Please enable JavaScript in your browser to view this site in optimal condition.
When displaying with JavaScript disabled, some functions may not be available or correct information may not be obtained.

Hiroshima for Global Peace

(7) CTBT

A) Signing and ratifying the CTBT

As of the end of 2021, 170 of the 185 signatories have deposited their instruments of ratification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Cuba and the Comoros newly ratified in 2021.

Among the 44 states listed in Annex 2 of the CTBT, whose ratification is a prerequisite for the treaty’s entry into force, five states (China, Egypt, Iran, Israel and the United States) have signed but not ratified, and three (India, North Korea and Pakistan) have not even signed. Among the countries surveyed, Saudi Arabia and Syria as well have yet to sign the CTBT. The United States said at the UNGA First Committee in October 2021, “[T]he United States supports the [CTBT] and is committed to work to achieve its entry into force.”186 On the other hand, at the UN Security Council, India stated, “India had participated in the negotiations of the draft CTBT in the [CD]. But, India could not join the Treaty as the Treaty did not address a number of core concerns raised by India.”187
On September 23-24, the Conference on Facilitating the Entry into Force of the CTBT was held virtually. Participating countries adopted the Final Declaration, which included a call for early signature and ratification by non-signatory and non-ratified states, mainly those listed in Annex 2 of the CTBT, a call for maintaining a moratorium on nuclear testing, and reaffirmation of support for the establishment of a verification system.188

Soon after the Conference, China made the following proposals at the UN Security Council for promoting the CTBT’s early entry into force:189

➢ To firmly uphold multilateralism, and create an enabling security environment for the entry into force of the treaty;
➢ To support the object and purpose of the treaty and build upon the strong political momentum for its entry into force. …Nuclear-weapon states should honor their commitment to a moratorium on nuclear testing, genuinely cut the weight of nuclear weapons in their national security policies and make a no first use pledge;
➢ To preserve the international arms control regime, and provide more robust institutional safeguards for the entry into force of the treaty; and
➢ To advance the preparations for the implementation of the treaty and reinforce a robust foundation of capacity for its entry into force. The international community should further push ahead with the development of the International Data Center, the International Monitoring System, and the on-site inspection mechanism in a comprehensive and balanced manner, and assist developing countries with capacity building, with a view to full technical readiness for the operation of the verification regime once the treaty enters into force.

At the 2021 UNGA, a resolution, titled “Comprehensive Nuclear-Test-Ban Treaty,”190 in which member states “[stress] the vital importance and urgency of signature and ratification, without delay and without conditions, in order to achieve the earliest entry into force of the [CTBT],” was adopted with 182 countries in favor, one against (North Korea) and three abstentions (India, Syria and others). The United States, which had voted against it the previous year, voted for it.

Regarding outreach activities for promoting the treaty’s entry into force, a document, “Activities Undertaken by Signatory and Ratifying States Under Measure (K) of the Final Declaration of the 2015 Article XIV Conference in the Period June 2019-May 2021,”191 was distributed at the Article XIV Conference on Facilitating the Entry-Into-Force of the CTBT, summarized activities conducted by ratifying and signatory states. It highlighted:

➢ Bilateral activities related to Annex 2 states (conducted by Australia, Austria, Belgium, Canada, Chile, Japan, Kazakhstan, New Zealand, Russia, Switzerland, the United Kingdom and others);
➢ Bilateral activities related to non- Annex 2 states (conducted by Australia, Austria, Belgium, Canada, Chile, Japan, Kazakhstan, New Zealand, Russia, the United Kingdom and others);
➢ Global-level activities (conducted by Australia, Austria, Belgium, Canada, Chile, Japan, Kazakhstan, New Zealand, Russia, Switzerland, the United Kingdom and others)
➢ Regional-level activities (conducted by Australia, Belgium, Chile, New Zealand, Russia and others).

B) Moratoria on nuclear test explosions pending CTBT’s entry into force

The five NWS plus India and Pakistan maintain a moratorium on nuclear test explosions. Israel, which has kept its nuclear policy opaque, has not disclosed the possibility of conducting nuclear tests.

