The incident occurred in the Petropavlovsk-Kamchatsky port, about 6,700 kilometers (4,200 miles) east of Moscow, when the gas used for cooling and refrigeration escaped from the ship's freezer plant, regional emergency official Sergei Viktorov said.
A mechanic died on the spot and four fishermen were hospitalized with gas burns, Viktorov said.
The trawler, the Koyo Maru, had been confiscated from Japan for alleged poaching and was now operated by a Russian company.
Russia has been developing an energy module on the basis of the megawatt-class nuclear power plant since 2010. The spaceship needs neither sunlight nor solar batteries
There are legitimate authorities in Donetsk and Luhansk republics now, with which Russia can implement the project of the economic integration of the Donbass