Steven Starr - Director of the Clinical Laboratory Science Program at the University of Missouri/Senior Scientist at Physicians for Social Responsibility - said:
Asahi Shimbum notes that the location of Fukushima melted fuel is unknown. It could be ‘scattered’ in piping, vessels ... “we’ve yet to identify all hotspots” around plant.
While the Japanese government tried to cover up the lack of containment with "mission accomplished" type announcements of "cold shutdown", the loss of containment has been known for years.
For example, AP wrote in December 2011:
As nuclear expert Arnie Gundersen pointed out last year:
The Japanese basically lied about what happened with the reactors for months. They said they were trying to prevent a meltdown, when in fact they knew within the first couple of days Reactors 1, 2, and 3 at Fukushima Daiichi had melted down, and they actually melted through the steel containment vessels. So there was a worst case scenario that they were trying to hide, they even knew that at that time enormous amounts of radiation were released over Japan and some of it even went over Tokyo [...] The melted core cracked the containment vessel, there really is no containment. So as soon as they pump the water in it leaks out again.
The nuclear fuel moved as it melted, so its condition and locations are little known.AP noted a couple of days later:
The complex still faces numerous concerns, triggering criticism that the announcement of “cold shutdown conditions” is based on a political decision rather than science. Nobody knows exactly where and how the melted fuel ended up in each reactor ….We noted last year:
New video of the inside of the torus room in Fukushima reactor 1 shows piles of sediment:If the reactors are “cold”, it may be because most of the hot radioactive fuel has leaked out. *** The New York Times pointed out last month:After drilling a hole in the containment vessel of Fukushima reactor 2, Tepco cannot find the fuel. As AP notes: The steam-blurred photos taken by remote control Thursday found none of the reactor’s melted fuel …. The photos also showed inner wall of the container heavily deteriorated after 10 months of exposure to high temperature and humidity, Matsumoto said. TEPCO workers inserted the endoscope — an industrial version of the kind of endoscope doctors use — through a hole in the beaker-shaped container at the Fukushima Dai-ichi plant’s No. 2 reactor ….A former nuclear engineer with three decades of experience at a major engineering firm … who has worked at all three nuclear power complexes operated by Tokyo Electric [said] “If the fuel is still inside the reactor core, that’s one thing” …. But if the fuel has been dispersed more widely, then we are far from any stable shutdown.”Indeed, if the center of the reactors are in fact relatively “cold”, it may be because most of the hot radioactive fuel has leaked out of the containment vessels and escaped into areas where it can do damage to the environment.
Tokyo Electric ran a probe into the basement of Unit 1. This is not inside the containment, this is outside the containment. On the top of the water surface they found lethal radiation, 1000 rem an hour. But then they put the probe down into the water and what’s even worse is the bottom, the sediment on the bottom, was thousand of times hotter than that. And what that indicates is that fuel, nuclear fuel, has left the containment, as particles, and settled out on the bottom outside the containment. So, I think that’s a pretty clear indication that the containment was breached. It just makes decommissioning these plants… it was going too be hard already, but this information makes it worse.Loss of containment of nuclear fuel also exists within the spent fuel pools at Fukushima. For example, Chris Harris, former licensed Senior Reactor Operator and engineer says of new video released by Tepco showing extensive damage and debris in Fukushima spent fuel pool 3:
Plenty of heavy steel beams and refueling equipment that must be cleared out of the way in order to see how badly damaged each fuel assembly is. There is little doubt that failed fuel exists, which is highly radioactive.Asahi Shimbum notes:
The water [inside Fuel Pool 4] was muddy and brown.The Fukushima fuel pools continue to be one of the main threats to Japan, the United States ... and all of humanity. And the Fukushima accident is presently causing higher and higher levels of contamination hundreds of miles away ... and is still contaminating wildlife thousands of miles away.