North Korea, at the Plenary Meeting of the Central Committee of the Workers’ Party of Korea on April 20, 2018, decided to stop nuclear tests and test launches of intermediate-range missiles and ICBMs. The next month, in the presence of foreign journalists, North Korea collapsed the entrances tunnels to its Punggye-ri nuclear test site. However, Chairman Kim Jong Un stated in late December 2019, that “the DPRK has found no grounds to be unilaterally bound any longer by the commitment” of stopping nuclear and ICBM tests.192 While North Korea did not resume nuclear test explosions in 2021, it is not likely that its nuclear test site was irreversibly destroyed. Rather, it is considered to be able to reuse the Punggye-ri nuclear test site after weeks or months of restoration work.193

C) Cooperation with the CTBTO Preparatory Commission

Regarding the countries surveyed in this study, the status of contribution payments to the CTBTO, as of December 31, 2021, is as follows:194

➢ Fully paid: Australia, Austria, Belgium, Canada, China, Egypt, France, Germany, Indonesia, Israel, Japan, Kazakhstan, South Korea, Mexico, the Netherlands, New Zealand, Norway, the Philippines, Poland, Russia, South Africa, Sweden, Switzerland, Turkey, the UAE, the United Kingdom, and the United States
➢ Voting right in the Preparatory Commission suspended because arrears are equal to or larger than its contributions due for the last two years: Brazil, Chile, Iran and Nigeria

D) Contribution to the development of the CTBT verification systems

The establishment of the CTBT verification system has steadily progressed. The pace of establishing International Monitoring System (IMS) stations in Egypt and Iran—in addition to those in India, North Korea, Pakistan and Saudi Arabia, which have yet to sign the CTBT—has been lagging behind, compared to that in the other signatory countries. As for China, nearly half of the stations have not yet been certified by the CTBTO Preparatory Committee.195

E) Nuclear testing

No country conducted a nuclear test explosion in 2021.

Meanwhile, in its annual report on “Adherence to and Compliance with Arms Control, Nonproliferation, and Disarmament Agreements and Commitments” published in June 2021, the U.S. State Department again alleged that China196 and Russia may have conducted nuclear tests which created nuclear yield, in violation of the CTBT that prohibits nuclear test explosions as “zero yield.”197 Both China and Russia strongly denied the U.S. allegations, stating that they have not conducted any nuclear tests that would violate the CTBT.198

Regarding experimental activities other than a nuclear explosion test, the United States continues to conduct various nonexplosive tests and experiments under the Stockpile Stewardship Program (SSP), in order to sustain and assess its nuclear weapons stockpile without the use of underground nuclear tests. These include subcritical tests and experiments using the Z machine, which generates X-rays by fast discharge of capacitors, thus allowing for exploring the properties of plutonium materials under extreme pressures and temperatures. The United States has conducted subcritical experiments at a rate of about once a year, but as of the end of 2021, it had not been reported that it conducted such experiments. The United States has been conducting subcritical experiments at a rate of about once a year, but as of the end of 2021, it had not been reported that such were conducted during the same year. The U.S. NNSA released quarterly reports on such experiments, but has not updated it since the first quarter of FY 2015. In addition, after 2018, past information could not be found on the NNSA homepage.

Among nuclear-armed states other than the United States, Russia’s Ministry of Defense announced in June 2021 that it had conducted subcritical experiments with the aim of verifying the reliability of its existing nuclear weapons.199 France clarified that it has conducted “activities aimed at guaranteeing the safety and reliability of its nuclear weapons [including] a simulation program and hydrodynamic experiments designed to model materials’ performance under extreme physical conditions and, more broadly, the weapons’ functioning.”200 However, there are no further reports as to whether France conducted such experiments during 2021. Meanwhile, France and the United Kingdom agreed to build and jointly operate radiographic and hydrodynamic testing facilities under the Teutates Treaty concluded in November 2010.201

Although the status of the remaining nuclear-armed states’ nonexplosive testing activities in this respect is not well known since they have not released any information, it was reported that China has a facility under construction, with the capacity to surpass the U.S. Z machine, and that said facility was expected to be completed soon.202

