若朝鲜武器装备精良，或许会促使美国方面采取反制措施，尤其是在导弹防御方面。美国北方司令部(Northern Command)司令、海军上将戈特尼(William Gortney)本月曾表示，国防官员相信朝鲜目前已有能力将核弹头装载到名为“KN-08”的洲际弹道导弹上。美国官员认为，这种导弹尚未进行试射，但专家们估计其射程约为5,600英里——也就是说，可以到达包括加州在内的美国本土西海岸。
知情人士称，美国官员没有参加本次会议，但一些官员在后来获知细节后表示惊讶。部分中方专家表示，这些在2月份披露的数字位于中国专家估测区间的偏高段。斯坦福大学(Stanford University)教授兼洛斯阿拉莫斯国家实验室(Los Alamos National Laboratory)前主管、美国团队的领头技术专家赫克(Siegfried Hecker)说，根据他的估测，迄今为止朝鲜手中握有的核弹可能不超过12枚，到明年达20枚。
Jeremy Page发自北京 / Jay Solomon发自华盛顿China Warns North Korean Nuclear Threat Is Rising
Pyongyang could double nuclear-weapons arsenal by next year, according to latest Beijing estimates
By Jeremy Page in Beijing and Jay Solomon in Washington
April 22, 2015 7:35 p.m. ET
China’s top nuclear experts have increased their estimates of North Korea’s nuclear weapons production well beyond most previous U.S. figures, suggesting Pyongyang can make enough warheads to threaten regional security for the U.S. and its allies.
The latest Chinese estimates, relayed in a closed-door meeting with U.S. nuclear specialists, showed that North Korea may already have 20 warheads, as well as the capability of producing enough weapons-grade uranium to double its arsenal by next year, according to people briefed on the matter.
A well-stocked nuclear armory in North Korea ramps up security fears in Japan and South Korea, neighboring U.S. allies that could seek their own nuclear weapons in defense. Washington has mutual defense treaties with Seoul and Tokyo, which mean an attack on South Korea or Japan is regarded as an attack on the U.S.
“I’m concerned that by 20, they actually have a nuclear arsenal,” said Siegfried Hecker, a Stanford University professor and former head of the Los Alamos National Laboratory, who attended the closed-door meeting in February. “The more they believe they have a fully functional nuclear arsenal and deterrent, the more difficult it’s going to be to walk them back from that.”
Chinese experts now believe North Korea has a greater domestic capacity to enrich uranium than previously thought, Mr. Hecker said.
The Chinese estimates reflect growing concern in Beijing over North Korea’s weapons program and what they see as U.S. inaction while President Barack Obama focuses on a nuclear deal with Iran.
A well-armed North Korea may prompt the U.S. to adopt countermeasures, especially in missile defense. Adm. William Gortney, head of U.S. Northern Command, said this month that defense officials believe North Korea can now mount a nuclear warhead on an intercontinental ballistic missile called the KN-08. U.S. officials don’t believe the missile has been tested, but experts estimate it has a range of about 5,600 miles-within reach of the western edge of the continental U.S., including California.
An increase in North Korea’s nuclear arsenal feeds international concern about proliferation from a country that, U.S. officials said, previously exported nuclear technology to Syria and missile components to Iran, Yemen and Egypt.
In Washington, some Republican lawmakers said the pending White House deal with Iran could mirror the 1994 nuclear agreement the Clinton administration made with North Korea. The deal was intended to halt Pyongyang’s nuclear weapons capabilities, but instead, they allege, provided diplomatic cover to expand them. North Korea tested its first nuclear device in 2006.
“We saw how North Korea was able to game this whole process,” U.S. Rep. Ed Royce (R., Calif.), chairman of the House Foreign Affairs Committee, said in an interview. “I wouldn’t be surprised if Iran had its hands on the same playbook.”
The pace of North Korea’s nuclear arms growth depends on its warhead designs and its uranium-enrichment capacity, Mr. Royce said: “We know they have one factory; we don’t know if they have another one.”
Recent estimates by U.S. experts range from 10 to 16 nuclear bombs today.
Mr. Royce said he met Chinese academics on a recent trip to Beijing and was struck by the concerns he heard about Pyongyang’s nuclear capabilities.
Relations between North Korea and China have deteriorated since Xi Jinping became China’s leader in 2012 and North Korea’s leader, Kim Jong Un, took power following the death of his father in late 2011.
China, which is North Korea’s largest investor, aid donor and trade partner, has for most of the past decade underestimated Pyongyang’s nuclear capabilities, nuclear experts said, including its capacity to produce fissile material.
Estimates of North Korea’s capabilities by Chinese experts began to align with those in the U.S. after 2010, and moved beyond after 2013, according to people familiar with exchanges on the matter between China and the U.S.
