VSL Sitemap | Contact us | VSL on the Web | Download HOME | THE COMPANY | CONSTRUCTION PARTNER | BUSINESS LINES | VSL BIM LIBRARY | CAREERS HOME BUSINESS LINES CONSTRUCTION NUCLEAR CONTAINMENT STRUCTURES NUCLEAR CONTAINMENT STRUCTURES VSL offers a complete range of post-tensioning materials and services complying with the international nuclear standards to guarantee that the nuclear containment safety requirements are achieved. Nuclear Containment Vessels VSL actively participates in the post-tensioning work for the containment vessels presently being built in France. France - 1985 read more .. GROUND ENGINEERING CONSTRUCTION Bridges Buildings Slab on grade LNG & LPG Containment structures Nuclear containment structures Offshore structures Heavy Lifting Formwork (Buildings & Bridges) REPAIR, STRENGTHENING & PRESERVATION SYSTEMS & TECHNOLOGIES Have you read it ? MORE+ Video Creating solutions together VSL's corporate movie → WATCH MORE + VSL's Offer Technology Applications Reliable solutions for nuclear containments VSL offers a complete range of services for the design and construction of post-tensioning system for the concrete nuclear containment vessels that use post-tensioning. The post-tensioning is the critical and essential component that insures the air tightness of the structure under a LOCA (Loss of cooling accident) and as such that stops the contaminated particles to dissipate into the atmosphere. Strong of its experience gained in the construction of 59 containment structures worldwide since 1974, VSL provides: efficient and reliable systems designed specifically for nuclear applications technical support to designers and contractors to develop optimised solutions state of the art equipment and construction methods providing a full and transparent traceability to the entire production and construction process. VSL has developed a specialized range of data acquisition systems attached to the installation equipment that keeps track of in-situ construction data. This allows traceability of every step of the works, and as such allows isolating problems and issues associated with the installation of large tendons and insures that the works have been carried out to the highest standards which ultimately translate in durability for the nuclear containment structure. MORE+ a strong commitment to R&D, to continue developing systems, equipment and methods to keep VSL its leading position in the post-tensioning industry Full-scale mock up MORE+ a dedicated supply chain for nuclear works to ensure system treatability and safety VSL offers components, equipment and installation methods that are customized and approved for all current nuclear containment designs. MORE+ turnkey services customised for each project Complete turnkey services can be customized to each project, covering design, approval assistance, supply and installation for new containments as well as monitoring and maintenance of existing structures. MORE+ specialised and skilled staff trained at the VSL Academy VSL staff dedicated to nuclear works are trained to carry out the specific installation methods and to operate the sophisticated equipment required for nuclear applications. Trained personnel are the key to guaranteeing the performance of post-tensioning systems and thus ensuring the performance and reliability of the nuclear containment structure. MORE+ VSL’s products and services VSL offers a full range of services to guarantee that the post-tensioning system fulfills all the containment safety requirements. These services include : engineering and design assistance to design, detail and integrate of the post-tensioning system into the structure. validation of the supply chain, by qualifying internal and external suppliers and carrying regular audits supply of all post-tensioning materials including strands and grout installation, including all the testing and checks required to ensure complete traceability of materials and site operations specifications and construction of monitoring systems to keep track of the containment’s structural behaviour and performance. That allows controlling safety, and optimizing maintenance works throughout the structure service life. Supply, installation and commissioning of the specialised working platforms to access the post-tensioning anchorages along the buttresses Local regulations do not always require the hiring of a specialized contractor for the installation of the post-tensioning materials. However, VSL strongly recommends that the full scope of post-tensioning supply and installation scope is carried out by a specialist, to insure the highest quality standards are achieved to safeguard the long-term critical performance of a nuclear containment. Post-tensioning is the essential part of that scheme. VSL is indeed fully geared to provide that entire service. Associated Services Upgrading the structural capacity to meet new seismic requirements VSL has developed effective strengthening and repair strategies specifically for the complex environment of nuclear facilities. These operations