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Russian science papers may or may not have been translated into english. If they have been translated, where would they be available?
Are there general methods or resources that can be used to find translations, either specifically for nuclear physics, physics in general, Russian translations, or generic to all foreign science translations?
JoeHobbit
The chances that it has been translated approach zero, I'm afraid; vanishingly little journal research is ever translated for republication. You'll almost certainly do better to find someone in your field who can read Russian to help you translate it.
You could try a few things in addition to finding someone who can read Russian:
You could check the "World index of scientific translations" (and its subsequent titles) if you have a copy in your library.
If you're willing to type (very slowly) in Russian, you could use the virtual keyboard or type phonetically into Google Translate . The translations aren't perfect, but they're often good enough so that you get the gist of it. For the paper you're referring to, the title translates into "A consequence of Dirac's theory of protons and electrons."
Ask one of the library lists that has many Physics librarians as members. One is PAMnet http://pam.sla.org/manual/pamnet-information/, which is the discussion list for members of the Physics-Astronomy-Math division of SLA. You don't have to be a member of the division to join the list. (Full disclosure: I am a member of the SLA-PAM division.)
In answer to the comment below, my colleague cpikas submitted a good answer to the more general question that is linked to in the comment.
I would add that while the chances of journal research having been translated is almost nil, the chances are actually decent for russian literature. My library contains quite a bit of scientific literature translated from Russian by The Consultants Bureau and other organizations.
To answer the comment below, there are no great sources for this. Worldcat has the most complete database, but even that is lacking when it comes to foreign materials. Our colleciton of rare materials has been built up over the past \~130 years, so the specific source is rarely known. For what it is worth, our holdings are in worldcat. After searching through Worldcat we tend to try combinations of titles, publishers, and journal names in Google and other search engines.
I hope I'm not completely out of scope going anecdotal here, for the episode in question had a highly educative content at least for me:
Recently I have witnessed a colleague from our ILL team trace down an elusive copy of a scientific Russian magazine. When the first request of a patron could not be fulfilled, the patron replied with a photo of the front page of the magazine in question - he had it in his hands some time ago and was by now desperately searching for an article he remembered reading to reference it.
With the help of another colleague it was determined that the title was of Ukrainian origin, and several attempts were made to transcribe the title from its original Cyrillic script. Eventually one of those transcriptions took hold on one of the search engines fed, and further refinements on the title could be made which made it possible to trace down that the magazine, while in Ukrainian, was actually printed and published in Toronto. From there it was routine work to find three copies existing within Europe, and initiate an ILL loan on one of them.
The key to searching in this case was the variety on transcriptions/romanizations of the Cyrillic title. Even with two Russian-speaking librarians cooperating on the challenge, it took several attempts to find the title hidden in the latin-scripted databases and weed out all the false positives.
So, apart from the excellent tips math_librarian already mentioned in his answer, I'd add that you might ask a native experienced with transcriptions (and their possible variations) to aid in finding references to the original that could in turn lead you to a possible translation.