While the CTBT does not prohibit any nuclear test unaccompanied by an explosion, the NAM countries have demanded that nuclear-armed states, inter alia, refrain from conducting nuclear weapon test explosions or any other nuclear explosions, and to close and dismantle—in a transparent, irreversible and verifiable manner—any remaining sites for nuclear test explosions and their associated infrastructure.203 As opposed to the CTBT, which prohibits any nuclear test “explosions,” the TPNW bans “nuclear tests,” which can be interpreted to ban even those nuclear tests that do not produce an explosion. On the other hand, the TPNW does not stipulate measures for verifying the testing ban.

186 “Statement by the United States,” General Debate, First Committee, UNGA, October 6, 2021.
187 Dipanjan Roy Chaudhury, “CTBT Doesn’t Address India’s Core Concerns: Harsh Vardhan Shringla,” Economic Times, September 28, 2021, address-indias-core-concerns-harsh-vardhan-shringla/articleshow/86567642.cms?from=mdr.
188 “Final Declaration and Measures to Promote the Entry Into Force of the Comprehensive Nuclear-Test-Ban Treaty,” September 24, 2021.
189 “Remarks by Ambassador Zhang Jun at Security Council Briefing on the Comprehensive Nuclear-Test-Ban Treaty,” Foreign Ministry of China, September 28, 2021, 663304/zwjg_665342/zwbd_665378/t1910387.shtml.
190 A/RES/76/66, December 6, 2021.
191 CTBT-Art.XIV/2021/4, September 22, 2021.
192 “Report on 5th Plenary Meeting of 7th C.C., WPK,” NCNK, January 1, 2020, resources/publications/kju_2020_new_years_plenum_report.pdf/file_view.
193 “(2nd LD) N. Korea Able to Use Punggye-ri Nuke Testing Site after Restoration Work: JCS,” Yonhap News Agency, October 8, 2019, defense.
194 CTBTO, “CTBTO Member States’ Payment as at 31-Dec-2021,” user_upload/treasury/52_31_Dec_2021_Member_States_Payments.pdf.
195 CTBTO, “Station Profiles,”
196 In July 2021, it was reported that according to satellite images, expansion works, including the excavation of new tunnels, were underway at the Lop Nur nuclear test site in China. “Satellite Photos Show China Expanding Its Mysterious Desert Airfield,” NPR, July 1, 2021, 01/1011806020/satellite-photos-show-china-expanding-its-mysterious-desert-airfield; “A New Tunnel Is Spotted at a Chinese Nuclear Test Site,” NPR, July 30, 2021, 1022209337/a-new-tunnel-is-spotted-at-a-chinese-nuclear-test-site.
197 The U.S. Department of State, “Adherence to and Compliance with Arms Control, Nonproliferation, and Disarmament Agreements and Commitments,” June 2021. This report also indicated: “[T]he term “nuclear explosive” test includes tests that are supercritical, i.e., that involve a limited multiplying fission chain reaction resulting in the release of nuclear fission energy, whether driven by high explosives or assembled by other means such as a gun assembly. Under the “zero-yield” standard to which the United States adheres in its own moratorium, … [s]upercritical testing is inconsistent with the zero-yield standard as defined by the United States.”
198 “Foreign Ministry Spokesperson Zhao Lijian’s Regular Press Conference,” April 16, 2020, https://; “Statement by Russia,” First Committee, UNGA, October 9, 2020.
199 Isaac Evans, “Russia Conducts Non-Nuclear Tests, Adhering to UN Treaty,” The Organization for World Peace, June 29, 2021,
200 NPT/CONF.2015/PC.III/14, April 25, 2014.
201 NPT/CONF.2015/29, April 22, 2015.
202 Michael Peck, “China Will Soon Have Its Own Z Machine to Test Mock Nuclear Explosions,” National Interest, August 15, 2020, chine-test-mock-nuclear-explosions-166995.
203 NPT/CONF.2020/PC.III/WP.16, March 21, 2019. The prefectural governments and city halls of Hiroshima and Nagasaki have also condemned the subcritical experiments.

< BackNext >