In October, North Korea tested an intermediate-range ballistic missile that it claims can manoeuvre to evade missile defences. For the first time, civilian technicians in Australia carried out maintenance on a US nuclear-powered submarine, a milestone in Australia’s preparations to operate its own submarines under AUKUS. Meanwhile, Pacific Island leaders meeting in Fiji called on nuclear-weapon states to fund environmental remediation and assistance for victims of nuclear testing. Each raises questions that run through this month’s work, from managing new nuclear capabilities to reducing the risk of escalation.

These developments reflect wider trends identified in our latest Quarterly Nuclear Memo, covering July to September, which highlights stalled US-Iran talks, emerging AI threats, and shifting signals on US-ROK denuclearisation and US-Saudi nuclear cooperation.

Our latest publications offer practical ways for states to pursue their security and energy ambitions while upholding their non-proliferation commitments. Matthew Sharp, Celia McDowall, and Toby Dalton outline concrete steps Seoul should take to reassure the international community that its plans for uranium enrichment and nuclear-powered submarines are not a path to nuclear weapons. In this month’s APLN Korea Times column, Peter Hayes explores the tension between international law and nuclear deterrence on the Korean Peninsula, and its implications for denuclearisation efforts.

On the maritime front, a new volume edited by Dongkeun Lee, brings together seven expert papers on the intersection of nuclear and undersea security in the Asia-Pacific, with recommendations for strengthening regional cooperation and reducing emerging security risks. Among its contributions, Ariel Phuphaphantakarn examines how quantum technologies could affect submarine capabilities, while Julius Cesar Trajano assesses regional preparedness for a maritime nuclear or radiological emergency. Complementing this, Sabariah Kader Ibrahim and Nur Dania Adnan propose an ASEANTOM-coordinated pilot to help Southeast Asian governments strengthen their safeguards capacity before committing to nuclear procurement.

We also continued to promote regional dialogue and cooperation. At the Sejong Institute in Seoul, we launched The Strategic Imperative for an Australia-India-Republic of Korea Partnership, a report on how the three countries can advance Asian-led institution-building and strengthen regional resilience. With the ASEAN and Indo-Pacific Studies Initiative at American University, we also co-hosted a senior Track-II dialogue on US and Chinese approaches to the region and the implications of the Xi–Trump summit for Asia-Pacific states.

As always, we are deeply grateful for your continued support and welcome your feedback on these updates.

Our third Quarterly Nuclear Memo tracks the nuclear developments shaping the Asia-Pacific from July to September 2026. Amid a collapsed US-Iran ceasefire, ambiguous US-ROK messaging on denuclearisation and growing AI-related risks, there were encouraging signs: Tonga ratified the CTBT and acceded to the TPNW, and Japan reaffirmed its Three Non-Nuclear Principles. The Memo also looks ahead to the first TPNW Review Conference and the 40th anniversary of the Rarotonga Treaty.

This Memo was prepared by APLN’s Senior Research Adviser Manpreet Sethi, Senior Policy Fellow Tanvi Kulkarni and Strategic Risk Reduction Fellow Hree P. Samudra.

South Korea’s plans for uranium enrichment, reprocessing and nuclear-powered submarines each have a stated civilian or defensive purpose. Taken together, and amid well-documented public interest in nuclear weapons, they could be read as a nuclear hedge. Matthew Sharp, Celia McDowall, and Toby Dalton argue that this ambiguity would undercut Seoul’s own goals. Drawing on the experience of Japan and Australia, they set out measures, from legally binding limits to greater transparency with the IAEA, that could reassure Washington, Beijing, Pyongyang and the wider international community.

Peter Hayes examines how both North Korea and the US-led alliance invoke international law to justify their nuclear doctrines, and the unresolved legal questions around nuclear threats and self-defence. As Pyongyang increasingly treats the two Koreas as separate states, he argues, these questions will shape the terms of any future denuclearisation agreement.

A new volume edited by Dongkeun Lee brings together seven papers examining the growing interconnectedness of nuclear and undersea security in the Asia-Pacific. The volume features expert insights from Jamie Kwong, Jennifer Parker, Sanghoe Lee, Joel Petersson-Ivre, Julius Cesar Trajano, and Ariel (Phantitra) Phuphaphantakarn on the rapid growth of nuclear-powered submarine fleets and examines three broad themes: the development of SSNs ASW capabilities among regional middle-power countries; US-China competition in the undersea domain; and non-traditional and emerging security risks associated with nuclear-powered submarine operations.

The project was supported by the Heinrich Böll Stiftung East Asia Office.

Ariel (Phantitra) Phuphaphantakarn examines how quantum technologies could reshape undersea nuclear deterrence. Quantum sensing may one day threaten the stealth of ballistic missile submarines, but she argues that “quantum anxiety” could fuel arms racing and escalation well before then. She proposes the a new framework to strengthen cooperation, transparency and risk reduction.

Julius Cesar Trajano warns that a nuclear-powered submarine accident in Southeast Asian waters could damage fisheries, food security and coastal livelihoods across borders, and that ASEAN’s emergency mechanisms are not designed for maritime incidents. He calls for adding submarine accident scenarios to regional exercises, expanding marine radiation monitoring and improving coordination among regulators.

As interest in nuclear energy grows across Southeast Asia, Sabariah Kader Ibrahim and Nur Dania Adnan argue that governments must first ask whether they have the safeguards capacity to meet their international obligations. They propose a voluntary 12-month pilot, coordinated by the ASEAN Network of Regulatory Bodies on Atomic Energy (ASEANTOM), to help governments test their systems and close gaps before signing nuclear procurement deals.

On 22 October, we launched The Strategic Imperative for an Australia-India-Republic of Korea Partnership at the Sejong Institute in Seoul. The report is a joint study with the Australia India Institute, Jawaharlal Nehru University, and the University of Melbourne. It explores how the three countries can advance Asian-led institution-building and strengthen regional resilience. The report is co-authored by Grace Corcoran, Alexander Hynd, Sandip Mishra, and APLN Policy Fellow Dongkeun Lee, with support from the Korea Foundation.

On 13 October, APLN and the ASEAN and Indo-Pacific Studies Initiative at American University (AIPSI), co-hosted a senior Track-II dialogue on US and Chinese approaches to the region and what the 24 September Xi–Trump White House summit means for Asia-Pacific states. Participants also discussed how regional minilaterals can better meet recipient states’ needs for economic development and security assistance, the growing securitisation of US-China cooperation and wider shifts in the regional security landscape.