Category Archives: Nuclear

Radioactive Tsunamis: Nuclear Torpedo Drones and their Legality in War

By Raul (Pete) Pedrozo


Russia and North Korea are both fielding a novel type of naval weapon – nuclear-armed torpedo drones. These new weapons introduce a variety of strategic and operational challenges that further complicate a worsening threat environment. They also pose critical legal questions about whether their intended concepts of operation are lawful. These weapons have a fearsome potential to weaponize the maritime environment, and precise questions of their legality should be resolved in order to dissuade their proliferation. 

North Korea and Russia’s Doomsday Torpedoes

On July 28, North Korea displayed a new nuclear-armed drone torpedo at the 2023 Victory Day Parade in Pyongyang. Although its official classification is unknown, the new weapon is likely a Haeil-class drone torpedo. The nuclear torpedo drone is approximately 52 feet long and 5 feet in diameter, has an estimated range of about 540 nautical miles, and can be fitted with a conventional or nuclear warhead. It could therefore be used against targets in both South Korea and Japan. The torpedo drone appears to have three air filters over the propulsion space for snorkeling, is likely powered by a diesel-electric (battery) propulsion system, has an average speed of 4.6 knots, and can operate at depths between 260-300 feet. Given the size of the drone, North Korea does not have a submarine large enough to launch it, which suggests that the new weapon system will need to be launched from shore, a floating platform, or a modified surface vessel.

The nuclear-armed underwater drone can be used to attack coastal naval installations or cities with little or no warning, providing North Korea with a strategic nuclear weapons delivery option that is difficult to detect and defend against. Thus, the Haeil-class drone provides North Korea with an additional strike option, increasing the resilience of its nuclear forces and making them less vulnerable to preemption or counterattack.

Pyongyang, July 27, 2023 – Haeil-class nuclear torpedo drones feature in a North Korean military parade. (Photo via North Korean state media)

The Haeil-class drone torpedo is similar to (but smaller than) the Russian Poseidon, an intercontinental, nuclear-powered, nuclear-armed autonomous torpedo that was first revealed by the Russian Navy in 2015. The Poseidon (also known as Kanyon or Status 6) can reportedly operate at speeds of around 70-100 knots and at depths of around 3,300 feet, which means it can outrun and out dive any conventional torpedo. The weapon is also equipped with “acoustic tracking devices and other traps” that make it difficult to detect. Moreover, the drone is equipped with its own power source—a nuclear reactor—which gives the torpedo unlimited range. Once launched, the drone is designed to be controlled by both remote communications and onboard automation. In January 2023, TASS reported that Russia had produced the first batch of Poseidon torpedoes for “use by the [K-329] Belgorod special-purpose nuclear submarine.” The Belgorod submarine can carry up to six Poseidon torpedoes, and will deploy to the Pacific Fleet area of responsibility as early as late 2024 or early 2025.

Click to expand. Cutaway illustration of Poseidon, based on analysis of images released by Russia. (Graphic by H I Sutton)

These drone torpedoes can be armed with up to a 100-megaton nuclear warhead, but their primary method of destruction is less about directly impacting targets. Instead, they focus on weaponizing the immediate aftereffects of nuclear detonations in the maritime environment. These nuclear torpedo drones are designed to trigger a radioactive tsunami-like ocean swell that destroys coastal cities and renders them uninhabitable, potentially resulting in large-scale displacement and millions of deaths. The legality of this concept of operations deserves closer scrutiny.

Depiction of nuclear torpedo drone concept of operation. (Graphic via DailyMail)

Legal Means and Methods of Warfare

Generally, the legal right of the belligerents to adopt means or methods of warfare during an international armed conflict is not unlimited (AP I, art. 35; HR, art. 22; Newport Manual, § 6.1). Specifically, a belligerent does not have the unlimited right to inflict superfluous injury or unnecessary suffering on the opposing belligerent (HR, art. 23; Newport Manual, § 6.1). Weapons law “regulates which weapons and means can lawfully be used during an armed conflict,” and is comprised on both customary international law and treaties (St. Petersburg Declaration; Newport Manual, § 6.2). The customary international law principle of distinction and the prohibition of unnecessary suffering regulate the legality of the means of warfare (Newport Manual, § 6.2). Weapons law is also codified in treaties, such as the Environmental Modification (ENMOD) Convention and Additional Protocol I (AP I) to the 1949 Geneva Conventions.

Damage to the environment is a concern. AP I places restrictions on weapons that “are intended or may be expected to cause widespread, long-term, and severe damage to the natural environment (AP I, art. 35(3); Newport Manual, § 6.3).” AP I further provides that the belligerent shall take care “in warfare to protect the natural environment against widespread, long-term and severe damage,” which includes a prohibition of the “use of methods or means of warfare which are intended or may be expected to cause such damage to the natural environment…” that prejudices the health or survival of the civilian population (AP I, art. 55(1); Newport Manual, § 6.3). The International Committee of the Red Cross interprets “long-term” to include damage over a period of decades (ICRC Commentary to AP I, ¶ 1453(c)).

The ENMOD convention prohibits States’ parties from engaging “in military or any other hostile use of environmental modification techniques having widespread, long-lasting or severe effects as the means of destruction, damage or injury to any other State Party (ENMOD Convention, art. I; Newport Manual, § 6.3.1).” For the purposes of the Convention, the terms “widespread,” “long lasting,” and “severe” have been interpreted by the convention’s Consultative Committee of Experts. “Widespread” means “encompassing an area on the scale of several hundred square kilometres.” “Long-lasting” means “lasting for a period of months, or approximately a season.” Finally, “severe” means “involving serious or significant disruption or harm to human life, natural and economic resources or other assets.” (See ENMOD, Understanding Relating to Article I). “Environmental modification techniques” are defined in article II as “any technique for changing—through the deliberate manipulation of natural processes—the dynamics, composition or structure of the earth, including its biota, lithosphere, hydrosphere and atmosphere.” Thus, the convention prohibits the use of “modification techniques that result in the environment itself being characterized as a weapon, rather than prohibiting certain military activities that cause damage to the environment (Newport Manual, § 6.3.1).”

