Seminar: Designing a Replacement Research Reactor for Advance Neutron Source at NIST

Abstract

A LEU-fueled research reactor as a replacement of the present NIST reactor is currently being designed and studied at NIST Center for Neutron Research (NCNR). The main goal of the new reactor is to provide advanced neutron sources for scientific experiments with a particular interest on high intensity cold neutron sources. The reactor was designed with 20 MW thermal power and 30-day operating cycle. After a brief introduction of the speaker’s technical background and the current NIST reactor’s status, this talk will mainly present the neutronics and thermal-hydraulics safety analysis results of the new reactor. The core physics studies were performed using the Monte-Carlo code MCNP6. The estimated maximum thermal flux of the core is ~5×1014 n/cm2-s. The calculated brightness of the cold neutron source (CNS) demonstrates the superiority of the cold neutron performance of the new design. Sufficient reactivity control worths and shutdown margins are realized by hafnium control elements. Negative Reactivity coefficients were ensured to provide negative thermal feedback. Thermal-hydraulics safety studies were performed using the multi-channel safety analysis code PARET/ANL. Steady-state analysis showed that the peak cladding temperature (PCT) and minimum critical heat flux ratio (MCHFR) are less than design limits with sufficient margins. Detailed transient analyses for a postulated reactivity insertion accident and a loss of flow accident showed that no fuel damage or cladding failure would occur with the protection of reactor scrams.

About the Speaker

Dr. Zeyun Wu is currently Research Associate in the Department of Material Sciences and Engineering at the University of Maryland (UMD). With this role, he is working as Lead Nuclear Engineer at National Institute of Standards and Technology (NIST) in charge of a replacement research reactor design project. Prior to joining UMD and NIST, he has had post-doc trainings at the Purdue University and North Carolina State University, respectively. Dr. Wu received his Bachelor degree from Tsinghua University at Beijing China and Ph.D. degree from Texas A&M University, both in nuclear engineering. His research interest includes reactor physics, reactor design and analysis, computational methods on neutron transport and uncertainty analysis for nuclear applications, etc.

Hosted by Professor Lei R. Cao