INTERVIEW-Japan Crisis Is Much Worse than Three Mile

* Man in charge at Three Mile Island sees big differences

* No one injured at Three Mile, and no radiation escaped

* Equipment failure, human error caused Three Mile Island

* Three Mile Island had only a single damaged reactor

By Bernie Woodall

DETROIT (Reuters) - The man who became the face of the Three Mile Island nuclear disaster in 1979 says he had it easy compared to those trying to regain control of Japan's stricken Fukushima Daiichi plant this week.

Harold Denton, a senior official with the U.S. Nuclear Regulatory Commission at the time, was picked by then-President Jimmy Carter to take charge at the Pennsylvania plant as operators were working to regain control of a reactor going into partial meltdown.

He quickly became the face of the Three Mile Island crisis, holding daily news conferences and making regular appearances at the press center set up at the plant, located near Harrisburg, Pennsylvania.

The incident terrified Americans and set back nuclear power plant developments in the United States for 30 years. Even so, Denton said conditions at the plant were far better than those at the plant at the center of the current crisis in Japan.

"This is certainly far worse than Three Mile Island," Denton said in a phone interview.

The Three Mile accident was a case of a valve malfunction compounded by human error, while Daiichi was the result a massive earthquake and tsunami, compounded by design faults and possible missteps. Parts of the plant are wrecked by a series of blasts whereas Three Mile remained fully intact.

"In Japan, it's clearly the problem caused by the double whammy of having an earthquake and then the tsunami," said Denton. <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Japan accident spooks Three Mile residents [ID:nN1393585] TIMELINE-Three Mile Island accident in 1979 [ID:nN1368129] Q+A-Risks at each reactor at Daiichi [ID:nL3E7EH1XZ] For more stories on Japanese quake [ID:nL3E7EB0V5]

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Now 75 and retired in Knoxville, Tennessee, Denton reels off the other differences:

--At Three Mile Island there were no injuries and only minor amounts of radiation released into the atmosphere. At Daiichi, at least two workers are missing and many other workers are risking heavy doses of radiation.

--There was only one troubled reactor at Three Mile; in Daiichi there are six.

--His team could work close to the reactor. In Japan it may well be too dangerous to do so because of high levels of radiation.

--The power was working at Three Mile. In Japan, it was knocked out by the earthquake and tsunami.

"Power is the lifeblood for a power plant," Denton said. "If you've got power you can do a lot, but if you don't have any power, the water in the reactor vessels heats up and boils away and fuel begins to melt and that's a problem they've gotten into now."

NO PHONES

In Three Mile Island, "there was no interruption of infrastructure. The biggest problem was the telephone communications because there was such an overload of the system."

In fact, poor communications was one of the biggest headaches at Three Mile Island.

There were no mobile phones in 1979, so Carter ordered a hot line with a drop cord to Denton's work trailer, allowing Denton to provide the President with regular updates.

"I called the president twice a day using the red telephone," Denton said.

"At the time, the computers were not as fast and didn't have the storage that they do now," said Denton. "The data flow at Three Mile Island exceeded the capacity of the printer to print the data."

Using computer printouts was the only way for Denton and his team to get a proper readout from the big and bulky computers in the power plant -- but having a printer go "clickity-click" as it slowly rolled over wasn't very helpful in such a new kind of crisis.

EVERYONE'S A CRITIC

Having coped with such events himself, Denton declined to join those piling on to criticize the Japanese plant operator, Tokyo Electric Power Co (TEPCO).

"I'm reluctant to criticize other people. During Three Mile Island, there were always pundits from a thousand miles away saying what we should be doing, and it used to upset me that the farther away people were from the site, the more authoritatively they came across."

Still, he did say that a freer flow of information would have helped as scientists outside the plant could have offered more assistance. Clearly those on the site had gotten too busy fighting fires, he said.

The extent of the damage at the two plants is clearly one of the most noticeable differences.

Three Mile Island suffered no structural damage. Operators didn't even know for two days after a hydrogen explosion in the primary containment on Wednesday, March 28, 1979, that a blast had even occurred .

They "realized they had heard a thud ... the day of the accident," he said. "They attributed it to a valve closing, not unlike other occasional noises in a power plant. By Friday, they realized they had heard an explosion the result of a hydrogen explosion," he said.

By contrast, the Daiichi reactor suffered numerous hydrogen explosions that partially destroyed the roof and walls, cracked the primary containment vessels on at least two of its six reactors, and damaged pools holding spent fuel.

THE LONG RETURN

A year after the accident, Denton went inside the reactor containment vessel after it had been vented.

"There was surprisingly little damage from the hydrogen explosion visible on the operating floor of the plant," he said. "The things that were visible were a telephone in that area seemed to have some melting on the plastic cover and perhaps a barrel that had caved in a little but it wasn't the scene of destruction by any means."

One of the biggest signs of how the Japanese crisis is so much worse than the U.S. incident 32 years ago is that Denton was able to take President Carter on a tour of the plant's control room on the fourth and final day of the Three Mile Island accident.

It is doubtful whether it will ever be safe for Japanese Prime Minister Naoto Kan to go to Daiichi.

Indeed, Japanese engineers conceded on Friday they may have to bury the plant in sand and concrete as a last resort to prevent a catastrophic radiation release, the method used to seal huge leakages from Chernobyl in 1986.

(Additional reporting by Scott DiSavino in New York. Editing by Martin Howell and Frank McGurty)