The French Nuclear construction company Areva has announced a contract to back-fit Japan’s Pressurized Water Reactors (PWR) with hydrogen recombiners. The devices use passive catalytic oxidation to convert free hydrogen into water vapor inside the domed containment buildings for PWRs. Areva says the technology will prevent hydrogen explosions and “preserve the integrity of the reactor”. The recombiners will be installed at the Ikata, Mihama, Oi, Sendai, Takahama, Tsuruga, Tomari and Genkai nuclear power stations having PWRs. Of Japan’s fifty nuclear power reactors, 23 are PWRs.
The Passive Autocatalytic Recombiner (PAR) is a state-of-the-art device that combines hydrogen emitted from damaged nuclear fuel bundles with atmospheric oxygen, producing water vapor. They do not need operator action or electricity to work. Thus, they are immune to full-station blackouts like the one that struck Fukushima Daiichi. In addition, once installed they have little or no operating or maintenance cost. Areva’s Philippe Samama says, “PARs represent a major step forward in nuclear plant safety, and AREVA is proud to be driving this progress with its Safety Alliance Program.”
140 international PWRs have been equipped with the PARs since the 1979 Three Mile Island accident. In addition, hydrogen recombiners have been installed throughout the United States after TMI for all domed containments surrounding both PWRs and Boiling Water Reactors (BWR). In addition, hydrogen “igniters” have been placed above the passive water volumes inside American containments to further mitigate hydrogen build-up. But, none of this happened in Japan.
Why? It seems we have yet another example of a Japanese financial conflict of interest and a ruthless persistence to ignore the potential for the rare-but-not-impossible nuclear accident. Since 3/11/11, knowledge of Japan’s decision to not upgrade emergency power supply systems to meet international reliability and safety standards has become well-understood. The lack of such safety improvements is (in this writer’s opinion) the single-most important technological cause for the accident at Fukushima Daiichi. Had the IAEA-recommended emergency power supply improvements been made at F. Daiichi during the years before 3/11/11, it is doubtful that the meltdowns and hydrogen explosions would have happened at all. Now we find that at least one additional international nuclear safety standard was ignored, and in all probability in the interest of monetary profit for the Japanese utility companies.
I’m sure that Japan will say they could not justify the cost of PAR installation relative to their view relative to likely benefits, which is just what they have said about their reason behind not waterproofing emergency power supplies for their nukes well-before the 3/11/11 tsunami. It makes this writer wonder what other safety compromises the Japanese have made over the past four decades, and further wonder if the new Nuclear Regulatory Authority will have the courage to do the right thing and make Japan meet all international nuclear safety standards.