The prohibitions in AP I and the ENMOD Convention are, therefore, not duplicative (ICRC Commentary to AP I, ¶ 1450). AP I protects the natural environment against damage which could be inflicted on it by any weapon, whereas the ENMOD Convention prevents the use of environmental modification techniques as a weapon. Additionally, AP I only applies during an international armed conflict, whereas the ENMOD Convention has a wider application—it applies to the use of environmental modification techniques for hostile purposes, even in cases where there is no international armed conflict.

On the one hand, the ENMOD Convention prohibits the deliberate manipulation of natural processes to change “the dynamics, composition or structure of the Earth, including its biota, lithosphere, hydrosphere and atmosphere, or of outer space, with the intention of damaging the armed forces of another State…, its civilian population, towns, industries, agriculture, transportation and communication networks, or its natural resources and wealth (ICRC Commentary to AP I, ¶ 1451).” Therefore, the convention does not prohibit environmental modifications that cause widespread, long-lasting, or severe damage as such, but only if they are used to cause damage to another State (ICRC Commentary to AP I, ¶ 1452).

AP I, on the other hand, “prohibits damaging the natural environment by any means whatsoever, whether direct or indirect, as opposed to effects on the human environment,” that is, “to external conditions and influences which affect the life, development and the survival of the civilian population and living organisms.” (ICRC Commentary to AP I, ¶ 1451). AP I therefore prohibits the use of any means that cause widespread, long-term, and severe damage to the natural environment (ICRC Commentary to AP I, ¶ 1452).

Taken together, AP I and the convention prohibit: (a) “any direct action on natural phenomena of which the effects would last more than three months or a season…;” (b) any direct action on natural phenomena of which the effects would be widespread or severe… regardless of the duration…” or (c) “any method of conventional or unconventional warfare which, by collateral effects, would cause widespread and severe damage to the natural environment as such, whenever this may occur over a period of decades (ICRC Commentary to AP I, ¶ 1453).”


Armed with multi-megaton nuclear warheads, these torpedo drones will be detonated along an adversary’s coast to create a powerful radioactive tsunami to destroy coastal cities and naval bases. Given that the concept of operations for these new weapons might unlawfully modify and weaponize the natural environment, both the North Korean Haeil and Russian Poseidon torpedo drones are likely unlawful weapons per se under the law of armed conflict.

The unleashing of environmental forces in such a manner is contrary to the law of war and likely violates the ENMOD Convention, which prohibits any method of warfare for changing—through the deliberate manipulation of natural processes—the dynamics, composition, or structure of the Earth (DoD Law of War Manual, §§ 6.10.1-6.10.2; FM 6-27, ¶¶ 2-139, 2-140). Examples of environmental effects likely to be widespread (encompassing an area of several hundred square kilometers), long-lasting (for a period of months or a season), or severe (serious or significant disruption or harm to human life, natural and economic resources, or other assets) likely include the inducement of a radioactive tsunami. Unlike a conventional or nuclear weapon designed to destroy enemy forces, the Haeil and Poseidon torpedoes weaponize the natural environment to inflict destruction and ignore the distinction between the enemy’s armed forces and the civilian population. (Newport Manual, § 6.3.1). As parties to AP I and the ENMOD Convention, both North Korea and Russia have legal obligations not to use environmental techniques that are prohibited by the Convention, or to employ means or methods of warfare that can cause widespread, long-term, and severe damage to the natural environment.

Professor Raul (Pete) Pedrozo, Captain, USN, Ret., is the Howard S. Levie Professor on the Law of Armed Conflict, U.S. Naval War College, Stockton Center for International Law. Prior to his retirement from active duty after 34 years of service, he served in numerous positions advising senior military and civilian Defense officials, including as the senior legal advisor to Commander, U.S. Pacific Command. He also served as the Director of the Navy’s International and Operational Law Department in the Pentagon.

The views expresses are those of the author and do not necessarily reflect the views of the Department of Defense or the U.S. Naval War College.

Featured Image: Pyongyang, July 27, 2023 – Supreme Leader of the Democratic People’s Republic of Korea Kim Jong Un applauds as Haeil-class nuclear torpedo drones are featured in a military parade. (Photo via North Korean state media)

Deak Parsons – The Story of the Atomic Admiral

By Rob Gates

The recent movie Oppenheimer focuses, as expected, on J. Robert Oppenheimer, the eponymous hero of the story and Director of Project Y in Los Alamos. However, it overlooks another important figure – Navy Captain William “Deak” Parsons, an Associate Director of Oppenheimer’s and leader of the Ordnance Division of the Manhattan Project. Parson’s substantial contributions warrant a closer examination, especially his evolution in becoming the “Atomic Admiral.”


William Sterling Parsons was born in Chicago in November 1901 but grew up in Fort Sumner, New Mexico after his father moved the family there in 1909. He was largely homeschooled although he attended the local elementary school for six years starting at age 8. He skipped grades and caught up to and passed his contemporaries. He finished grade school at home after being pulled out of the local school, and started at Santa Rosa High School. He moved from freshman to junior in one year. He was encouraged to take the Naval Academy exam before his senior year, passed it, and became the second alternate. He received the appointment when neither the principal nor first alternate passed the exam.

He reported to the Naval Academy at age 16 for the physical exam. He was viewed as too short and underweight and was rejected. He argued before the examining board that he was younger than the other candidates and, of course smaller, and that he would be the required size when he reached their age. The board bought his argument and gave him a waiver. He became a member of the class of 1922, overlapping with Hyman Rickover’s time at the academy. His family called him Bill but, as was custom at the Naval Academy, he was given a nickname – Deacon, as a play on his last name, which was shortened to Deac or Deak.

