The Benefits of Cementitious Encapsulation Matrices for the Conditioning of Intermediate Level Waste

2003 ◽  
Author(s):  
R. M. Guppy ◽  
S. P. Vines ◽  
S. J. Wisbey
Keyword(s):  
Nuclear Power ◽  
Raw Materials ◽  
Chemical Diversity ◽  
Intermediate Level ◽  
Quality Data ◽  
Extensive Experience ◽  
Wide Range ◽  
The Uk ◽  
High Level ◽  
Interim Storage

The UK has significant quantities of radioactive waste, which have arisen over the past fifty years or so, largely as a result of nuclear power, reprocessing and defence programmes. The intermediate level wastes arising as a result of these activities, exhibit a high level of physical and chemical diversity, and must be managed safely in a way that protects existing and future generations and the environment. Development work has been conducted since the early 1980s to identify suitable conditioning materials and techniques that are compatible with the needs of safe long-term management, including interim storage, transport and future deep geological disposal. From these studies cementation emerged as the one medium which could satisfy all the key waste management criteria. Other materials were not ruled out and may offer benefits in specific applications. The advantages of conditioning ILW with cement include: • the extensive experience of its use in a wide variety of contexts; • the raw materials are relatively cheap and have a long shelf life; • cement is processed in relatively simple plant at room temperature, with safety and cost benefits for plant operators; • the product is fire resistant and of relatively low toxicity; • cement is capable of immobilising a wide range of wastes ranging from solids to aqueous slurries; • cement provides desirable product properties. Desirable properties include: • suitable strength, • chemical control of radionuclide leading to enhanced retention, • good corrosion protection for steels, • low permeability, • tolerance to radiation, • durability over extended timescales, and • good radiation self-shielding properties. Several waste packaging plants are now operational in the UK using cement-based encapsulants. These are currently conditioning ILW for interim storage, in a manner suitable for future transport and compatible with the Nirex phased deep disposal concept. This paper will describe the development of cement-based encapsulants to meet the needs of UK radioactive wastes, and will provide examples of the supporting product quality data.

Gamma Spectrometry Systems for the Assay of Uranium Residues and Potentially Contaminated Low Level Wastes at the Capenhurst Site

2003 ◽  
Author(s):  
P. A. Clark ◽  
D. F. Parvin ◽  
C. Y. Powrie ◽  
C. H. Orr ◽  
G. Mottershead ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Matrix Correction ◽  
Uranium Recovery ◽  
Measurement Systems ◽  
Low Level ◽  
Fuel Fabrication ◽  
Wide Range ◽  
Contaminated Waste ◽  
The Uk ◽  
High Level

BNFL has produced and operates a wide range of DrumScan® gamma measurement systems for monitoring packages, drums and boxed wastes arising from nuclear power plant reprocessing, fuel fabrication and decommissioning operations. The challenges associated with decommissioning operations are met by employing a range of technologies predominantly High Resolution and Low Resolution spectrometry (HRGS & LRGS). This paper describes how BNFL Instruments’ LRGS and HRGS DrumScan® gamma measurement systems have been used for the assay of uranium resides and potentially contaminated low level wastes by Capenhurst Integrated Decommissioning Project (IDP) in the UK. A description of the two Capenhurst segmented HRGS systems is included. Whilst Segmented Gamma Scanning is a well established technique for the non-destructive assay of gamma emitting radioisotopes in drummed waste, these systems utlise unique features to address the specific measurement requirements. The first system is configured for the accurate measurement of both small sized containers of uranium residues arising from recovery operations and low level wastes potentially contaminated with uranium contained in 200 litre drums. To achieve a high level of accuracy, this system uses a novel mechanical arrangement to overcome the wide variety of container sizes, and the unique “TransWeight” and “Transmission” matrix correction techniques which provide significant improvements over conventional Segmented Gamma Scanner matrix correction techniques. The second system is configured for Nuclear Safety purposes to provide an upper limit of the 235U present in 200 litre drums of potentially contaminated waste prior to the opening of the drums for sorting and uranium recovery operations. This system is configured to report an appropriately pessimistic upper estimate of the 235U present. A brief description of the LRGS systems used by Capenhurst is also provided. These systems have served to quantify the 235U content within a variety of potentially contaminated waste items ranging from 200 litre drums to 1m3 boxed waste.

