Review of the experimental research on the thermal‐hydraulic characteristics in the pebble bed nuclear reactor core and fusion breeder blankets

Abstract

Summary Merits in the inherent safety characteristics and multiple applications, cause the pebble‐bed‐type nuclear reactors, including the High‐Temperature Gas‐cooled Reactors, Fluoride‐salt‐cooled High‐temperature Reactors and Water‐cooled Pebble‐bed Reactors, to gain more focus in recent years. Thermal‐hydraulic characteristics in the pebble bed reactor core are of great significance to the safety evaluation and design of such reactors. Experimental investigations on the thermal‐hydraulics of different fluids in the pebble‐bed‐type of nuclear reactor core have been reviewed in this paper. Main experimental methods to determine the flow regime transition, convective heat transfer coefficients, and effective thermal conductivity have been summarized, with the merits and disadvantages discussed. Discussions are given on the main factors that can influence the flow, convective heat transfer and effective thermal conductivity in the pebble bed.

Improvements of SAM Heat Transfer Models for Molten Salt-Cooled Pebble Bed Reactors

“…The developed correlation was also confirmed with a large set of steady and transient heat transfer experiment data. This is a commonly adopted correlation for pebble bed convective heat transfer, having been suggested and applied by numerous authors [18][19][20][21] and has been included as a user selectable model for its comparability to other system code analyses and familiarity to users who simulate pebble bed flows. Although initially developed with gas fluids, Huddar [18] was able to demonstrate experimentally that this correlation was able to model convective heat transfer within ±15.4% using Drakesol 260AT synthetic oil as a surrogate fluid for molten salt.…”

The Influence of High-Temperature Tests on the Resistance to Degradation and Reduction in Strength Properties of Lithium-Containing Ceramics Used as Blanket Materials for Tritium Breeding

“…Two primary factors that could be influenced are the thermal stability [10,11] and radiation resistance [12,13] of materials. In the elevated temperatures characteristic of a fusion reactor, materials undergo thermal stress, which can result in phase transformations, thermal expansion, and potential cracking within the material [14,15]. Such alterations can diminish the ceramic's strength properties and raise the risk of degradation.…”