1,721,111 research outputs found
Nirex Biosphere Research: Report on Current Status in 1994. Nirex Science Report S/95/003.
No full textNirex is responsible for the development of a deep geological repository for the disposal of solid intermediate-level and some low-level radioactive waste. In 1991 an area near Sellafield, West Cumbria was chosen as the focus for further investigations following preliminary investigation of two sites. The Nirex Science Programme is directed at establishing the suitability, or otherwise, of the site at Sellafield to host the deep repository. This requires, amongst other things, that an assessment be developed of the post-closure performance of a repository located there and that this assessment should be supported by information from a suitably designed research programme. The Nirex Safety Assessment Research Programme (NSARP) is a wide ranging programme providing detailed understanding and data on the physical, chemical and biological processes that may be of relevance to repository post-closure safety together with mathematical models describing the way that these processes operate and interact. The NSARP is principally concerned with improving our knowledge of two important pathways, groundwater and gas, through which radionuclides may return to the human environment and it is supplemented by a more engineering-orientated programme of research into the Nirex Reference Vault Backfill. Current Status Reports are intended to provide an overview of the research programme and so help to document its development. They rely on detailed information contained in Nirex reports and other documents in the public domain. The Nirex reports referred to here are mostly Nirex Safety Series (NSS) reports or the Nirex Science reports that have been introduced recently. All these reports have been produced by contractors partly or fully funded by Nirex and working under Quality Assurance arrangements which are either in strict accordance with BS5750 or, particularly for some of the earlier reports, in keeping with its intent
Waste and decommissioning
No full textThis paper is the fifth in a series of 8 that make up the evidence base for SDC report 'The role of nuclear power in a low carbon economy'.This document is an extensive review of the nuclear waste issue, covering radioactive waste management in both practice and policy.Publisher PD
The UK Nirex approach to scenario analysis Summary and conclusions
No full textIm Aufgrag des Bundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit (BMU) untersucht und bewertet die GRS Koeln Methoden zur Szenarienanalyse im Rahmen von Langzeitsicherheitsanalysen fuer geologische Endlager fuer radioaktive Abfaelle, um die Entwicklung auf diesem Gebiet in Deutschland zu unterstuetzen. In Abstimmung mit anderen deutschen Organisationen war der Zugang zur Entwicklung von Szenarien und konzeputalen Modellen, der in Grossbritannien von AEA Technology und UK Nirex entwickelt und angewendet wird, als vielversprechend fuer eine eingehende Untersuchung identifiziert worden. Die verfuegbare Dokumentation wurde von der GRS Koeln durchgesehen und die Methodik wurde in einem einwoechigen Seminar von AEA Technology und UK Nirex vorgestellt. Die wesentlichen Schlussfolgerungen und Empfehlungen sind im vorliegenden Bericht zusammengestellt. (orig.)On behalf of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), GRS Koeln studies and evaluates methods for scenario analysis within the framework of long-term safety assessments for geological radioactive waste repositories in order to support the development of this subject in Germany. In agreement with other German organisations, the approach for scenario and conceptual model development developed and applied by AEA Technology and UK Nirex, UK, has been identified as promising for a detailed investigation. The available documents have been reviewed by GRS Koeln and the methodology has been presented to GRS Koeln during a one-week seminar held by AEA Technology and UK Nirex. The major findings and recommendations are given in the report presented here. (orig.)SIGLEAvailable from TIB Hannover: RO 3190(557) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Overview of the Nirex Core characterisation programme
Get PDFThe British Geological Survey was commissioned by United Kingdom Nirex Limited (‘Nirex’) to manage the Off-Site Core Characterisation Programme (OSCCP) as part of its investigations into the Sellafield and Dounreay areas as possible sites for a deep repository for solid low and intermediate level radioactive waste. The OSCCP provides rock property data for geological interpretation, safety assessment, and design studies associated with the repository development. A broad range of geoscientific tests and analyses were performed on samples of core, and on pore-waters extracted from core, from Nirex’s deep drilling programme. In addition, the geological and geotechnical properties of the core were comprehensively logged. Interactive matching of core features and geophysical images allows the core to be orientated. The OSCCP draws on the expertise of geoscientists from many disciplines including stratigraphy, structural geology, mineralogy, petrology, sedimentology, biostratigraphy, hydrogeology, geochemistry, engineering geology, geotechnics, and geophysics. The broad scope of the programme was met by establishing liaison between a number of scientific consulting organisations. Work carried out under the OSCCP was controlled by Quality Assurance standards. A sample tracking database allows each sample to be identified along with its current location, sub-samples, and the tests to which it has been subjected.
