On August 11, Sendai Nuclear Power Plant of Kyushu Electric Power restarted operation. To restart a nuclear power plant, they say it is inevitable to expand fire-fighting equipment of gas type. There is an influx of orders now for halon fire extinguishers, but we hear a rising chorus of concern about shortage of halon.

According to the manufacturers of fire-fighting extinguishers, electric companies have placed orders for halon as an effective extinguishing gas considering the past result and capability, although there exists no written rule compelling to use halon as an extinguishing gas for a nuclear power plant. At a certain station, as they say, there is a maximum demand of 50 tons, and the halo manufacturers are so busy now to catch up the demand.

In the aforementioned case of Sendai Nuclear Power Plant, about 300 halon extinguishers were newly installed at 30 locations in Plant No. 1 and 2 as told by Kyushu Electric Power. In addition, according to our estimation, it seems that there were new installation or revision of halon fire-extinguishing equipment at 9 locations including Genkai, Takahama and Ikata out of 18 locations across the country.

Since the production of halon was discontinued domestically as an ozone depleting substance in 1994, only the halon which had been stockpiled before then has not been exempted from the restriction. Therefore, halon has so far been used only for such indispensable purposes as so-called “Critical Use” taking advantage of the accumulated reserve of recycled halon from the disassembling works of structures or the inspection of valves.

According to the data of Fire and Disaster Management Agency as of November 2014, the stockpiled halon reserved by the manufacturers of fire-distinguishing equipment amounted to 700 tons, but some manufacturers say that only 100 tons or so are in stock even by a company having the biggest reserve and some other rumors that the special demand for nuclear power plants at this time might have halved the stockpile in total. Now that the manufacturers have to cover other requirements of halon fire-prevention equipment than the nuclear power plants, they are afraid of serious shortage of supply.

Under these circumstances, each manufacturer of fire-prevention equipment jointly deliver halon to one location of nuclear power plant with several other manufacturers or is taking some responsive measures by means of proposing the use of nitrogen gas, carbon dioxide gas or an alternative fluorocarbon gas (HFC227ea etc.)

In case of carbon dioxide, however, inhalation may cause a toxic condition. Nitrogen or alternative fluorocarbon, on the other hand, may cause an issue of safety or the environments which may harm human health causing requirements for a facility to remove the inside pressure when gas blasts. It seems that the manufacturers will have much more difficulty to respond to the issues from now on.