TOKYO — IN a few weeks, a Japanese ship loaded with nearly a ton of plutonium will set sail on a passage as obscure and uncertain as the voyage of Columbus 500 years ago. It may be the last such shipment Japan ever tries.
With the ship's route shrouded in secrecy to evade potential terrorists, the voyage of the 3,800-ton Akatsuki Maru from the French port of Cherbourg, where it will pick up the plutonium, and then back to Tokyo Bay, has brought rare rebukes of Japan and an official review of the nation's drive for a plutonium energy system.
The mysterious voyage has even raised doubts about Japan's postwar pledge never to build a nuclear weapon. Critics claim the plutonium shipment has enough weapons-grade material to make more than 100 atomic bombs equivalent to the one dropped on Nagasaki in 1945.
Recycled in a French reprocessing plant from the spent uranium of a Japanese nuclear power plant, the plutonium is destined for use in civilian reactors. At least 29 more shipments are tentatively planned.
"The government is thinking of stopping all shipments," says Inzaburo Takagi, director of the Citizens' Nuclear Information Center. "But it doesn't want to lose face by canceling this one under international pressure." `Please steer clear'
Ever since the ship left Yokohama for France with an empty cargo hold on Aug. 24, one nation after another, ranging from South Africa to the tiny South Pacific nation of Nauru, has asked Japan to have the vessel steer clear of their coastal waters. Japan claims the special cask holding the plutonium is safe, and that the Akatsuki Maru needs only one lightly armed military escort ship for protection.
One obvious short-cut for the ship, through the Malacca Straits, has already been eliminated after concerns were raised by Singapore, Indonesia, and Malaysia. Chile and perhaps Argentina may also block coastal passage through the Magellan Straits.
After Australia raised its concerns, Japan told Foreign Minister Gareth Evans that the vessel will stay outside the 200-mile economic zone of all countries, at least "in principle."
If that is the case, then the Akatsuki Maru and its lightly armed military escort ship will be limited to either the rough Antarctic passage far south of the perilous Cape Horn or a circuitous route south of Australia and far into the Pacific, says Andrew Mack, professor of international politics at Australian National University. Either way, the ship will need to travel at least 15,000 miles over many weeks.
The United States, which provided the original uranium fuel to Japan and whose approval was needed for the voyage, is expected to assist in the ship's security with satellite surveillance.
Even though the ship has already set out to pick up its cargo, France has yet to approve the export of the plutonium. Under a contract, Japan must show a "need" for the fuel. Mr. Takagi says his study of government data reveals a surplus of plutonium at present. Japan officially claims a plutonium deficit.
One possible reason the Japanese government decided to go ahead with this shipment, Professor Mack says, is that it wants to send a signal to the world, or at least to Asia, that Japan has the capability to build a nuclear weapon, if it ever chooses to.
"Japan says it won't stockpile plutonium, yet it needs a stockpile for energy security. Why is it doing something that is not exactly rational?" he asks.
North Korea, he notes, justifies its own nuclear research because of Japan's plutonium program. One result could be "a catastrophic nuclear arms race in the region within five years," Mack says.
Another problem with the shipment, says Jon Van Dyke, law professor at the University of Hawaii, is that Japan may be violating customary international law by not consulting with affected nations and by being lax about security and safety.
Some electric-utility officials in Japan have quietly raised doubts about the high cost of Japan's program to build its Monju fast-breeder reactor, which uses plutonium. Japan is likely to have access to an abundance of plutonium from the bombs of the former Soviet Union. Independent energy
Reversing course on a long-range commitment to a plutonium system is difficult in Japan, where there remains a strong interest in being independent of foreign energy supplies. Unlike Germany, France, Britain, and the US, Japan has not backed off from its commitment to build breeder reactors.
"What bothers the country now is the realization that, quite unlike the earlier period when she could always look to countries who were moving ahead and learn from their experience, Japan now is in a position to create her own path into the uncertain future of nuclear power," states Ryukichi Imai, an adviser to the Japan Atomic Power Company.
In addition, a series of recent accidents at nuclear power plants, including one in which officials lied about the amount of radiation that leaked, has slightly shaken Japan's drive to almost double the number of nuclear plants by 2010.