Study of space-time evolution of flux in a long-life traveling wave reactor

Shrestha, Rijan

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https://hdl.handle.net/2142/31132 Copy

Description

Title

Study of space-time evolution of flux in a long-life traveling wave reactor

Author(s)

Shrestha, Rijan

Issue Date

2012-05-22T00:30:06Z

Director of Research (if dissertation) or Advisor (if thesis)

Uddin, Rizwan

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear, Plasma, Radiolgc Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Traveling wave reactor
• space-time evolution of flux
• MCNPX model
• Monte Carlo N-Particle eXtended (MCNPX)

Abstract

Simulations using MCNPX have been carried out to analyze the space and time evolution of flux in a Traveling Wave Reactor under constant thermal power condition. For the analyses of flux shape, a 3-D box-shaped model of the reactor is developed. The reactor core is divided into two primary regions: the smaller, enriched region with fissile material; and the larger non-enriched region with fertile material. This enrichment strategy is aimed to allow breed-and-burn in the core. The core, on the outside, is surrounded by reflector of uniform thickness. To facilitate the study of flux profile, the two primary regions in the core are further divided into finer thin slab-like regions called cells. Results presented in this thesis show the propagation of flux profile from the enriched region to the non-enriched region at a near constant speed. This shift in the flux profile is due to the continuous breeding of fissile material and its immediate burning. Analyses of local power density (power fraction) at three specified locations in the core as a function of time are presented. Space and time evolution of the overall core burn-up and localized burn-up are presented and discussed. A history of inventory, according to mass, is reported for selected nuclides. Simplified thermal-hydraulics analysis is carried out to estimate the core-averaged velocity and mass flow rate of sodium coolant through the core. Spatially varying velocity profile and corresponding coolant flow rate based on flux profile (local power density) at any given time is also reported.

Graduation Semester

2012-05

Permalink

http://hdl.handle.net/2142/31132

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© 2012 by Rijan P Shrestha. All Rights Reserved.

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