RDS-1 and Beyond

William Park
March 17, 2019

Submitted as coursework for PH241, Stanford University, Winter 2019

Post-World War II

Fig. 1: Mock-up of RDS-1. (Source: Wikimedia Commons)

On August 6 and August 9 of 1945, the world witnessed the horrific grandeur and significance of the nuclear bombings of two Japanese cities: Hiroshima and Nagasaki. The bombs that were dropped on Hiroshima and Nagasaki displayed astonishing level of explosive and destructive forces. However, years following the bomb droppings on Japan, other countries began experimenting with nuclear technology of their own. The Union of Soviet Socialist Republics (USSR, or the Soviet Union) was one group that began testing nuclear technology following World War II.

Detection of Radioactivity and the RDS-1

On September 3 of 1949, a filter paper (exposed for 3 hours at an altitude of 18,000 feet) on a weather plane flying from Japan to Alaska detected radioactivity of 85 counts per minute, which was 35 counts past the official limit or threshold of significance. [1]

To note, "counts per minute" (cpm) is a conventional method of measuring the detection rate of ionizing radiation per minute.

Following the detection from the weather plane, additional analysis of the filter paper by the Air Force's contractor Tracerlab and the Los Alamos Scientific Laboratory showed with a certain degree of certainty that the Soviets succeeded in detonating a plutonium-based nuclear bomb. [1] In fact, on September 23 of 1949, President Harry S. Truman announced that an atomic device was detonated by the USSR. [1]

The detonation itself took place on August 29 of 1949 on the Semipalatinsk Test Site (which was a common testing venue for the Soviet Union's nuclear weapons). The bomb, known as RDS-1 (Fig. 1), was a plutonium bomb that yielded an explosive force of about 22,000 tons of TNT (where 1 ton of TNT is an equivalent of 4.184 × 109 Joules). [2]

Fig. 2: Mock-up of the Tsar Bomba. (Source: Wikimedia Commons)


After World War II, several countries began testing nuclear weapons of their own. Where is the limit? How much explosive force can we generate? On October 30 of 1961, the Tsar Bomba (Fig. 2) was tested which yielded an explosive force of 50 million tons of TNT, the "most powerful nuclear weapon ever detonated in the history of mankind". [3] With this much explosive force from a nuclear weapon, it brings up a question of how far we can actually go in the construction of nuclear bombs and the possible ramifications or consequences that may arise if one of these bombs were put to use in the future. Although there are countless advantages to advancements in technology, there should certainly be a degree of responsibility that follows with the innovations.

© William Park. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] D. L. Northrup and D. H. Rock, "The Detection of Joe 1," CIA Stud. Intell. Ser. 10, 23 (1966).

[2] O. Bukharin and F. V. Hippel, Russian Strategic Nuclear Forces (MIT Press, 2004).

[3] S. Narayanan, "The Tsar Bomba," Physics 241 Stanford University, Winter 2015.