The United States government denied that it participated in the negotiations. The Wall Street Journal quoted the U.S. Department of Energy spokesperson as saying that "The U.S. government is not negotiating a deal to send spent nuclear fuel to Mongolia. No discussions or potential fuel leasing services involve U.S.-origin spent nuclear fuel." However, at the Carnegie Nuclear Policy Conference held in March 2011, a U.S. State Department official said that "there are discussions about whether or not Mongolia would harbor - or take a spent fuel storage depot for third-country fuel," indicating that discussions were indeed underway. At the time, Mongolia denied having plans to bring "harmful waste" to the country (see coverage of the story at Armscontrolwonk.com).
In Japan, a deputy foreign minister said on Monday that the countries had "an informal exchange of views" and no agreement had been reached, according to the Wall Street Journal report.
The Embassy of Mongolia in Vienna also issued a statement which denied plans to bring nuclear waste to the country. The statement largely repeated official statements issues in March 2011. It states that
[The] Law on Nuclear Energy [...] does not envisage import of nuclear waste from other countries. Also Article 4 of Mongolia's law regarding its nuclear-weapon-free status clearly prohibits dumping or disposing of.... nuclear waste [...]. Moreover, Article 4.1 of Mongolia's law on exporting and banning import and trans-border shipments of dangerous waste unequivocally bans import of dangerous waste for the purpose of exploiting, storing, or depositing.
It should be noted, however, that the statements refer to "nuclear waste." As a discussion of a similar law in Russia in the end of 1990s showed, proponents of spent fuel import arrangements argue that spent fuel should not be classified as waste because of the energy contents of the plutonium contained in it. It is therefore plausible that the discussions that Mongolia held with other countries assumed that spent fuel would be exempt from the provisions of the law that regulates handling of nuclear waste. It is not clear, however, how the law is interpreted in Mongolia.
It should be noted that there is a public opposition to the spent fuel plans in Mongolia, which grew significantly stronger after the Fukushima incident, according to people familiar with the situation there. Russia encountered similar opposition to its plans to bring spent fuel, forcing Rosatom to pledge that it will not be bringing foreign-origin fuel to Russia.