North Korea showed a visiting American nuclear scientist earlier this month a vast new facility it secretly and rapidly built to enrich uranium, confronting the Obama administration with the prospect that the country is preparing to expand its nuclear arsenal or build a far more powerful type of atomic bomb.
Whether the calculated revelation is a negotiating ploy by North Korea or a signal that it plans to accelerate its weapons program even as it goes through a perilous leadership change, it creates a new challenge for President Obama at a moment when his program for gradual, global nuclear disarmament appears imperiled at home and abroad. The administration hurriedly began to brief allies and lawmakers on Friday and Saturday — and braced for an international debate over the repercussions.
The scientist, Siegfried S. Hecker, a Stanford professor who previously directed the Los Alamos National Laboratory, said in an interview that he had been “stunned” by the sophistication of the new plant, where he saw “hundreds and hundreds” of centrifuges that had just been installed in a recently gutted building that had housed an aging fuel fabrication center, and that were operated from what he called “an ultra-modern control room.” The North Koreans claimed 2,000 centrifuges were already installed and running, he said.
American officials know that the plant did not exist in April 2009, when the last Americans and international inspectors were thrown out of the country. The speed with which it was built strongly suggests that the impoverished, isolated country, which tested its first nuclear device in 2006, had foreign help and evaded strict new United Nations Security Council sanctions imposed to punish its rejection of international controls.
A delegation of American experts that included Dr. Hecker has already reported that it confirmed satellite photographic evidence of another new advance by the North — a light-water reactor being built on the site of a facility the country had dismantled as part of an agreement with the international community to end its nuclear weapons program.
Dr. Hecker did not initially mention the surprising discovery of the uranium enrichment operation as he left North Korea. He privately informed the White House a few days ago.
The White House is clearly eager to use the new information to show that North Korea, in violation of United Nations mandates, continues to make significant progress toward advancing its nuclear program, even though it remains under international sanctions for its past violations.
American officials were sent to China, Japan, Russia and South Korea, the other members in the moribund “six-party talks.” The Obama administration also hopes to persuade China, by far North Korea’s most important source of political and economic support, to put more pressure on the government of Kim Jong-il, which has shown signs of becoming more militaristic as it undergoes a leadership transition.
China has been hesitant to cut off trade or fuel to the North, and it appears determined to support its longtime, if difficult, ally during its succession process. But in the past China has taken modest steps to support a tougher line when North Korea has tested nuclear weapons or missiles, defying international commitments.
Dr. Hecker said he was forbidden from taking pictures during his tour of the uranium plant on Nov. 12, and was not allowed to verify North Korean claims that it was already beginning to produce low-enriched uranium. He also said he had doubts that North Korea would fulfill its promise to build a light-water reactor to utilize the fuel. “There are reasons to question whether that’s true,” he said.
There are two routes to a nuclear weapon: obtaining plutonium from the spent fuel produced by a nuclear reactor, and enriching uranium to weapons grade.
Since the 1950s, North Korea pursued the first path, and its arsenal of weapons was manufactured from fuel harvested from a small nuclear reactor at Yongbyon. That produced enough for roughly a dozen weapons, but the facility was decrepit, and under an agreement with the Bush administration it was shut down in 2008, with television cameras running as its cooling tower was blown up.
But meanwhile, the North was already well down the second path, uranium enrichment, much the way Iran has pursued its nuclear program. Like Iran, North Korea insists the fuel is intended for a yet-to-be-built experimental reactor to make electricity.
American officials, though, say they think the intent of the enrichment program is to make weapons fuel. Since the North has blocked international inspections, it may be impossible to monitor how much fuel it has made, or if it could be used to produce or improve atomic bombs.
For roughly 15 years, American intelligence agencies have reported evidence the North was seeking to enrich uranium, largely based on technology it bought from A. Q. Khan, the rogue Pakistani nuclear dealer, in a transaction that dates from 1996. There were later reports of North Korean efforts to buy critical centrifuge components, and a suspicious shipment of uranium hexafluoride to Libya that appeared to be of North Korean origin. The Bush administration accused the North in 2003 of secretly pursuing the technology, leading to the ouster of inspectors.
In interviews, administration officials said that they were watching the area by satellite where Dr. Hecker saw the new facility, but they would not say whether they knew about it before he reported back.
“The intel agencies dropped the ball,” said Jack Pritchard, a former State Department official who visited North Korea’s main nuclear complex, Yongbyon, a week before Dr. Hecker’s visit and heard North Korean boasts of a new capability.
A senior intelligence official said Saturday evening that “it is wrong for anyone to assert that U.S. intelligence agencies somehow missed the boat,” adding, “We have been aware of North Korean uranium enrichment activities for years.”
A senior administration official said the North Koreans “very probably have other facilities” that pre-dated the one at Yongbyon and have not been detected.
In interviews, administration officials said they did not want to talk about possible responses to the North Korean action. But their options are limited. North Korea is already a de facto nuclear state; it conducted its first nuclear test in 2006 and another shortly after President Obama took office. Sanctions have crippled some of the country’s ability to do business, but clearly they have not forced it to give up its nuclear ambitions.
Military attacks on Yongbyon have been all but ruled out. In interviews over the past two days, administration officials have described several possible motives for the North to build the facility, and to boast about it.
The most obvious is to create a new bargaining chip to try to force Mr. Obama to pay off the country. “It’s typical of North Korea, to see if we will reward them” for suspending operations or dismantling the facility, said one senior administration official.
But there are other possible explanations. Just as the North used the sinking of a South Korean warship this year to build the credentials of its leader-in-waiting, Kim Jong-un, the son of the current leader and grandson of the country’s founder, this effort could be designed to show that the North must be accepted as a nuclear state along with the major nuclear powers and Pakistan, India and Israel.
Administration officials said they had no intention of reopening negotiations with the North unless it “demonstrated a seriousness of purpose and constructive action” to live up to its past promises to dismantle its nuclear facilities.
Another possibility, which administration officials declined to discuss, is that the North ultimately intends to build a new generation of hydrogen bombs or thermonuclear weapons, far more powerful than anything in its current arsenal.
The North’s current arsenal of 8 to 12 weapons are all based on plutonium. But uranium, enriched to bomb grade, can also be used to drastically increase the destructive power of a nuclear blast, and that is the main use of uranium in modern arsenals, including United States warheads.
Experts caution, however, that true hydrogen bombs are quite hard to make, so it seems unlikely that North Korea would succeed in that anytime soon.
William J. Broad contributed reporting from New York.