The Crown Prince and Princess are taking their small daughter to the imperial retreat in Nasu in Tochigi Prefecture. Radioactive rice hay containing 106,000 becquerels/kg of cesium was found in nearby Nasu Shiobara.
In Professor Hayakawa's map, you can see why. The area's radiation contour is at least above 0.5 microsievert/hour. (Look for the area just outside 100 kilometer radius, southwest from Fukushima I Nuke Plant.) You can view one of his photographs and see why (picture taken on July 12 at the rice field in Nasu Shiobara, air radiation level of 1.358 microsievert/hour).
From Gendai Media magazine (7/30/2011):
夏休みシーズンを迎え、今年も皇室ご一家は各地へ静養に出かけるが、原発事故の影響により、その行き先が一部で注目されていた。
Now it's a summer vacation season, and Japan's imperial families will spend the summer in imperial retreats. After the nuclear plant accident, some people have been wondering where they choose to go.「天皇・皇后ご夫妻は須崎御用邸と軽井沢、皇太子ご一家は須崎と栃木の那須御用邸へ行かれるのが、ここ数年の通例ですが、今年は原発事故により、那須で非常に高い線量の放射線が検出されている。本当に那須で静養されるのかが、焦点になっていたのです。
According to one journalist who follows the Japanese imperial families, "The Emperor and Empress go to the retreat in Suzaki [in Shizuoka Prefecture] and Karuizawa [in Nagano Prefecture], and the Crown Prince's family goes to the retreat in Suzaki and Nasu, in Tochigi Prefecture. It has been like that for several years now. But this year, a very high level of radiation has been detected in Nasu. So we've been wondering if they go to Nasu this year.
これまでは、とくに雅子妃が那須をお気に入りということで、例年10日以上にわたって長期滞在されていたが、まだ9歳の愛子内親王のことを考えると、高線量の那須に長期滞在するのはどうか、という声が宮内庁内にあった」(皇室ジャーナリスト)
The Crown Princess particularly likes the Nasu retreat, and the family usually spends more than 10 days there. But there are some who voiced concern over staying in the high-radiation Nasu for an extended time, considering their daughter, Princess Aiko is only 9 years old."
軽井沢のほうが線量は比較的低いため、宮内庁内部では皇太子一家の軽井沢行きを勧める声もあったというが、結局例年通り那須と決定した。
The radiation level in Karuizawa is lower compared to Nasu. There were those in the Imperial Household Agency who recommended the Crown Prince's family to go to Karuizawa for the summer, but it was decided that the family would go to Nasu, just like last year.
「宮内庁幹部は、『(静養先は)例年通り。東電管内でないとまずいだろう』と話していました。
"Officials at the Imperial Household Agency were saying, "The summer retreat will be the same as last year. It cannot be outside the area served by TEPCO."
実は軽井沢は、中部電力管内なんです。国民が真夏に『節電』で暑さに耐えているときに、皇太子一家だけが東電の管内から逃れるというのは、国民の 理解を得にくいだろうという判断があったようです。那須は職員用の風呂を開放して被災者から好評を博したこともありますし」(前出・皇室ジャーナリスト)
Karuizawa is the area served by Chubu Electric. When the Japanese citizens are suffering the heat of the summer in order to "conserve electricity", they may not look kindly at the Crown Prince family escaping the TEPCO area. The imperial retreat in Nasu let the earthquake/tsunami evacuees use the bath for the employees and it was very popular with the evacuees", added the same journalist.
放射能の影響が心配でないはずがないが、国民とともに歩む皇室像を貫いた、ということのようだ。
There's no way that the Crown Prince and Princess are not worried about the effect of radiation, but they [or the Imperial Household Agency] decided to portray themselves as one with the citizens of Japan.
At least some citizens of Japan would understand if they escape TEPCO, and rather have them take their young daughter to a lower radiation location and state the reason clearly - to avoid radiation.