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Science and Technology of Nuclear Installations
Volume 2017, Article ID 1345938, 15 pages
Research Article

Modeling Loss-of-Flow Accidents and Their Impact on Radiation Heat Transfer

Center for Advanced Energy Studies (CAES), University of Idaho, 995 University Blvd., Idaho Falls, ID 83401, USA

Correspondence should be addressed to Fatih Aydogan; moc.liamg@nagodyaf

Received 10 April 2017; Revised 19 July 2017; Accepted 14 August 2017; Published 31 October 2017

Academic Editor: Michael I. Ojovan

Copyright © 2017 Jivan Khatry and Fatih Aydogan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Long-term high payload missions necessitate the need for nuclear space propulsion. The National Aeronautics and Space Administration (NASA) investigated several reactor designs from 1959 to 1973 in order to develop the Nuclear Engine for Rocket Vehicle Application (NERVA). Study of planned/unplanned transients on nuclear thermal rockets is important due to the need for long-term missions. In this work, a system model based on RELAP5 is developed to simulate loss-of-flow accidents on the Pewee I test reactor. This paper investigates the radiation heat transfer between the fuel elements and the structures around it. In addition, the impact on the core fuel element temperature and average core pressure was also investigated. The following expected results were achieved: (i) greater than normal fuel element temperatures, (ii) fuel element temperatures exceeding the uranium carbide melting point, and (iii) average core pressure less than normal. Results show that the radiation heat transfer rate between fuel elements and cold surfaces increases with decreasing flow rate through the reactor system. However, radiation heat transfer decreases when there is a complete LOFA. When there is a complete LOFA, the peripheral coolant channels of the fuel elements handle most of the radiation heat transfer. A safety system needs to be designed to counteract the decay heat resulting from a post-LOFA reactor scram.