On October 3 last the Russian Federation suspended the agreement reached in 2000 with the United States to downblend the bilateral surplus plutonium for nuclear weapons.

  The two powers had 34 metric tons of weapons grade plutonium each, at least according to the agreement signed in June 2000, at the time of the famous Reset between Russia and the United States.

  The above stated agreement was reconfirmed in 2010, .but President Obama’s 2017 budget submission proposes a “dilution and disposal” approach as enabling the plutonium to be disposed of sooner, at lower cost and with lower technical risk than conversion to mixed-oxide (MOX) fuel.

  Incidentally, some technological considerations are appropriate in this regard.

  Mixed-oxide fuel, which accounts for 5% of the nuclear fuel currently used, consists of plutonium recovered from nuclear reactors mixed with depleted uranium, which can also produce electricity.

  Hence, for budgetary and strategic reasons, President Obama has proposed halting the construction of a facility in South Carolina to downblend the plutonium into MOX fuel for use in commercial reactors.

  However, regardless of the plutonium downblending  technology, the MOX use had been defined in the 2010 agreement between Russia and the United States.

  Hence, in essence, as early as last April, Vladimir Putin has been accusing the United States of not keeping their word, as they have failed to destroy military plutonium by instead permitting a reprocessing method that allows plutonium to be extracted and used again in nuclear warheads.

  The bill Putin submitted to the State Duma sets out pre-conditions for the 2000 agreement to be resumed, including the reduction of US military infrastructure and troops in the countries that joined NATO after September 1, 2000, namely Bulgaria, Estonia, Lithuania, Latvia, Romania, Slovakia and Slovenia.

 Putin also requires the lifting of all US sanctions against Russia and “compensation for the damage they have caused to the country.”

  Furthermore, in May 2015, President Obama drew a line under the completed “Megatons to Megawatts” program by terminating a state of national emergency that had been declared in 2000 to help to ensure payments to Russia under the 1993 agreement.

 The agreement regarded the US downblending of surplus military highly-enriched uranium that could not be assigned otherwise.

  President Obama told Congress that “the conversion of 500 tons of highly-enriched uranium extracted from Russian nuclear weapons was over”.

  In fact, in 1993, the US and Russian governments signed an agreement to purchase, over a 20-year period, 500 tons of Russian “surplus” highly-enriched uranium from nuclear disarmament and military stockpiles.

  The material was bought by the United States for use as fuel in civil nuclear reactors.

  Under the deal, the United States had to transfer to Russia a similar quantity of natural uranium to that used to downblend the highly-enriched uranium.

  The deal was signed and complied with by Russia until last year.

  The agreements suspended by Putin also include the Research & Development one signed in 2003 and again related to the nuclear sector.

  We must consider, however, the complex strategic logic behind these seemingly quick Russian decisions.

  The main shock was Ukraine.

  During the Russian operations in the country, Putin and his aides launched many nuclear signals to NATO.

  In March 2015 Putin said that he “could put the nuclear system on alert during Crimea’s annexation”.

  Hence Russia still wants to “escalate to terminate” a possible nuclear attack on the EU and NATO, while continuing to perfect the sub-nuclear weapons and focusing on an increasing role of the nuclear strategy in its military posture towards the West.

  A case in point was the simulated nuclear attack on Sweden in August 2015.

  What is missing, in fact, is the implementation of the New Start Treaty signed in 2015 by Obama and Medvedev, which reduces to 1,550 the  nuclear warheads available to each of the two countries.

 The Intercontinental Ballistic Missiles (ICBM) and the strategic bombers have been both reduced to 700 units.

  The United States, however, have 741 launchers with 1,481 nuclear warheads, while Russia has 521 launchers with 1,735 warheads.

  From this viewpoint, apart from the other military nuclear technologies, the United States and Russia have an  equivalent potential. The difference is that the Russian weapons seem to be better and more effective than the American ones, from the technological and operational viewpoints.

  Nevertheless the United States have not honoured the deal  with Russia, thus instilling the legitimate doubt that much of the plutonium and uranium assigned by Russia is used by the United States for military purposes.

  Putin, however, is right in substance and has probably not studied the US arguments and reasons well.

 Let us go back in time: in the 1990s, the United States  reported to have a surplus of 61.5 metric tons of plutonium out of a total equal to 90 metric tons, all intended for military use.

 Russia had a stock of 180 metric tons of plutonium, 128 of which already adapted for military use, while also reporting to have a surplus of 50 metric tons of fissile material.

  Plutonium is always hard to be downblended: either it is used to produce MOX, which is suitable for civil nuclear power plants, or it is “immobilized”, which means it is  mixed with highly radioactive material, so that these substances can cover and prevent the radiation of plutonium itself.

 However, with a with to making the radioactive material safe, a long and complex industrial process is needed.

 The United States had started to build their own ad hoc facility along the Savannah River banks in South Carolina but, for various organizational and technical reasons, the cost of the project agreed with Russia proved to be not affordable for the federal government.

 There is speculation that today the completion of the project agreed by the United States with Russia would cost over 30 billion dollars.

 Hence President Obama stopped the construction of the facility in the Savannah River site.

  At that juncture, the above stated dilute and dispose approach was developed.

  It consisted in mixing plutonium with inert material and burying it underground in New Mexico.

   As already noted, this is the reason why President Obama  halted the construction of the facility in the Savannah River site and started the dilute and dispose project.

 In the agreements with Russia, however, the only way to manage excess plutonium is the production of MOX – the dilute and dispose approach is not contemplated at all.

 In fact, as underlined by Russia, this technique leaves the plutonium isotopic composition intact.

 Hence there is the not remote possibility that plutonium can be extracted from the ground and used again for military purposes.

  Therefore, at technical and political levels, Putin is right and, as also US scientists maintain, nothing prevents the buried plutonium from being really reused for military purposes.

 However, both for technical and scientific reasons and for a cost analysis, the United States cannot really afford to convert all military plutonium into MOX.

 Hence what can be done?

 The US plutonium can be transferred to IAEA, which could downblend it in “third party” facilities, also under the Russian Federation’s control, or deal with a European nuclear country to downblend the US plutonium, again under Russian control.

 Nevertheless, we must once again note the growing US military and technological backwardness, which seems ever more suited to an Iraq or Syria-style war rather than to a fair confrontation on an equal footing.

 If the EU begins to think wisely on these issues, time will come to envisage a small pan-European nuclear military  unit, particularly capable of seriously controlling its own borders.

 But we already know that this is an impossible dream.

Honorable de l’Académie des Sciences de l’Institut de France