Impact of permafrost factor in ecological disasters due to spills of fuel and lubricants in the cryolithozone (with Norilsk region as an example)

Abstract:

The accumulators of fuel and lubricants necessary for the smooth functioning of infrastructure facilities in the Arctic are made as reservoirs constructed on bedding or pile foundations, the stability of which depends on permafrost conditions. Existing reservoirs can undergo serious deformations, for example, on May 29, 2020, an accident with such storage device occurred in the vicinity of Norilsk, more than 20 thousand tons of diesel fuel spilled into the environment, intended for possible emergency supply of one of the largest in Siberia Heat and Power Plants (ThEC–3) Nadezhdinsky plant in Norilsk, normally operating on gas fuel.

According to the project, the tanks were to be supported on end-bearing piles, but this was not achieved. The foundations frozen into the ground with a temperature of minus 3–5°C have been working for many years, with the stored diesel fuel served as a cold accumulator, cooling the soil, while the uneven heating-cooling of the frozen base, among other things, was determined by the unevenness of snow accumulation around the structure.

The abnormally warm winter of 2019–20 and an unusually early arrival of a warm period with record outdoor temperatures in April–May 2020 turned this reservoir into a kind of warming “press” that caused uneven thawing of permafrost. The disappearance of the freezing forces led to uneven movement of piles unsupported on the rock, together with the “frost destruction” of the concrete slab, uniting the pile heads for over 37 years of operation, led to collapse in the form of an outflow of more than 20 thousand tons of diesel fuel into the environment. Of course, regular permafrost and geotechnical monitoring could help prevent this catastrophe.

The research was supported by the RFBR grant No. 18-05-60080 “Hazardous nival-glacial and cryogenic processes and their impact on infrastructure in the Arctic”.