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朝鲜核武器数量的估计  

2015-04-24 11:10:09|  分类: 半岛风云 |  标签: |举报 |字号 订阅

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中国告知美国朝鲜核威胁正在上升

《华尔街日报》中文版 2015年4月23日

中国高级核专家将其对朝鲜核武器生产的估计上调至远高于此前的大部分美国估计数字,显示出朝鲜可生产足够多的核弹头威胁美国及其盟友的地区安全。

最新的中国估计数字是在与美国核专家的闭门会议中转告给美方的。据听取了汇报的人士称,中国的估计数字显示,朝鲜可能已拥有20枚核弹头以及生产足够多武器级铀以在明年前将其核弹头数量增加一倍的能力。

朝鲜核武器储备充足将加剧美国的盟友、邻国日本和韩国对安全的担忧,日韩可能寻求开发自己的核武器作为防御。美国与韩日签订有共同防务条约,意味着对韩国或日本的攻击将被视为是对美国的攻击。

中国的估计数字反映出中国政府对朝鲜核武器计划以及他们眼中美国在朝鲜问题上的不作为日益加剧的担忧。目前美国总统奥巴马(Barack Obama)正专注于与伊朗的核协议。

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。

上述估计数字不仅包括朝鲜截至去年年底或已拥有20枚核弹头,还认为到2016年朝鲜可能会再生产20枚核弹头。据知晓会议内容的知情人士称,这些内容是中国一位高级核专家在介绍情况时公布的。知情人士还说,这是他们第一次听到如此高的中方估测数字。

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):
朝鲜核武器数量的估计 - kktt - 长缨在手  敢缚苍龙

===

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.

朝鲜核武器数量的估计 - kktt - 长缨在手  敢缚苍龙
 
朝鲜核武器数量的估计 - kktt - 长缨在手  敢缚苍龙
 
朝鲜核武器数量的估计 - kktt - 长缨在手  敢缚苍龙
 
朝鲜核武器数量的估计 - kktt - 长缨在手  敢缚苍龙


http://cisac.fsi.stanford.edu/news/hecker-qa-estimates-north-korea%E2%80%99s-nuclear-arsenal

April 24, 2015
Hecker Q&A on estimates of North Korea’s nuclear arsenal
Isabella Uria

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?

This 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 nuclear experts.

Have you conferred with Chinese nuclear experts about the North Korean nuclear program before the referenced meeting?

As 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 Pyongyang).

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?

I 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?

During 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.

Pyongyang’s 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?

It 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.

If you base your estimates on the same information, what accounts for the discrepancies between your assessments and the estimates from your Chinese colleagues?

Developing these 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.

The 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?

I 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 United States.

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?

I 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?

The 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 arsenal now.

Why does an expanding arsenal matter?

I 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 greater reach.



第六届中美安全关系与合作国际研讨会在我院召开
中国国际问题研究院 时间: 2015-02-09 

第六届中美安全关系与合作国际研讨会于2015年2月2日至3日在我院举行,会议就中美政治与政策决策过程、双方在安全领域里的关切、地区核问题以及中美两国关系未来等进行研讨。美国代表包括前美国朝鲜政策特别代表博斯沃斯等前政府官员和斯坦福大学的研究人员共16人。此次会议是中国国际问题研究院和美国斯坦福大学联合举办的年度性研讨会,此前先后在中国和美国举办过五次。

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