Sellafield Decommissioning Programme: Progress Update

2003 ◽  
Author(s):  
S. F. Challinor
Keyword(s):  
Research And Development ◽  
Fuel Cycle ◽  
Step Change ◽  
Nuclear Facilities ◽  
Extensive Experience ◽  
Strategic Direction ◽  
Wide Range ◽  
Uk Government ◽  
The Uk

In 1999 the UK government announced a step change in the strategy for the delivery of the UK civil nuclear clean-up programme. BNFL has responded to the Governments announcement by changing the strategic direction and increasing the priority on remediation activities across the Company. BNFL has extensive experience in decommissioning nuclear facilities having undertaken remediation and decommissioning operations on BNFL sites for many years, encompassing a wide range of projects including reactors, fuel cycle plants and Research and Development facilities. This paper describes the challenges posed by, and the progress made, on some of the range of decommissioning projects undertaken on the Sellafield site as part of its decommissioning and remediation portfolio. These decommissioning operations cover a variety of redundant fuel cycle facilities ranging in size and complexity in both beta gamma and alpha contamination environments utilising manual and remote decommissioning techniques to systematically and progressively reduce the hazard on the site.

Presenting Medical Statistics from Proposal to Publication

2017 ◽  
Author(s):  
Janet L. Peacock ◽  
Sally M. Kerry ◽  
Raymond R. Balise
Keyword(s):  
Journal Article ◽  
Real Data ◽  
Research Process ◽  
Research Report ◽  
Medical Statistics ◽  
Extensive Experience ◽  
Wide Range ◽  
Sample Size Calculations ◽  
The Usa ◽  
The Uk

Presenting Medical Statistics from Proposal to Publication (second edition) aims to show readers how to conduct a wide range of statistical analyses from sample size calculations through to multifactorial regressions that are needed in the research process. The second edition of ‘Presenting’ has been revised and updated and now includes Stata, SAS, SPSS, and R. The book shows how to interpret each computer output and illustrates how to present the results and accompanying text in a format suitable for a peer-reviewed journal article or research report. All analyses are illustrated using real data and all programming code, outputs, and datasets used in the book are available on a website for readers to freely download and use. ‘Presenting’ includes practical information and helpful tips for software, all statistical methods used, and the research process. It is written by three experienced biostatisticians, Janet Peacock, Sally Kerry, and Ray Balise from the UK and the USA, and is born out of their extensive experience conducting collaborative medical research, teaching medical students, physicians, and other health professionals, and providing researchers with advice.

Brian Eyre CBE FREng. 29 November 1933 — 28 July 2014

2016 ◽  
Vol 62 ◽  
pp. 147-166
Author(s):  
Derek Pooley ◽  
George Smith ◽  
Colin Windsor
Keyword(s):  
Nuclear Power ◽  
Chief Executive ◽  
Structural Components ◽  
Theoretical Understanding ◽  
Leading Role ◽  
Void Swelling ◽  
Intergranular Embrittlement ◽  
Wide Range ◽  
East End ◽  
The Uk

Brian Eyre was an outstanding metallurgist who played a leading role in the development of nuclear engineering materials. His experiments on irradiated metals enabled a theoretical understanding of the mechanisms of radiation damage, and in particular the formation of voids and void swelling in structural steels. His work on the fracture of metals advanced our understanding of intergranular embrittlement and helped define the specifications of the structural components in nuclear reactors. He rose from a humble upbringing in London's East End to become Chief Executive of the UK Atomic Energy Authority (UKAEA). He was instrumental in transforming the UKAEA from a organization whose mission was to develop nuclear power generating systems into the privatized AEA Technology, which worked on a wide range of technologies on a customer–contractor basis.

scholarly journals Opportunities and Challenges for Structural Health Monitoring of Radioactive Waste Systems and Structures

2013 ◽  
Author(s):  
Victor Giurgiutiu ◽  
Adrián E. Méndez Torres
Keyword(s):  
Structural Health Monitoring ◽  
Radioactive Waste ◽  
Nuclear Fuel ◽  
Health Monitoring ◽  
Nuclear Power ◽  
High Level Radioactive Waste ◽  
Structural Health ◽  
Used Nuclear Fuel ◽  
Wide Range ◽  
High Level

