Russia’s nuclear fuel industry remains conspicuously untouched by European sanctions more than seven months into the Kremlin’s war in Ukraine — much to the dismay of Kyiv officials and environmental campaigners.

Despite eight rounds of sanctions, targeted measures against energy exports and calls from Ukraine to impose a full embargo on nuclear trade, shipments of nuclear fuel to EU member states continue to make their way from Russia.

Ariadna Rodrigo, EU sustainable finance manager at environmental group Greenpeace, told CNBC via telephone that it is “absolute madness” for the bloc to continue bankrolling the Kremlin by ignoring Russia’s nuclear fuel trade.

“If EU governments are serious about stopping war, they need to cut the European nuclear industry’s umbilical cord to the Kremlin and focus instead on accelerating energy savings and renewables,” Rodrigo said.

On presenting its latest sanctions package, the European Commission did not propose targeting the trade of Russian nuclear fuel. The EU’s executive arm has previously targeted Russian oil, gas and coal as part of a broader strategy to ratchet up the economic pressure on the Kremlin.

Hungary and Bulgaria were the most vocal in opposing sanctions on Russian uranium and other nuclear tech last week, according to Rodrigo.

The commission has repeatedly condemned Russia’s war in Ukraine, accusing President Vladimir Putin of using energy as a weapon to drive up commodity prices and sow uncertainty across the 27-nation bloc. Moscow denies weaponizing energy supplies.

The few EU prohibitions on Russia’s nuclear energy sector that are in place, such as a port access ban on Russian-flagged vessels for the transport of nuclear fuel, contain numerous loopholes and campaigners argue much tougher measures are needed to reduce the bloc’s dependency on Russian nuclear services.

That sentiment is echoed by Kyiv.

Ukrainian President Volodymyr Zelenskyy said in early August that he had spoken with European Council President Charles Michel about the need for the EU to impose sanctions on the Russian nuclear industry.

“Russian nuclear terror requires a stronger response from the international community – sanctions on the Russian nuclear industry and nuclear fuel,” Zelenskyy said via Twitter at the time.

More recently, a top economic advisor to Zelenskky doubled down on this message, saying it was “extremely important to impose sanctions, not only on Russian oil.”

“Oil, gas, uranium and coal, all this should be banned. Because they are using this money in order to finance this war,” Oleg Ustenko said in late September, according to The Associated Press.

The Russian Foreign Ministry and the Russian Embassy in London did not immediately respond to a CNBC request for comment.

In April, a European Parliament resolution called for an “immediate” embargo on Russian imports of nuclear fuel and urged member states to stop working with Russia’s state-run nuclear giant Rosatom on existing and new projects.

But Russia is a dominant player in the global nuclear fuel market and any move to break the EU’s reliance on its services would likely be far from pain-free, particularly with Rosatom at the heart of Europe’s dependency.

Backed by Putin, Rosatom not only dominates the civilian industry but is also in charge of Russia’s nuclear weapons arsenal and is currently overseeing the occupied Zaporizhzhia nuclear power station in Ukraine.

There are 18 Russian nuclear reactors in Europe, in countries including Finland, Slovakia, Hungary, Bulgaria and the Czech Republic. All of these reactors rely on Rosatom for the supply of nuclear fuel and other services.

Underlining the scale of Russia’s nuclear energy influence in some member states, even as the Kremlin’s onslaught in Ukraine continues, Hungary in late August announced the construction of two new nuclear reactors by Rosatom.

Moscow accounted for almost one-fifth (19.7%) of the EU’s uranium imports last year, according to the latest available data from the Euratom Supply Agency. Only Niger (24.3%) and former Soviet republic Kazakhstan (23%) were bigger suppliers of uranium to the bloc.

The EU paid around 210 million euros ($203.7 million) to import raw uranium from Russia last year, according to estimates reported by Investigate Europe, and another 245 million euros was paid to import uranium from Kazakhstan, where mining of the nuclear fuel is controlled by Rosatom.

“We are talking about a serious amount of money here,” Greenpeace’s Rodrigo told CNBC, noting that these estimates only accounted for uranium imports and the EU’s dependency covers services across the supply chain.

Asked to what extent Europe’s uranium imports from Russia undermines its efforts to encourage others to stop importing Russian energy, Rodrigo replied: “The fact that we are not discussing this properly just shows the double standards of the EU.”

A spokesperson for the commission did not comment when contacted by CNBC.

Advocates of nuclear power argue it has the potential to play a major role in helping countries generate electricity while slashing carbon emissions and reducing their reliance on fossil fuels.

However, critics argue that nuclear power is an expensive and harmful distraction to faster, cheaper and cleaner alternatives. Instead, environmental campaign groups argue technologies such as wind and solar should be prioritized in the planned shift to renewable energy sources.

As part of the EU’s taxonomy — a mechanism that defines which investment options can be considered “green” — the bloc controversially recognized nuclear power and gas, a fossil fuel, as sustainable under some circumstances.

Austria on Monday launched a lawsuit against the EU and is seeking help from allies over the bloc’s labeling of nuclear power and gas as sustainable investment options, calling it “irresponsible and unreasonable.”

The EU has acknowledged the legal action but said it would not comment on the substance of the case.