Deak Parsons as a Midshipman. (Photo via U.S. Naval Academy)

Early Career

His first assignment after graduation was as a gunnery officer on the USS Idaho (BB-42). After a successful tour, he was sent to the Naval Postgraduate School (NPS) in Annapolis in 1927, where he was a student in the ordnance course and studied under Dr. Charles C. Bramble.1 At the conclusion of the NPS course, students were required to take a field posting, and Parsons came to Dahlgren in early 1930. While there, Dr. L.T.E. Thompson saw promise in him and advised Parsons to become an Engineering Duty Officer so his shore assignments would not be interrupted by periods of sea duty. Parsons saw himself as a line officer and declined the advice. In June 1930, he was assigned to the USS Texas (BB-35).

At the end of that tour, in 1933, he was assigned to the Bureau of Ordnance (BuOrd) as liaison to the Naval Research Laboratory. This proved to be an important assignment, where he was introduced to radar. He became something of an expert in radar and one of its strongest advocates in the Navy, especially for fire control. His advocacy, however, resulted in little as his superiors in the Bureau of Ordnance did not share his enthusiasm.

His next assignments were at sea. He served as the Executive Officer on the USS Aylwin (DD-355) from June 1936 until March 1938. He was then assigned as gunnery officer to improve the gunnery scores of USS Detroit, the flagship of Rear Admiral William R. Sexton, who was serving as Commander of destroyers in the Pacific’s battle fleet. In mid-1939, Parsons was assigned to the Naval Proving Ground in Dahlgren as Experimental Officer. 

Early War Years and the VT Fuze

As Experimental Officer he was responsible for planning and scheduling all testing at Dahlgren. Merle Tuve (of the National Defense Research Committee, NDRC) visited Dahlgren in 1940 to discuss concepts for improved anti-aircraft defense. Parsons knew of Tuve from his radar work and began collaborating with him. He offered Dahlgren’s facilities for testing the early versions of the VT fuze. There was promise but little success in testing at first with 90 percent of the fuzes failing. Finally in January 1942, there were 26 successful tests of a batch of 50 fuzes – exceeding BuOrd’s 50 percent threshold – and Parsons recommended that the fuze go into production. The Navy took over program direction and scheduling but wanted the Office of Scientific Research and Development (OSRD), specifically Vannevar Bush and Merle Tuve, to retain technical direction. Parsons was detailed from Dahlgren to serve as Bush’s deputy overseeing the work of Tuve’s Section T.

Testing of the fuze continued with a successful test in the Chesapeake Bay near Tangier Island in June 1942. The USS Cleveland (CL-55) engaged and destroyed three target drones, reportedly with only three shots. The Cleveland was immediately sent to North Africa and then the Pacific. When an inventory of 5,000 fuzes was available at Mare Island,2 plans were made to send them to the fleet for testing in combat. Parson went onboard the USS Helena (CL-50) and, on January 5, 1943, the ship successfully engaged two Aichi dive bombers and shot down both. He and others spent the next three months training crews in the Pacific on the use of the new weapon.

He returned to Dahlgren at the end of March, hoping to wrap up his fuze work and be assigned sea duty in the war zone. It was not to be.

Project Y – The Manhattan Project at Los Alamos

Vannevar Bush was concerned about Brigadier General Leslie R. Groves’ direction and Army dominance of the Manhattan Project, as well as Groves’ insensitivity to scientists. The Military Policy Committee met and recommended some changes. Groves also wanted an ordnance and fuze expert assigned to the project. No qualified Army officers were available and the opportunity to assign a navy officer, and one who understood military-scientist relationships, presented itself. Bush knew Parsons from his VT fuze work and recommended him to Groves.

Parson subsequently received orders to report to Admiral Ernest King, Commander in Chief, United States Fleet and Chief of Naval Operations, without delay. In a ten-minute meeting, King filled him in on Project Y and then had him meet with General Groves. Groves approved of his appointment and had him meet with J. Robert Oppenheimer, Project Y Director, the next day. Parsons was assigned to King’s staff with the rank of Captain on June 1, 1943 and named Associate Director of Project Y and Head of the Ordnance Division.3

Within a few days the Parsons and Oppenheimer were on the train bound for Los Alamos.4 They spent the time talking before they reached their destination, where they laid out their philosophies and the new organizational structure. Oppenheimer was happy to turn over the responsibilities for ordnance matters to Parsons and to focus on physics. Likewise, Parsons’s strength was in “weaponizing” the bomb and addressing the operational problems associated with its combat delivery.

Parsons had to bring on additional staff and approached people he knew from the VT fuze and radar work. He also went back to the Naval Proving Ground and recruited several people, including Thomas Olmstead, a technician, Norris Bradbury, an expert in exterior ballistics, and Frederick Ashworth, the senior naval aviator at the Proving Ground. Parsons was later criticized for his propensity to hire Navy people.

Parsons also went to Dahlgren for ballistic testing of the gun-type bomb shape. The testing was performed using Parsons’ “sewer pipe” bombs. The test bombs were made by cutting a standard bomb in half and extending the bomb by inserting a length of sewer pipe. The NPG employees and aviators speculated on what they were testing but apparently, no one guessed the right answer.

Parsons’s division was primarily responsible for developing the gun-type/Uranium-235 bomb that was initially called “Thin Man” (after Franklin D. Roosevelt) and, later, “Little Boy.” The division also studied the implosion-type/Plutonium bomb known as “Fat Man” (after Winston Churchill). Plutonium had advantages over Uranium-235, and when it was discovered that it was not suitable for a gun-type bomb, the implosion-type bomb took on greater importance. There was another reorganization in July 1944 and Parsons’s group took on the responsibility of making both bombs combat-deliverable.

