Papers in this volume: 4
1. Operational waste removal from Windscale advanced gas-cooled reactor (WAGR)
Author(s): Murray C.L. and Green M.A.
Page: 37
Keywords: Advanced gas-cooled reactors (AGRs), Radioactive waste management - transport and disposal, Remote handling techniques, Waste management & disposal
Abstract: The Windscale advanced gas-cooled reactor (WAGR) is in the process of being decommissioned by BNFL. Prior to beginning decommissioning of the hot gas manifold (hot box) above the reactor's neutron shield and graphite core, it has first been necessary to retrieve stored operational waste in order to clear the reactor's fuel channels. Operational waste is a generic term applied to items associated with the operating reactor, such as fuel stringer plug unit components and other items more permanently resident in the reactor in the period 1963�1981. The reactor shut down in 1981. After the reactor was defuelled in the early 1980s no agreed route for intermediate-level waste disposal was available and of necessity operational wastes were stored in the reactor's fuel channels as an expedient. This paper describes some of the assay findings in terms of operational waste radioactivity levels and compares these with calculations carried out prior to decommissioning.
2. Radiation fields in Siemens-designed PWRs
Author(s): Riess R. and Marchl T.
Page: 49
Keywords: Chemical processes, Chemical processes (including corrosion), Nuclear power plant (NPP), Pressurised water reactors (PWRs), Radiation monitoring and dose management, Radiation protection, Radiation source reduction, Water chemistry
Abstract: the last three decades, 16 pressurised water reactors (PWRs) designed by Siemens-KWU have been commissioned in Germany and elsewhere. The design, materials and operating condition (water chemistry) of these reactors have been progressively modified in successive units. Early plants exhibited rather poor performance from the viewpoint of radiation fields, especially caused by 60Co. However, recently they have shown some improvements based on the introduction of reasonable countermeasures. The latest plants have a much improved performance with occupational radiation exposure rates well below 0�5?manSv/year. This group of plants started operation between 1985 and 1989. This paper will describe the actual status of the radiation fields in Siemens-KWU-designed PWRs by giving an overview on all plants and discussing the countermeasures introduced, and will present the results obtained in two specific cases, namely Philippsburg-2 and Obrigheim.
3. Use of combined isotropic non-linear kinematic hardening model to predict evolutionary cyclic stress-strain behaviour in an austenitic stainless steel
Author(s): O'Donnell M.P.
Page: 61
Keywords: Engineering Structural Integrity Assessment, Fatigue, Materials, Mathematical modelling, Plasticity, Stress analysis
Abstract: Evaluation of fatigue damage in components is commonly carried out using power law deformation equations to define stress and strain ranges for the applied loading conditions. These equations are generally based on cyclically stabilised hysteresis loops defined for a particular strain range. Where loading conditions change or an assessment of a complex geometry is required, the component may be subjected to a range of loading conditions and variations of strain range through the component thickness. In addition, some components are subjected to relatively few, but severe, loading cycles during their lifetimes. It follows that accurate representation of the evolutionary stress�strain behaviour, prior to obtaining the cyclically stable material response, can give rise to benefits for structural integrity assessments. This paper gives details of a non-unified combined isotropic non-linear kinematic hardening model, the fast reactor state variable (FRSV) model. The specific advantage of this type of model is that it provides a good representation of the cyclic evolution of material hardening or softening behaviour. The model is used to predict the evolutionary cyclic stress�strain behaviour in an austenitic stainless steel over a range of strain ranges. The cyclic stress�strain data are obtained on standard uniaxial cylindrical test specimens. Details of the constitutive model are outlined together with the methodology used to derive the six material constants required to characterise the evolutionary cyclic plastic behaviour. Additionally, the quality of the derived parameters is assessed through comparison of the numerically calculated results with the experimental data over the strain ranges of interest.
4. Nuclear waste management in France
Author(s): Rahman A.
Page: 69
Keywords: France, Legislation, Nuclear industry (civil), Radioactive waste management - transport and disposal, Research & development, Waste management & disposal
Abstract: This paper was compiled from an international seminar on nuclear waste management which was organised by the INSTN (Institut Nationale des Sciences et Techniques Nucl�aires) of France from 18 to 22 June 2001 inclusive at Saclay, France. Delegates from Belgium, France, Russia, Romania, South Africa and the UK attended the seminar. The seminar gave a broad overview of the French nuclear industry in general and the nuclear waste management strategy in particular. Also presented were the regulatory conditions and research undertakings to solve problems important to the nuclear industry. In addition to the formal presentation of papers at the seminar, there were extensive site visits giving the foreign delegates an opportunity to view French nuclear activities and achievements. This paper looks at nuclear waste management in France with particular emphasis on Law No. 91-1381.