Efforts to plug the hole with concrete failed completely . Officials will try again Sunday and use sand instead . The trip , described by the prime minister 's office as aimed at boosting morale among utility company workers and soldiers involved in the effort , put Kan on the edge of the 20-kilometer evacuation zone . Water testing has been ordered further south and offshore . Japan 's prime minister personally thanks crisis workers at the staging area .
Efforts to plug the hole with concrete failed completely . Officials will try again Sunday and use sand instead . Water testing has been ordered further south and offshore . Japan 's prime minister personally thanks crisis workers at the staging area .