restore and/or enhance structural functions. After years of service, the containment walls may need to be strengthened if they no longer meet the latest design standard requirements. VSL’s strengthening systems use the principle of post-tensioning. Strengthening can be carried out by the use of either post-tensioning steel strand or by bonding fibre reinforced polymer materials such as carbon fibre plates onto weak spots in a structure. The advantages of that latter strengthening technique are manifold: low weight, low structural height, high geometric flexibility, no corrosion, very fast application and efficient handling. Strengthening or alterations may be needed if there has been a change in use and/or loading or if the structural system has been modified or needs repairs. Upgrading of structures in seismically endangered zones may also be required to meet the latest standards. Custom-engineered solutions for heavy lifting works VSL Group’s Heavy lifting division covers a wide range of services from initial concept through engineering, planning, equipment supply and execution of heavy lift projects. It has a proven track record within the nuclear power industry. VSL Heavy lifting offers tailored solutions to accomplish the most difficult works in the most stringent situations during the construction, maintenance, refurbishment or decommissioning of nuclear power plants. VSL Heavy lifting is specialized in: Nuclear commissioning or decommissioning projects Installation or replacement of steam generator and reactor vessel heads, or handling of any other heavy components within or outside of the nuclear structure Specialised transportation of heavy loads Design and supply of any special equipment and temporary structures related to heavy lifting Lifting a steam generator at the nuclear power plant Beznau I, Switerzrland, 1993 All work executed by VSL Heavy lifting follows a very stringent quality assurance programme to ensure that the temporary works are built to the required standards and that the processes follow established and checked plans. Before the lift proceeds, there are systematic load tests of the entire system of heavy lifting equipment and its associated temporary structures. VSL’s Heavy lifting equipment VSL’s equipment range includes a large variety of hydraulic jacks with piston strokes between 160mm and 550mm and capacities from 100kN to 5,800kN. These units can be used in tandem in cases where high speeds are required. Equipment such as hydraulic coilers, emergency devices and sensor-controlled measuring units are also available to complete the system. VSL can design and supply custom-built hydraulic systems as required for special applications. MORE+ Infrastructure Protection VSL Infrastructure Protection is a division of VSL specialising in the analysis, design, development and implementation of solutions to safeguard critical infrastructure against blast, weapons and other extreme events. VSL has the experience and the capability to provide boundary deterrence to meet antiram, intrusion and blast protection requirements. It can also provide blast resilience measures for control buildings and associated structures at nuclear power plants, as well as protecting against aircraft impact. VSL’s solution portfolio includes a range of proven technologies and tested products for blast mitigation measures. Enhanced structural durability with Ductal® Cattenom France VSL can provide solutions that use Ductal® material to protect or replace concrete structures subjected to extreme aggressive conditions. Ductal® has very high mechanical properties combined with extremely low porosity and a very high resistance to chemicals and abrasion. The material has been used successfully in the Cattenom nuclear power plant, where it forms a beam grid at the bottom of the cooling tower. It was chosen instead of conventional concrete or steel beams because of the very aggressive environment featuring saturated humidity. Maximum versatility through a combination of high-grade bar systems with VSL’s expertise VSL offers a high-grade bar system (grade 900 to 1050) in both coarse-threaded and cold-threaded options. The bars can be used in short straight lengths in place of post-tensioned strand tendons. This provides better efficiency due to the short draw-in and the ability to re-stress the bars during stressing. Grade 650 reinforcement bars Nuclear containment structures are often very congested with rebar, with ratios locally exceeding 500kg/m3. VSL provides design assistance and materials to reduce the congestion by replacing the standard grade 500 reinforcement with higher-grade material. Coarse threaded SAS and CT Bars – the key to efficiency around the world Bars with coarse threads offer important advantages in all applications, particularly geotechnical ones: good bond behaviour threaded along the full length, allowing cutting or extension at any position robust economical and readily available Metric thread bars – great value for specific needs metric threading at both ends of the bar, with