TOKYO — THREE weeks after Japan's worst nuclear power accident, the political fallout has taken its first victim: the confidence of a once-boastful Japanese nuclear industry. ``We deeply apologize for the accident, which made you worry,'' said Mamoru Yoshida, a Kansai Electric Power Co. official, to a few dozen angry antinuclear activists after the accident.
Mr. Yoshida's humility was evident as he performed a deep and long bow to his public opponents. ``We take the accident seriously and are investigating to find the cause,'' he said.
The Feb. 9 accident at a reactor in Mihama, some 220 miles west of Tokyo, was the first time that Japan had been forced to use an emergency cooling system designed to prevent a meltdown of the hot uranium core.
Although Japan's electric power officials claim that ``the system worked,'' they are nonetheless eager to restore the credibility of the world's most ambitious nuclear program, one that calls for adding two new plants every year over the next two decades. Japan plans to receive 43 percent of its electricity from nuclear power.
Even before the accident, only 10 percent of Japanese surveyed in a 1990 poll had faith in government statements on nuclear issues. ``All the information that Kansai Electric is now slowly disclosing are lies,'' says Jinzaburo Takagi, leader of the Citizen's Nuclear Information Center.
In the days after the accident, the industry's woes were compounded by two minor incidents at other nuclear plants. Now government and industry have launched an unusual examination of their own practices and to give stricter standards for operators to follow.
``The accident was sort of expected,'' says Kazuhisa Mori, executive managing director of the Japan Atomic Industrial Forum, Inc., ``but the way it happened was so drastic that the electric power people were shocked.
``When you present a picture of complete safety, it's hard to explain to the public when something happens.''
Kansai Electric officials admitted to antinuclear activists that the utility still does not know how much radioactivity has been released to the air and sea. They had earlier reported a specific amount of radioactive emissions, which was considered harmless.
The immediate cause of the accident was the breakage of one finger-size tube that carries radioactive water from the reactor core. In this type of reactor, known as a pressurized water reactor (PWR) and built by the US-based Westinghouse Corp., 6,520 tubes are used to transfer heat to a secondary water system that is used to turn a turbine and generate electricity.
Yearly inspections of the tubes often reveal cracks and other problems as the tubes slowly corrode from the effects of high-level radiation. In many plants, as much as 18 percent of the tubes have been blocked off to prevent their possible rupture. Thirty percent is judged to be the limit for full-power operation.
Sixteen of Japan's 39 reactors are of PWR design. A similar tube rupture took place in 1987 at the North Anna power plant in Virginia. In a 1988 speech, an official of the US Nuclear Regulatory Commission cited degradation of PWR tubes as ``a loaded gun, an accident waiting to happen.''
In Mihama, the break allowed a massive amount of radioactive water to flow into the secondary system. In addition, an automatic valve designed to help cool the water failed to operate.
On a scale of severity used by the International Atomic Energy Agency (IAEA), the Mihama accident was rated by Japanese officials as a one or two out a maximum of seven. The IAEA rated the Three Mile Island accident in 1979 as a three and the 1986 Chernobyl accident as a five.
On Feb. 19, the Ministry of International Trade and Industry told officials of five utilities to implement a set of new procedures in an attempt to avoid a similar accident.
Few Japanese have called for an independent body to probe the accident. ``The antinuclear groups would be out of work if there was an independent investigation,'' says Mr. Mori.
But officials will have a more difficult time in persuading local residents to accept new nuclear plants in their areas, Mori adds. Antinuclear activists hope they can revive their movement, which has declined recently.
``At least in this area, the antinuclear movement is growing,'' says Tetsuen Nakajima, an activist in Fukui prefecture, a relatively poor area, where the accident took place and which is the site of 12 reactors.
One way that the national government softens local resistance is to provide provide special grants to small towns near the plants. Fukui, for instance, received over $600,000 last year.
``By providing benefits, the government makes a network of people who can overwhelm the antinuclear people in numbers,'' says Mr. Nakajima.