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  (Source: nationalgeographic.com)
It's a seven-point scale

The Fukushima Daiichi nuclear plant in Japan has had issues with toxic water leaving the site of its damaged reactor, and now, Japan's nuclear agency is upping the toxicity level of this water. 

Japan's Nuclear Regulation Authority is looking to raise the alert level of a leak at the plant from a one to a three on the International Nuclear and Radiological Event Scale (INES). INES is a seven-point scale. 

The move still has to be approved by the United Nations' nuclear agency.

The reason behind this increase in severity is the fact that 300 tonnes of radioactive water is leaking into the Pacific Ocean from the plant daily, which contains radioactive particles of cesium, tritium and strontium. To make matters worse, Tokyo Electric Power Company (Tepco) said that one puddle of the toxic water emits 100 millisieverts an hour of radiation. 

"One hundred millisieverts per hour is equivalent to the limit for accumulated exposure over five years for nuclear workers; so it can be said that we found a radiation level strong enough to give someone a five-year dose of radiation within one hour," said Masayuki Ono, general manager of Tepco.

Officials are already working to try and prevent more toxic water from leaving storage tanks, such as the leak that may receive a three on the scale. For instance, sandbags are being used to surround the tank and absorb water. 

Just last week, it was announced that Japan was looking into creating an ice wall, which would turn soil into a permafrost-type condition through the use of refrigerated coolant. This would build an underground containment wall made of ice to hold the water and stop it from going into the Pacific. 

However, the government doesn't have a cost estimate for the project yet. Kajima Corp. -- the construction company that largely built the nuclear plant -- has until March 31, 2014 to create a feasibility study of the ice wall.

The government would like the project to be completed by July 2015. 

Back in March 2011, a 9.0-magnitude earthquake shook Japan and crippled the reactor at Fukushima Daiichi nuclear plant. It caused quite a bit of havoc with the release of radioactive watercontamination of crops and of course, the thousands of lives lost.

Source: BBC News



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By marvdmartian on 8/22/2013 11:23:14 AM , Rating: 2
Being old school, I had to look up the conversion rate to millirem (what I learned). 100 millisievert/hr, times 1 millisieverts per 100 millirem, comes out to 10,000 millirem per hour, or 10 Rem/hr.

While I wouldn't want to stand next to that source for any appreciable amount of time, this does show that the Japanese limit is ~2 Rem/year. Substantially higher than the US Navy dose limit of 0.5 Rem/year, but about equivalent to what US companies running nuclear reactors have for their maximum yearly dose.

It should be noted, however, that it would take nearly half a day's exposure, at this dose rate, in order to absorb a sufficient dose to experience even the first symptoms of radiation poisoning (usually experienced, in healthy adults, at 100 Rem exposure), which would include nausea, vomiting, and a slight fever. Like I said, not something I'd want to spend any significant time around!

However, you made this point, which was confusing:
quote:
The government of Japan tried to downplay the event saying it was safe to be at a certain distance, but the evidence shows for itself.

Perhaps your understanding of radiation dose rate is lacking?

Dose rate from a radiation source is determined by 3 aspects, time, distance and shielding. The more time you spend around it, the higher the dose (like I just talked about). The more shielding you have between you and the source, the lower the dose (lead jock strap, anyone?). And the more distance between you and the source, the lower the dose.....so the Japanese government's saying that it's safe at a certain distance would be entirely correct.

I'm not downplaying this, by any means, just trying to get people to understand the reality of the situation. Maybe then, we won't have people freaking out about thousands of gallons of contaminated water flowing into trillions of gallons of ocean??


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