[en] In this paper, the Intelligent physical start-up system for nuclear reactor introduced the system composing, hardware design and software design. The system has some merits such as handy operation, fast and accurate mathematic and nicer human-machine interface. (authors)

[en] Nuclear reactor doubling time is an important parameter in nuclear reactor engineering. Reactor operator can know the reactor running state and control the reactor reactivity according the doubling time during reactor start-up and power-up process. In digital neutron monitoring system, the doubling time was calculated with the sampled and processed voltage signal which was proportional to the reactor power. In practical applications, the voltage signal often contains amount of measurement noise which causes a large uncertainty on the calculation result. In this paper, the sensitivity of nuclear reactor doubling time calculation was analyzed, and some relevant calculation examples were given. (authors)

[en] During the commissioning of new plants, before initial startup, an important step is to clean debris from pipes and equipment. This is usually done by flushing with water or blowing with steam or air. It is not the intention of this article to give recommendation about how to proceed, but rather to give a general method to estimate the effectiveness of this operation. The method is based on the general theory of particle dynamics and the concept of drag force - the force needed to displace particles and move them along through the system. We want to make sure the degree of cleanliness obtained at the end of flushing or blowing is such that, later, in the most critical case during operation or operational upset, the particles which are left in the pipework or equipment will not move further. Therefore, the notion of drag force is useful to make comparisons between normal operation and cleaning operation. The concept can also be used to compare the efficiency of different cleaning media; for example, whether to use air blowing or water flushing

[en] Reactor physics tests at initial startup and after refueling are performed to verify the nuclear design and to assure safe operations thereafter. Analogue computers and instruments have been widely used for the acquisition of data and those data have been reduced by hand. These conventional procedures, however, require much time and labor. On the other hand, the development of digital computers and devices has made great progress. Under these circumstances the authors have digitalized the procedures mentioned. As described in the paper, the digitalized reactivity meter and data processor system proved to function satisfactorily as intended at the design stage

[en] The Nuclear Regulatory Commission has developed regulations that will require licensees to perform tests to detect significant losses of strategic nuclear material on a timely basis and to resolve any anomalies resulting from such tests. The ability to achieve timely detection of anomalies and to identify their source has been demonstrated for processes operating at equilibrium. However, the conditions that exist during transition periods, i.e., at startup, shutdown, and during process upsets, will likely impact a facility's ability to achieve the same level of loss detection sensitivity and alarm resolution. This report discusses the types of data available, loss tests, and steps that can be used in developing models of the transition periods. Modeling of the transition includes defining the transition periods, what to include in the model, methods of establishing alarm thresholds for abrupt loss tests, response to process upsets, and the impact of process upsets on recurring loss tests. 23 refs., 6 figs., 6 tabs

[en] A solution for the problem of optimization of transients in power reactors during manoeuvre operations in case of reactor start-up and shutdown is proposed. The results of computer algorithm realization, using the problem of optimization of xenon-samarium transients, as an example are presented

[en] The conference 20 years of energy start-up of IVG reactor was held on 26-28 April, 1995 in Kurchatov, National Nuclear Centre. There were 31 reports in the program of the conference and its were divided into following sections: 1) Plenary reports; 2) Physics and technique of reactor experiment; 3) Atomic scientific and industrial complex of the Republic of Kazakstan; 4) Experimental and theoretical investigations within frame of ITER project. People of 35 different institutions from Kazakstan, Russia, USA and Japan were took part in this conference

[en] The characteristics and the test results of initial loading fuel and first physical start-up for the first pulsed reactor in China (PRC-1) are described. Safe measure to ensure safety of first physical start-up are also described. The experiments show that performances of PRC-1 are in accord with design requirements

[en] The purpose of this project has been to propose a model for how operational readiness decisions are made and to identify important factors influencing these decisions. The project has also studied the support from the management system for decision making, and made a comparison to how decisions are made in practice. This is mainly an explorative study, but it also deals with relevant research and theories about decision making. The project consists of several parts. The first part is composed of descriptions of important notations and terms, and a summary of relevant research about decision making and its relation to the management system. The project proposes a model for the decision making process. The second part consists of analyses of reports from SKI about operational readiness decisions. The last part is a case study at a nuclear power plant. The case study describes the support from work method theories at the nuclear power plant to the decision maker. Decision makers with different roles in the safety management system were interviewed to give a description of the decision making process and of factors influencing the decisions made in practice. The case study also consists of an analysis of decisions in some real events at the nuclear power plant, as well as of making interviews in connection with these. To sum up, this report presents a model for the decision process and describes the work method theories that support the different parts in the process, how the different parts are applied in practice and circumstances that influence the decision process. The results of the project give an understanding for decision making in operational readiness decisions and the factors that influence the decision. The results are meant to be used as a basis for further studies in other nuclear power plants. The results indicate that the decision process is facilitated if there are clear criteria and work methods, if the work methods are well established and if the staff is confident that the work methods work in practice. The circumstances in the decision situations vary. The more explicit the regulations, the easier to make a decision. Some important characteristics for operational readiness decisions in grey area situations are that there is a lack of information, the consequences of a deviation are not known, and the time to verify the operational readiness is short. The decision makers in the operative level state that grey area decisions are unusual since there in most cases are explicit regulations. The reason for this can be that when the regulations are not clear, the problem will be passed over to an analysing unit or to managers at a higher level in the organisation. The decisions are more difficult to make when the organisation and decision makers lack previous experience of the issue, when the consequences are difficult to estimate and when the time perspective is long. The balance between safety and production, which has become more important, creates a more complex decision situation - there are more circumstances to consider in the decision making. The demands on optimization create a more limited scope of action. There are work methods to make decisions and to execute them. To sum up, the work methods do not give much support for the analytical part of the decision process, while the support for bringing the plant back into operation when the problem and measures are identified is more developed and is used to a greater extent. How the work methods are used depends on the time perspective, meeting forms and what competence is participating in the decision process. Which factors that influence the decision making vary over time and depends on what happens in the world around. Therefore, from a safety point of view, it is important to always be able to motivate every decision. Safety always comes first at every level. The decision makers state in the interviews that the decisions are more conservative when there is a shortage of time, which also is shown in previous studies

[en] For the designed commissioning of a VVER-1000 nuclear power plant (NPP) in Germany, the calculation code package PHYBER VVER-1000 was developed at KAB AG Berlin. The primary objective of this code package is the calculation of the safety-relevant parameters during startup and operation for stationary core conditions. This paper presents a description of the code package, the experience accumulated and the results obtained