Advanced study of tritium recovery from molten salt Flibe blanket in fusion reactor

聚变反应堆熔盐Flibe包层回收氚的最新研究

基本信息

批准号：
14380220
负责人：
FUKADA Satoshi
金额：
$ 4.8万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Flibe (2LiF+BeF_2 mixed molten salt) is expected to be an advanced liquid blanket fluid for a helical-type DEMO fusion reactor called FFHR-2 because it has an ability of good thermal conductance and high tritium breeding ratio under high magnetic field and high-density neutron flux. However, it has disadvantages that it is difficult to handle tritium in the molten salt because of generation of tritium fluoride and the recovery and enclosure of tritium are difficult. Therefore, there was less application to conceptual design of fusion reactors and therefore less experimental studies on Flibe/tritium chemistry. In the present study, we investigated experimentally the permeability of hydrogen isotopes through Flibe and reduction-oxidation (redox) control by Be rods immersed in Flibe that will provide important data to design fusion reactors. The main purpose of the present study is to propose a new blanket circulation loop system composed of Flibe ducts, a tritium extraction system and a … More heat exchanger that can control to a rate lower than 10 Ci/day of acceptable tritium leak rate and a tritium concentration lower than 1 ppm of acceptable tritium inventory. The following findings were obtained from the experiment and analysis of the present study :1.We determined the permeability of deuterium through molten Flibe enclosed in a dual-tube Ni permeation vessel. Judging from the permeability, diffusivity and solubility of deuterium in Flibe, hydrogen isotopes are resent as a H^+ ion in Flibe. Therefore strong interaction between H^+ and F^- ions was observed, and HF (DF or TF) is a main species diffusing in non-redox controlled Flibe.2.We determined hydrogen H_2 through Flinak (a LiF+NaF+KF mixed molten salt), and hydrogen was present as a molecular form in it. This is because there is no tetragonal network of BeF_4^<2-> different from the Flibe case. F^- ions in Flinak were localized in the vicinity of Li^+, K^+ and Na^+ ions. In other words, there are much less free F^- ions in Flinak, and therefore Flinak corresponds to the well redox-controlled Flibe.3.Flibe was successfully redox-controlled by Be immersed in it. This is because free F- ions that were present in non-controlled Flibe were changed to BeF_2 by the reaction with Be dissolved in Flibe physically. The free F^- ions were consumed by the redox reaction and hydrogen in Flibe was present in a molecular form. Consequently, tritium will be present in a molecular form in well redox-controlled fusion reactor blankets when Be is used as a neutron multiplier.4.In order to maintain the tritium leak rate in a 1GW fusion reactor lower than the acceptable level (10 Ci/day), we need a sophisticated tritium recovery system made of low permeable materials. We provided design equations for tritium permeable window, bubbling tower and spray tower for high tritium recovery, and each apparatus was designed using the equations. Less

Flibe（2LiF+BeF_2混合熔盐）由于在高磁场和高温下具有良好的导热性和高氚增殖率，有望成为螺旋型DEMO聚变反应堆FFHR-2的先进液态覆盖流体。但其缺点是由于会产生氟化氚以及回收和封闭熔盐中的氚，因此难以处理。因此，在聚变反应堆概念设计中的应用较少，因此对 Flibe/氚化学的实验研究也较少。在本研究中，我们通过 Flibe 和还原氧化（氧化还原）控制实验研究了氢同位素的渗透性。浸入 Flibe 中的 Be 棒将为设计聚变反应堆提供重要数据。本研究的主要目的是提出一种由 Flibe 管道组成的新型毯状循环回路系统。氚提取系统和热交换器可以将可接受的氚泄漏率控制在低于 10 Ci/天，并且氚浓度低于可接受的氚库存的 1 ppm 以下结果是从实验和分析中获得的。本研究的内容： 1.我们通过封闭在双管镍渗透容器中的熔融Flibe的渗透率、扩散率和溶解度来确定氘的渗透率。 Flibe 中含有氘，氢同位素在 Flibe 中以 H^+ 离子的形式存在，因此观察到 H^+ 和 F^- 离子之间存在强烈的相互作用，并且 HF（DF 或 TF）是非氧化还原控制的 Flibe 中扩散的主要物质。 .2.我们通过Flinak（一种LiF+NaF+KF混合熔盐）测定了氢H_2，氢在其中以分子形式存在，这是因为不存在四方网络。与 Flibe 情况不同，BeF_4^<2-> 离子集中在 Li^+、K^+ 和 Na^+ 离子附近，换句话说，自由 F^- 离子要少得多。 Flinak 中存在离子，因此 Flinak 对应于氧化还原控制良好的 Flibe。3.Flibe 被浸入其中成功地实现了氧化还原控制。这是因为 Flinak 中存在自由 F- 离子。非受控的Flibe通过与溶解在Flibe中的Be物理反应而变成BeF_2，游离的F^-离子被氧化还原反应消耗，并且Flibe中的氢以分子形式存在，氚将以分子形式存在。当Be用作中子倍增器时，在氧化还原控制良好的聚变反应堆包层中形成。4.为了保持1GW聚变反应堆中的氚泄漏率低于可接受的水平（10 Ci/day），我们需要一个由低渗透性材料制成的复杂的氚回收系统，我们提供了用于高氚回收率的透氚窗、鼓泡塔和喷淋塔的设计方程，并且每个装置都使用方程进行设计。