Recent Developments in D&D of Nuclear Facilities in Spain

Author(s):  
Juan L. Santiago ◽  
Sergio Vidaechea

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.

2021 ◽  
Vol 24 (3) ◽  
pp. 291-301
Author(s):  
Akhmad Tri Prasetyo ◽  
Muslim Muslim ◽  
Heny Suseno

The study of radioactive dispersion in the ocean should be conducted to prepare the construction of nuclear power plant (NPP) in Gosong Coast, West Kalimantan. This study estimated the distribution of 137Cs radioactive from various scenarios of radioactive waste dumping if nuclear emergency is occurred during NPP’s operation. These scenarios were distinguished based on their volume discharges of radioactive waste into the ocean, included 10 m3 (Scenario I), 50 m3 (Scenario II), and 100 m3 (Scenario III).  Model dispersions were constructed for 15 days by Delft3D-Flow module. The simulation showed that ocean current directions were not significantly different among spring and neap tide, instead the ocean current during the spring period dominantly increased rather than neap period. Ocean currents at Gosong Coast flowed parallel to the shoreline towards Singkawang Coastal Area during ebb tide. Meanwhile, during flood tide, ocean currents at Gosong Coast flowed offshore through Burung Archipelagic. The dispersed model showed the distribution of 137Cs radioactive for 15 days reaching to coastal areas of Burung Archipelagic, Singkawang, and Southern Sambas Coast. Each scenario of the disposal system did not influence the marine pollution of the West Kalimantan Sea.


Author(s):  
Borys Ya. Oskolkov ◽  
Yuri A. Neretin ◽  
Valeryi P. Saliy ◽  
Valeryi A. Seyda ◽  
Vyascheslav V. Fomin

According to the assessments the overall amount of radioactive waste (RAW) to be reprocessed and buried at the Chornobyl NPP site amounts to 1,696,738 m3 (without regard for reactor metal structures, dismantling of building structures and plan constructions, and the Unit Shelter building). The overall activity of radioactive waste are evaluated at 1,640,504.64 ΤBq. The RAW management activities are implemented at the Chornoby1 NPP within the frame of several programs of different hierarchy including the State Comprehensive Program for RAW Management in Ukraine, Integrated Program of RAW Management at the Chornoby1 NPP Shutdown Stage and Transformation of the Unit Shelter into an Ecologically Safe System. At the present time a number of key RAW management facilities are being constructed within the frame of the international aid to Ukraine. They are the Liquid Radioactive Waste Plant and Solid Radioactive Waste Reprocessing Complex. As of now, the issues concerning RAW utilization at the Unit Shelter are resolved at a conceptual level. There has not practical decision in relation to a geologic facility. The complexity and scale of ChNPP RAW management problems will require significant efforts of both Ukraine and the whole world community to solve these issues. The task related to removal and final burial of accumulated and generating radioactive waste is one of the main aspects of decommissioning activities at any nuclear power plant. RAW management work is the most important and complicated work performed at the Chornoby1 NPP. The specific features of ChNPP RAW management are as follows: • Variety of RAW generation sources, their types, physical and chemical properties. • Large amount of radioactive wastes which already exist and those generated in the decommissioning process. • Presence of disorganized RAW characterized by wide spatial distribution within the Unit Shelter and at the plant site. • Need to apply a very wide spectrum of various RAW management techniques depending on their location and type. • Need in developing unique techniques to manage special types of RAW located at the site (fuel containing masses of the Unit Shelter). • Large amount and variety of facilities required for RAW final storage. • Absence of reliable and serviceable instrumental procedures and necessary equipment to define RAW properties for RAW separation and classification. • Ecological peculiarities of RAW management within the Chornoby1 zone. • Multiphase decontamination and restoration processes resulting in RAW formation. • Need in integrating RAW management problems at the ChNPP and within the Chornoby1 Exclusion Zone taken as whole. • Long time period required for implementing the whole program of RAW management at the ChNPP. • Large quantity of people involved in RAW management process (local and foreign participants, different organization operated by various departments).


Author(s):  
Peter J. Carrato ◽  
Martin Reifschneider

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.


Author(s):  
Manfred Schaaf ◽  
Friedrich Schoeckle ◽  
Jaroslav Bartonicek

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.).


2014 ◽  
Vol 521 ◽  
pp. 530-535
Author(s):  
Meng Wang ◽  
Jian Ding ◽  
Tian Tang ◽  
Zhang Sui Lin ◽  
Zhen Da Hu ◽  
...  

The current situation of nuclear power plants at home and abroad is described, and the impact of large-scale nuclear power accessing to the grid is analyzed, specifically in the aspects of nuclear power modeling, simulation, load following, reliability, fault diagnosis, etc. Nuclear power accessing to the grid will bring a series of problems, the causes of each problem, the main solutions and future development directions are summarized.


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