I have 1 year to learn Russian from completely scratch to at least B2 level in TORFL. I will go to an intensive language course in St. Petersburg, Russia. The course will be 20 hours per week, I assume. How likely to achieve such a goal? My entire work will be this in Russia. Also, my native language is Turkish and I am B2/C1 level in English.
The Test of Russian as a Foreign Language or TORFL has six levels that are mapped to the six levels of the CEFR. So the Second Level Certificate (TORFL-II) in the TORFL should correspond to B2 in the CEFR.
According to the Russian Language Centre in the UK, which also administers TORFL tests, the number of hours of study required to pass TORFL-II is roughly 1100. (Russian online gives slightly lower numbers: “Ca. 820 Stunden ["hours"] + 120 Stunden Berufssprache ["hours professional langauge"]”.)
So if you attend a course of 20 hours per week, you would need roughly 55 weeks or just over a year to pass the test. However, the course participants in the UK don't have the advantage of immersion that a course participant in Russia has, so in the latter case, 52 weeks may be feasible.
In addition to Christophe Strobbe's answer: because you can dedicate another 60+ hours per week to your study of Russian, as you disclosed in comments, it should be feasible.
Consider immersing yourself as much as you can in Russian, 7 days a week. As soon as feasible, find a tandem partner for language exchange (trading your English for Russian), so you can get few more hours of conversation in Russian every week. You don't need a conversational level of Russian for that, leverage your English.
I had similar experience (I had better fundamentals, not starting from zero like you do) and after a year, I dreamed in Russian.
In my personal opinion... Studying for 20 hours/week for one year in a classroom is not going to be enough to reach B2 level.
For example, there are programs to prepare foreign students for studying in a Russian University. Programs like this one typically last one academic year with 6-8 hours/day (30-40 hours/week) of studying Russian, and professional subjects (e.g. physics, math, chemistry, etc.) in Russian. After completing such program many students speak at B2/C1 level, but not everyone.
However, immersion in the environment is a very important positive factor in your case. Try to use it to your benefit.
Walk around the city, read the street signs, billboards, etc.
Talk to people in the school, and outside the school. Most likely you will have to communicate with locals in grocery stores, and such.
Watch movies. Action movies often contain simple and predictable dialogues.
From my observation of adult immigrants to North America. After two years of living and working here, almost everyone can speak reasonable English independent of cultural background, or foreign language they learned in school.
The Google (English) and Yandex (Russian) web browsers have implemented the Microsoft multi-lingual translator apps. The Google translator (translate.google.com) will accept both English, Turkish, and Russian characters, returning answers in both English, Turkish, and Russian as well. On input, Google converts English characters to Russian characters; it may do the same with Turkish characters as well. Google's grammar checker also flags incorrect spellings with a "Did you mean?" followed by a suggested correction. Google also has a two-speed (speaking speed, learning speed) for both input and output, a real advantage when learning not only reading and writing, but also speaking Russian.
Like Google, the Yandex web browser has also implemented the Microsoft multi-language translator. The Yandex translator (translate.yandex.ru) also has pronunciation, but apparently only for Russian language inputs and outputs. To my ear the Russian pronunciation in Yandex is much more lifelike than Google's.
The Yandex translator (Переводчик)can also be accessed from the Yandex browser's home page -- it's included in the list of options above the search box on the home page. Additionally,the Yandex web browser (yandex.ru) has many interesting features for a student in and of itself.
Both apps have excellent dictionaries, including multiple meanings of words, phrases, and sentences, along with synonyms and antonyms for the definition.
Once one has learned how to use the many advantages of the two translator applications (along with their individual peculiarities as well) the two translator apps can be exceptionally useful for students learning one or more languages.