I have heard of 3.5 million year old bacteria being revived, but 250 mya is much longer, and I can find no modern mention of this astonishing claim anywhere. However, it was mentioned in multiple contemporary newspapers, such as https://www.newspapers.com/newspage/60105743/ Dr. Chudinov seems to be a real person, as there is a bacteria named after him, Haloferax chudinovii.
Although there seems to be some remaining controversy over definitions between alive, re-animate, survive, dead etc. For example: Where the bacteria 'alive' while no longer metabolising anything?
The initial skepticism regarding the actual findings however can no longer be denied: Were they really that old? Apparently yes. Or was this a result of unclean working conditions? Cannot be ruled out for 'back-then', but when 'working certified cleanly' now the results can be replicated.
That a species within that range of extremophiles is named after him for his pioneering work should give a hint.
Description of Haloferax chudinovii sp. nov chudinovii (chu. di. nov’ii. L. masc. adj. chudinovii referring to Nikolay K. Chudinov, a pioneer in the isolation of microorganismus from ancient salt deposits in Russia). (link)
Although in the West some skepticism indeed greeted this obscure discovery from Soviet scientists:
— F. E. Clark: "Problems and Perspectives in Microbial Ecology", Bulletins from the Ecological Research Committee/NFR, No. 17, Modern Methods in the Study of Microbial Ecology (1973), pp. 13-16
But his name is really more present in the Russian language internet, where we find some acknowledgements:
– Litovskiy Vladimir Vasilievich: To The Update Of The History Of Discovery By Geochemist N.K. Chudinov In Potassium Salts Of The Verkhnekamsky Deposit The Phenomena Of Geobiogenesis And Superlong-Long Anabiosis Of Paleomicroorganisms", History and modern worldview, Issue No. 4, 2019. (pp100–114) (In Russian.)
That looks like an 'inside report' or even almost a homestory – in very patriotic Russian – of how Chudinov made his discovery, (and apparently already in 1955?!). The initial discovery looks indeed not very trustworthy in terms of methodology etc, but it was a chance finding after all and it took a few years for him to get these results recognised and published.
On that page however, we find not only the famous Bruchkov-story as a correlate to Chudinov's discovery, but also a lot of footnoted references, and among them also links to social media, where the original report is shown in pictures:
Николай Чудинов Nikolai Chudinov https://vk.com/id429555674?z=photo429555674_456239292%2Fwall429555674_96
And he now even has had a museum dedicated to his groundbreaking discovery:
"ARE THEY ALIVE ?!" - New Exhibition At The Museum Of Permian Antiquities 27 August 2019
The new exhibition will tell about the study of microorganisms of the Permian period.
A mini-exhibition dedicated to Nikolai Konstantinovich Chudinov will open at the Museum of Perm Antiquities on August 27.
Nikolai Konstantinovich Chudinov in the 1960s became interested in the nature of the color of the salts of the ancient Permian Sea. He was not satisfied with the theory that existed at that time, which explained the color of salts by the presence of iron oxides. Nikolai Konstantinovich put forward a hypothesis that the color was influenced by microorganisms. After dissolving a sample of potassium salt in water and examining the undissolved sediment through a microscope, he discovered many types of growing microbes.
It would seem that there is nothing surprising – microbes are present in our environment. But these microorganisms were found in rocks of 250 million years old, and, as N.K. Chudinov, got out of the state of suspended animation, that is, "woke up", finding themselves from the Permian period immediately into the present.
The discovery of N.K. Chudinov caused controversial reviews in scientific circles, and at one time it was not recognized. Discussions about ancient "living" microorganisms are still going on in the scientific community.
At the exhibition "Are They Alive ?!" in the Museum of Perm Antiquities, for the first time in many years, the story of Nikolai Konstantinovich Chudinov will be presented. The main exhibits of the exhibition will be copies of archival documents showing the history of Nikolai Konstantinovich's attempts to prove his discovery. The documents were provided by the scientist's niece, Galina Vasilievna Chudinova. Samples of minerals from the Verkhnekamskoye deposit will also be presented. Visitors to the exhibition will be able to watch the popular science film "Prisoners of the Perm Sea" about this discovery, which was shot in 1970 by the chief director of the "Lennauchfilm" studio Tamara Ivanovna Iovleva.
The exhibition will run until the end of 2019. (link "ОНИ ЖИВЫЕ?!" – НОВАЯ ВЫСТАВКА В МУЗЕЕ ПЕРМСКИХ ДРЕВНОСТЕЙ)
It appears the original scientific publications were
Чудинов Н.К. Водоросли в калийных солях Березниковского рудника // За калий. 3 ноября 1961. № 44. @@[Chudinov N.K. Algae in the potash salts of the Bereznikov mine. For potassium. November 3 1961. No. 44.] Чудинов Н.К. Загадки соляных толщ. // За калий. 1962. № 8. @@[Chudinov N.K. Riddles of Salt Thickness. For Potassium. 1962. No. 8.] Чудинов Н.К. Тайны соляных толщ // За калий. 1962. № 19-21. @@ [Chudinov N.K. Mysteries of salt thicknesses. For Potassium. 1962. No. 19-21.] Чудинов Н.К. 200 миллионов лет сна // Комсомольская правда. 1 сентября 1962. @@[Chudinov N.K. 200 million years of sleep. Komsomolskaya Pravda. September 1 1962.]
Those I cannot locate at the moment, but the date discrepancy towards "1972" in question seems rather noteworthy.
In any case, such findings like those of Chudinov's are reproducible:
Here we report the isolation and growth of a previously unrecognized spore-forming bacterium (Bacillus species, designated 2-9-3) from a brine inclusion within a 250 million-year-old salt crystal from the Permian Salado Formation.
Previous reports of bacteria isolated from salt have met with resistance, partly because of concerns for contamination. Samples from many studies have been described as brines, rock salt, efflorescences, recrystallized salt or wet salt. These terms provide little or no assurance of the provenance of the sample or geological history. Flowing brines and salt efflorescences, for example, may be contaminated and young, and recrystallized salts may be of indeterminate age.
In our study, however, we support the discovery by geological evidence of the overall age and stability of both the formation and the individual crystals, as well as the documented sterility maintained during the sampling and lab work. This research doubles the length of time bacteria can survive trapped inside stable geological materials.
— Russell H. Vreeland, William D. Rosenzweig & Dennis W. Powers: "Isolation of a 250 million-year-old halotolerant bacterium from a primary salt crystal", Nature volume 407, pages 897–900, 2000.