## 1 Introduction
However, the 2018 budget of President [PERSON] provides $120 million to restart the licensing process for the Yucca Mountain as a permanent nuclear waste repository as well as to initiate a \"robust interim storage program\" to safely store nuclear waste for 10,000 years (World Nuclear News. [PERSON] speaks out for Yucca Mountain, 2017. Accessed via the internet on 29.01.2018 at [[http://www.world-nuclear-news.org/NP-Perry-speaks-out-for-Yucca-Mountain-2306178.html](http://www.world-nuclear-news.org/NP-Perry-speaks-out-for-Yucca-Mountain-2306178.html)]([http://www.world-nuclear-news.org/[PERSON]](http://www.world-nuclear-news.org/NP-Perry-speaks-out-for-Yucca-Mountain-2306178.html))) These funds are probably not sufficient to start using Yucca Mountain as a permanent repository but they are a step towards a possible opening of a long-term storage site. At this given point, it is also the only step in this direction as in the status quo the site in Nevada remains the only relevant option. To explore other options would firstly require at least 30 years before being able to operate [6], and secondly imply very speculative potential locations.  
These facts lead to the decision that in the following only the sites of Yucca Mountain and WIPP shall be taken into account. Both serve only as an example as WIPP is a military installation and can therefore not accept any civilian waste and there have been some concern that Yucca Mountain does not have the necessary geology to keep the waste from migrating ([8], p. 15) and ([9], p. 228-232). Their locations, however, seem sensible as possible long-term repositories due to the fact that the Nuclear Waste Policy Amendments Act (NWPAA) of 1987 singled-out Yucca Mountain as the only repository site to be studied and abandoned all studies on the East Coast (e.g., Granite in New Hampshire); any other site would need congressional action [3; 10]. Furthermore, WIPP lies in a salt deposit which are generally fitting geological conditions ([9], p. 181).  
Another possible way of dealing with SNF is reprocessing it to recover plutonium and uranium in order to partially reinsert the plutonium into nuclear reactors (thereby between 25% and 30% more energy can be gained from the original uranium and the volume of the material that has to be disposed as waste can be reduced to about one fifth of the original volume [11]. At the moment (only) plutonium is reintroduced as mixed oxide fuel into nuclear reactors). Although France, Japan, Russia, and India currently practice reprocessing (The United Kingdom abandoned reprocessing recently in 2018), one has to at least acknowledge that these countries are nuclear weapons states (except for Japan). The U.S. has practised reprocessing for many years for mostly military reasons to gain plutonium for nuclear weapons (three reprocessing plants for commercial use were built, but only one in West Valley, New York was operating from 1966-1976 [12]). However, in 1977 President [PERSON] suspended all reprocessing for civil purposes in the U.S. Factored in that decision were technological, economic, and safety problems, but the main concerns were about proliferation [13]. The plutonium is contained in the SNF and essentially inaccessible; thus, a proliferation risk only exists if it is extracted by reprocessing [14]. In 2005/2006 the Global Nuclear Energy Partnership (GNEP) and the Energy Policy Act revived reprocessing prospects. Therefore, and for the sake of evaluating all options, which are limited when it comes to HLW, the model presented takes reprocessing into account in some of the scenarios.  
The great amounts of HLW are located very unequally in the different states. As can be seen in Figure 1, the distribution of HLW is mainly focused on the Eastern states, especially the coastal ones, where also most NPPs are situated. The importance of this observation is that there are not only big amounts of HLW that need to be transported but the distance to the final repository, no matter whether in the are of Yucca Mountain or WIPP, will be very long as well. Therefore, it becomes obvious that the handling of nuclear waste is partly a transportation problem, and why the location of possible intermediates storages must be chosen wisely. However, research exists stating that transportation costs have little impact on the nuclear waste management system ([15], p. V). Still, this paper focuses on infrastructure and transportation costs because optimization is possible, depending on the processing management. Many more decisive and cost relevant decisions are political and cannot be made by an economic model. According to a study prepared for the Department of Energy (DOE) in 2016, the impact of the overall transportation costs is about 7%, in contrast to the impact of the at-reactor costs which cover the remaining 93% ([15], p. VI). Nevertheless, keeping in mind that the at-reactor costs can hardly be optimized and that the overall transportation costs, with about $4.1 billion, are still a significant amount of money, a modeling and optimization of these costs seems appropriate.