The Nirex core characterisation programme for the Sellafield and Dounreay sites was designed for a hard, fractured rock site. The methodologies used in the Nirex Programme are not necessarily directly applicable or relevant to site investigation in a soft rock/clay site such as Horonobe
NIREX petrological samples archive
Get PDFThis report describes archival curation of petrological samples and related digital records
arising from past investigations undertaken by the BGS under the Nirex Site
Investigations Programmes at Sellafield and, to a lesser extent, Dounreay. This consisted
of the following tasks:
1. Log all relevant samples and subsamples in order to verify which can be readily made
available for future investigations.
2. Record their present storage locations within the BGS site at Keyworth.
3. Determine the extent of electronic records relating to these samples and held on the
Apple Mac databases within the (former) Mineralogy and Petrology Group.
4. Transfer these databases into the BGS data architecture.
5. Prepare a report recording these activities and metadata necessary to locate the
samples/subsamples and records for subsequent use.
The collections and electronic records were assembled during a series of investigations
carried out mostly by the Mineralogy and Petrology Group (MPG) of the British
Geological Survey in the early to mid 1990s, and some carried out by field staff of BGS.
These investigations formed part of the Site Investigations carried out by Nirex in
seeking a site acceptable for construction of a repository for low and medium level
radioactive waste
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NIREX 97: an assessment of the post-closure performance of a deep waste repository at Sellafield
No full textA Preliminary Chemical Toxicity Assessment for the Nirex Disposal Concept
No full textABSTRACTThe role of Nirex is to provide the United Kingdom with safe, environmentally sound and publicly acceptable options for the long-term management of all intermediate level and some low level radioactive waste. Nirex has developed its Phased Disposal Concept as one option for the long-term management of radioactive materials. The Phased Disposal Concept represents a stepwise and reversible approach to the disposal of radioactive waste within a deep geological repository that involves the immobilisation of wastes in containers (mainly fabricated from stainless steel) that are surrounded by a cementitious backfill.The wastes for potential disposal contain materials that may require consideration on the basis of their potential non-radiological hazards. This paper describes a preliminary two-stage methodology for assessing the post-closure impact of the disposal of chemically toxic materials to a conceptual Nirex repository. The study suggests some materials either exceeded current estimates of safe levels, or their impact could not be quantified at this stage but was considered to be of concern. These materials included beryllium, phenol, benzene, and nitrite.</jats:p
Nirex approach to publication and peer review
No full textSIGLEAvailable from British Library Document Supply Centre-DSC:9091.900(S/97/001) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
The Sorption of Niobium, Tin, Iodine and Chlorine onto Nirex Reference Vault Backfill
No full textABSTRACTUK Nirex Ltd is proposing to develop a deep underground repository for the disposal of solid low- and intermediate-level radioactive wastes in the UK, and is currently investigating Sellafield in Cumbria as a possible site. The Nirex Safety Assessment Research Programme (NSARP) comprises scientific research to support the post-closure performance assessment of the repository. One of the investigations carried out by AEA Technology under the NSARP is the study of the sorption of radionuclides onto the backfill. Sorption is one of the key parameters determining the rate of release of radionuclides from the repository. The radionuclides present in the waste include 94Nb, 126Sn, 129I and 36Cl. This paper reports the measurement of the sorption of niobium, tin, iodine and chlorine onto the Nirex reference vault backfill at 20±5°C by the batch sorption method. The temperature dependence of tin sorption was investigated by carrying out additional experiments at 77±5°C. Experiments on niobium solubility and sorption were carried out under saline conditions to reflect the nature of the groundwater at Sellafield. Sorption coefficients (Rd) for niobium are within the range measured in other work, whereas for tin the results are a factor of ten lower than literature values. For iodine and chlorine, the results are consistent with the literature; they also show an increase in Rd with decreasing initial inventory. The Rd values for niobium and tin are significantly higher than those for chlorine and iodine.</jats:p
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