Abstracts and Available Papers Presented at the
2002 International RERTR Meeting

STARTUP TEST RESULTS AND MODEL EVALUATION FOR THE HEU TO LEU CONVERSION OF THE UMASS-LOWELL RESEARCH REACTOR

John R. White, Professor, Chemical and Nuclear Engineering Department

Leo Bobek, Reactor Supervisor, UMass-Lowell Radiation Laboratory

University of Massachusetts Lowell
Lowell, MA 01854

ABSTRACT

The 1 MW UMass-Lowell Research Reactor (UMLRR) switched from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel in August 2000.  Several months prior to conversion, a detailed physics study was undertaken to fully characterize the new LEU core, with focus on providing computational support for the actual startup and on estimating the radiation environment in the various experimental facilities in the new LEU-fueled core.

During startup testing, a series of actual reactivity evaluations and thermal flux magnitude and distribution measurements were made.  These startup tests not only established operability of the new core, they also allowed direct evaluation of the computational models and methods used to design and characterize the new LEU core.

This paper highlights this evaluation by summarizing the overall startup test program and the computational methods in use at UMass-Lowell, and by providing a set of comparisons between the measurement results and the computational estimates.  Although some differences were observed, it is apparent from the results presented that the overall computational methodology was quite satisfactory  --  since the as-built system operates essentially as designed.