Snapshot - Japan's nuclear crisis
* Japan's Trade Ministry, which oversees nuclear safety, says comprehensive rules will be drawn up for power plant operators in light of the accident that ripped apart the Fukushima Daiichi nuclear power station. It was the first acknowledgment that norms were insufficient when the March 11 earthquake and tsunami wrecked the facility.
* Japan's cabinet secretary Yukio Edano, chief spokesman for the accident, acknowledges that there is no end in sight for the crisis "by a certain period."
* The plant's operator, Tokyo Electric Power (TEPCO), says it will take a "fairly long time" to stabilise overheating reactors.
TEPCO says its chairman is at the firm's helm after its president, barely seen since the crisis began, was taken to hospital suffering from high blood pressure and extreme dizziness.
Chairman Tsunehisa Katsumata says TEPCO wants to remain a publicly listed company while acknowledging that emergency loans of 2 trillion yen (15 billion pounds) will not cover current costs.
National Strategy Minister Koichiro Gemba said on Tuesday that nationalisation of TEPCO, Asia's largest utility, was one option being considered.
- New readings show a sharp rise in radioactive iodine in the sea off the Fukushima Daiichi nuclear power plant to 3,355 times the legal limit, according to the state nuclear safety agency. The agency plays down the impact, saying residents have left the area and fishing has stopped.
- French President Nicolas Sarkozy, who chairs the G20 and G8 blocs of nations, plans to visit Tokyo on Thursday. He will be the first foreign leader in Japan since the disasters.
France also flew in two experts from state-owned nuclear reactor maker Areva and its nuclear research body to assist Japan's heavily criticised plant operator Tokyo Electric Power Co (TEPCO).
- Japanese Prime Minister Naoto Kan and U.S. President Barack Obama agree that close cooperation is essential in handling the problems at the plant. The two leaders pledge to help people affected by the quake.
- On Tuesday, plutonium was found in soil in five places at the plant, heightening public alarm. TEPCO says traces of plutonium found were of level not harmful to human health. The nuclear safety agency said the discovery could mean the reactor's containment mechanism had been breached.
- Around 27,500 people dead or missing from the earthquake and tsunami.
- Some opposition lawmakers have criticised Prime Minister Naoto Kan for not widening the exclusion zone around the plant.
- PM Kan says the situation at the nuclear power station requires utmost vigilance.
- Environmental group Greenpeace says it has detected high levels of radiation outside the 20-km (12-mile) exclusion zone, but Japanese officials say levels away from the plant are not dangerous for humans. Experts say radiation in the Pacific will quickly dissipate.
- Estimated cost of damage from the earthquake and tsunami to top $300 billion, making it the world's costliest natural disaster. The 1995 Kobe quake cost $100 billion while Hurricane Katrina in 2005 caused $81 billion (50 billion pounds) in damage.
(Tokyo bureau; Compiled by World Desk Asia)