architectural benefits no need to use lock nuts non post-tensioned bars can be welded wide variety of accessories and fittings available Advantages of VSL’s offer Several reactor technologies are available worldwide and the most common technology used is the Pressurised Water Reactor (PWR). The containments are designed to withstand the high internal pressures that would result from a loss of coolant accident (LOCA). Applying such pressure to the inside surface of the containment causes tensile forces inside its walls, which are offset by the use of post-tensioning. As such, the post tensioning is the critical component of the containment that provides structural integrity to the containment vessel and ensures that it remains leak-tight. Meeting the most stringent standards VSL’s post-tensioning systems meet the advanced technical and practical requirements of today’s engineers and construction professionals. The systems comply with national and international standards such as those of European Technical Approval Guide ETAG 013, ASME (American Society of Mechanical Engineers) and the French technical code for civil works, ETC-C, produced by AFCEN. These standards define stringent test criteria, approval procedures, manufacturing certification and periodic audit requirements to insure the post-tensioning quality and performance, and thus its durability. Post-tensioning anchorages undergo stringent tests including: Static load tests Load transfer tests Fatigue load tests VSL’s Post-tensioning materials are manufactured under strictly defined and controlled conditions, with: Approved factories Approved material Standardized QA / QC Continuous internal and external auditing Supply chain continuity guarantees safety For nuclear projects, the list of materials to be supplied is very large, ranging from the steel strip used in manufacturing the corrugated ducts, through the components of an anchorage system to the cement or grease that will ensure the system’s final corrosion protection. The VSL supply chain is organised for smooth integration of all the different steps that guarantee the timely supply of components to the right quality. Component production originates from three sources: In-house factories in Europe and Asia Approved suppliers On-site facilities Each relies on different production processes, all must comply with the project specifications and regulations. VSL has developed the necessary QA/QC procedures to meet these requirements. Installation: Specialist required The assembly and installation of the post-tensioning components is carried out on site, in accordance with stringent procedures, tolerances and quality control. This covers aspects including duct placement, tendon installation, stressing and filling with the final protection material. The installation works must be carried out by a specialist contractor in order to guarantee the system’s efficiency and safety as per the design. Specialist contractors must have qualified and experienced supervisors and well-trained labour knowledgeable about all installation aspects of the post-tensioning system. As a specialist contractor, VSL undertakes this entire scope of post-tensioning works. Contributing to sustainable solutions The use of VSL Post-tensioning delivers the maximum cost-benefit for a project by enhancing the durability of a structure and has as well a beneficial impact on its sustainability and CO2 emissions during construction. Compared with conventional reinforced concrete structures, the use of post-tensioning results in more durable structures with reduced concrete volumes, thus lowering the CO2 emissions in some cases by up to 37% Durability Every step of implementation must be carefully planned and controlled in order to ensure durability of the nuclear post-tensioning and its long term performance: At the design stage - by defining quality standards and procedures to ensure control and traceability at every stage of the supply and installation processes, as well as in the provision of long-term monitoring systems During manufacturing of the components and their installation - by strict implementation of processes and quality procedures By the development and use of specialised equipment to enhance accuracy and quality Through the training and qualifications of skilled personnel By the careful and thorough implementation of corrosion protection systems such as cementitious grout, wax or grease In due course, by regular monitoring, inspection and maintenance procedures VSL has the experience to implement all of these steps, guaranteeing that the expected post-tensioning durability is achieved SEND TO A FRIEND Top of page Project references MORE+ Related brochures View: Download: MORE+ Press releases | VSL News magazine | Project references | Brochures | Videos THE COMPANY | CONSTRUCTION PARTNER | BUSINESS LINES | SUSTAINABLE DEVELOPMENT | CAREERS | CONTACT US | DOWNLOAD Press releases VSL News magazine Project references Brochures Videos © 2013 Welcome to VSL International Ltd. / CH-053.3.001.465-2 | Disclaimer | Accessibility