From the beginning, Parsons had planned on being the weaponeer for the first combat use of the bomb and expressed that to Groves. When the push to completion started – called Project Alberta – in March 1945, Parsons informed Groves that in accordance with his (Groves) wishes, he was going to be the weaponeer when Little Boy was used. He was officially named the Officer in Charge of the Los Alamos Overseas Technical Group and weaponeer on the first mission.

Frederick Ashworth had been brought in to work with the Army Air Force on the B-29. Parsons planned to fly in a B-29, piloted by Ashworth, over the test at Trinity as a dress rehearsal for the first mission. It did not transpire as he hoped for because he was required to stay 25 miles away from the test site. Nevertheless, he had a great view of the Trinity detonation.

Ashworth led the group that selected Tinian Island as the location of the B-29 base. Once it was constructed, the elements of the bomb, Los Alamos staff, and the 509th Composite Group (under the command of Col. Paul Tibbets) were moved to Tinian. Parsons also went to make final preparations.

Deak Parsons (left), standing next to Col. Paul Tibbets, briefs the 509th Composite Group on Tinian. (Photo via Wikimedia Commons)

After weather delays, the mission was scheduled for August 6. Groves’ direction was that the bomb was to be assembled on the ground before the flight. But Parsons had seen four overloaded B-29s crash on takeoff and was concerned about taking off with a fully armed atomic bomb. Early on August 5, he expressed his concerns to Brigadier General Thomas Farrell, deputy director of the Manhattan Project, reportedly saying, “If that happens tomorrow morning, we could get a nuclear explosion and blow up half the island.” He decided to disregard Groves’ instructions and arm the bomb in flight. He spent the rest of the day (and evening) developing and practicing the process to do just that.

The B-29 took off at 0245 on August 6 and, after it reached cruising altitude, Parsons and Electronics Test Officer, Lieutenant Morris Jeppson entered the bomb bay. Jeppson held the flashlight while Parsons followed the 11-point checklist that he had developed the previous day, and placed the gunpowder-armed fuze behind the Uranium-235 “bullet.” At 0630, Parsons directed Jeppson to return to the bomb bay and replace the green safety plug with a red plug. The bomb was now fully armed, and was successfully dropped at 0915.

That essentially ended Parsons’s role in the Manhattan Project. Ashworth was the weaponeer on the second mission when the Fat Man bomb was dropped on Nagasaki on August 9. The war ended five days later.

Postwar Years

Parsons knew that when he accepted the Manhattan Project assignment that he had given up the opportunity for wartime command at sea. After the war, he concluded that without that command experience, his chances for promotion and his future in the Navy were not good. As it happened, he was promoted to Commodore and Rear Admiral while on Tinian. It also turned out that he was in demand because of his atomic experience and was named technical deputy to the Commander, Operation Crossroads.5 He went on to other positions, including Director of Atomic Defense under the Deputy CNO (Air), and Deputy Director of the Armed Forces Special Weapons Project under General Groves. He also reprised his role as technical deputy to Commander, Operation Sandstone, a series of atomic bomb tests conducted in April 1948. These and other assignments led to his being known as the “Atomic Admiral.”

Detonation of Shot Baker during Operation Crossroads on July 25, 1946.

In 1951, he finally got his command at sea when he was named Commander, Cruiser Division Six in the Atlantic Ocean and Mediterranean Sea. In March 1952, he became Deputy Chief, Bureau of Ordnance and his future looked bright, He used his influence to promote research and establish Navy laboratories and, because of his expertise, was involved in many technical initiatives. He was busy to the point of exhaustion.

When he went to Los Alamos in 1943, he worked closely with Oppenheimer. They lived in adjacent houses on “Bathtub Row” (so called because they were the largest houses in Los Alamos and the only ones on the mesa with bathtubs) and their families became close. They stayed in touch after the war and occasionally vacationed together.

Rear Admiral Deak Parsons. (Photo via

When Parsons learned that President Eisenhower had decided that a “blank wall be placed between Dr. Oppenheimer and secret data,” effectively negating Oppenheimer’s Q-level security clearance, according to Parson’s wife, he became “visibly upset” and began to suffer chest pains. He concluded that it was not a heart attack but, when he was no better the next morning, his wife insisted that he go to the Bethesda Naval Hospital. While being prepared for an electrocardiogram, the Atomic Admiral died at the age of 52 on December 5, 1953.

Although Deak Parsons died young, his contributions to the Navy were significant and his legacy is intact. His early Navy career was much like many other junior officers of the time, but even then, his expertise in ordnance and gunnery were apparent. His legacy came later in his career and is mostly seen in his technical contributions, beginning at the Naval Proving Ground. His partnership with Dr. L.T.E. Thompson had a great impact on the Proving Ground and the Navy. Their vision was of a naval laboratory where scientists and officers would work closely together on creative research that was key to the Navy’s future. This vision would take root and set the pattern for Navy laboratories that has persisted to the present. His contributions to the Variable Time fuze and Project Y show the successful application of that principle to some of the most important projects of World War II. After the war, Parsons became the Navy’s leading authority on nuclear issues and an early advocate of nuclear power for ships and nuclear strike capability for aircraft carriers. In short, he helped lead the Navy into the nuclear age. He was on track to become the Chief of the Bureau of Ordnance when he died. Undoubtedly, many more accomplishments would have followed.

Robert V. (Rob) Gates, a retired Navy Senior Executive, served as the Technical Director at the Naval Surface Warfare Center (NSWC), Indian Head Division, and in many technical and executive positions at NSWC, Dahlgren Division, including head of the Strategic and Strike Systems Department. He holds a B.S. in Physics from the Virginia Military Institute, a Masters in Engineering Science from Penn State, and a Masters and PhD in Public Administration from Virginia Tech. He is a graduate of the U.S. Naval War College.  Dr. Gates is the Vice President of the board of the Dahlgren Heritage Foundation.


