Ever since a massive earthquake and tsunami struck the Fukushima Daiichi nuclear power plant on 11 March, activities at the site have been hasty, improvised, and often uncoordinated. For engineers, project managers (and reporters who cover large projects), nothing has made the chaos more pronounced than the lack of a flowchart. Yesterday that all changed: the world now has a brightly coloured chart of the next six to nine months at Fukushima.
Flowcharts are omnipresent in the world of big projects. They impose order on the myriad little tasks needed to complete a spacecraft or particle accelerator. They ensure that the hundreds or thousands of people involved have a clear view of the goal, and where their own efforts fit in. They’re often derided, but as a reporter, I find them invaluable.
For the first month, Fukushima had no public flowchart. Instead, workers seemed to be pursuing an ad hoc strategy of flooding reactors and pumping out contaminated water. That made sense in the short term, but bringing the reactors under control is a mammoth task that will require careful planning and coordination. A flowchart is long overdue.
The new plan from the owner of the plant, the Tokyo Electric Power Company (TEPCO), reflects the complex task ahead. It can be roughly broken down into three parts:
First, workers will continue to cool the reactors, whose nuclear fuel is still generating significant amounts of heat. In the near term, the cooling will be done as it is now, with water pumped in through the Emergency Core Cooling system. But in the long term, TEPCO would like to restore a “heat exchange function”, which I take to mean they would like to have some system for re-circulating water through the core. This would avoid the massive build-up of contaminated water that has been a problem at the site for the past few weeks.
Second, but in parallel with the cooling effort, is a plan to deal with contamination on the site. The most pressing problem is the thousands of tons of radioactive water building up as a result of emergency cooling. Here, the utility seems to be taking a two-pronged approach. For lightly contaminated water the plan is to decontaminate it, possibly with zeolite filters of the sort we’ve discussed elsewhere. Higher level water will be stored in new tanks and other waste facilities at the site.
TEPCO is also planning to build a structure or structures over the reactors, which will keep radiation in, and hopefully keep rain and wind out. These structures will initially be flimsy, but the company plans to design more substantial concrete buildings to cover the reactors.
Finally, TEPCO is planning a coordinated monitoring system that will allow local residents to accurately gauge the risk they face as they begin to return to the evacuation zone.
The entire plan should, theoretically, be completed in six to nine months. It’s an ambitious schedule, but if it were successful, it would bring a degree of stability to the residents of Fukushima prefecture.
It is very important to note that there is still quite a bit missing from the new plan. Most importantly, there is no mention of whether or how TEPCO might remove the roughly one thousand tonnes of nuclear fuel from the broken reactors before they are dismantled. This may be because radiation levels near the reactors are too high to contemplate further cleanup, or perhaps because the utility does not expect to be in charge of the next phase of the clean up.
For full coverage of the Fukushima disaster, go to Nature’s news special.
For a selection of our coverage in Japanese, see Nature Asia Pacific.