[en] The Belgian nuclear tradition is made up of openness to technological innovation and of careful consideration to all aspects of safety. The future of the Belgian nuclear program is, however, uncertain. Public acceptance of the now existing reactors is apparently marginal, although the precautions taken at the design stage as well as during operation has led to an enviable good safety record. Therefore, Belgium has joined other European utilities (from France, Germany, UK and Spain) to define new requirements which will be imposed on any new reactor proposed on the European market the EUR program. The European utilities requirements document will define minimum requirements to be met by any potential supplier and will hopefully contain most of the safety requirements to be imposed by the national Authorities. This document is substantially similar to the document written by the American utilities for the same purpose under the agreement of the EPRI program. The existence of those documents should ease the revival of the nuclear option in the Western countries, which is felt by all specialists to be a necessary outcome of the present world energy situation. (author)

[en] The prospect for future nuclear power plants has led the utilities of seven European countries to launch an effort to define the requirements that should be common to all utilities for the next reactors to be built in Europe. These requirements will ultimately be part of a four-volume document and will cover all aspects of a plant: performance, grid connection, codes and standards, materials, quality assurance, cost, and, of course, safety. The seven European countries - France, the United Kingdom, Germany, Spain, Italy, the Netherlands, and Belgium - issued revision A of Vols 1 and 2 in Nov. 1994, which deal with all the general requirements, not specific to any design, originally issued in March 1994. Comments were requested from most of the nuclear utilities as well as from reactor vendors worldwide. This gave rise to an enormous number of comments, which were duly considered by the European Union. The relevant ones were incorporated into revision B of Vols. 1 and 2, which was issued in Nov 1995, the objective of this revision B being essentially to gain approval from the safety authorities. A particular aspect of the European approach resides in the fact that these European requirements will have to be discussed and agreed on by at least nine safety authorities, i.e., the authorities of the seven counties that launched revision B, plus the authorities of two newcomers, Finland and Sweden, which have just applied for European Union membership

[en] The EUR (European Utilities Requirements) effort was launched in December 1991 by five European utilities, later rejoined by four others. The objective was to write down common requirements for light water reactors of the next generation, which would be built in the near future. Benefits from this approach are expected in the fields of plant licensing, public acceptance as well as the strengthening of nuclear energy competitiveness. These requirements address both evolutive reactors and the ones using intensively passive safety devices, PWRs as well as BWRs. A number of new features appear in these requirements, like the concept of Design Extension Conditions, which is developed to cover the severe accident issue, and a new classification system for all structures, systems, and components. Emphasis is put on standardisation and simplification, but also on margins and cost objectives. (orig./GL)

[en] The licensing practice in Belgium is evolving from the precedent compliance with the USNRC rules (as applied to the 4 last Belgian PWRs) to a more sophisticated approach applied to the next Belgian PWR (N8), which incorporates a mixed compliance with the USNRC or with French rules, depending on the equipment, the structure or the system considered. In this paper is presented the approach concerning the licensing rules applicable to N8. The following aspects are covered: rules applicable to the NSSS, rules applicable to the BOP (codes of design for systems and structures), rules applicable to the equipment (code of construction for mechanical and electrical components), and impact on the lay-out of the plant. Some examples of application of the methodology are given

[en] The site selection criteria and data requirements for nuclear power plant of Belgium are presented and the examples of application are given

[en] The licensing practice in Belgium is evolving from the precedent compliance with the USNRC rules (as applied to the 4 last Belgian PWRs) to a more sophisticated approach applied to the next Belgian PWR (N8), which incorporates a mixed compliance with the USNRC or with French rules, depending on the equipment, the structure or the system considered. In this paper, we present the approach concerning the licensing rules applicable to N8. The following aspects are covered: rules applicable to the NSSS; rules applicable to the BOP (codes of design for systems and structures); rules applicable to the equipment (code of construction for mechanical and electrical components); impact on the lay-out of the plant. Some examples of application of this methodology are given. (author)

[en] In this report a comparison is made of the rules and practices applied in various countries (Belgium, France, Federal Republic of Germany, United Kingdom and United States of America) in designing PWR plants to resist natural hazards (first part of the report) and hazards associated with human activities (second part). The third part of the report deals with the practices in different countries concerning the protection against accidents of internal origin

[en] It is generally accepted that reactivity accidents in PWR cold conditions, like refueling outage, do not pose any big safety problem, due to the facts that only boron dilution is believed able to produce reactivity increase and that such an incident would be detected largely in time so that no inadvertent criticality would occur (as indicated in the Safety Analysis Report). In addition, even if such a very improbable inadvertent criticality did occur, the energy produced would be so low that no radiological consequences would result. Accordingly, dilution probability is usually estimated by relating the number of inadvertent criticalities to the number of reactor-years of operation. After the Chernobyl accident, a study was started in Belgium to investigate whether a more analytical approach was possible and whether this approach could help in improving the operational safety of the Belgian plants. The number and importance of errors made by the operators at Chernobyl indicate indeed that operator errors should be examined thoroughly. This study, carried out for one Belgian nuclear power unit, was developed along two lines, trying to tackle the problem from both ends: - what is actually the probability of starting a dilution - if a reactivity excursion actually occurred in the conditions examined, what would be the reactivity transient and the resulting consequences on the core

[en] Safety studies for nuclear power plants in Belgium are performed on behalf of the owner by architect-engineers and submitted to the authorities for technical assessment. US safety rules are applied in Belgium, but there is also experience of French, German and IAEA safety rules through participation in foreign projects

[en] The purpose of this work was the study of vulnerability to tornado event Vandellos II NPP. To do this, we have evaluated all structures (buildings), security systems and components to the installation of wind stresses, depression and impact of projectiles, generated by a tornado on the site.