Concept for the Guarantee of the Integrity of Bolted Flanged Connections in a German Nuclear Power Plant

2008 ◽  
Author(s):  
Manfred Schaaf ◽  
Friedrich Schoeckle ◽  
Jaroslav Bartonicek
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Data Base ◽  
Nuclear Power ◽  
Test Laboratory ◽  
Third Party ◽  
Nuclear Facilities ◽  
Systematic Treatment ◽  
Bolted Flange ◽  
Test Loading

In nuclear facilities in Germany a systematic treatment of all sealing connections which are opened during the annual shutdowns is performed since several years. Special attention is paid to a design which meets specifications of the bolted flange connections (BFC’s). Apart from the use of suitable and certified materials this includes also the calculation of the required torques in accordance to the present rules. For the calculation procedure the nuclear code KTA 3211.2 (draft 2003) is applied which allows a tightness proof of the BFC, besides a stress analysis. For this calculation, experimentally achieved gasket characteristics according to DIN 28090-1 are required, which are either supplied by the gasket manufacturers or determined in the amtec test laboratory. The geometry and material data of each BFC are stored in a special data base. In addition, the data of the operating state as well as the design and test loading cases are included in the data base, so that all inputs for a later calculation are available. The results of the calculation which must be checked and approved by an expert third-party are stored in the flange data base, too (assembly state settings of each flange connection). On this base individual flange data sheets can be provided to the flange fitter teams that include all necessary information for assembly of each BFC (bolts, nuts, gasket, geometry and material specifications, lubricant, etc.).

Use of Shear Lugs for Anchorage to Concrete

2009 ◽  
Author(s):  
Peter J. Carrato ◽  
Martin Reifschneider
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Design Method ◽  
American Concrete Institute ◽  
Significant Activity ◽  
Lateral Loads ◽  
Nuclear Facilities ◽  
Shear Loads ◽  
Full Scale Tests

Anchoring structures, systems and components to concrete is a significant activity in the design and construction of a nuclear power plant. Early in this decade the Concrete Capacity Design method (CCD) was adopted by the American Concrete Institute (ACI) for use in the structural design for both commercial and nuclear facilities. This design method and associated qualification tests brings new challenges to designing efficient means for anchoring to concrete structures. Although the CCD method provides guidance on many aspects of concrete anchorage there are a few areas, pertinent to nuclear power plant construction, that are not covered or require significant interpretation of the most recent codes. This paper will focus on the design of shear lugs used to resist significant lateral loads. Results from laboratory tests of shear lugs are presented. These full scale tests considered the interaction of tension and shear loads on the performance of shear lug assemblies. Recommendations for the efficient use of shear lugs are provided.

scholarly journals Historic Perspective on the Conversations to Restart the Kashiwazaki-Kariwa Nuclear Power Plant

2021 ◽  
Vol 10 (29) ◽  
pp. 147-172
Author(s):  
Andrea Carolina Ávalos Salgado ◽  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Local Community ◽  
Nuclear Facilities ◽  
The Public ◽  
Before And After ◽  
The Government

Following the accident of Fukushima in 2011, nuclear facilities in Japan were shut down, and a new evaluation and restart process was developed. Despite the public safety concerns, the current administration expects nuclear energy to become a pillar for economic recovery in the coming years. This paper compares the historic context of restarting Kashiwazaki-Kariwa Nuclear Power Plant before and after Fukushima. The evolution is analyzed through a series of interviews in 2012 and 2013 in the community and with government officers, as well as a close follow-up of the official statements by TEPCO and the government agencies up until the end of 2020. It tackles the development in the relation between TEPCO, local authorities, and local community of this nuclear plant, before and after Fukushima. This historic relation has shown to be the key element in the restart process, even above the legal process.

scholarly journals Levels, Variations and Sources of 90sr and 137cs in Environmental and Food Samples Around Qinshan Nuclear Power Plant, China in 2012-2019

2021 ◽  
Author(s):  
Yiyao Cao ◽  
Zhixin Zhao ◽  
Xiaoming Lou ◽  
Shunfei Yu ◽  
Meibian Zhang ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Local Population ◽  
Temporal Variations ◽  
Food Samples ◽  
Nuclear Facilities ◽  
Local Facility ◽  
Radioactivity Monitoring ◽  
Radioactive Release

