Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors

Abstract

This report describes e preliminary comparative evaluation of pebble bed and pris matic fuel configurations for high-temperature gas-cooled reactor cores and was prepared fcr the Gas Cooled Reactor Programs Division (G. A. Newby, Acting Director), U.S. Depart ment of Energy. Reactor outlet coolant temperatures of 730, 850. and S50°C and reactor siies of 3000 and 1000 MW(t) were considered. The basic studies were carried out over a period of about six months and involved specific relative evaluations, as well as a review of the general information that was available Because of the time limitations, fie evaluations were largely carried out utilizing reference designs in comparing the two reactor concepts. Although not evident on r.he basis of the understanding developed during this study, design reoptimization relative to some of the specific parameters considered to be important here might influence the comparative results; such reoptimizations were not carried out here. The evaluation results given here are those determined by Oak Ridge National Laboratory; however, we wish to acknowledge the significant contributions made by other participants in providing information useful to this study. In particular, we wish to acknowledge the assistance of (1) General Atomic Company (E. 0. Winkler, coordinator) in the areas of design, thermal hydraulics, fission-product behavior, safety studies, fuel cycle performance, maintenance requirements, and fuel reprocessing technology and costs; (2) General Electric Company (G. R. Pflasterer, coordinator) in the areas of reactor avail-aDility, control and design; (3) Gas-Cooled Reactor Associates (D. P. Harmon, coordinator) in providing utility perspectives on reactor maint lance and operations; (4) Management Analysis Company (L. W. Perry, principal) in provide "• the methodology for estimating the overall cost uncertainties of the two reactor concepts; and (5) the U.S. Department of Energy in providing guidance and comments on study emphasis, report organization, and r r esentation of infirmation. Finally, we wish to express our gratitude to Katie Lawhorn of ORNL who, working with the editors, typed numerous iterative drafts of the report, including this final one.

Monte carlo evaluation of VHTR cell calculational model with emphasis on resonance integral.

“…In order to investigate the difference between the infinite multiplication coefficients K~'s of SHE-8 and SHE-14 cores from a physical viewpoint, fot1r factors are derived from the values calculated by the Monte Carlo code, ( 2) where e denotes the fast fission factor, r; the r;-·value, f the thermal utilization factor and p the resonance escape probability. The e is obtained as the ratio of the fission reaction rate over the entire energy range to that in the thermal energy region.…”

“…High temperature reactors can be classified into two types depending on the structure of the fuel elements; pebble-bed( 2 ) and block (or prism) ( 3 ). The West German AVR ( 4 ) is an example of the former type and…”