http://www.tripadvisor.com/ShowTopic-g294232-i525-k4993265-Safe_to_travel_in_Japan_Tokyo-Japan.html
If you do not have an absolutely urgent need to travel to Japan, do not go, or try to minimize the stay within Japan.
If you go, wear a mask over your face whenever you go out. Try to stay Western part of Japan. Drink only imported water in bottles. Avoid Japanese green tea, fish, seaweed, rice (due to mixing of radiation fallout contamination in food supply chain). I'm a Japanese, so this makes me very sad to say (this should be no way interpreted as Japan bashing), but I will not visit Japan for the next couple of years at least (or at least avoid if possible) for the following reasons:
1. Right now, Fukushima nuclear plant still continue to spew radioactive emissions and they are leaking thousands of tons of radioactive water underground and into the Pacific Ocean every day.
Three (3) Fukushima nuclear reactors suffered "melt-through" (more serious than 'melt-down'). The super-heated nuclear fuel melted through the steel containment vessels and now thought to be eating away the concrete beneath them. Neither Tokyo Electric (the Fumushima plant owner) or Japanese government know where the melted fuels are currently or what temperature or what state they are (they’ve admitted so), but they are sure, based on many computer simulations, that this is the best case scenario. (See " yomiuri.co.jp/dy/national/T111215006237.htm ")
The spent fuel pool in reactor #4 contains over 1500 plutonium rich spent fuel rods as well as new rods. This reactor building is also badly damaged; the pool is barely staying up on the building frame, exposed to outer elements. If there is another big earthquake, these fuel rods could fall out directly into the ground, causing severe groundwater contamination or even an explosion.
2. External Radiation Exposure. This happens from being in a high radiation location. Although the most danger lies in the disaster area (Fukushima, Miyagi, Iwate), considerable amounts of nuclear particles were scattered across most part of Japan and there are many radiation ‘hot spots’ even in Tokyo. A recent study reported high dose of radioactive contamination even in Tokyo house dust.
Japanese government recently began publishing atmospheric radiation measurements in each region and they say the most areas are safe. But if you look closely at their practice, often the measuring meters are located at 18 meter or higher. The radioactive fallout concentrate on the ground and that is where people conduct daily activities. So, the artificially diluted measurement at 18m means no assurance to humans.
3. Japanese government recently began a new initiative of transporting the earthquake/tsunami debris from the disaster area to cities all over Japan and forcing the local governments to bury and burn the disaster debris in community incinerators that do not have proper filters or emission monitoring. Citizen’s protests are simply ignored or vetoed by governors of many cities. This debris is likely to be contaminated with Fukushima radiation. You do not need a science degree to foresee that such burning would re-disperse and re-contaminate not only the Eastern Japan but the entire Japanese cities that had minimum contamination so far.
This burning will continue every day all over Japan from now through 2014 at the least, according to Japanese central government estimate. With this initiative, trucks, rails, and ships carrying the radioactive debris are freely and without any protection crisscrossing through major train stations and ports of Japan where you as a tourist would most likely use to transit.
4. Internal Radiation Exposure. Japanese government has done very little to secure the nations’ food supply chain since the March 11, 2011 disaster. It is always several weeks to months later after the contaminated foods (beef, milk, water, vegetables, fish, etc.) were already shipped out and consumed by consumers when the government makes an announcement like “oh, by the way, such and such beef was contaminated with cesium but it was already distributed and consumed, don’t worry there would be no immediate problem to health…”
In some cases, they’ve found even school lunches in Tokyo nursery and elementary schools as well as baby formula were contaminated with Fukushima radioactive fallout.
Japanese government again began publishing sample inspection results, but their sampling methods cannot be trusted. For example, when testing beef, they initially tested the radiation only on the cow hide and determined the meat safe. It did not even occur to them that they needed a different testing for beef.
This naturally calls attention to water supply safety. Again, their only action was post-event measurements publication. The man-made world’s largest lake that supposed to supply water to Tokyo metropolitan area is already contaminated. Most people in Japan use bottled water and even that is questionable because no manufacturer is willing to publish their water quality data or source information.
I’ve heard that a US sport team (most teenagers and young adults) used imported bottled water for showering when they had a meet in Tokyo several months ago. A German opera group is bringing all of their food and water supply from Germany to perform in Tokyo.
Many Japanese who only read officially published announcements and news are adamant to stress the safety of Japanese produce and water, saying things like “this passed the government standard” or “the level [of contamination] was within the standard.” What they are not telling you (or perhaps they do not know) is that Japanese government has raised the maximum permissible radiation contamination level for food and beverage by 20 to 100 times of what was before 3-11-2011. Currently the Japanese standard is higher than that is being used for Chernobyl restricted area, according to a Belarus doctor who visited Fukushima . Japanese government lately promoted Shizuoka green tea in New York, stressing its safety (meaning the tea passed the Japanese standard). But in reality, none of Shizuoka green tea and many food and beverage items from Japan can meet the U.S. standard.
There is also a misconception about low dose radioactive contamination. Some people try to convince you that a food is safe because the contamination level is low. Obviously they did not pay attention in the high school science class. Even at low radiation level, internal exposure is highly dangerous. The level that your whole body might tolerate can easily kill or damage your internal organs and cells that make up them.
If you go to Japan now or for the next couple of years, it is inevitable that you will have some degrees of internal radiation exposure because it is impossible not to breathe air, consume food or drinks, or take showers with tap water while you are there no matter how short your stay may be.
I would assume that any airplanes leaving Japan would be re-stoked with such local tap water and food.
5. Japanese government did nothing to protect its citizen from nuclear fallout. The government has a super computer called SPEEDI that can forecast the direction and levels of nuclear particle movement in case of an emergency like Fukushima. The government had data from this computer shortly after the earthquake and tsunami hit, but they did not share the findings with the residents of Fukushima and surrounding area until many months later. As a result, many people who lived near the Fukushima nuclear plant evacuated to a city called Iidate, falsely believing that is far enough and safe. The SPEEDI forecast accurately, back in March, that the radioactive fallout would most likely concentrate in Iidate. Those who evacuated to Iidate unknowingly got extra high doses of radioactive contamination as a result.
Even now, much wider areas of Fukushima prefecture should be evacuated, including its capital, but neither the central or local government of Japan is willing to protect even the babies, school children, pregnant women, and women of child-bearing ages who live in those high radiation areas. Without governmental logistic and financial help, many have no means to relocate to a safer location.
The Japanese government and tourism agencies are currently spending millions of dollars and political arm breaking to convince the world that Japan is safe, back to normal, come visit the country. But based on their track record of how they are handling their own citizens, you can bet they have very little concern for the safety of tourists, especially foreign tourists, in terms of the current situation of radioactive contamination all over Japan (that is worsening due to the debris buring).
If another emergency like Fukushima happens (it is conceivable for Japan to have another big earthquakes in the same region), the government and tourism agencies would most likely spend many months and money again trying convince the world that there is no nuclear danger whatsoever, just like they did in back March 2011 and are doing now --- even as they have admitted that they have no clue as to the location and status of the melted through nuclear materials in three reactors!
Radiation is invisible, you cannot smell it, you cannot see it or feel it. So, things may appear normal and everything in cities may be functioning. But any levels of exposure can increase your future risk of developing cancer, tumors, even heart alignments. It may not happen right away, but you will be many times more likely to develop serious health problems in the coming years.
People who say it is safe (radiation in Japan) are not paying attention to the latest reports by various reputable scientists and governments (Japan, US, European countries, etc.) or perhaps they do not understand the nature of radiation, or they may have some financial ties with Japanese government.