Analysis of flow coastdown for an MTR-pool type research reactor

In the present paper a mathematical model is developed upon which the velocity of flow during coastdown transient is determined analytically without the use of characteristics of centrifugal pump. The influence of the two most important parameters, kinetic energy in the piping system and kinetic energy of the pump, is considered in the form of a ratio called hereafter an effective energy ratio. This parameter, the effective energy ratio, is found to be a very accurate indicator of the pumping task duration. Preliminary test of the model were made on the existing piping systems related to nuclear reactors. As a case of study the safety of the Tehran Research Reactor (TRR) primary cooling system, an open pool MTR-type research reactor, is investigated. An excellent agreement is noted when the results of the present analytical model are compared with those obtained by the use of experimental characteristics of centrifugal pump of the TRR. A further comparison of the analytical results with collected experimental data for flow coastdown also shows a very good agreement. (C) 2010 Elsevier Ltd. All rights reserved.