atw - International Journal for Nuclear Power | 04.2019

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atw Vol. 64 (2019) | Issue 4 ı April OPERATION AND NEW BUILD 220 (Figure 9). As the allowable crack length is 4.9 inches and it is greater than 4 inches. Thus, brittle failure is not expected to occur. The evaluation against ductile failure showed that the allowable circumferential projection of the crack length is 16.36 inches (Figure 10). As this value is greater than 4 inches. It is not expected ductile failure to occur. These conditions were also evaluated with the R6 Failure Diagram, Figure 14. For this purpose, the following parameters were calcu lated: and . The results showed that this arrangement has structural integrity and can continue its operation. A critical condition is expected along the circumferential projection. There is a tendency to a fragile fracture. It is advisable to inspect this crack periodically. 6.3 Unsafe helical crack A helical crack, which has a length of 18”, was postulated. Its components in the axial and circumferential directions are 7.19 inches and 16.5 inches, respectively. The reactor operates with 100 % of the output power and the flow through the core is 107 %. The two headers of the RRC are in operation and 100 % of the flow of water has been passing through the core. The projection of the crack in the axial direction is evaluated with Figure 7. The allowable crack length, in accordance with Fracture Mechanics, is 11.6 inches. It is bigger than 7.19 inches. So, it is acceptable. Regarding the limit load collapse analysis, it was carried out with Figure 8. The allowable crack length is 11.11 inches. As, it is bigger than 7.19 inches. It is accepted. These evaluations were completed with the Failure Assessment Diagram, Figure 15. In a second phase, the projection in the circumferential direction is evaluated, considering the principles of fracture mechanics. In accordance with Figure 9, the allowable crack length is 4.9 inches. This should not be accepted, because the crack projection (16.5 inches) is bigger than the allowable crack length. The same analysis was done with the Collapse Limit Load analysis. The allowable circumferential crack is 16.36 inches. However, the crack projection is 16.5 inches. Under this condition, it can be accepted. In order to confirm these results, this situation was analyzed with the Failure Assessment Diagram. For this purpose, the following parameters were calcu lated: and . These values are located outside of the safe zone. It is illustrated in Figure 16 and it is confirmed that the structural integrity of the riser has been compromised. It can be expected a failure in which brittle behavior will be predominant. 7 Conclusions The helical or diagonal cracks that may take place on the riser close to the weld of the riser brace weld. It was considered that a torsional mode of vibration around the axial axis of the riser generated the loading conditions for the crack propagation. The operational loads that could take place were considered in the methodology, which was applied. It is considered that the system has enough structural integrity when the conditions that avoid ductile and brittle failures along the circumferential and axial directions are fulfilled. Otherwise, the component has to be repaired. One alternative is to substitute the damaged part. However, it should to be cut and a new replacement component should be welded. These operations should have to be done below the water level and during the outage of the nuclear power plant. Under these conditions, it is difficult to get a good quality in this job. It would be advisable to install a reinforcement structure, in such way that a compression load must be applied to avoid fracture mode I on the crack. Besides, torsion and bending have to for limited. Regarding the inspections, they have to be done periodically. Crack propagation has to be monitored and the structural integrity of the reinforcement frame has to be evaluated. Misalignments, deterioration and corrosion have to be avoided. Acknowledgements The authors kindly acknowledge the grant for the development of the Project 211704. It was awarded by the National Council of Science and Technology (CONACyT). Statement The conclusions and opinions stated in this paper do not represent the position of the National Commission on Nuclear Safety and Safeguards, where the co-author P. Ruiz-López is working as an employee. Although special care has been taken to maintain the accuracy of the information and results, all the authors do not assume any responsibility on the consequences of its use. The