Authorities in Japan announced this morning that there is likely a breach in the containment vessel of the No. 3 reactor at the stricken Fukushima Daiichi nuclear power plant. This is potentially a disasterous development in the race to prevent a large-scale release of radiation. Radiation levels in the water that plant workers stepped into yesterday was 10,000 times the normal level and much higher than was expected. The workers were sent to the hospital due to their injuries. That water likely indicates “some sort of leakage” from the reactor core, signaling a possible break of the containment vessel that houses the core.
The contaminated water likely seeped through the containment vessel protecting from the reactor’s core, said Hidehiko Nishiyama of the Japan nuclear and industrial safety agency this morning. The incident raised questions about radiation control measures at the plant as 536 people — including government authorities and firefighters — continued working there Friday, according to an official with Tokyo Electric. Workers are using various measures to prevent the further release of radioactive substances into the air and beyond.
In an effort to keep workers at the plant and addressing the issues there at all reactors Japan’s Health Ministry recently raised the maximum level of exposure for a person working to address the crisis at the nuclear plant from 100 millisieverts to 250 millisieverts per year.
Reactor 1: remains a chief concern, with the Japan Atomic Industrial Forum noting Friday that its containment vessel was experiencing “increased” pressure. Earlier, buildups of hydrogen gas had driven up pressure that led to explosions at three of the nuclear plant’s reactors, including the No. 1 unit.
Reactor 2: Switching to fresh water, instead of seawater, is also a priority for the reactor’s core (as well as for its spent fuel pool). The aim is to prevent further corrosion and damage inside, which may be worsened by the buildup of salt.
Reactor 3: Considering “other routes” to accomplish their goals of restarting its cooling systems around the reactor and keeping its spent nuclear fuel pool in check and other aims. Authorities have not yet determined how to get around the obstacle. Firefighters from Tokyo and Kawasaki were expected to resume spraying toward the No. 3 reactor and its fuel pool on Friday afternoon, according to Nishiyama’s report this morning.
Reactor 4, 5, and 6: Efforts are ongoing each of which have their own concerns, though less worrisome because the units were on scheduled outages when the quake struck. None of these three units had nuclear fuel inside their reactors, though efforts are ongoing to control temperatures inside the spent fuel pools. On Friday morning, a concrete pump truck was used once again to inject seawater into the No. 4 unit’s fuel pool.