Expert view: Could Kursk be another Chernobyl?

Valentin Gibalov, an independent nuclear expert, in conversation with Kommersant correspondents Elena Chernenko and Polina Smertina

In recent days, the situation around the Kursk nuclear power plant (NPP) has become more complicated. Last Thursday, debris and fragments of downed missiles were found on its complex, including in the radioactive waste processing area. On Friday, a substation was knocked out, leaving the town of Kurchatov, the nearest to the plant, without electricity. Russia’s state atomic energy concern Rosatom warned on Saturday that “at the moment there is still a real danger of strikes and provocations by the Ukrainian army at the nuclear power plant.”

Russian daily Kommersant spoke to Valentin Gibalov, an independent nuclear expert who specializes in dosimetry equipment, about various scenarios for the plants.

— How does the security situation at Kursk NPP differ from that at Zaporozhye NPP (held by Russia on former Ukrainian land)? Each is close to the conflict zone, but what are their special features? What is the difference between the high-power channel-type reactors (RBMK) at Kursk and the water-water energetic reactors (VVER) at Zaporozhye?

— Yes, for the second time in history we risk seeing a large NPP in a war zone. Kursk has four units with RBMK-1000 reactors, with two more units with VVER-TOI reactors under construction. The main difference between RBMK and VVER-1000 is the absence of a containment vessel in the former– a thick, reinforced-concrete shell designed to keep steam inside the reactor chamber in the event of a depressurization event. RBMKs have no such structure. This increases the vulnerability of a NPP with this type of reactor to accidental or non-accidental strikes by shells, missiles, bombs and the like, which can lead to a radiation accident with the release of radioactive substances. However, it should be borne in mind that even an ‘unprotected’ RBMK is a massive and large-scale industrial structure, i.e. the heaviest types of weapons would have to be used to damage a nuclear plant with a radiation accident. Moreover, unlike the Zaporozhye NPP, the Kursk NPP is likely to be covered by a powerful air defense system, which makes this scenario generally unlikely.

— What other scenarios are possible if the plant is bombed? For example, if the reactor is not hit but the machine room or transformers are?

— It should be noted that a nuclear power plant is a huge industrial facility and everything that is dangerous from a radiation point of view (reactor, spent-fuel pools, solid radioactive waste and liquid radioactive waste storage facilities) occupies a small part of its surface area, less than 5%. In the case of accidental strikes with munitions, it is unlikely that the damage will even lead to a shutdown of the plant, although, if the situation is prolonged, it is likely that, to reduce risk, a decision will be taken to shut down the units with reactor cooling. A hit on the turbine hall or the transformers would, of course, result in a man-made accident, possibly severe, but it would not end up in a release of radiation because the NPP is generally designed with staged protection of the reactor against overheating and loss of containment, which makes it possible to survive damage to other systems, even those that are important to the ongoing life of the plant.

— So, a repeat of the 1986 Chernobyl accident is impossible? I’m saying that because the reactors there were the same.

— Yes, this is impossible. The root cause of the accident at Unit 4 of the Chernobyl nuclear power plant was design flaws in the RBMK-1000, which led to the rapid release of nuclear energy equivalent to hundreds of tonnes of TNT. These design flaws were corrected in the late 1980s and early 1990s. The reactors were extensively upgraded. Now it is impossible to reproduce the same explosion on the existing RBMKs by any external or internal impact. Even if we assume a rather unlikely scenario of a large-scale military attack leading to the opening of the reactor – the scale of the radiation accident will be much smaller than in the case of the Chernobyl accident.

— In July, it was reported that fresh fuel had been delivered to the first power unit of Kursk NPP-2 and that preparations were underway for ‘cold and hot running-in of the reactor.’ Are there any risks?

— This is probably the least dangerous issue in the Kursk NPP attack scenarios. The fresh fuel has negligible radioactivity, is completely chemically inert and is located in a protected fresh fuel assembly. The NPP-2 Unit 1 reactor, which is under construction, has no loaded radioactive or fissile material at the moment, the unit is being commissioned, i.e. it is not yet an operating nuclear power plant.

— How critical is the reduction of personnel at the Kursk NPP-2 construction site? After all, this is the largest nuclear construction site in Russia at the moment.

— Well, from the point of view of the broader problems we are discussing, it is not critical at all. The worst-case scenario is that the first unit, currently scheduled for 2025, will be delayed for some time. At best, even that will not happen.

This article was first published by Kommersant, and was translated and edited by the RT team.