I don't know of any. I read some years ago that a long-term study had been done to assess the long-term effects of the prompt radiation dose on the surviving inhabitants. The finding was that the frequency of diseases like cancer in the populations of those two cities was not much different from the general population of Japan.
This is in contrast to the effects of continuous exposure to radioactive contamination over a period of years. If you are exposed for a long period, that increases the probability of many diseases over time, but if you are exposed for only a short time and don't die right away, your prospects are about the same as everyone else's. So they should just avoid the real risk--smoking.
What this means is that a documentary on contemporary life in Hiroshima and Nagasaki would be not much different from a documentary about any other Japanese city.
But there are many documentaries about the short term effects--blast, burns and radiation sickness.
One group of women (known as the Hiroshima maidens) were working in a rice field, and were hit with the intense flash. The burns only affected exposed skin, their eyes were protected by their sun hats, but their faces and hands had the skin fried. They were later taken to the US to have their faces reconstructed and their hands skin-grafted, but they still looked scarey and most never married.
One unusual case was a Hiroshima maiden that married an American WWII soldier--in fact I think he was a bomber pilot. She was very disfigured, even after surgery, but he said she was beautiful inside.
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I don't do it for the money, babe. I do it to entertain people.-- Susan Boyle