In the same week as Japan unveils its Pacific-Rim-esque anti-tsunami wall public works project [6], and Japanese government auditors say the operator of the Fukushima Dai-ichi nuclear plant has wasted more than a third of the 190 billion yen ($1.6 billion) in taxpayer money [7] allocated for cleaning up the plant after it was destroyed by a March 2011 earthquake and tsunami; Science Journal reports [8], Fukushima won't be truly safe until engineers can remove the reactors' nuclear fuel. But first, they have to find it... And so, in February of this year two muon detectors were installed outside the Fukushima Daiichi unit-1 ruins at reactor vessel height for the purpose of finding that ‘missing’ reactor fuel.
First, as AP reports, [7] Japanese government auditors say the operator of the Fukushima Dai-ichi nuclear plant has wasted more than a third of the 190 billion yen ($1.6 billion) in taxpayer money allocated for cleaning up the plant after it was destroyed by a March 2011 earthquake and tsunami.
A Board of Audit report describes various expensive machines and untested measures that ended in failure. It also says the cleanup work has been dominated by one group of Japanese utility, construction and electronics giants despite repeated calls for more transparency and greater access for international bidders.
Tokyo Electric Power Co. spokesman Teruaki Kobayashi said all of the equipment contributed to stabilizing the plant, even though some operated only briefly.
Some of the failures cited in the report:
- FRENCH IMPORT: Among the costliest failures was a 32 billion yen ($270 million) machine made by French nuclear giant Areva SA to remove radioactive cesium from water leaking from the three wrecked reactors. The trouble-plagued machine lasted just three months and treated only 77,000 tons of water, a tiny fraction of the volume leaking every day. It has since been replaced with Japanese and American machines.
- SALT REMOVAL: Sea water was used early in the crisis to cool the reactors after the normal cooling systems failed. Machines costing 18.4 billion yen ($150 million) from several companies including Hitachi GE Nuclear Energy, Toshiba Corp. and Areva were supposed to remove the salt from the contaminated water at the plant. One of the machines functioned only five days, and the longest lasted just six weeks.
- SHODDY TANKS: TEPCO hurriedly built dozens of storage tanks for the contaminated water at a cost of 16 billion yen ($134 million). The shoddy tanks, using rubber seals and assembled by unskilled workers, began leaking and some water seeped into the ground and then into the ocean. The tanks are now being replaced with more durable welded ones.
- GIANT UNDERGROUND POOLS: A total of 2.1 billion yen ($18 million) was spent on seven huge underground pools built by Maeda Corp. to store the contaminated water. They leaked within weeks, and the water had to be transferred to steel tanks.
- UNFROZEN TRENCH: A 100 million yen ($840,000) project to contain highly contaminated water in a maintenance tunnel by freezing it failed because the water never completely froze. TEPCO subsidiary Tokyo Power Technology even threw in chunks of ice, but eventually had to pour in cement to seal the trench.
* * *
So it is even more distressing that, as Science Journal reports [8], Japan's Fukushima Daiichi Nuclear Power Station, destroyed 4 years ago in explosions and meltdowns triggered by an earthquake and tsunami, won't be truly safe until engineers can remove the reactors' nuclear fuel. But first, they have to find it...
The image below is from a TEPCO handout [9] (in Japanese). As expected, the Fukushima scans revealed no fuel in the reactor vessel.
[10]
Fukushima Update goes on to explain... [11]
In February of this year two muon detectors from the High Energy Accelerator Research Organization [KEK] in Tsukuba, Japan were installed outside the Fukushima Daiichi unit-1 ruins at reactor vessel height for the purpose of finding that ‘missing’ reactor fuel.
...
Now the plan is to go ahead and insert the new shape-changing robot in April to see if there is enough left of the control rod drive rail to get that robot onto the containment catwalk, where it should be able to circle inside the containment itself to collect more data about the location of the corium (melted fuel). Hopefully it’s still in the containment drywell, not having melted through the base pad into the lower level basement or ground below. If it exited the drywell it may have melted through the downcomer vents and into the torus in the first level basement, and some may have found its way into drains and drainpipes as one of the flows at Chernobyl did to produce the corium formation known as the “elephant’s foot.”
The geology at Chernobyl is quite different from Fukushima, having been built atop a solid granite bedrock rather than rock and gravel fill. The Chernobyl “elephant’s foot” formation exits a large drainpipe in what was the basement of that plant and melted 3 meters (~9 feet) into the granite. If the Fukushima unit-1 corium made it to the ground underneath the plant it is likely to have spread much further through the fill and be much more difficult to retrieve, even as the ‘underground river’ of groundwater that runs beneath the facility picks up contamination and takes it on out to the ocean. Decommissioning requires that all nuclear fuel – in whatever state – be removed from direct contact with the environment and safely isolated.
The unit-1 muon scans apparently also found some evidence that some fuel fragments may have been relocated from the reactor vessel to the spent fuel pool and refueling floor, though the precise nature of this evidence and how the fuel managed to get to these locations is not explained. If there is corium/fuel debris in these locations it will make cleanup in preparation for defueling the SFP more complicated, especially in light of the re-contamination of rice fields downwind during the cleanup of the unit-3 refueling floor [12]. Now that the glorified ‘tent’ over unit-1 has been removed, cleanup of that mess is scheduled to start sometime in the next week.
* * *
But apart from that, it's totally safe for the looming Olympics... which will include the individual three-and-a-half-legged sprint...