Until recently, the Chinese “had a pretty low opinion of what the North Koreans could do,” said David Albright, an expert on North Korea’s nuclear weapons and head of the Institute for Science and International Security in Washington. “I think they’re worried now.”
China’s foreign and defense ministries didn’t respond to requests for comment. Diplomats at North Korea’s mission to the United Nations didn’t respond to attempts to seek comment. The White House, State Department and Pentagon declined to provide U.S. estimates of North Korea’s nuclear arsenal.
“We have been and remain concerned about North Korea’s nuclear program and believe China should continue to use its influence to curtail North Korea’s provocative actions,” said Patrick Ventrell, a spokesman for the U.S. National Security Council.
He said the U.S. was working with other countries to implement U.N. sanctions designed to press North Korea “to return to credible and authentic denuclearization talks and to take concrete steps to denuclearize.”
The U.S. hasn’t engaged in regular high-level talks with Pyongyang since 2012, when North Korea conducted a long-range missile test. The U.S. has instead pressed China to use its economic leverage to rein in North Korea.
The latest Chinese estimates of North Korea’s nuclear capability were shared during a February meeting at the China Institute of International Studies, the Chinese foreign ministry’s think tank. The Chinese brought technical, political and diplomatic experts on North Korea’s nuclear program, as well as military representatives, said people familiar with the meeting.
Mr. Hecker, the U.S. team’s lead technical expert, has long been part of international efforts to understand North Korea’s nuclear program. In 2010, he revealed North Korea had a large uranium enrichment program after he saw the facilities during a visit there.The estimate that North Korea may have had 20 warheads at the end of last year-and could build 20 more by 2016-was given during a presentation by one of China’s top uranium enrichment experts,
according to people familiar with the meeting. They said it was the first time they had heard such a high Chinese estimate.
Mr. Hecker declined to comment on the meeting but said he had met with Chinese experts to discuss North Korea’s capabilities at least once a year since 2004.
“They believe on the basis of what they’ve put together now that the North Koreans have enough enriched uranium capacity to be able to make eight to 10 bombs’ worth of highly enriched uranium per year,” said Mr. Hecker, who added that estimates by China and the U.S. involved a great deal of guesswork.
U.S. officials didn’t attend the meeting but some expressed surprise when they were later briefed on the details, said people familiar with the matter. Some Chinese experts said the estimates revealed in February were at the higher range among local peers. Mr. Hecker said he estimated North Korea could have no more than 12 nuclear bombs now, and as many as 20 next year.
“Some eight, nine or 10 years ago, they had the bomb but not much of a nuclear arsenal,” he said. “I had hoped they wouldn’t go in this direction, but that’s what happened in the past five years.”
中美专家对朝鲜核武器数量估计的比较，中方的估计位于美方估计的偏高段区间 (by WSJ)：
美国专家2015年2月发表的对朝鲜核武器数量估计的论文：“North Korea’s Nuclear Futures Project: Technology and Strategy,”
by Joel S. Wit and Sun Young Ahn.
April 24, 2015Hecker Q&A on estimates of North Korea’s nuclear arsenal
On April 22, 2015, the Wall Street Journal published the article “China Warns North Korean Threat is Rising,”
reporting on estimates from Chinese and American nuclear experts of the
DPRK nuclear arsenal. The article quotes CISAC’s Siegfried Hecker,
director of the Nuclear Risk Reduction Project, on his assessment of the
North Korean nuclear crisis and presents the estimates of Dr. Hecker’s
Chinese counterparts. In the following Q&A, Hecker, who has been an
authority in the United States on technical assessments of the progress
of the North Korean nuclear program — having visited North Korea seven
times since 2004 and having been granted unprecedented access to North
Korea’s Yongbyon nuclear facilities — discusses the information
presented in the Wall Street Journal article and provides insight both
on the nature of technical estimates of the DPRK nuclear arsenal as well
as on the critical takeaways from these assessments.
What was the nature of the meeting referenced in the Wall Street Journal article in which China’s estimates were presented?
meeting was an off-the-record, non-governmental, non-official dialogue
on U.S. – China security issues. The discussion on North Korea’s nuclear
program was one of many security topics discussed. Both Chinese and
American experts made presentations. The headline of the WSJ article is
misleading – it is not “China” that made these estimates, but Chinese
Have you conferred with Chinese nuclear experts about the North Korean nuclear program before the referenced meeting?
part of my Nuclear Risk Reduction project at Stanford University, I
have conferred regularly with nuclear and policy experts in China and
Russia, as well as American experts and officials, of course. We have
done so since January in 2004, when I first visited the Yongbyon Nuclear
Center and returned through Beijing (the normal transit in and out of
On that trip, North
Korean nuclear officials showed me plutonium metal that they had
reprocessed from the spent fuel rods that were stored since the
beginning of the Agreed Framework in 1994. When the Agreed Framework
fell apart in late 2002, Pyongyang expelled the international inspectors
and withdrew from the Nonproliferation Treaty. I believed they showed
me their nuclear facilities and the plutonium to try to convince
Washington that they had the bomb.