Baldwin, Ralph B. The Deadly Fuze: Secret Weapon of World War II, Presidio Press, 1980.

Bird, Kai and Martin J. Sherwin, American Prometheus: The Triumph and Tragedy of J, Robert Oppenheimer, Alfred A. Knopf, 2005.

Christman, Albert B. Target Hiroshima: Deke Parsons and the Creation of the Atomic Bomb. Annapolis, Naval Institute Press, 1998.

Christman, Al, “Deak Parsons: Officer-Scientist.” U.S. Naval Institute Proceedings, 56-61, January 1992.

Christman, Al, “A New Kind of Officer.” U.S. Naval Institute Proceedings, 79-80, May 1998.

Furer, Julius Augustus, Administration of the Navy Department in World War II, Department of the Navy, 1959.

Gates, Robert V, “Dahlgren’s Secret: It’s People,” Northern Neck of Virginia Historical Magazine, 9458-9470, December 2022.

McCollum, Kenneth G., Ed, Dahlgren, NSWC, 1977.

Rife, James P. and Rodney P. Carlisle, The Sound of Freedom: Naval Weapons Technology at Dahlgren, Virginia 1918-2006, NSWCDD, 2007.

Rowland, Buford and William B. Boyd, U.S. Navy Bureau of Ordnance in World War II, Bureau of Ordnance, Department of the Navy, 1953.

Stern, Philip M. and Harold P. Green, The Oppenheimer Case: Security on Trial, Harper & Row, 1969.


1. Interestingly, Bramble also has a connection to Dahlgren. He occasionally visited Dahlgren, while teaching at the NPS, to stay current in ordnance developments (starting in 1924). He came to Dahlgren in 1942 when ordnance work was moved out of Washington and stayed until 1946, when he went back to the NPS. He returned to Dahlgren in 1947 and stayed until the end of 1954. He was Dahlgren’s first Director of Research beginning in 1951. He was succeeded by Dr. Russell Lyddane, the first to be called Technical Director.

2. Ten per cent of each batch was sent to Dahlgren for testing.

3. He continued to be listed as a member of King’s staff since it provided “cover” and kept his actual assignment secret.

4. Groves prohibited senior project leaders and scientists from flying. He changed his policy in the spring of 1945.

5. Operation Crossroads was a pair of atomic bomb tests at Bikini Atoll in mid-1946.

Featured Image: The “Baker Day” atomic bomb test, Bikini Atoll, July 25, 1946.

Containing the Bomb: An Assessment of Nuclear Weapons Free Zones

This article is part of a series that will explore the use and legal issues surrounding military zones employed during peace and war to control the entry, exit, and activities of forces operating in these zones. These works build on the previous Maritime Operational Zones Manual published by the predecessor of the Stockton Center for International Law, the International Law Department, of the U.S. Naval War College. A new Maritime Operational Zones Manual is forthcoming.

By LtCol Brent Stricker

Nuclear Weapons Free Zones (NWFZ) are an attempt to prohibit the use or deployment of nuclear weapons within a nation’s territory. None of the signatories to these treaties possess nuclear weapons, where NFWZs stand as a pledge not to develop these weapons. The established nuclear powers of the world have similarly pledged to respect some NFWZs.1 It remains to be seen whether such pledges will be observed or dismissed as a simple “scrap of paper.”2


The legality of the use of nuclear weapons is an unsettled issue. The International Court of Justice issued an advisory opinion stating the threat or use of nuclear weapons must be examined under the United Nations Charter Article 2(4) prohibition on the use of force and Article 51’s right of self-defense.3 The Court could not “conclude definitively whether the threat or use of nuclear weapons would be lawful or unlawful in an extreme circumstance of self-defense in which the very survival of the state was at stake.”4

The Nuclear Non-Proliferation Treaty (NPT) was an early attempt to limit and eventually eliminate nuclear weapons. Article 1 of the NPT prohibits Nuclear Weapons States (NWS) from transferring nuclear weapons to a Non-Nuclear Weapon State (NNWS) or encouraging a NNWS to develop nuclear weapons. Article 6 of the NPT requires states to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.”

Since the signing of NPT, the number of NWS has expanded. Two of the newly acknowledged nuclear powers, India and Pakistan, never signed the treaty. North Korea signed and subsequently withdrew. Finally, Israel, a suspected and unacknowledged nuclear power, never signed the treaty.5

The concept of NWFZ predates the NPT with a proposal for a Central European NWFZ by the Soviet Union to the General Assembly in 1956.6 In 1958, Poland proposed the Rapaki Plan, “banning the manufacture, possession, stationing, and stockpiling of nuclear weapons and equipment, the proposal called for the prohibition of nuclear attacks against state members in the zone.” The proposal would have included Poland, Czechoslovakia, and East and West Germany. Such a proposal would have prevented NATO’s use of nuclear weapons and played to the Warsaw Pact’s advantage due to its overwhelming conventional forces arrayed against NATO, causing this proposal to fail.7

A NWFZ is either implemented unilaterally, through a state’s domestic law, or bilaterally through regional agreements to prohibit the possession, use, testing, and/or transit of nuclear weapons within a designated territory.8 A vital part of the viability of NWFZ is buy-in from the NWS. Typically, the NWS will sign negative security assurances to the NWFZ states pledging to respect the NWFZ’s prohibitions.9 The NWS may refuse to issue a negative security assurance due to other concerns. For example, none of the NWS have signed onto the South East Asian proposal due to its impact on freedom of navigation.10 It should be noted that four of the five NWFZs allow the vessels and aircraft of signatory states to transit their territory with nuclear weapons.11

