Research Group on 'The Indo-Pacific' FY2021－# 3
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On September 15, 2021, US President Biden, UK Prime Minister Johnson and Australian Prime Minister Morrison issued a joint statement on AUKUS. AUKUS is an acronym for Australia, United Kingdom (UK), and the United States (US). This is a new framework for trilateral security cooperation, and its main objective is to help Australia acquire a nuclear submarine. This paper discusses the specifications of nuclear submarines and examines the current significance of the Joint Statement.
1. Status of countries with nuclear submarines
Six countries have nuclear submarines: the United States, the United Kingdom, France, China, Russia, and India. They are members of the Nuclear-Powered Submarine Club. Aside from India, these countries are also permanent members of the United Nations Security Council. Countries possessing nuclear submarines hold an important place in the international security framework, particularly in terms of their high technological capabilities. The United States has 68 high-tech submarines. China has almost the same number of submarines as the United States, if one includes conventional powered submarines. It is estimated that China will have 76 submarines by 2030 by increasing the number of new submarines while removing old ones. 
2. Features of nuclear submarines
Submarines provide concealment and offensive power. They are concealed when dived into the sea. Once below depths they are difficult to detect, and this difficulty increases with time. Submarines can deploy torpedoes, ballistic missiles, cruise missiles, and mines in offensive actions. Torpedoes are a major threat because they have the power to sink surface ships with a single strike. Missiles can be equipped with nuclear warheads. This makes submarines strategic weapons platforms.
Nuclear submarines include ballistic missile nuclear submarines (SSBN), cruise missile nuclear submarines (SSGN), and attack nuclear submarines (SSN). The SSBN and the SSGN can submerge to launch a retaliatory attack against a nuclear attack and assume the role of nuclear deterrent (SLBM Patrol). The SSN are tasked with following submarines and preventing ballistic missile launches and can protect surface fleets from enemy submarines.
Submarines do have drawbacks. Once they are exposed, they are vulnerable, and if they are found, by, for example, maritime aircraft, they have no way to counterattack. Their only option is escape. Therefore, submarine crews' strong wish is to have enough underwater speed that allows them to escape at high speeds after detection. Exposure resulting from attacks by submarines sharply weakens their effectiveness. It is estimated that the underwater speed of nuclear submarines is 34 Kt (Approx. 60 km/h) in the Virginia class in the US Navy and 29 Kt (Approx. 53 km/h) in the Astute class in the UK Navy. High speed at submerged levels allows for maneuverability and rapid deployment to mission sites.
3. Nuclear propulsion in nuclear submarines
Nuclear submarines use steam pressurized in nuclear reactors to power turbines. They do not require oxygen and can stay underwater until depleting their nuclear fuel. However, the maximum period of submersion is about 70 days to keep crews mentally fit and supplied. As with nuclear power plants, several 100 megawatts of electricity are required. This is due to the following reasons.
(1) Power consumption increases at the power of speed cubed, so if speed increases by 3 times, 27 times more power is required.
(2) High power shall be required not only for high-speed underwater navigation, but also for the cooling of crew support equipment, sonar (Sensor) and combat systems.
(3) It can be used without replacing fuel rods during the submarine's life of 30 to 40 years.
(4) It is necessary for operations to enable high-speed navigation whenever necessary without giving much consideration to the life of fuel rods.
On the other hand, nuclear reactors on submarines are pressurized water reactors that can continue to cool fuel rods even when they are shaken, but these reactors are more complex than boiling water reactors that are not suitable for shaking, and they need to be downsized to be installed in the limited space of submarines. Highly enriched uranium and Burnable Poison are also required to avoid the replacement of nuclear fuel rods between 30 and 40 years of age. High technology is necessary for all of these, and the United States, the United Kingdom, and Russia have this technology. China and Russia have reached an agreement to expand cooperation in the development of floating nuclear power plants, which generate nuclear power at sea. If cooperation between China and Russia deepens, it is likely that China's nuclear submarine capabilities will increase. 
4. Limits of conventional powered submarines
The JMSDF does not possess nuclear submarines and has 21 conventional powered submarines (set to be increased to 22). Conventional powered submarines charge their batteries with electricity generated by a diesel generator, and use the batteries to drive an electric motor while submerged. When the batteries are depleted, they float near the surface of the sea, sticking out an air intake called a snorkel on the surface of the sea, and pass air through the ship to run the diesel generator, then charge the battery. Like the situation after attack, they are easy to detect in this state. While it is necessary to reduce power consumption to avoid doing this as much as possible, batteries are used not only for navigation but also to cool sonar (Sensor) and combat systems. As the battery is consumed at the power of the speed cubed, it cannot achieve high speed underwater. Therefore, their operational capabilities are limited compared to a nuclear submarine. In recent years, in an effort to cope with this situation, the JMSDF has increased operations flexibility by installing AIP (Air-Independent Propulsion), a Stirling engine that does not require oxygen, and lithium-ion batteries with larger battery capacity and longer consumption times. However, nuclear submarines have a completely different level of high-speed navigation capability. Therefore, the missions of Japanese and US submarines are different. Since the JMSDF's conventional powered submarines are not capable of mobile deployment, they stay in chalk points (points where enemy submarines or surface ships are expected to sail) in the Nansei-shoto, Tsushima, Tsugaru, and Soya Straits to conduct ISR operations as well as operations to prevent navigation. On the other hand, US nuclear submarines conduct operations in open waters and respond to Chinese and Russian SLBM patrols, and provide protection for US carrier strike groups. Thus, the operations carried out on nuclear powered submarines and conventional powered submarines are completely different.
