in pipes. Identification of two generic intermittency routes automatically gives a quantitative prediction concerning the length distribution of laminar and turbulent (slug) phases. Spatiotemporal analysis, based on the bi-orthogonal decomposition and concepts from information theory, provides quantitative characterization and prediction of slug flows and the possible mechanism of transition from spatiotemporal intermittency to spatiotemporal chaos (turbulence) is outlined. The analysis of the intermittency in two-phase flows was performed on the experimental data obtained in the study of natural circulation instabilities during small break loss-of-coolant accident.

Key words: two phase flows, intermittency, spatiotemporal structures, chaos

NUCLEAR POWER PLANTS IN SURROUNDING OF YUGOSLAVIA
MAIN DESIGN AND SITE SAFETY ASPECTS
by Dušan SPASOJEVIĆ, Valerije JOVIĆ

Abstract: Sixteen units of the nuclear power plants, with approximately 25000 MWt of the total installed heat capacity and more then 2000 t nuclear fuel including 800 t of radioactive spent nuclear fuel are located in nearest surrounding of Yugoslavia. Based on the analyses of design and site safety aspects as well as operating experience of the mentioned nuclear power plant units, it is concluded that the further analyses of their actual operating experience and changes of main safety characteristics is a real continuous task for our experts.

Key words: nuclear power plant, site characteristics, safety, reliability, availability, safety systems, operating experience, systems failures, Paks, Kozloduj, Bohunice, Cernavoda, Krsko, surroundings of Yugoslavia

Note: Full text published in Serbian