Prominent Ukrainian physics institute imperiled by Russian attacks

The National Science Center, Kharkiv Institute of Physics and Technology (KIPT), which was a hotbed of early nuclear research in the former Soviet Union and currently hosts a newly installed neutron source, has suffered significant damage from Russia’s relentless attack on Kharkiv, Ukraine’s second-largest city. Rockets and bombs have damaged buildings and left civilians wounded, says Oleksandr Bakai, who heads the department of condensed matter and nuclear theory at KIPT and lives near the institute.

The damaged facilities include the constructed but not fully operational Ukraine Neutron Source, according to the State Nuclear Regulatory Inspectorate of Ukraine . After saying in a 7 March press briefing that the neutron source had been destroyed, International Atomic Energy Agency director general Rafael Mariano Grossi said in a statement that Ukraine had informed the IAEA that the facility was “damaged by shelling.”

Despite reports of concerns about a nuclear accident, the facility is an accelerator-driven subcritical assembly and not a critical nuclear reactor. The assembly cannot sustain a chain reaction without neutrons from the accelerator, says Harvard proliferation researcher Matthew Bunn, and it generates virtually zero fission products. In addition, there is no highly enriched uranium onsite. “The danger is from bullets and bombs, not from radiation from this facility,” he says. Both Grossi and Ukraine’s nuclear regulator said on 7 March that there has been no release of radiation.

Since the start of the invasion on 24 February, the Russian military has been attacking both Kharkiv neighborhoods where KIPT is located: the city center and the Piatykhatky area to the north. On the first day of the war, at least one building in the Piatykhatky neighborhood near the institute caught fire, and a 10-foot-long rocket struck an apartment complex but did not detonate, Bakai says. But what had been sporadic attacks became a concentrated “bombardment” on 6 March, he reports. The Kharkiv branch of Ukraine’s Security Service wrote that the Russians were using Grad multiple rocket launchers. The US Department of Defense is looking into reports of a rocket attack on KIPT, a senior defense official said on 7 March, but at that time was not independently able to verify them.

More than 400 scientists conduct research at KIPT in condensed matter, plasma physics, nuclear physics, and theoretical physics, according to the institute’s website . Eugene Chudnovsky, a cochair of the Committee of Concerned Scientists who received his physics education at the institute and worked at a university department associated with it, says he has had trouble reaching even close acquaintances in the battered city. The people he has heard from “told me that they were hiding inside underground facilities.”

The 6 March shelling heavily damaged the Ukraine Neutron Source. Ukraine’s nuclear regulatory agency reported a destroyed substation, damaged heating and cooling systems, and broken windows.

The Neutron Source was developed in collaboration with the US Department of Energy’s Argonne National Laboratory and is designed for research and medical isotope production. Several institutes in Russia were involved in the systems engineering, equipment making, and construction, which was completed in 2018, says Mark Hibbs, a senior fellow in the nuclear policy program of the Carnegie Endowment for International Peace. An electron linear accelerator generates neutrons that hit a tungsten or low-enriched uranium target. The unit is considered a research reactor by the IAEA, which maintains a database of both critical assemblies and subcritical ones like KIPT’s.

Staff at KIPT loaded the first fuel assemblies last October, according to the National Academy of Sciences of Ukraine, and since then researchers had been preparing for operation and working to secure necessary licenses. The source of the uranium oxide fuel, enriched to about 19% ²³⁵U, has been the Russian vendor TVEL, Hibbs says. Ukraine’s nuclear regulator reports that the reactor contained fresh fuel as recently as the eve of the Russian invasion. However, the agency adds that by 24 February the reactor had been “transferred to a deep subcritical state,” which Hibbs says suggests that the fuel was proactively removed.

On 6 March DOE’s National Nuclear Security Administration received reports from its Ukrainian partners that the facility “sustained damage due to an explosion,” says NNSA spokeswoman Kate Hewitt. She says that NNSA “is in frequent contact with facility staff and is monitoring the situation closely,” and that KIPT has reported no casualties at the site.

In describing the attack on KIPT, Ukraine’s Security Service said that the Neutron Source has 37 loaded nuclear fuel elements and that the destruction of the facility “could lead to a large-scale ecological disaster.” Bunn, however, says the risk of widespread radiation contamination is “nearly zero” because of the subcritical nature of the facility. Hibbs agrees, adding that even when operational, there would be only grams of uranium fuel in the core. Russian military action at nuclear power plants such as Zaporizhzhya in southeastern Ukraine is of much greater concern, Bunn adds.

A rich but turbulent history

Founded by physicist Abram Ioffe in 1928, when Kharkiv was the capital of the Ukrainian Soviet Republic, the institute stood out for the “high quality of its personnel from the start,” says Russian and Soviet historian Paul Josephson of Colby College in Maine. Early alumni included theoretical physicists Lev Landau and Ilya and Evgeny Lifshitz and low-temperature experimentalist Lev Shubnikov . In 1932 physicists at the institute reproduced the splitting of an atom by fast protons, which had been demonstrated by John Cockcroft and Ernest T. S. Walton at the Cavendish Laboratory earlier that year.

“KIPT has a glorious history,” Josephson says, “but also a very painful one.” In the late 1930s numerous scientists at the institute were arrested as part of the Stalin regime’s Great Purge; Shubnikov, the codiscoverer of type II superconductivity, was executed in 1937. Then came World War II and the German occupation of Ukraine.

Following the war, scientists at the institute turned their attention to the Soviet atomic bomb project. KIPT was known as Laboratory No. 1; Moscow’s Kurchatov Institute became Laboratory No. 2 and took the lead in developing the Soviet Union’s first nuclear weapons. In subsequent years, a number of KIPT physicists turned their attention to fusion energy projects, with some research informing the ITER project that is under construction in France, Josephson says.

Ukrainian science suffered from the severe funding cuts that followed the collapse of the Soviet Union, and KIPT was no exception. Still, the institute possessed dozens of kilograms of highly enriched uranium left over from the Cold War—"the biggest and most worrisome single cache” of highly enriched uranium in Ukraine, says Bunn, who as a White House nonproliferation policy adviser tried unsuccessfully to get the US to purchase the uranium in 1994. As part of a 2011 agreement with the Obama administration, the Ukrainian government agreed to remove the remainder of the highly enriched uranium at KIPT and received funding and support to build the neutron source.

Ukraine hosts three other operational research reactors, according to the IAEA. One is in Kyiv, at the Science Center Institute for Nuclear Research. The other two are in Sevastopol, a city that has been controlled by Russia since it annexed Crimea in 2014.

Editor’s note, 8 March: The article has been updated with information from the US Department of Defense and the US Department of Energy’s National Nuclear Security Administration (NNSA). It also includes an updated statement from the International Atomic Energy Agency.

Editor’s note, 7 March: The article has been updated with information from the NNSA.