Abstract Environmental radioactivity monitoring in the surroundings of nuclear facilities is important to provide baseline data for effective detection in case of any radioactive release in the region. In this work, we report for the first time the long-term monitoring data of 137Cs and 90Sr in environmental and food samples around Qinshan Nuclear Power Plant (QNPP) in 2012-2019. The distribution levels, temporal variations and source terms of 137Cs and 90Sr in the investigated samples were discussed. The annual effective dose (AED) for the local population from the ingestion of foods was also evaluated. Peak values of 90Sr and 137Cs concentrations and 137Cs/90Sr radioactivity ratio were observed in total atmospheric deposition in 2016 and some water and food samples in the following years. This seems to be associated to an additional radioactive input, mostly likely from the operational release of a local facility. This demonstrates that 90Sr and 137Cs, especially the 137Cs/90Sr activity ratio, are sensitive indicators for detecting potential radioactive releases. Nevertheless, overall 90Sr and 137Cs activity concentrations measured during 2012-2019 in this work were at the background levels with average AED far below the internationally permissible limit and recommendation.

Recent Developments in D&D of Nuclear Facilities in Spain

2001 ◽  
Author(s):  
Juan L. Santiago ◽  
Sergio Vidaechea
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radioactive Waste ◽  
Nuclear Power ◽  
International Level ◽  
Final Phase ◽  
Nuclear Facilities ◽  
Recent Developments ◽  
Leading Position ◽  
Key Issues

Abstract Spain occupies a leading position at international level in the field of installation decommissioning. Decommissioning projects have already been performed in relation to uranium mills, the rehabilitation of disused uranium mines is currently in the final phase and the dismantling of the Vandellós-I Nuclear Power Plant is now under way. On the basis of this experience, this paper describes the key issues in decommissioning technology and presents the approaches adopted by ENRESA to tackle the decommissioning strategy in Spain. In particular practical dismantling and decontamination methods are described, and material and radioactive waste management are discussed.

Maximizing Value of Existing Nuclear Power Plant Generating Assets: A Case Study

2007 ◽  
Author(s):  
Komandur S. Sunder Raj
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Fossil Fuels ◽  
Nuclear Facilities ◽  
Operation Performance ◽  
Generating Capacity ◽  
Greenhouse Effects ◽  
And Performance

The nuclear power industry is presently witnessing a renaissance. Global warming, greenhouse effects, concerns with use of as well as rising costs of fossil fuels, the desire to be weaned from foreign oil are all factors driving the need for increased reliance on nuclear power. Consequently, nuclear power plant owners are seeking to maximize the value of their generating assets through various means: improved operation, performance, capacity, availability, reliability and efficiency; license renewals, and; power uprates. Capacity factors are currently averaging well over 90% and, forced outage rates have decreased significantly, reflecting the maturation of operating and maintenance practices. In recognition of low fuel and relatively stable operating costs of their nuclear facilities, nuclear power plant owners have not only applied for license renewals, but have also upgraded the operation and, added electrical generating capacity to the operating units. Using a case study, this paper describes current efforts in maximizing the value of existing nuclear power plant generating assets. The focus of the paper is on maximizing benefits through improved operations and performance.

How a Knowledge Data Base Assists the Process of Aging Management

2011 ◽  
Author(s):  
Horst Rothenho¨fer ◽  
Friedrich Scho¨ckle ◽  
Gu¨nter Ko¨nig
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Data Base ◽  
Nuclear Power ◽  
Collaborative Work ◽  
Operational Experience ◽  
Operational Parameters ◽  
Pdca Cycle ◽  
Definition Of ◽  
Status Analysis