A further potential limitation of NWFZs occurs when a NNWS is in a defensive treaty agreement with an NWS. To illustrate, Australia is a signatory to the South Pacific NWFZ but has stated it will rely on the United States’ nuclear deterrent capability for its defense. Australia also supports the United States by allowing assets to be based in Australia that forms part of the Communications, Command, Control and Intelligence (C3I) network the U.S. would use in a nuclear exchange.12

Current Nuclear Weapons Free Zones

There are currently nine NWFZs in existence. Five of these were created by regional agreements. Three of them were created by international treaty but only occur in unpopulated areas: Outer Space, the Moon, and the seabed. The last NWFZ was created unilaterally by Mongolia. NWFZs cover more than two billion people and 111 countries.13

African NWFZ (ANWFZ)

The Treaty of Pelindaba established the African NWFZ. It was opened for signature on April 11, 1996, and came into effect on July 15, 1990.[14] Article 3 of the treaty renounces nuclear weapons, and the signatories pledge “not to conduct research on, develop, manufacture, stockpile or otherwise acquire, possess or have control over any nuclear explosive device by any means anywhere” and “not to seek or receive any assistance in the research on, development, manufacture, stockpiling or acquisition, or possession of any nuclear explosive device.” Article 4 is a prohibition on stationing nuclear weapons on their territory, but it allows individual nations the ability to allow foreign aircraft and ships to visit or exercise innocent passage without reference to whether such aircraft and ships may be armed with nuclear weapons. This thereby creates a loophole allowing nuclear weapons within the NWFZ. The treaty also makes no mention of control or assistance to an NWS in a defensive agreement.

A map of participating and non-participating nations in the ANWFZ. Green: Signed and Ratified. Yellow: Signed not Ratified. Grey: Not signatories. (Graphic via Wikimedia Commons)

There are three protocols to the treaty for other nations to sign. Protocol I calls for the 5 acknowledged NWS to pledge not to use or threaten to use nuclear weapons against signatories or on territory within the African NWFZ. Protocol II is a nuclear weapons test ban. Protocol III is open for Spain and France to sign onto, pledging to the Treaty on behalf of their dependent territories within the African NWFZ. The five acknowledged NWS have signed Protocols I and II.

The United States made a cautionary reservation when signing onto the Protocols by “reserve[ing] the right to respond with all options implying possible use of nuclear weapons, to a chemical or biological weapons attack by a member of the zone.”15 These Weapons of Mass Destruction (WMD) Reservations mean the United States may still use nuclear weapons in the African NWFZ.

South Pacific NWFZ (SPNFZ)

The Treaty of Rarotonga established the South Pacific Nuclear Free Zone. It was signed on August 6, 1985, and came into effect on December 11, 1985. All five acknowledged NWS have signed onto its Protocols. Annex 1 to the treaty describes the South Pacific Nuclear Free Zone, which includes both territorial land, waters, and the high seas. Article 3 of the treaty pledges signatories “not to manufacture or otherwise acquire, possess or have control over any nuclear explosive device by any means anywhere inside or outside the South Pacific Nuclear Free Zone” and “not to seek or receive any assistance in the manufacture or acquisition of any nuclear explosive device.” Article 5 prohibits stationing nuclear weapons on the territory of signatory states. Article 5 also includes a loophole allowing signatory states to allow visits and transit by foreign aircraft and ships that may be armed with nuclear weapons. Article 7 includes a prohibition on dumping radioactive matter within the SPNFZ.”16

A second loophole appears in Article 3(c) of the treaty. There is no prohibition on the research of nuclear weapons. This leaves signatories the option to research nuclear weapons. The most likely being Australia if it needs to rapidly develop such weapons for nuclear deterrence.17

A map of the participating nations of the SPNFZ. (Graphic via Wikimedia Commons)

Australia poses a unique challenge to the SPNFZ due to its defensive alliance with the United States. The Australia, New Zealand, and the United States Security Treaty (ANZUS) was signed in 1951, joining the three nations in a collective security arrangement.18 New Zealand banned nuclear-powered vessels in 1984 and later created its own nuclear-free zone with the passage of the New Zealand Nuclear Free Zone, Disarmament, and Arms Control Act 1987. In response, the Reagan Administration suspended New Zealand’s obligations under the ANZUS Treaty.19 Australia remains a party.

Australia has publicly stated in its 2017 Foreign Policy White Paper it would rely on the deterrence power of the United States’ nuclear weapons.20 Australia also hosts US military installations that are vital to worldwide command and control.21 Undoubtedly, these facilities would be part of the Communication, Command, Control, and Intelligence (C3I) the United States would rely on during a nuclear crisis. Australia is in a dilemma then of being a party to the SPNFZ and an ally of an NWS poised to potentially assist in a nuclear attack. The treaty does not address this issue of C3I by a signatory state, with Article 3(c) only prohibiting the manufacture or acquisition of nuclear weapons.22 Australia’s decision to cancel an order of French diesel-electric submarines and order nuclear-powered submarines from the United States does not violate SPNFZ. These submarines will only be nuclear-powered, and will not house nuclear weapons.

