Abstract

Mitigating the release of tritium produced from neutron irradiation of molten salts containing lithium or beryllium is a technical challenge for several advanced reactor designs. In a pebble bed Fluoride-Salt-Cooled High-Temperature Reactor (FHR), tritium generated in the Li₂BeF₄ (Flibe) coolant is expected to interact with the large inventory of graphite in the core. The degree to which tritium is retained in the FHR core graphite is important to understand in order to predict the tritium distribution in the reactor, operational dose rates in the plant, tritium source term, and optimal strategies to mitigate environmental release. Tritium retention in graphite is simulated in this work based on a model that considers tritium diffusion from Flibe into graphite pores as well as diffusion and trapping in graphite grains. The retention model was implemented into the TRIDENT model framework to study tritium transport at the FHR system level. Tritium permeation through the FHR primary heat exchanger was the largest source of release from the primary system, followed by tritium retention and recirculation of graphite fuel pebbles.

摘要

对于几种先进的反应堆设计，减轻由中子辐照含锂或铍的熔融盐产生的tri的释放是一项技术挑战。在卵石床氟化物-盐冷却高温反应器（FHR）中，Li ₂ BeF _4中生成tri（Flibe）冷却剂有望与堆芯中大量的石墨相互作用。为了预测t在反应堆中的分布，工厂中的操作剂量率，source的来源术语以及减轻环境释放的最佳策略，了解to在FHR核心石墨中的保留程度非常重要。在这项工作中，on的保留时间是基于考虑了F从Flibe扩散到石墨孔中以及石墨颗粒中的扩散和俘获的模型而模拟的。在TRIDENT模型框架中实施了保留模型，以研究FHR系统级别的tri运输。通过FHR主热交换器的t渗透是从主系统释放的最大来源，