An analytical approach for loca (Loss of coolant accident)
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Date
1982-04
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Publisher
Turkish Atomic Energy Commission
Abstract
Soğutucu Kaybı Kazası (SKK) oldukça karmaşık dinamik bir süreçtir. İncelenmesi çoğunlukla, ele alınması külfetli bilgisayar programlarının ilgili verilerle koşulmasını gerektirir. Bu programlar üzerinde egemen olunması birikim ister. Bu sağlansa bile elde olunan sonuçların yer yer, fiziksel mi, yoksa çeşitli bilgisayar cilvelerinden bir demet mi olduğunu anlamak kolay olmayabilmektedir. O nedenle, özellikle de eğitimsel amaçla, SKK'nın anatomisinin resmedilmesinde çok yarar bulunmak gerekir. Burada sunulan çalışma işte böyle bir yaklaşımla oluşturulmaktadır. Mümkün en basit düzenek ele alınmış olup, SKK analitik bir çerçeve içinde formüle edilmek istenmektedir. Geliştirilen modelin eğitimsel açıdan yaran, SKK'yi birçok karmaşık, çizgisinden kurtarıp, yakıt içi artık ısı üretimi ve kanal girişindeki soğutucu akışkan hızı gibi iki ana parametresi cinsinden adeta karikatürize ediyor olmasıdır. Sonuçta-süreç boyunca seyri merak konusu olan yakıt merkez sıcaklığı, yakıt duvar sıcaklığı ve akışkan sıcaklığı, yakıt yüksekliği üzerinden ortalanmış anlamda-sözü edilen iki ana parametreye bağlı ve analitik olarak ifade oluna- bilmektedir.
It is proposed to display the main characteristics of a LOCA via a simple model. For this purpose we consider a fuel rod surrounded by a cylindrical coolant channel. The heat transfer equations related to the fuel rod and coolant are written down supposing that the heat conduction is on the radial direction only; the source term that represents the fission products decay can be put into an exponential form; there is no radial temperature gradient within the coolant channel; the fluid is incompressible and (for simplicity) the coolant velocity does not change after LOCA takes place. The heat transfer equations are now undertaken via a weighted residual technique through which appropriate space dependencies for the rod and coolant temperatures respectively in the radial and axial directions are adopted. Mathematical manipulations lead us to time dependent equations only, that show very well the anatomy of LOCA in terms of coolant velocity, fission products heat release, and the center line, the rod wall and the coolant temperatures. An analytical solution of the equations in question is given. A parametric study on the solution is carried out and the behaviour of the related temperatures are drawn with respect to time.
It is proposed to display the main characteristics of a LOCA via a simple model. For this purpose we consider a fuel rod surrounded by a cylindrical coolant channel. The heat transfer equations related to the fuel rod and coolant are written down supposing that the heat conduction is on the radial direction only; the source term that represents the fission products decay can be put into an exponential form; there is no radial temperature gradient within the coolant channel; the fluid is incompressible and (for simplicity) the coolant velocity does not change after LOCA takes place. The heat transfer equations are now undertaken via a weighted residual technique through which appropriate space dependencies for the rod and coolant temperatures respectively in the radial and axial directions are adopted. Mathematical manipulations lead us to time dependent equations only, that show very well the anatomy of LOCA in terms of coolant velocity, fission products heat release, and the center line, the rod wall and the coolant temperatures. An analytical solution of the equations in question is given. A parametric study on the solution is carried out and the behaviour of the related temperatures are drawn with respect to time.
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Keywords
Analytical approach, Analitik yaklaşım, Loss of coolant accident), Soğutma sıvısı kaybı kazası, Loca
Citation
Saldıray, E. S., İşyar, A. ve Yarman, T. (1982). Determination of the concentration of uranium in geochemical samples. Turkish Journal of Nuclear Sciences, 9(1), 3-9.