Radioactive waste systems and structures (RWSS) are safety-critical facilities in need of monitoring over prolonged periods of time. Structural health monitoring (SHM) is an emerging technology that aims at monitoring the state of a structure through the use of networks of permanently mounted sensors. SHM technologies have been developed primarily within the aerospace and civil engineering communities. This paper addresses the issue of transitioning the SHM concept to the monitoring of RWSS and evaluates the opportunities and challenges associated with this process. Guided wave SHM technologies utilizing structurally-mounted piezoelectric wafer active sensors (PWAS) have a wide range of applications based on both propagating-wave and standing-wave methodologies. Hence, opportunities exist for transitioning these SHM technologies into RWSS monitoring. However, there exist certain special operational conditions specific to RWSS such as: radiation field, caustic environments, marine environments, and chemical, mechanical and thermal stressors. In order to address the high discharge of used nuclear fuel (UNF) and the limited space in the storage pools the U.S. the Department of Energy (DOE) has adopted a “Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste” (January 2013). This strategy endorses the key principles that underpin the Blue Ribbon Commission’s on America’s Nuclear Future recommendations to develop a sustainable program for deploying an integrated system capable of transporting, storing, and disposing of UNF and high-level radioactive waste from civilian nuclear power generation, defense, national security, and other activities. This will require research to develop monitoring, diagnosis, and prognosis tools that can aid to establish a strong technical basis for extended storage and transportation of UNF. Monitoring of such structures is critical for assuring the safety and security of the nation’s spent nuclear fuel until a national policy for closure of the nuclear fuel cycle is defined and implemented. In addition, such tools can provide invaluable and timely information for verification of the predicted mechanical performance of RWSS (e.g. concrete or steel barriers) during off-normal occurrence and accident events such as the tsunami and earthquake event that affected Fukushima Daiichi nuclear power plant. The ability to verify the conditions, health, and degradation behavior of RWSS over time by applying nondestructive testing (NDT) as well as development of nondestructive evaluation (NDE) tools for new degradation processes will become challenging. The paper discusses some of the challenges associated to verification and diagnosis for RWSS and identifies SHM technologies which are more readily available for transitioning into RWSS applications. Fundamental research objectives that should be considered for the transition of SHM technologies (e.g., radiation hardened piezoelectric materials) for RWSS applications are discussed. The paper ends with summary, conclusions, and suggestions for further work.

Building the UK ABWR: Developments in Structural Integrity Safety Cases for Highest Reliability Components in the UK

2018 ◽  
Author(s):  
Tim Jelfs ◽  
James O’Neill ◽  
Angus Beveridge
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Advisory Group ◽  
Manufacturing Processes ◽  
Design And Manufacturing ◽  
Safety Case ◽  
Safety Cases ◽  
The Uk ◽  
High Level

Nuclear power plants contain certain components whose gross failure would lead to intolerable radiological consequences. In the UK, a common terminology used for such components is Very High Integrity (VHI). If it is not possible to engineer lines of protection for these components, a safety case must demonstrate to UK regulators that the probability of gross failure is demonstrably so low that it can be discounted. A previous paper [Ref. 1] has described, at a high level, how the structural integrity safety case for a nuclear new build project in the UK — the UK Advanced Boiling Water Reactor (UK ABWR) is being structured. As described in [Ref. 1], the structural integrity safety case for the UK ABWR is based on the guidance provided by the UK Technical Advisory Group on Structural Integrity (TAGSI) and aims to demonstrate a multi-legged safety case with robust and independent legs giving confidence of defense in depth. Design to the internationally recognized ASME code [Refs. 2, 3, 4] is supplemented by a significant number of beyond code requirements such as supplementary inspection and inspection qualification, augmented material testing requirements, defect tolerance assessment to the well-established R6 procedure [Ref. 5], and demonstration that design and manufacturing processes have reduced risks to As Low as Reasonably Practicable (ALARP). This paper provides an updated position of the progress made on the UK ABWR project. It also provides more specific details on the activities the future licensee, Horizon Nuclear Power, has performed in support of the demonstration that design and manufacturing processes have reduced risks to ALARP. This kind of additional work is vital to providing the UK regulator with confidence that the risk of failure of VHI components has been reduced to ALARP.

