In what may be somewhat disappointing news for the domestic power industry, Japan will not be able to sign a long-awaited nuclear energy treaty with the European Union at a regular summit next month.

When the landmark treaty, which is aimed at promoting cooperation in the peaceful use of nuclear energy, was initialed at the end of last year after years of hectic negotiations, it was widely expected to take effect as early as this summer, after being signed and ratified by both sides.

But the treaty will not be ready for signature at the 11th regular Japan-EU summit, scheduled for July 8 in Tokyo, for purely procedural reasons on both sides, according to government sources.