第四届核安全峰会3月底在华盛顿召开。核安全峰会是由奥巴马总统亲自倡议的，从2010年开始每两年举办一次。奥巴马也有意使之成为自己的重要政治遗产之一。虽然奥巴马在2009年提出建立“无核世界”的想法并因此获得诺贝尔和平奖，但现实却是国际核安全形势日趋严峻。眼下美国总统大选选战正酣，不论谁在2017年1月入主白宫，美国都将面临一个自冷战结束以来最复杂、最棘手的核安全形势。

应当说，造成“无核世界”离现实越发遥远的主要因素恰恰是美国自身。奥巴马政府一边倡导“无核世界”，一边却在大规模升级美国的核武器库，力图巩固和扩展本国在核领域的安全优势。按照奥巴马政府提出的方案，未来30年，美国将花费约1万亿美元用于完善核武器库，包括更新12艘核潜艇和数百枚核弹。美国至今还没有通过《全面禁止核试验条约》。

此外，美国的盟友似乎对“无核世界”也不怎么买账。英国卡梅伦政府正大力购置新的核潜艇，以便在2030年左右使英国具备焕然一新的海上核威慑能力。日本则加紧推动向印度等国推销自己的核能力。如果日本在出口核电技术等方面给予印度特殊待遇，这无疑也会给核不扩散体系增加新的难题。

当然，美俄关系的恶化极大地加剧了国际核安全挑战，俄罗斯领导人未参加此次华盛顿核安全峰会。由于继承了苏联时代的核能力，俄罗斯在全球核不扩散领域一直扮演举足轻重的角色。然而，乌克兰危机、叙利亚冲突等因素使美俄博弈越发激烈，莫斯科方面甚至怀疑“新冷战”已经开启。普京政府强烈批评美国在核安全问题上的霸权主义心态。美俄两国的核裁军谈判完全陷入停滞。

同中国一样，俄罗斯方面认为，美国在欧洲和亚太地区大力部署反导系统，打破了全球战略稳定。美国甚至将战术核武器直接部署在俄罗斯家门口。实际上，在如今的技术条件下，导弹防御和导弹攻击的转换非常容易，美国人的绝对安全就意味着别国的不安全。

而让美国战略家担心的是，俄罗斯正在大力修改自己的核军事学说，以降低在冲突中使用核武器的门槛，加大针对北约的战略威慑。考虑到这一情况，2016年2月德国“慕尼黑安全会议”发布的年度报告指出，在欧洲-大西洋地区，使用核武器的风险正在上升，而这种风险大于冷战结束以来的任何时候。

在这种情况下，美国需要争取使中国成为自己在核安全领域的合作伙伴。而中国也正在成为核安全国际合作的坚定支持者。习近平亲自参加了多次核安全峰会，这正是对美国给予支持的一种重要姿态。2014年，习近平在海牙核安全峰会上还首次提出中国的核安全观。在此次华盛顿核安全峰会上，中国提交了国家核安全报告，习近平提出了加强全球核安全的实质性倡议。

中国为什么在核安全问题上展现出越发积极的态度？首先，不少有核国家都位于中国的周边地区，这些国家之间还存在爆发大规模冲突的可能性，如巴基斯坦和印度。据独立的斯德哥尔摩国际和平研究所（SIPRI）估计，印度大约拥有90-110颗低当量核弹头，巴基斯坦则拥有多达120颗。另外，在朝鲜核问题越发紧张的情况下，韩国国内的“拥核”呼声进一步升高。约三分之二的韩国民众赞同本国开发核武器或要求美国将核武器重新部署在韩国。

其次，中国正在大力发展核能，以改善能源消费结构，但需要对相关的安全风险进行防范和管理。到2020年，中国大陆在运核电装机容量将达到5800万千瓦，届时将超过日本成为世界上最大的核电使用国。

第三，中国需要加大应对“核恐怖主义”的力度。近年，国际上已发生多起高浓缩铀等核材料被偷窃和走私的案件，一旦恐怖主义团伙获得这些核材料，有可能制造出一些粗糙的核武器。它们可能还会蓄意破坏中国的核设施，用“脏弹”在中国的大城市散布放射性核污染。

虽然中美在很多方面存在分歧，但双方均有意探索如何在核安全方面深化合作。中国与美国等密切协作，在2015年促成了伊朗核协定的达成。2016年2月，中美两国举行了首次核安全对话。中国国家原子能机构与美国能源部在北京共同建设的核安保示范中心，也已经在近期投入运行。这是全球规模最大、设施最先进的机构。

此次华盛顿峰会的主题为“加强国际核安全体系”，50多位国家元首和政府首脑与会，而奥巴马举行的唯一一场双边会谈是与习近平主席。在探索构建中美新型大国关系的进程中，围绕核安全的合作有望成为两国关系新的亮点。

The Fourth Nuclear Security Summit is held in Washington D.C from March 31 to April 1. Personally advocated by United States President Barack Obama, the nuclear summit has been convened once every two years since 2010. Obama also intends to make it one of his major political legacies. Though Obama made the proposal to build a “nuclear-free world” in 2009 and won a Nobel Prize because of it, the truth is international nuclear security has been deteriorating. No matter who is elected the next US president, the US will face the most complicated and thorny nuclear security conditions since the end of the Cold War.

