Abstract

We assess the viability of energy generation with depleted uranium irradiated with fast neutrons from the reaction of DT fusion driven by a tokamak reactor. Since existing nuclear power plants employ uranium fuel enriched to 4.5% ²³⁵U, over 90% of natural uranium currently goes to nuclear waste and is no longer used for power generation. The amount of depleted uranium with the ²³⁵U content of 0.2–0.3% accumulated in the world exceeds 1 500 000 t and is continually increasing owing to the operation of thermal neutron power plants. Industrial fast neutron power plants using depleted uranium as nuclear fuel are still at the development stage. Therefore, alternative approaches to utilizing depleted uranium for power generation should be considered. Compared to fast reactors with a closed cycle utilizing plutonium, the proposed facility involves less radiation hazard since the irradiated fuel has to be reprocessed and reloaded less frequently. Apart from that, the proposed hybrid power reactor operates in the deeply subcritical regime, which provides a high level of nuclear safety. A tokamak reactor similar to that of the ITER project is selected as a source of a high-power flux of fusion neutrons whereby a reactor blanket of depleted uranium is irradiated. The heat will be removed with a liquid metal coolant rather than with water as in the ITER reactor. This will help maintain the hardness of the neutron spectrum, thereby maximizing the rate of ²³⁸U fission. With such a neutron source and a blanket of natural uranium with an optimized thickness of ~20 cm, each fission of uranium (with an energy release of 200 MeV) is estimated to finally produce four ²³⁹Pu atoms in the blanket (see the 2009 proceedings of the ROSATOM commission on optimizing the development of power generation with tokamaks). This estimate equally applies to a reactor blanket of depleted uranium. According to estimates, an “ideal” reactor with a blanket of depleted uranium operating in a stationary mode with a capacity factor of 70% would generate nearly 1.5 GW of electric power. However, only an estimated one-third of the total power can actually be delivered to the electrical network since the rest is required for breeding tritium and powering the facility itself. Toward maximizing the capacity factor, the first wall of the fusion reactor will be coated with lithium for protection against plasma-induced erosion.

中文翻译：

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带有托卡马克和贫铀毯的混合聚变裂变动力反应堆的概念设计

摘要

我们评估了由托卡马克反应堆驱动的DT聚变反应产生的快中子辐照的贫化铀产生能量的可行性。由于现有的核电厂使用浓缩至4.5％²³⁵ U的铀燃料，因此目前90％以上的天然铀用于核废料，不再用于发电。²³⁵贫铀量全球累积的U含量为0.2-0.3％，超过150万吨，并且由于热中子发电厂的运行而不断增加。使用贫铀作为核燃料的工业快速中子发电厂仍处于开发阶段。因此，应考虑利用贫铀发电的替代方法。与使用utilizing的封闭循环的快速反应堆相比，拟议的设施所涉及的辐射危害较小，因为所辐射的燃料不必再频繁地进行处理和重新装载。除此之外，拟议的混合动力反应堆在深亚临界状态下运行，可提供高水平的核安全。选择了与国际热核实验堆项目相似的托卡马克反应堆作为聚变中子高功率通量的来源，从而辐照了贫铀反应堆。热量将通过液态金属冷却剂去除，而不是像ITER反应器那样通过水去除。这将有助于保持中子光谱的硬度，从而最大程度地提高²³⁸ U裂变。使用这种中子源和优化厚度约为20厘米的天然铀覆盖层，铀的每个裂变（能量释放为200 MeV）估计最终将产生4 ²³⁹毯子中的Pu原子（请参阅ROSATOM委员会2009年关于优化托卡马克发电厂发展的会议记录）。该估计数同样适用于贫铀反应堆。据估计，一个带有贫铀层的“理想”反应堆以固定模式运行，容量系数为70％，将产生近1.5吉瓦的电力。但是，实际上估计只有总功率的三分之一可以传送到电网，因为其余的功率用于繁殖tri和为设施本身供电。为了使容量因子最大化，聚变反应堆的第一壁将涂有锂，以防止等离子体引起的腐蚀。