Friday, October 04, 2013

one of these things..., (somebody lyin!!!!)

thebulletin | Tepco and the Japanese government have done a good job of containing most of the highly contaminated water, which poses the highest risk to the public. They are, however, having great difficulty in managing the overall contaminated-water situation, especially from a public-confidence perspective. The engineering challenge—control of a complex, ad hoc system of more than 1,000 temporary radioactive water tanks and tens of miles of pipes and hoses throughout the severely damaged plant—is truly a herculean task. Explaining what is going on and what has to be done to an emotional, traumatized, and mistrusting public is an even larger challenge.

Approximately 340,000 tons (90 million gallons) of radioactive water is now stored in large tanks at the site. A variety of water-processing systems have been built fairly rapidly under very difficult circumstances. To minimize the increases in water inventory growth, all cooling water now being injected into the damaged reactor cores is recycled.  It is initially pumped from the building basements and processed through new systems that remove most of the gamma emitting cesium 137 and cesium 134, oils, and salt contaminates, so that the water can be pumped back into the three reactor cores to keep them cool. Because the cores are mostly melted debris, the injected water picks up more radionuclides and flows back into the basements. The water-processing systems now in use are not capable of removing strontium 90, which is only a beta emitter and not a major radiological hazard to trained workers who wear protective clothing. But strontium 90 is an environmental concern and will need to be removed from water before it can be returned to the environment.

The reactor and turbine buildings are not watertight up to the surface; the basements are below the present groundwater elevation, and relatively clean groundwater seeps into the buildings. Tepco is maintaining the water levels in the basements slightly below the groundwater elevation to prevent the leakage of highly contaminated water from the basements into the general environment. But this in-leakage—estimated to be approximately 400 tons (105,000 gallons) per day—mixes with the water already in the basements, also becoming highly contaminated. So each day, despite Tepco’s water-recycling efforts, the volume of contaminated water at the plant increases; this is why 340,000 tons of water are currently stored on site.

This building-basement water is the highest-risk water associated with the Fukushima situation. That water is being handled reasonably well at present, but because of the constant in-leakage of groundwater, some ultimate disposition will eventually be necessary. To further clean this huge and increasing volume of medium-level radioactive water, the Tepco team has built a major new water processing system called the Advanced Liquid Waste Processing System. Built by Toshiba, this state-of-the-art system is based on technology from a major US waste management company, EnergySolutions.

Although this system is in a testing phase, with startup design and operational issues being resolved, it aims to remove more than 99.999 percent of radioactive contamination for most radioisotopes. The radioactivity levels in the effluent of the Advanced Liquid Waste Processing System are expected to be very low and to meet international and Japanese discharge standards for the important isotopes of cesium and strontium. This means that, from a radiological risk point of view, the risk from water treated by this system and released to the sea will be extremely low—a small fraction of the natural variations in the environment’s background radiation. In fact, I am writing this article while sitting on an airplane, and I am receiving more ionizing radiation from cosmic rays at this higher altitude than I would receive from drinking effluent water from the Advanced Liquid Waste Processing System.


woodensplinter said...

This writer is not a scientist, he's a technical bureaucrat, and he's lying on behalf of the industry that conferred him status.

CNu said...

Do you think those were examples of the notorious "science trolls" in the comments attached to this article?