Cements in Radioactive Waste Disposal

MRS Bulletin ◽  
1994 ◽  
Vol 19 (12) ◽  
pp. 33-38 ◽  
Author(s):  
F.P. Glasser ◽  
M. Atkins
Keyword(s):  
Radioactive Wastes ◽  
Radioactive Waste Disposal ◽  
Laboratory Equipment ◽  
Engineered Structures ◽  
Exchange Resins ◽  
The Uk ◽  
High Level ◽  
National Programs ◽  
Interim Storage ◽  
Considerable Depth

Depending on their radioactive content and abundance of long-lived radionuclides, radioactive wastes are often described as low, intermediate or high-level. Cements play a major role in the engineered structures, existing and planned, of most national programs for low- and intermediate-level (ILW) radioactive wastes. Final disposal of ILW is usually by burial at considerable depth (>250 meters), e.g., in planned repositories in clay at Mol (Belgium), in salt at Gorleben (Germany), and in volcanic tuffs at Sellafield (United Kingdom). A sample disposal concept is shown in Figure 1. Shallow land burial is also employed, mostly for low-level wastes (LLW) and often in concrete-lined vaults, e.g., at Drigg (UK) and Center de la Manche (France). Cements are likely to be used in a waste repository as structural elements in the engineered structure and for encapsulation of the actual waste itself (see Figure 1). In the UK, cements are also the favored material for infilling of the vault space (backfilling), and sealing.LLW and ILW are characterized by considerable heterogeneity, and comprise liquids, solids, floes, sludges, exchange resins, and contaminated laboratory equipment. Cements are capable of converting most of these waste streams into solid and stable monoliths that can be further encapsulated in a steel or concrete container. Such a product is ideal for interim storage, transportation, and final emplacement in a repository. The technology of cementation is well-established, and suited to automation and remote handling (thereby reducing the radiation dose to workers).

scholarly journals CTF and FLOCAL Thermal Hydraulics Validations and Verifications within a Multiscale and Multiphysics Software Development

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1220
Author(s):  
Sebastian Davies ◽  
Ulrich Rohde ◽  
Dzianis Litskevich ◽  
Bruno Merk ◽  
Paul Bryce ◽  
...  
Keyword(s):  
Software Development ◽  
Turbulent Mixing ◽  
Nuclear Power ◽  
Nuclear Reactor ◽  
Journal Article ◽  
Thermal Hydraulics ◽  
Reactor Physics ◽  
Wide Range ◽  
The Uk ◽  
Simulation Codes

Simulation codes allow one to reduce the high conservativism in nuclear reactor design improving the reliability and sustainability associated with nuclear power. Full-core coupled reactor physics at the rod level are not provided by most simulation codes. This has led in the UK to the development of a multiscale and multiphysics software development focused on LWRS. In terms of the thermal hydraulics, simulation codes suitable for this multiscale and multiphysics software development include the subchannel code CTF and the thermal hydraulics module FLOCAL of the nodal code DYN3D. In this journal article, CTF and FLOCAL thermal hydraulics validations and verifications within the multiscale and multiphysics software development have been performed to evaluate the accuracy and methodology available to obtain thermal hydraulics at the rod level in both simulation codes. These validations and verifications have proved that CTF is a highly accurate subchannel code for thermal hydraulics. In addition, these verifications have proved that CTF provides a wide range of crossflow and turbulent mixing methods, while FLOCAL in general provides the simplified no-crossflow method as the rest of the methods were only tested during its implementation into DYN3D.

scholarly journals МЕТОД РАСШИРЕНИЯ МОДЕЛИ ЛОГИСТИЧЕСКОЙ ЦЕПИ ПОСТАВОК, ПРЕДСТАВЛЕННОЙ В ФОРМЕ ДВУХУРОВНЕВОЙ ВЛОЖЕННОЙ СЕТИ ПЕТРИ