Southeast Asian NWFZ (SEANWFZ)

The Bangkok Treaty established the Southeast Asian Nuclear Weapon Free Zone. The treaty was signed on December 15, 1995, and went into effect on March 28, 1997. The ten members of the Association of South East Asian Nations (ASEAN) agreed not to “develop, manufacture or otherwise acquire, possess or have control over nuclear weapons; station or transport nuclear weapons by any means; test or use nuclear weapons.”23 The Treaty also prohibited control, stationing, or testing of nuclear weapons in the SEANWFZ.24 The Bangkok Treaty thus closed the visit, transit, research, and control loopholes for vessels and aircraft with nuclear weapons. Finally, the Bangkok Treaty prohibited dumping or discharging into the atmosphere of radioactive material or waste.25 

A map of the participating nations of the SEANWFZ. (Graphic via Wikimedia Commons)

The SEANWFZ is striking due to the size of the zone defined in the treaty. The zone is expanded to include the continental shelf and exclusive economic zones of the signatory nations.26 The Zone embraces an area of strategic importance to maritime shipping. The treaty would prevent the 5 NWS from transporting nuclear weapons through this zone. This is likely why no NWS has signed onto the treaty’s protocols and provides a negative security assurance to the ASEAN signatories.27 

Central Asian NWFZ (CANWFZ)

The Central Asian Nuclear Weapons Free Zone was created by the Treaty of Semipalatinsk. The treaty was signed on September 8, 2006, and went into effect on Mar 21, 2009. The CANWFZ is defined as the land, internal waters, and airspace of the signatories.28 Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan, all former Soviet Republics, agreed to prohibit research, development, manufacture, stockpiling, acquisition, possession, or control over any nuclear weapon. The treaty also prohibited the location of such weapons in the zone. The treaty closed the control loophole for aircraft and vessels harboring nuclear weapons while transiting through the zone. Article 4 of the treaty allows the individual states to determine how to handle passage and transit by foreign ships, aircraft, and ground transportation, thus leaving loopholes open. The five acknowledged NWS have signed onto the Protocols of the treaty.

A map of the participating nations of the CANWFZ. (Graphic via Wikimedia Commons)

Kazakhstan, Kyrgyzstan, and Tajikistan have a similar problem to Australia noted above. They are members of the 1992 Tashkent Collective Security Treaty, which includes the Russian Federation, one of the five acknowledged NWS. Article 4 of the treaty requires the Member States to provide all assistance, including military assistance, if one member is attacked.29 It remains to be seen how this will affect the CANWFZ.

Mongolian NWFZ

The Mongolian Nuclear Weapons Free Zone is unique as a unilateral action by domestic law similar to the New Zealand Nuclear Free Zone noted above. Mongolia made this declaration in 1992 and called for a regional NWFZ.30 This seemed improbable as Mongolia is surrounded by the Russian and Chinese NWS. The Mongolian NWFZ was recognized with UN General Assembly Resolution 53/77 D.31

Mongolia’s history makes its NWFZ unique, considering it was caught between the two struggling NWS for most of its existence. Emerging as an independent nation within the Soviet sphere of influence after centuries of involvement with Imperial China, Mongolia continued as part of the struggle between the Sino-Soviet split.32 Russia and China signed negative security assurances with Mongolia in 1993 and 1994, respectively. The other acknowledged NWS has agreed to respect Mongolia’s NWFZ.33

Latin American and the Caribbean NWFZ

The Treaty of Tlatelolco created the Latin American NWFZ. It was signed on February 1967 and went into effect on April 25, 1969. Article 1 of the treaty prohibits “the testing, use, manufacture, production or acquisition, by any means, of any nuclear weapon [signatory states] by order of third parties or in any other way,” and “the receipt, storage, installation, location or any form of possession of any nuclear weapon, directly or indirectly, by [signatory states], by mandate to third parties or in any other way.” The NWFZ is defined in Article 4 of the treaty in a manner similar to the 1939 Panama Declaration expanding the zone into international waters.34 Article 18 makes one exception for the peaceful use of nuclear explosions. All five acknowledged NWS have signed Additional Protocol II of the treaty respecting the NWFZ with the United States stating a reservation on the right to transit of nuclear weapons through the zone.35

A map of the participating nations of the Treaty of Tlatelolco. (Graphic via Wikimedia Commons)

The Latin American and Caribbean NWFZ has a similar problem shared by Australia and the CANWFZ due to the mutual defense obligations imposed by the Inter-American Treaty of Reciprocal Assistance. This treaty was signed in 1947 by all of the states in North and South America, including the nuclear-armed United States. While it may be in decline with the withdrawal of member states and attempts to replace this treaty with sub-regional treaties, it remains valid international law.

Antarctica, the Moon, and Seabed NWFZ

It is interesting to note that the first NWFZs were created in places that humans normally do not inhabit: Antarctica, Outer Space, and the deep seabed. Article V of the Antarctic Treaty prohibits nuclear explosions or the dumping of radioactive material on the continent. Article IV of the Outer Space Treaty prohibits the stationing of nuclear weapons or weapons of mass destruction in space or on celestial bodies. This prohibition also prohibits the militarization of celestial bodies. The Outer Space Treaty does not address military activities in orbit, though. Article I of the Seabed Arms Control Treaty prohibits the emplacement of nuclear weapons and other weapons of mass destruction including structures to test, launch, or store such devices on the deep seabed.

It has been speculated that support for these NWFZs by the five acknowledged NWS was to limit the area to deploy nuclear weapons and the increased pressure on the arms race this would impose.36 The strategic value of making Antarctica off-limits for nuclear weapons seems to belie this argument since all NWS, acknowledged or not, are located in the Northern Hemisphere. The future possibilities for weaponizing outer space may render the Space NWFZ irrelevant.

2017 United Nations Nuclear Prohibition Treaty

The Treaty on the Prohibition of Nuclear Weapons could create the largest NWFZ in the world. It was proposed on 23 December 2016 with UN General Assembly Resolution 71/258. It was open for signature on September 20, 2017, and in effect on January 22, 2021.37 The NWS acknowledged and unacknowledged, do not support the treaty.38

Under Article 1 of the treaty: “Each State Party undertakes never under any circumstances to:

(a) Develop, test, produce, manufacture, otherwise acquire, possess or stockpile nuclear weapons or other nuclear explosive devices;

(b) Transfer to any recipient whatsoever nuclear weapons or other nuclear explosive devices or control over such weapons or explosive devices directly or indirectly;

(c) Receive the transfer of or control over nuclear weapons or other nuclear explosive devices directly or indirectly;

(d) Use or threaten to use nuclear weapons or other nuclear explosive devices;

(e) Assist, encourage or induce, in any way, anyone to engage in any activity prohibited to a State Party under this Treaty;

(f) Seek or receive any assistance, in any way, from anyone to engage in any activity prohibited to a State Party under this Treaty;

(g) Allow any stationing, installation, or deployment of any nuclear weapons or other nuclear explosive devices in its territory or at any place under its jurisdiction or control.”

