I've posted quite a bit in the past about the various devices TEPCO drops into Fukushima Daiichi unit 1 (e.g., see a clear view of device here and discussion here).
The device being used today in Unit 1 is deployed by TEPCO when atmospheric emissions start looking worse, as they have the last few days. You can see the crane dropping the device in unit 1 in this screenshot with the TEPCO time stamp of June 27 13:04:
The device is a bit clearer in this cropped and enlarged section from the screenshot above. You can see the steam from the device so perhaps it is injecting water, although some commentators believe some sort of sticky substance is being sprayed to keep down the dispersion of radioactive particles:
Daiichi has not been looking too good the last few days, as illustrated in this screenshot from today, with TEPCO's timestamp of June 27, 1:36:
Vertical emissions are visible here and the coloration is particularly bad with lots of green, purple and red.