use of particular mentions of countries, territories, companies, associations, products or methodologies do not imply any judgment or promotion by all the authors. References [1] K. B., Department of Nuclear Regulation, Atomic Energy Council, Taiwan, Recent Material Ageing Degradation Related Issues, Washington D.C.: The Fifth USNRC/TAEC Bilateral Technical Meeting, June 2007. [2] N. M. Cuahquentzi et al.: Evaluation of the Structural Integrity of the Jet Pumps of a Boiling Water Reactor under Hydrodynamic Loading, Defect and Diffusion Forum, vol. 348, pp. 261-270, 2014. [3] Inc. Computers and Structures: CSI Analysis Reference Manual for SAP2000, in ETABS, SAFE and CSiBridge, March 2013. [4] R. D. Blevins: Flow Induced Vibrations, New Orleans, USA: Course ASME PD-146, 2012. [5] G. L. Stevens et al.: Jet pump flaw evaluation procedures, in 8 th International Conference on Nuclear Engineering, Baltimore, USA, April 2000. [6] EPRI: BWRVIP-41: BWR Vessel and Internals Project, in BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines, USA, 1997. [7] G. E. Paredes et al: Severe Accident Simulation of the Laguna Verde Nuclear Power Plant, Science and Technology of Nuclear Installations, vol. 2012, March. [8] R. C. Camargo et al: Análisis de transitorios operacionales con el Código RELAP/SCDAPSIM, Apoyo a las actividades del proceso de certificación para el simulador de la CNLV a condiciones de aumento de potencia, Comisión Nacional de Seguridad Nuclear y Salvaguardias, México, June 2003. [9] American Society of Mechanical Engineers: Section III, Division 1-Appendices. Rules for Construction of Nuclear Facility Components, in Boiler and Pressure Vessel Code, USA, ASME, 2007, pp. 301-302. [10] United States Nuclear Regulatory Commission: Technical Training Center, BWR/4 Technology Manual (R-104B), General Electric Systems, USA. [11] United States Nuclear Regulatory Commission: Technical Training Center, BWR/4 Technology Manual (R-304B), General Electric Systems, USA. [12] United States Nuclear Regulatory Commission: Technical Training Center, BWR/4 Technology Manual (R-504B), General Electric Systems, USA. [13] U.S. Atomic Energy Commission: Regulatory Guide 1.60 Design Response Spectra for Seismic Design of Nuclear Power Plants, U.S. Atomic Energy Commission, USA, December 1973. [14] American Society of Mechanical Engineers: Section XI. Rules for Inservice Inspection of Nuclear Power Plant Components, in Boiler and Pressure Vessel Code, USA, American Society of Mechanical Engineers, 2007. [15] A. Zahoor: Ductile Fracture Handbook, Vol. 2, Electric Power Research Institute Report NP-6301, USA: EPRI, October 1990, pp. 6.1-1, 6.3-1. [16] A. Zahoor: Ductile Fracture Handbook, Vol. 1, Electric Power Research Institute Report NP-6301, USA: EPRI, October 1990, pp. 1-1, 1-4. Authors Pablo Ruiz-López, Ph.D. Comisión Nacional de Seguridad Nuclear y Salvaguardias Head of the Licensing Area México Luis Héctor Hernández-Gómez, Ph.D. Juan Cruz-Castro, M.Sc. Gilberto Soto-Mendoza, M.Sc. Juan Alfonso Beltrán-Fernánde, Ph.D. Guillermo Manuel Urriolagoitia- Calderón, Ph.D. S.E.P.I. Zacatenco, I.P.N. México Operation and New Build Failure Analysis of the Jet Pumps Riser in a Boiling Water Reactor-5 ı Pablo Ruiz-López, Luis Héctor Hernández-Gómez, Juan Cruz-Castro, Gilberto Soto-Mendoza, Juan Alfonso Beltrán-Fernánde and Guillermo Manuel Urriolagoitia-Calderón
atw Vol. 64 (2019) | Issue 4 ı April A World’s Dilemma ‘Upon Which the Sun Never Sets’: The Nuclear Waste Management Strategy: Russia, Asia and the Southern Hemisphere Part I Mark Callis Sanders and Charlotta E. Sanders Due to the length of the article, the article is published in three parts. The authors and editor hope you will enjoy and look forward to reading the entire article, as each portion is published. Part I provides the background to the discussion. Part II considers nuclear waste management from the perspective of Russia and Asia, while Part III considers those States in the Southern Hemisphere. This republication is a shortened version of an article originally published in the journal Progress in Nuclear Energy. The full-length version of the article may be found at: Sanders, M, & Sanders, C 2019 “A world’s dilemma ‘upon which the sun never sets’ – The nuclear waste management strategy (part II): Russia, Asia and the Southern Hemisphere”, Progress in Nuclear Energy 110, 148-169. 