New article published in 12(4B) - ENFIR/INAC 2024

Closed nuclear fuel cycle strategy for NuScale-like reactor: safety parameters evaluation

Abstract: The present study evaluates the potential implementation of two different closed fuel cycle strategies for a NuScale-like reactor core. After undergoing three burnup cycles of approximately 12 MWd/kgU in the NuScale-like initial core and five years of cooling in a spent fuel pool, the spent fuel was theoretically reprocessed using GANEX or UREX+ methods. These reprocessed fuel compositions were then mixed with thorium (Th) and inserted into specific batch positions of the core. As a result, the proposed NuScale-like core configurations contain fuel assemblies loaded with both conventional uranium-based fuel and reprocessed fuel, resulting in the following combinations: UO₂ and GANEX spiked with Th, and UO₂ and UREX+ spiked with Th. The primary goal is to assess the safety margins of the proposed cores and compare them with the reference case. The results indicate that all scenarios with reprocessed fuel improved the fuel temperature reactivity coefficient and maximum initial excess of reactivity, while varying the boron concentration in the coolant. Additionally, it was found that both proposed cores met the power peak factor (PPF) design requirements, despite the high PPF value observed at the C03 central position. The simulations were performed using the Serpent code version 2.1.32, developed by VTT. Read full article. 

IPR-R1 Triga Reactor aging management approach

Abstract: A global nuclear safety regime is in place and is being continuously improved. In this context, the aging management of research reactors is one of the requirements for licensing by the regulatory body. The IPR-R1 Triga reactor, located at the for Nuclear Technology Development Center (CDTN), is a nuclear reactor used primarily to research support. It has been in operation for over 60 years and its activities are expected to continue.  Thus, the aging management of components, structures and systems is one of the safety factors included in the Periodic Safety Report and encompasses several programs and activities, following the Specific Safety Guide SSG-10 (Aging Management for Research Reactors) of the International Atomic Energy Agency (IAEA). These programs are broad and transversal, serving as input for critical analysis of the Aging Management Plan (AMP), aimed at its continuous improvement. This paper aims to systematically present information related to the AMP of the CDTN IPR-R1 Triga reactor, such as visual inspection, reactor pool water quality control, maintenance, obsolescence control, investigation of operational parameters and all necessary controls to ensure that the safety margins required in the reactor design are maintained throughout its useful life.  Read full article.