January 24, 2022

Japanese Reactor Damage Is Worse Than Expected

The company released a plan last month to bring the plant into a relatively stable state in six to nine months, but that was predicated on the notion that it could efficiently cool the fuel in several reactors — a harder task if water is leaking out. The company had long suspected that the containment vessels at two other reactors were breached and leaking, but it had hoped the No. 1 reactor was intact and therefore easiest to bring under control.

The company, Tokyo Electric Power Company, or Tepco, was able to better assess the reactor on Thursday because workers had recently been able to get close enough to fix a water gauge. It showed that the water level in the reactor was much lower than expected despite the infusion of tons of water since a devastating earthquake and tsunami knocked out the plant’s crucial cooling systems.

One of the most startling findings announced Thursday was that water levels in the reactor vessel, which houses the fuel rods, appeared to be about three feet below where the bottom of the fuel rods would normally stand. Ever since the reactor shut down, workers’ primary task has been to keep pouring water into the reactors to ensure the nuclear fuel remained covered so that it would not melt. But the new information suggests the fuel was uncovered for at least some time, probably early in the crisis.

That indicated that the exposed fuel has probably melted and slumped to the bottom of the vessel in little pellets, Junichi Matsumoto, a Tepco spokesman, said Thursday at a news conference.

Still, the worst fears did not materialize. Experts have long worried that such melting would allow a nuclear chain reaction to restart, producing enough heat to burn through all barriers — resulting in a full meltdown and a catastrophic release of radioactive material.

Mr. Matsumoto said relatively low temperature readings on the surface of the reactor, between 100 and 120 degrees Celsius (or 212 to 248 degrees Fahrenheit), suggested that the slumped fuel was being kept cool to some extent by the water inside the reactor and therefore was not as dangerous as some expected.

“We are not seeing a China Syndrome,” Mr. Matsumoto said, using a term coined in the United States in the 1970s to describe a severe nuclear meltdown of the fuel, which could sink into the ground and cause an explosion. The term is a satiric reference to the idea that in such an uncontrolled reaction, the core could burn through the earth.

David Lochbaum of the Union of Concerned Scientists, a nonprofit group usually critical of the nuclear industry, agreed that the temperature readings were a good sign.

He said he believed that the damage to the fuel at Reactor No. 1 was already finished, and that even if some fuel rods were still standing — and therefore exposed — they were no longer hot enough to keep melting.

“As bad as things are,” Mr. Lochbaum said, “they’re getting better.”

He cautioned that dangers remain. Conditions could get worse, he said, if the continued addition of water creates conditions more conducive to a nuclear reaction.

At the Nuclear Regulatory Commission in Washington, R. William Borchardt, the top staff official, briefed the five members of the commission on Thursday morning about the new disclosures, but did not describe them as major developments. Over all, he described the status of the Fukushima complex as “not exactly stable, but you might say that they’re static.”

Hiroko Tabuchi reported from Tokyo, and Matthew L. Wald from Washington.

Article source: http://www.nytimes.com/2011/05/13/world/asia/13japan.html?partner=rss&emc=rss

Nuclear Agency Is Criticized as Too Close to Its Industry

The resulting leak caused a 12-day shutdown of the two reactors for repairs.

The plant’s owner, the Exelon Corporation, had long known that corrosion was thinning most of these pipes. But rather than fix them, it repeatedly lowered the minimum thickness it deemed safe. By the time the pipe broke, Exelon had declared that pipe walls just three-hundredths of an inch thick — less than one-tenth the original minimum thickness — would be good enough.

Though no radioactive material was released, safety experts say that if enough pipes had ruptured during a reactor accident, the result could easily have been a nuclear catastrophe at a plant just 100 miles west of Chicago.

Exelon’s risky decisions occurred under the noses of on-site inspectors from the federal Nuclear Regulatory Commission. No documented inspection of the pipes was made by anyone from the N.R.C. for at least the eight years preceding the leak, and the agency also failed to notice that Exelon kept lowering the acceptable standard, according to a subsequent investigation by the commission’s inspector general.

Exelon’s penalty? A reprimand for two low-level violations — a tepid response all too common at the N.R.C., said George A. Mulley Jr., a former investigator with the inspector general’s office who led the Byron inquiry. “They always say, ‘Oh, but nothing happened,’ ” Mr. Mulley said. “Well, sooner or later, our luck — you know, we’re going to end up rolling craps.”

Critics have long painted the commission as well-intentioned but weak and compliant, and incapable of keeping close tabs on an industry to which it remains closely tied. The concerns have greater urgency because of the crisis at the Fukushima Daiichi plant in Japan, which many experts say they believe was caused as much by lax government oversight as by a natural disaster.

The Byron pipe leak is just one recent example of the agency’s shortcomings, critics say. It has also taken nearly 30 years for the commission to get effective fireproofing installed in plants after an accident in Alabama. The N.R.C.’s decision to back down in a standoff with the operator of an Ohio plant a decade ago meant that a potentially dangerous hole went undetected for months. And the number of civil penalties paid by licensees has plummeted nearly 80 percent since the late 1990s — a reflection, critics say, of the commission’s inclination to avoid ruffling the feathers of the nuclear industry and its Washington lobbyists.

Although the agency says plants are operating more safely today than they were at the dawn of the nuclear industry, when shutdowns were common, safety experts, Congressional critics and even the agency’s own internal monitors say the N.R.C. is prone to dither when companies complain that its proposed actions would cost time or money. The promise of lucrative industry work after officials leave the commission probably doesn’t help, critics say, pointing to dozens over the years who have taken jobs with nuclear power companies and lobbying firms.

Now, as most of the country’s 104 aging reactors are applying for, and receiving, 20-year extensions from the N.R.C on their original 40-year licenses, reform advocates say a thorough review of the system is urgently needed.

The agency’s shortcomings are especially vexing because Congress created it in the mid-1970s to separate the government’s roles as safety regulator and promoter of nuclear energy — an inherent conflict that dogged its predecessor, the Atomic Energy Commission.

“It wasn’t much of a change,” said Peter A. Bradford, a former N.R.C. commissioner who now teaches at Vermont Law School. “The N.R.C. inherited the regulatory staff and adopted the rules and regulations of the A.E.C. intact.”

Mr. Bradford said the nuclear industry had implicitly or explicitly supported every nomination to the commission until Gregory B. Jaczko’s in 2005. Mr. Jaczko, who was elevated to chairman by President Obama in 2009, had previously worked for both Representative Edward J. Markey, the Massachusetts Democrat and longtime critic of the nuclear industry, and Senator Harry Reid, the Nevada Democrat and current Senate majority leader who sought to block a nuclear waste repository in his state.

Article source: http://www.nytimes.com/2011/05/08/business/energy-environment/08nrc.html?partner=rss&emc=rss