Integrated Power Recovery Using Markov Modeling

2010 ◽  
Author(s):  
Shawn Rodgers ◽  
Paul Nelson ◽  
Coral Betancourt ◽  
Ernie Kee ◽  
Fatma Yilmaz
Keyword(s):  
Power Supply ◽  
Integral Approach ◽  
Markov Modeling ◽  
Pressurized Water Reactor ◽  
Convolution Integral ◽  
Pressurized Water ◽  
Electric Power Supply ◽  
Alternative Methodology ◽  
Power Recovery ◽  
Convolution Method

The solution to a Markov chain modeling electric power supply to critical equipment in a typical 4-loop pressurized water reactor following a Loss of offsite power event is compared with a convolution method. The standard “convolution integral” approach is described, and an alternative methodology based on a Markov model is illustrated.

Integrated Power Recovery Using Markov Modeling

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Shawn Rodgers ◽  
Coral Betancourt ◽  
Ernie Kee ◽  
Fatma Yilmaz ◽  
Paul Nelson
Keyword(s):  
Power Supply ◽  
Integral Approach ◽  
Markov Modeling ◽  
Pressurized Water Reactor ◽  
Convolution Integral ◽  
Pressurized Water ◽  
Electric Power Supply ◽  
Alternative Methodology ◽  
Power Recovery ◽  
Convolution Method

The solution to a Markov chain modeling electric power supply to critical equipment in a typical four-loop pressurized water reactor following a loss of offsite power event is compared with a convolution method. The standard “convolution integral” approach is described, and an alternative methodology based on a Markov model is illustrated.

Electric Power Supply of German NPPs: Defence in Depth, Protection Against External Hazards and Retrofitting as a Consequence of the Fukushima Accident

2016 ◽  
Author(s):  
Sebastian A. Meiss
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Power Plants ◽  
Science And Technology ◽  
Electrical Power ◽  
Regulatory Framework ◽  
Original Design ◽  
Fukushima Accident ◽  
Pressurized Water ◽  
Electric Power Supply

The history of building and operating nuclear power plants (NPPs) in Germany dates back to the late 1950s and will come to an end in 2022. By then all NPPs still in operation will have to shut down in a defined sequence, according to the revisions made to the German Atomic Energy Act as a consequence of the accident at the Fukushima Dai-Ichi NPP. Nine out of 17 NPPs have already been shut down permanently as a consequence. Due to the progress in science and technology, the design of the electrical power supply of German NPPs got more complex and hardened against various scenarios with time. The latest generation of NPPs built in Germany in the late 1980’s — the pressurized water reactor of type Konvoi — was designed with Defence in Depth in mind. They are connected to several voltage levels of the power grid and feature two layers of AC emergency power systems, each of which fulfills the n+2 redundancy criteria. The second of those layers is especially hardened against the influence of certain internal and external events and is part of an emergency control system which can keep the plant in a safe state autonomously for 10 hours under certain conditions. With this being the state of science and technology at that time in Germany, most of the older NPPs in operation had been retrofitted by 2011 with systems that were designed to partially compensate for these plants’ weaker original design. Various events such as the accident at the Chernobyl 4 NPP in 1986 and also the accident at the Fukushima Dai-Ichi NPP in 2011 led to changes in the German regulatory framework and recommendations to the NPPs for further retrofitting activities. In the regime of electrical power supply, the latest changes in requirements and corresponding retrofitting of the NPPs in operation include mobile diesel generators with corresponding, redundant feeding points, an enhanced coping capability for station blackouts with only DC-power left and measures to ensure bringing back AC-power within the available time. In this presentation the author gives an overview over the historic development of the electric design in German NPPs and discuss details of the most recently added requirements on retrofitting — e.g. in the new regulatory framework — to enhance the robustness of the electrical power supply of those NPPs. An update on the progress on the actual retrofitting process of the German NPPs with respect to these new requirements is given.

Leaching Studies of Cement-Glass Package Containing Sodium Borate

1986 ◽  
Vol 84 ◽  
Author(s):  
Masahiro Okamoto ◽  
Koichi Chino ◽  
Tsutomu Baba ◽  
Tatsuo Izumida ◽  
Fumio Kawamura ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Liquid Waste ◽  
Sodium Borate ◽  
Pressurized Water Reactor ◽  
X Ray Diffraction ◽  
Adsorption Ability ◽  
Pressurized Water ◽  
X Ray ◽  
Solidification Reaction ◽  
Main Components

AbstractA new solidification technique using cement-glass, which is a mixture of sodium silicate, cement, additives, and initiator of the solidification reaction, was developed for sodium borate liquid waste generated from pressurized water reactor (PWR) plants. The cement-glass could solidify eight times as much sodium borate as cement could, because the solidifying reaction of the cement-glass is not hindered by borate ions.The reaction mechanism of sodium silicate and phosphoric silicate (initiator), the main components of cement-glass, was studied through X-ray diffraction and compressive strength measurements. It was found that three- dimensionally bonded silicon dioxide was produced by polymerization of the two silicates. The leaching ratio of cesium from the cement-glass package was one-tenth that of the cement one. This low value was attributed to a high cesium adsorption ability of the cement-glass and it could be theoretically predicted accordingly.

A Combined Wind-and-Sola Generator for Autonomous Electric Power Supply Systems

2018 ◽  
pp. 19-27
Author(s):  
BAGAUDIN Kh. GAITOV ◽  
◽  
Yakov M. KASHIN ◽  
Lev E. KOPELEVICH ◽  
Aleksandr V. SAMORODOV ◽  
...  
Keyword(s):  
Electric Power ◽  
Power Supply ◽  
Electric Power Supply ◽  
Supply Systems
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