It was the US itself that has made the prospect of a “nuclear-free world” drifting increasingly farther from reality. The Obama administration on one hand advocates a “nuclear-free world”, on the other hand is engaging in large-scale upgrade of US nuclear arsenal, trying hard to consolidate and expand its security advantages in the nuclear field. According to the scheme proposed by the Obama administration, in the next 30 years, the US will spend about $1 trillion on improving nuclear arsenal, including renewing 12 nuclear submarines and hundreds of nuclear bombs. The US has not passed the Comprehensive Nuclear Test Ban Treaty to date.

In addition, US allies seem not that enthusiastic about a “nuclear-free world”. The Cameron government in Great Britain is making all-out efforts to purchase new nuclear-powered submarines, so that the country could achieve brand-new maritime nuclear deterrence around 2030. Japan is peddling its nuclear capabilities to countries like India. If Japan offers India special treatments in such aspects as nuclear power technologies, it will undoubtedly create fresh difficulties for the nuclear non-proliferation regime.

Of course, worsening US-Russia relations have tremendously aggravated international nuclear security challenges, and Russian leaders will not attend the nuclear security summit in Washington. Since Russia has inherited nuclear capabilities from the Soviet Union, it has been playing a substantial role in international nuclear non-proliferation. However, such factors as the Ukraine crisis and conflicts in Syria have made US-Russia wrangling increasingly fierce. So much so that Russia even suspects a “New Cold War” has begun. The Putin government has strongly criticized US hegomonistic mindset regarding nuclear security. US-Russia nuclear disarmament negotiations have thus stopped completely.

Like China, Russia believes the US has broken global strategic stability by deploying anti-missile systems in Europe and Asia. The US has even deployed tactical nuclear weapons on Russia's doorsteps. In fact, under current technological conditions, it is very easy to transform missile defense into missile attack. Therefore, absolute security for the US means insecurity for other countries.

What worries US strategists even more is the fact that Russia is making major revisions to its nuclear military theory to lower the threshold for using nuclear weapons in conflicts, and to strengthen strategic deterrence against the NATO. Given this, the annual report published at the Munich Security Conference in February 2016 pointed out that the risk of using nuclear weapons in the Europe-Atlantic area is rising, and such risk is greater than any time after the Cold War.

Under such conditions, the US needs to try to turn China into a partner in the field of nuclear security. Meanwhile, China is becoming a firm supporter of international cooperation in nuclear security. Xi Jinping has attended several nuclear security summits, which is an important gesture of support for the US. In 2014, Xi for the first time put forward China's outlook on nuclear security at the summit in The Hague. China is reportedly to deliver a national nuclear security report at the Washington summit, and Xi is expected to make substantive proposals on enhancing global nuclear security.

Why is China becoming increasing proactive on the issue of nuclear security? First, a number of countries with nuclear capabilities are on China's periphery, and possibilities of large-scale conflicts between such countries, Pakistan and India for instance, do exist. The independent Stockholm International Peace Research Institute estimated that India has 90 to 110 low-equivalent nuclear warheads, while Pakistan has as many as 120. As tension escalates regarding the North Korea nuclear issue, there have been louder calls for developing nuclear weapons in South Korea. About two-thirds of South Koreans agree that their country should develop nuclear weapons, or ask the US to re-deploy nuclear weapons there.

Second, China is in all-out efforts to develop nuclear energy so as to improve structure of energy consumption. But there is a greater need for preventing and managing corresponding security risks. By 2020, installed power-generating capacity on China's mainland will reach 58 million kilowatts, and China will take Japan's place as the world's largest nuclear energy user.

Third, China needs to upgrade precautions against “nuclear terrorism”. In recent years, there have been multiple cases where such nuclear materials as highly enriched uranium were stolen or smuggled in other countries. Once such materials fall in the hands of terrorist organizations, they may make some crude nuclear weapons. They may even intend to sabotage Chinese nuclear facilities, or release radioactive nuclear pollutants in major Chinese cities using “dirty bombs”.

Though China and the US disagree in many aspects, both are willing to deepen cooperation on nuclear security. China cooperated closely with the US and other countries and maneuvered the agreement on the Iran nuclear issue. The two countries held their first dialogue on nuclear security in February 2016. The nuclear security demonstration center the China Atomic Energy Agency and US Energy Department jointly built in Beijing has come into operation recently. It is the largest facility with the most advanced equipments the world over.

Themed on enhancing international nuclear security regime, the Washington summit will feature 52 national leaders and heads of governments. Obama will hold the only one-on-one meeting with Xi. In the process of building a new-type major-country relationship between China and the US, cooperation surrounding nuclear security may become a new highlight in bilateral relations.