Japan is expected to introduce new nuclear regulations from July 8 in a move to overhaul safety requirements for commercial reactors following the 2011 Fukushima Daiichi nuclear plant disaster, sources close to the matter said Tuesday.
Four power suppliers will likely apply by the end of July with the Nuclear Regulation Authority for safety assessment to bring 12 reactors at six nuclear plants back online, according to the sources.
The four are Hokkaido Electric Power Co., Kansai Electric Power Co., Shikoku Electric Power Co. and Kyushu Electric Power Co.
The new requirements, to be officially decided by the authority on Wednesday, will for the first time oblige utilities to put in place specific countermeasures against possible severe accidents like reactor core meltdowns, as well as against huge tsunami -- the direct cause of the Fukushima crisis.
For example, utilities will be urged to equip reactors with filtered venting systems so that radioactive substances will be reduced when gas and steam need to be released to prevent damage to containment vessels.
The operation of the reactors will also be limited to 40 years in principle, although an exceptional extension of no more than 20 years is allowed if safety is confirmed.
The NRA has been devising the new regulations since its launch in September last year. It compiled draft regulations in April and solicited opinions from the public before finalizing them.
The legal deadline for enacting the new safety criteria is July 18, but calls have been growing from the power industry for earlier implementation so that utilities can start applying for the NRA's safety assessment.
Three teams under the NRA will be in charge of the screening, a process which some senior officials of the NRA secretariat expect to take at least six months.
Of the 50 commercial reactors in Japan, only two in western Japan are currently online. The two will also be shut down in September at the latest for mandatory routine checkups.
In the Fukushima nuclear crisis, triggered by a huge earthquake and tsunami on March 11, 2011, three reactors suffered core meltdowns because their key cooling systems failed due to a loss of power supply.
A series of hydrogen explosions also took place, resulting in the release of massive amounts of radioactive substances into the environment.