Doctoral Dissertations

Keywords and Phrases

Radioactive Particle Tracking


"The Pebble Bed Reactor (PBR) is a 4th generation nuclear reactor which is conceptually similar to moving bed reactors used in the chemical and petrochemical industries. In a PBR core, nuclear fuel in the form of pebbles moves slowly under the influence of gravity. Due to the dynamic nature of the core, a thorough understanding about slow and dense granular flow of pebbles is required from both a reactor safety and performance evaluation point of view.

In this dissertation, a new integrated experimental and computational study of granular flow in a PBR has been performed. Continuous pebble re-circulation experimental set-up, mimicking flow of pebbles in a PBR, is designed and developed. Experimental investigation of the flow of pebbles in a mimicked test reactor was carried out for the first time using non-invasive radioactive particle tracking (RPT) and residence time distribution (RTD) techniques to measure the pebble trajectory, velocity, overall/zonal residence times, flow patterns etc. The tracer trajectory length and overall/zonal residence time is found to increase with change in pebble's initial seeding position from the center towards the wall of the test reactor. Overall and zonal average velocities of pebbles are found to decrease from the center towards the wall. Discrete element method (DEM) based simulations of test reactor geometry were also carried out using commercial code EDEM and simulation results were validated using the obtained benchmark experimental data. In addition, EDEM based parametric sensitivity study of interaction properties was carried out which suggests that static friction characteristics play an important role from a packed/pebble beds structural characterization point of view. To make the RPT technique viable for practical applications and to enhance its accuracy, a novel and dynamic technique for RPT calibration was designed and developed. Preliminary feasibility results suggest that it can be implemented as a non-invasive and dynamic calibration methodology for RPT technique which will enable its industrial applications."--Abstract, page iii.


Al-Dahhan, Muthanna H.

Committee Member(s)

Smith, Joseph D.
Liang, Xinhua
Park, Joontaek
Mueller, Gary Edward, 1954-


Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering


United States. Department of Energy


Missouri University of Science and Technology

Publication Date

Spring 2014


xvii, 284 pages

Note about bibliography

Includes bibliographical references (pages 2737-283).


© 2014 Vaibhav B. Khane, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Pebble bed reactors -- Computer simulation
Chemical reactors -- Fluid dynamics -- Mathematical models
Finite element method

Thesis Number

T 10456

Electronic OCLC #