2019 ◽  
pp. 82-90
Author(s):  
Игорь Владимирович Шостак ◽  
Yashar Rahimi
Keyword(s):  
Supply Chain ◽  
Network Model ◽  
Business Processes ◽  
Raw Materials ◽  
Network Models ◽  
Raw Material ◽  
Wide Range ◽  
Dried Fruit ◽  
Time Dependencies ◽  
High Level

The issues related to the development of adequate network models of the processes of creating, deploying and supporting the functioning of the full logistics supply chain of dried fruit (SCDF) in Ukraine are considered. It is shown that the creation and operation of the SCDF, compared to other SCM class systems, raises a number of specific problems caused by the complexity of the interaction of raw material suppliers (fresh fruit), manufacturers of final products (drying, packaging), storage terminals, distributors, 3PL and 4PL providers (retailers). These problems are due to the fact that the interaction of participants in business processes in the SCDF generates a lot of material, financial and information flows, as well as flows of services from sources of raw materials to the final consumer. The variety of world regions from which dried fruit is delivered to Ukraine, a wide range of products supplied, yield, currency fluctuations, seasonality are the causes of a high level of uncertainty in the processes of formation and decision-making by the SCDF participants. The urgency of the problem is substantiated, the essence of which is to develop a temporal component in the network model of the SCDF, which adequately reflects in time the logistic processes that take place during the operation of the supply chain. A model of a full SCDF in the form of a two-level nested Petri net (NPN) is considered. At the same time, the network model of SCDF functioning in the form of a NPN includes two types of objects - the central link reflecting the activity of the focusing company on processing raw materials (dried fruits), and a number of subnets that simulate the activity of suppliers of raw materials and distributors of finished products. It is indicated that to predict the consequences of the current (or some predetermined) situation and to respond to inquiries about the future state of elements of the SCDF, a predictive model can be used that explicitly takes into account time dependencies. In this case, requests can be about the time of occurrence of certain events, and the fact that certain circumstances are present at a certain point in time. A method is described for extending the network model of the SCDF to comply with the 'just-in-time' principle when modeling business processes that take place supply chain.

scholarly journals Challenges of SMR Licensing Practices

2012 ◽  
Vol 1 (2) ◽  
pp. 19-31 ◽  
Author(s):  
K. Söderholm
Keyword(s):  
Nuclear Power ◽  
Public Information ◽  
Lessons Learned ◽  
Point Of View ◽  
Aviation Industry ◽  
Small Modular Reactor ◽  
The Usa ◽  
Serial Construction ◽  
The Uk ◽  
High Level

This paper aims to increase the understanding of high level Nuclear Power Plant (NPP) licensing processes in Finland, France, the UK, Canada and the USA. These countries have been selected for this study because of their different licensing processes and recent actions in new NPP construction. After discussing their similarities and differences, suitable features for Small Modular Reactor licensing can be emphasized and suggested. Some of the studied licensing processes have elements that are already quite well suited for application to SMRs, but all of these different national processes can benefit from studying and implementing lessons learned from SMR specific licensing needs. The main SMR features to take into account in licensing are standardization of the design, modularity, mass production and serial construction. Modularity can be divided into two different categories: the first category is simply a single unit facility constructed of independently engineered modules (e.g., construction process for Westinghouse AP-1000 NPP) and the second is a facility structure composed of many reactor modules where modules are manufactured in factories and installed into the facility as needed (e.g., NuScale Power SMR design). Short construction schedules will not be fully benefitted from if the long licensing process prolongs the commissioning and approach to full-power operation. The focus area of this study is to better understand the possibility of SMR deployment in small nuclear countries, such as Finland, which currently has four operating NPPs. The licensing process needs to be simple and clear to make SMR deployment feasible from an economical point of view. This paper uses public information and interviews with experts to establish the overview of the different licensing processes and their main steps. A high-level comparison of the licensing steps has been carried out. Certain aspects of the aviation industry licensing process have also been studied and certain practices have been investigated as possibly suitable for use in nuclear licensing. All of the current licensing processes were found to be quite heavy and time-consuming and further streamlining could be possible without compromising safety or the need for public participation in the licensing process. Some examples of the modification possibilities for SMR applications are discussed. A profound discussion on SMR-specific licensing models, and on ways to simplify and harmonize them, will be needed in the near future in Europe too. This would be a natural continuation to the harmonization efforts underway for existing and new large reactors.

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