A stated reason for the treaty is the failure of the promises under NPT for the acknowledged NWS to eliminate nuclear weapons. Regional NWFZs, as discussed in this chapter, have increased the area on Earth for nuclear weapons, but as noted above, these are all reliant on Negative Security Assurances by NWS.39 As noted above, many NWS refuse to provide such assurances when transit rights are impacted. It is also unclear how useful a NWFZ agreement will be when one of its signatories is involved in a collective defense agreement with a NWS if an armed conflict occurs. It seems unlikely that the Treaty on the Prohibition of Nuclear Weapons will be supported by the NWS anytime soon.40

LtCol Brent Stricker, U.S. Marine Corps serves as the Director for Expeditionary Operations and as a military professor of international law at the Stockton Center for International Law at the U.S. Naval War College. The views presented are those of the author and do not necessarily reflect the policy or position of the U.S. Marine Corps, the U.S. Navy, the Naval War College, or the Department of Defense.


[1] See the Southeast Asian NWFZ where no NWS has granted a negative security assurance due to its prohibition on transit of nuclear weapons through the zone.

[2] “Scrap of paper” was allegedly the phrase used by German Chancellor Theobald von Bethmann Hollweg, on 4 August 1914 to justify ignoring the 1839 Treaty of London guaranteeing the neutrality of Belgium. Germany was caught in a two-front war for national survival, and its war plans called for sending military forces in and across Belgium. T. G. Otte (2007) A “German Paperchase”: The “Scrap of Paper” Controversy and the Problem of Myth and Memory in International History, Diplomacy and Statecraft, 18:1, 53-87, 55.

[3] Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion of July 8, 1996) ICJ, 35 ILM 809 & 1343 (1996), Para. 105(2)(C).

[4] Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion of July 8, 1996) ICJ, 35 ILM 809 & 1343 (1996), Para. 105(2)(E).

[5] Paul J. Magnarella, “Attempts to Reduce and Eliminate Nuclear Weapons through the Nuclear Non-Proliferation Treaty and the Creation of Nuclear-Weapon-Free Zones” PEACE & CHANGE, Vol. 33, No. 4, October 2008 507-521, 510.

[6] Gawdat Bahgat, A Nuclear Weapons Free Zone in the Middle East – A Pipe Dream?, The Journal of Social, Political and Economic Studies Volume 36, Number 3, Fall 2011 360-383, 364.

[7] Bahgat at 364.

[8] Magnarella at 511; Bahgat at 362.

[9] Bahgat at 363.

[10] Bahgat at 363.

[11] Elizabeth Mendenhall, “Nuclear-Weapon-Free Zones and Contemporary Arms Control” STRATEGIC STUDIES QUARTERLY WINTER 2020 122-151, 131.

[12] Michael Hamel-Green (2018) The implications of the 2017 UN Nuclear Prohibition Treaty for existing and proposed nuclear-weapon-free zones, Global Change, Peace & Security, 30:2, 209-232, 221.

[13] Bahgat at 365.

[14] Bahgat at 365-66.

[15] Bahgat at 363.

[16] Hamel- Green at 218.

[17] Hamel-Green at 222.

[18] ANZUS Treaty, Article V; Richard Baker, “ANZUS On Two Legs?” Far Eastern economic review, 1989-05-25, Vol.144 (21), p.30.

[19] Richard Baker, “ANZUS On Two Legs?” Far Eastern economic review, 1989-05-25, Vol.144 (21), p.30.

[20] Hamel-Green at 218.

[21] Hamel-Green at 219.

[22] Hamel-Green at 221.

[23] Bangkok Treaty Article 3.

[24] Bangkok Treaty Article 3.

[25] Bangkok Treaty, Article 3.

[26] Bangkok Treaty Article 2.

[27] Marangella at 515; Hamel-Green at 212.

[28] Treaty of Semipalatinsk Article 2.

[29] Collective Security Treaty Organization

[30] Marangella at 512.

[31] UN General Assembly Resolution 53/77 D (1998)

[32] Enkhsaikhan Jargalsaikhan (2005) MONGOLIA, The Nonproliferation Review, 12:1, 153-162, 156.

[33] Jargalsaikhan at 156.

[34] Article 4, Treaty of Tlateloco.

[35] Hamel-Green at 217.

[36] Mendenhal at 124-25.; See Doore at 7-8 for a discussion of the proposed demilitarization of the deep seabed and draft treaties submitted to the Eighteen Nation Disarmament Conference in 1969 by the Soviet Union and the United States with the Soviets advocating for denuclearization and the U.S. advocating for banning weapons of mass destruction. Article 1 of the Seabed Treaty is a combination of both positions.

[37] As of this writing, 56 member nations have signed the treaty.

[38] Hamel-Green at 209-10.

[39] Hamel-Green at 210-12.

[40] “‘We do not intend to sign, ratify or ever become party to it. Therefore, there will be no change in the legal obligations on our countries with respect to nuclear weapons.” United States Mission to the United Nations, Joint Press Statement from the Permanent Representatives to the United Nations of the United States, United Kingdom, and France Following the Adoption of a Treaty Banning Nuclear Weapons, New York City, July 7, 2017 Hamel-Green at 214 (

Featured Image: The “Baker” explosion, part of Operation Crossroads, a nuclear weapon test by the United States military at Bikini Atoll, Micronesia, on 25 July 1946. (Photo via Wikimedia Commons)