1 Introduction This article contemplates the various waste management schemes that are being considered or undertaken to include Russia, Japan, China, South Korea, India, Argentina, Brazil and South Africa. Except for Japan, Argentina and South Korea, these nation states are chosen for discussion because these make up a charac teristic collection of nation states able to shape world policy and events as middle powers commonly referred as ‘BRIC’ or ‘BRICS’ (Brazil, Russia, India, China plus South Africa). These nation states share certain positive and negative similarities including: planned and/or expanding nuclear power programs; large or expanding populations with emergent economies; “high GDP but relatively low GDP per capita; large domestic inequalities; and high absolute poverty levels” [1]. Japan and South Korea are chosen for discussion due to their expansive nuclear power programs, and their unique challenges in finalizing a nuclear waste management disposal facility because of internal political struggles. Argentina is unique in that while it developed and maintained a small nuclear power program for years, despite economic and political difficulties, it is now expanding its nuclear power program with the help of Chinese financial support. 2 Future energy consumption outlook – BRICS Certainly, one of the parallel requirements facing developed and new comer nuclear nation states is the need to gain access to stable, clean, and plentiful sources of power production to drive a burgeoning eco nomy in a cost effective and environmentally friendly manner. Techno logical advances starting in the mid-2000’s have provided an abundance of cheap natural gas through fracking, with an 80 % growth in gas demand led by mostly Asian nation states, including China and India, over the next 20 years [2]. Current predictions for China estimate that it will experience power growth at a rate of 3.8 to 4.6 % per annum through the year 2020, with chronic pollution estimated to cause China an economic loss at almost 6 % of Gross Domestic Product 1 [3]. In its fight to tackle pollution, China is seeking to obtain the environmental benefits of clean energy technologies using wind, solar, and nuclear power generation [4]. Brazil has a small but budding nuclear power program generating about 3 % of its electricity, with 84 % generated through hydro. Brazil’s overreliance on hydro generated power is creating potential challenges due to changing weather patterns and climatic shifts [5]. From the early 1990’s, India has experienced rapid growth in energy consumption as its economic output has risen but is also suffering extreme levels of pollution in its major cities [6]. South Africa currently has two nuclear reactors at one site responsible for generating ~ 5 to 6 % of its electricity with plans to add 9.6 GW of nuclear generation capability across the country over the next 10 to 12 years, costing between 37 to 100 billion USD [7]. 3 Legitimacy through linkage To ensure the long-term viability of a nuclear waste management program, the legal framework supporting the program must be built upon trust and fairness, with the flexibility of a State to work within its own historical processes establishing the rule of law. The Joint Convention on the Safety of Spent Nuclear Fuel Management and on the Safety of Radioactive Waste Management (Joint Convention) are built upon the concept of adequacy, allowing a nation state that is a party to the convention to use its national sovereignty to develop a nuclear waste management strategy that is “comparable to those of the other nation states, which are [also] party to the convention” [8]. The Joint Convention, as the first international treaty covering radioactive waste management, does not provide explicit detail for each intended action allowing for Contracting Parties to enjoy certain levels of flexibility in a nuclear waste management strategy. Pronto adds that this type of general working structure is often the intended design of the framers to guide the actions of those parties at the international level through non-formally binding rules of engagement [9]. Additionally, there are four compartments to consider when developing a nuclear waste management program and which potentially affects its legitimacy. Shown in Figure 1, these compartments comprise (1) concerns surrounding the economic viability towards the funding and building of a nuclear waste disposal facility; (2) that any environmental concerns are duly considered to ensure any negative effects on all stakeholders have been thoroughly 221 DECOMMISSIONING AND WASTE MANAGEMENT Decommissioning and Waste Management A World’s Dilemma ‘Upon Which the Sun Never Sets’: The Nuclear Waste Management Strategy: Russia, Asia and the Southern Hemisphere Part I ı Mark Callis Sanders and Charlotta E. Sanders
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