5. Current significance of Australian nuclear submarines
As stated earlier, Australia's operation capability will be greatly enhanced if it possesses advanced nuclear submarines, like those of the US and UK Navies. However, this will take about 20 years. President Biden cited workforce, training requirements, production timelines, safeguards, nonproliferation measures, nuclear stewardship, and safety as issues that need to be considered in the next 18 months.  These are major issues generic to the acquisition of nuclear propulsion equipment. There are also fears that if these workforce and budget requirements are to be realized on the scale of the current Australian Navy, force structures will be considerably distorted. My honest impression is that the realization of this project will be extremely difficult. Therefore, it is important to consider the current significance of the AUKUS Joint Statement, not the significance of the introduction of Australian nuclear submarines in 20 years. This following part considers the current significance in terms of policy towards China and nuclear non-proliferation.
(1) China policy
In the joint statement, the three leaders stressed their commitment to stability in the Indo-Pacific region. IN January 2021, the US government released the Trump administration's "U.S. Strategic Framework for the Indo-Pacific" drawn up in February 2018. This Strategic Framework indicated (1) the maintenance of US strategic primacy, (2) vigilance against China (Defense within the first Island chain), (3) an emphasis on India, (4) relations with Southeast Asian and Pacific countries. The United States believes that cooperation with its allies and partners, such as Japan, Australia, and India, as well as capacity building and the sharing of responsibilities among them, are important for the superiority of American power in the Indo-Pacific.  To realize such an Indo-Pacific strategy, the United States not only cooperates with allies such as Japan, South Korea, Australia, and the Philippines, but also establishes various frameworks such as the QUAD (Japan, United States, Australia, India). In addition, the United States is aiming for superiority through security cooperation and economic cooperation in order to realize a "free and open Indo-Pacific". Many countries do not want their economic partnerships with China to deteriorate, and some Indo-Pacific countries such as ASEAN members maintain close relations with China. Under these circumstances, the United States is not only containing China through hard power, but also building loose partnerships such as the QUAD. As part of US strategy in the Indo-Pacific, AUKUS looks like hard power containment to China. It connects Atlantic and Pacific Ocean geopolitical networks. A symbolic joint statement of the United Kingdom's commitment to stability in the Indo-Pacific region also involves the FPDA (Five Power Defense Arrangements: Agreement between the United Kingdom and Australia, New Zealand, Singapore, and Malaysia).
(2) nuclear non-proliferation
It is difficult to predict the status of nuclear proliferation 20 years from now (when Australia owns a nuclear submarine), but it is possible to consider whether the current situation of nuclear proliferation is heading in the right or wrong direction. The spread of nuclear missiles to India, Pakistan, North Korea and Iran, fear of spread of nuclear weapons to terrorist organizations, the US withdrawal from INF (The Intermediate-Range Nuclear Forces Treaty), Russia developing low yield nuclear missiles. It is hard to say that the prevention of nuclear proliferation is progressing positively. The reasons for the withdrawal of the United States from the INF are that China, which is not a party to the treaty, is developing intermediate-range nuclear forces, thus impairing the nuclear balance in the Indo-Pacific region, and that Russia is developing land-based cruise missiles that violate the treaty. The United States wants to start talks with China and Russia after scrapping the INF, but China refuses, and Russia agrees with China's position. For the United States, the task ahead is to engage in arms control negotiations with China and Russia to balance intermediate-range nuclear forces in the Indo-Pacific region. It is also assumed that the United States would like the major nuclear power, itself with China and Russia, to take steps to correct the global trend toward nuclear proliferation.
The AUKUS Joint Statement is a strong message to China from the United States, which wants to start such negotiations.
6. What Japan should do
In the joint statement, President Biden stated that one of the reasons for AUKUS is to ensure its superiority in the underwater domain. The Japanese National Defense Program Guidelines point out the importance of operations in new domains such as cyberspace, space, and electromagnetic waves, in addition to land, sea, and air battle fields. This statement reiterates the importance of the underwater domain. The reason is that the struggle for mastery in the underwater domain has a significant impact on the nuclear strategic balance. Underwater battle spaces have new dynamics that are not always linked to other new domains. Electromagnetic waves do not reach the underwater battlespaces. Also, because network connections are weak underwater, the frequency of cyber-attacks is low. In the Indo-Pacific region, the nuclear balance has been lost in terms of intermediate-range nuclear forces. Therefore, securing the superiority of the US nuclear force in the underwater domain is a major challenge for Japan as well. This is because the target area for intermediate-range nuclear forces is not the US mainland but the western Pacific, including Japan.
Immediately after taking office, Prime Minister Kishida announced a review of the National Security Strategy. The review should consider the fact that the balance of nuclear threats around Japan has been lost and reconsider the heretofore sacrosanct three nonnuclear principles. And we need to consider what kind of strategy to pursue with the United States to improve this balance. Enemy attack points exist not only on the ground but also in underwater. Supporting the introduction of Australian nuclear submarines at AUKUS is a new way to correct the nuclear balance in the region. With that in mind, Japan, which is at the forefront of the threat, must review its national security strategy so that it can respond to further measures by the United States.
 China Naval Modernization: Implications for U.S. Navy Capabilities -- Background and Issues for Congress Updated August 3, 2021, AAUKU Congressional Research Service
 Australia Badly Needs Nuclear Submarines The country's maritime scope, and China's rise, makes the AUKUS deal a no brainer. By Andrew S. Erickson 20. Sep. 2021
 Southwest Islands off Kyushu and in the Okinawa archipelago
 Remarks by President Biden, Prime Minister Morrison of Australia, and Prime Minister Johnson of the United Kingdom Announcing the Creation of AUKUS
The White House BRIEFING ROOM 15. Sep. 2021
 U.S. Strategic Framework for the Indo-Pacific and Implications for Japan (NIDS Commentary No. 154 January 26, 2021): Tomohiko Satake, Institute for Defense Policy