International Journal of Computing and Network Technology ISSN 2210-1519 Int. J. Com. Net. Teach. 3, No. 1 (Jan. 2015) Email: binkpenther@yahoo.com, magy_kandil@yahoo.com, elsoliman@yahoo.com, hussein43@hotmail.com http://journals.uob.edu.bh Evaluation of the Cables Types during the Fire Conditions in Nuclear Power Plants Walaa El-Kattan 1 , Magy Kandil 1 , El-Sayed A. Said 2 , Abd El-Razik Hussein 1 1 Egyptian Nuclear and Radiological Regulatory Authority (ENNRA), Cairo, Egypt 3 Electrical Eng, AL-Azhar University, Cairo, Egypt Received: 14 Oct. 2014, Revised: 5 Dec. 2014, Accepted: 18 Dec. 2014, Published: 1 Jan. 2015 Abstract: The relatively high dangerous thermal effects of electric cable in the Nuclear Power Plants (NPPs) is the concern to study the cable insulation behavior during a fire accident. This paper provides a comprehensive evaluation for the thermal failure in different cables types of the standard main control room (MCR) in nuclear power plants. Evaluation of the effective parameters is carried out using (CFAST) zone fire modeling. The fire growth in a MCR, is modeled and simulated to determine the effect of thermal failure temperatures corresponding to cable functional failures. This is to develop realistic single point thermal failure thresholds and probability distributions for specific cable insulation types.The output data are assessed for the different cable insulation materials according to the specific thermal failure thresholds, as well as to develop the electrical cable thermal fragility distributions. The present results show the cable functionality interdependence on the external firing. Keywords: Main control room, Fire modeling, CFAST, Cable insulation heat flux. 1. INTRODUCTION Extending the lifetime of a nuclear power plants (NPPs) to 60+ years is one of the most important concerns in the global nuclear industry. For instance, in case of the electric cables that are one of the long life items that have not been considered for replacement during the design life of NPPs (typically 40 years), assessing their degradation state and predicting their remaining lifetime are very critical issues. [1] The nuclear energy standards coordination collaborative (NESCC) is a joint initiative established under the sponsorship of the U.S. department of energy (DOE) and the U.S. nuclear regulatory commission (NRC) in coordination with the national institute of standards and technology (NIST) and the American national standard institute (ANSI) [2]. NESCC discussions revealed electrical cable aging and condition monitoring to be two common concerns with nuclear power plant cables as plants age. Electrical cables, especially their insulation and jacket materials, are susceptible to aging degradation under service conditions in nuclear power plants. Historically, cables for this application have been subjected to accelerated thermal and radiation aging and testing to demonstrate a qualified life of 40 years. Installed cables have subsequently been qualified for an extended qualified life of 60 years or more. Improved methods for monitoring and assessing the in‐service performance and condition of cables are needed. In Nuclear Power Plants the cables „fire causes many dangerous events in electrical or mechanical operations that may lead to nuclear reactor melt down; thus main control room (MCR) in NPPs have special concern in fire protection system. There is different models of fire that divide the building into different numbers of control volume [3]. The most common model is the zone model that uses two control volumes, upper layer and lower layer to describe a compartment. This approach is based on simulation of real-scale fire scenario and are taken from real experiments. Hot gases are collected up the ceiling and fill the compartment layer at the top. While the experiments show some variation in conditions within the layer, those may be small compared to the differences between both layers. Thus, the zone model can produce a fairly realistic simulation. On the other hand, field model divides the compartment into thousands of volumes. Accordingly, field models are able to predict the variation in conditions within the layers, but require much longer run times than zone models. Thus, it is used when highly detailed calculations are essential where the compartment is highly