The process of aging management in a nuclear power plant requires collaborative work of different departments. In this process information has to be gathered and evaluated systematically. At the beginning of the process it is important to classify all systems, structures and components (SSCs) into 3 categories of descending importance concerning safety where only the first two categories have to be considered for aging management. Basic information on the material and dimensions, operational parameters, quality status, analysis reports and relevant degradation mechanisms is stored in the data base for all SSCs of category 1 and 2. While a nuclear power plant is in service numerous events may occur which are related to aging and may have an influence on the quality of SSCs. Relevant events may be malfunction messages, maintenance results, operational experience, results of surveillance or events in external installations. It is important to evaluate these events concerning the aspect of aging and to decide which measures are required to prevent unexpected events of the same kind in the future. In some cases the new experience has to be assigned to comparable SSCs. These evaluations, the definition of measures and the tracking of their effectiveness have to be done by an aging management team that meets regularly every 3 months. The knowledge data base supports the application of the PDCA cycle and provides an overview and fast access to all quality documents related to each SSC including surveillance measures and results. It simplifies the generation of annual status reports which are valuable quality documents that reveal the effectiveness of aging management. Finally the procedure can be extended to SSCs which are important for the availability of the plant and thus take a step forward from aging management to plant life management.

Update on Jose´ Cabrera NPP Decommissioning

2011 ◽  
Author(s):  
Nieves Marti´n ◽  
Manuel Rodri´guez
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Steam Generator ◽  
Nuclear Power ◽  
Storage Facility ◽  
Spent Fuel ◽  
Nuclear Facilities ◽  
Material Management ◽  
Primary Loop ◽  
Dry Storage

ENRESA is the National Spanish Agency responsible of the dismantling of Nuclear Facilities, previous Transfer of ownership of the facility from the Utility to ENRESA. On April 30th 2006, Jose´ Cabrera Nuclear Power Plant (Fig. 1) was definitively shutdown, and two years later, on April 30th 2008, ENRESA requested the transfer of the ownership of the Plant from the Ministry along with the corresponding authorization for performance of the Dismantling and Decommissioning Plan. On February 1st 2010, ENRESA was authorized to initiate the dismantling of Jose´ Cabrera NPP, once the spent fuel has been stored on-site at a dry storage facility (ISFSI). Currently, preparatory activities are underway, including the modification of systems and auxiliary facilities for waste and material management. Main challenges of the project include the removal of major components (vessel, steam generator, pressurizer, main pump and primary loop), and the use of large containers (CE-2b) to reduce segmentation of activated parts.

scholarly journals Safety Assessment of Low-Contaminated Equipment Dismantling at Nuclear Power Plants

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Egidijus Babilas ◽  
Eugenijus Ušpuras ◽  
Sigitas Rimkevičius ◽  
Gintautas Dundulis ◽  
Mindaugas Vaišnoras
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Structural Integrity ◽  
Building Structures ◽  
Nuclear Facilities ◽  
Energy Agency ◽  
Force Calculation

The decommissioning of nuclear facilities requires adequate planning and demonstration that dismantling and decontamination activities can be conducted safely. Existing safety standards require that an appropriate safety assessment be performed to support the decommissioning plan for each facility (International Atomic Energy Agency, 2006). This paper presents safety assessment approach used in Lithuania during the development of the first dismantling and decontamination project for Ignalina NPP. The paper will mainly focus on the identification and assessment of the hazards raised due to dismantling and decontamination activities at Ignalina Nuclear Power Plant and on the assessment of the nonradiological and radiological consequences of the indicated most dangerous initiating event. The drop of heavy item was indicated as one of most dangerous initiating events for the discussed Ignalina Nuclear Power Plant dismantling and decontamination project. For the analysis of the nonradiological impact the finite element model for the load drop force calculation was developed. The radiological impact was evaluated in those accident cases which would lead to the worst radiological consequences. The assessments results show that structural integrity of the building and supporting columns of building structures will be maintained and radiological consequences are lower than the annual regulatory operator dose limit.

Spanish Approach to Large Decommissioning Projects

2011 ◽  
Author(s):  
Juan Luis Santiago ◽  
Alejandro Rodri´guez
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Nuclear Research ◽  
Lessons Learned ◽  
Research Centre ◽  
Nuclear Facilities ◽  
Material Management ◽  
Site Remediation ◽  
Key Aspects

The Spanish experience related to the decommissioning of nuclear facilities includes the decommissioning of the Vandello´s I Nuclear Power Plant, the decommissioning of the CIEMAT Nuclear Research Centre and the decommissioning of the Jose´ Cabrera Nuclear Power Plant. This paper reviews the key aspects of these projects and describes the lessons learned related to preparatory activities, auxiliary facilities, decommissioning technologies, material management and site remediation and release.

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