How did these visits inform your assessment of the DPRK nuclear program?
visited North Korea seven times in total, with four of those visits to
the Yongbyon Nuclear Center. After each of these visits, I compared
observations and analyses with Chinese nuclear experts. During the first
few visits, the Chinese experts and Chinese international relations
scholars were quite skeptical of North Korea’s nuclear capabilities. I
believe that my observations helped to inform their subsequent analysis
since Chinese experts did not have access to Yongbyon at the time.
So what precipitated the change in the perception of your Chinese colleagues of North Korea’s nuclear capabilities?
the first few years of discussion, my estimates of North Korea’s
capabilities exceeded those of Chinese experts. However, during my most
recent visit to Yongbyon in November 2010, North Korean nuclear
officials showed me their newly constructed uranium enrichment facility,
housing 2,000 modern centrifuges, and the beginning of the construction
of an experimental light water reactor. Overhead imagery shows that the
exterior of the reactor is essentially complete, that the size of the
centrifuge hall has been doubled, and that significant additional
construction has occurred in the fuel fabrication complex, where the
centrifuge facility is housed.
move to augment their limited plutonium production in the 5 MW-electric
reactor (at most one bomb’s worth of plutonium per year) with enriched
uranium changed the game.
Changed the game, how?
opened the second path to the bomb and made it difficult to assess
North Korea’s nuclear capabilities. Unlike the reactor production of
plutonium, centrifuges are easy to hide. So, post-2010 it became more
difficult to make accurate estimates, but all of us believed that North
Korea enhanced its nuclear capacity significantly.
I published my most recent estimates in an article in the Bulletin of the Atomic Scientists along
with a brief history of North Korea’s nuclear build-up. The latest
estimates by Chinese nuclear experts now exceed mine. I believe that we
base our estimates on the same open-source data.
you base your estimates on the same information, what accounts for the
discrepancies between your assessments and the estimates from your
estimates is not an exact science. There are huge uncertainties in
estimating the enrichment capacity that is likely present at covert
sites. One particular problem is the difficulty in assessing how much
indigenous capacity North Korea has to make the key materials and
components for centrifuges. To demonstrate the great uncertainties, the
WSJ article cites a recent report by David Albright of
the Institute of Science and International Security that shows the
possible range of bomb-fuel capacity in 2020 to vary from 20 to 100
bombs. The Chinese experts’ and my estimates fall within that range.
Wall Street Journal article reported that American officials recently
stated that North Korea possesses an intercontinental ballistic missile
with sufficient range to reach the United States. Is the threat of
nuclear attack on the United States from North Korea imminent?
view the threat to the United States posed by an untested missile, the
so-called KN-08, with a hypothetical miniaturized nuclear warhead as
unrealistic any time in the near future. The KN-08 has not been tested
to our knowledge. I believe North Korea would require more long-range
missile tests and more nuclear tests to pose a direct threat to the
With the international community’s
attention directed toward the U.S.-Iran nuclear deal, what are your
thoughts on the analogy made in the article between the Iran Nuclear
Deal and the 1994 Agreed Framework with North Korea?
don’t concur with the analogy of the failings of the Agreed Framework
to the potential Iran deal. It is true that North Korea continued to
develop uranium enrichment capabilities during the Agreed Framework.
However, without the Agreed Framework, North Korea could have produced a
nuclear arsenal as large as they have today 10 years earlier. And, by
terminating the Agreed Framework, Washington traded the threat of
uranium bombs that was at least 10 more years away for plutonium bombs
that were built within a year.
Then what is the critical takeaway from your and your Chinese colleagues’ assessments of North Korea’s nuclear capabilities?
real tragedy, in my opinion, is that whereas in 2003 North Korea likely
had no nuclear weapons, it appears to have a rapidly expanding arsenal
today. During the past 12 years we have witnessed the North Korean
program grow from having the option for a bomb in 2003, to having a
handful of bombs five years later, to having an expanding nuclear
Why does an expanding arsenal matter?
believe it has made Pyongyang increasingly reliant on its nuclear
weapons for regime survival and has dimmed the prospect of a
denuclearized Korean peninsula. Such an arsenal may instill Pyongyang’s
leadership with a false sense of confidence and almost certainly expands
what it may think are its tactical and strategic options. The potential
for miscalculations and accidents increases, and the consequences will
be greater if it has more bombs and more sophisticated bombs with