Frisch–Peierls memorandum

E8572

The Frisch–Peierls memorandum was a pivotal 1940 document by physicists Otto Frisch and Rudolf Peierls that first outlined the feasibility of a small, practical uranium-based atomic bomb, helping to catalyze British and later Allied nuclear weapons research.


Statements (47)
Predicate Object
instanceOf historical document
nuclear weapons proposal
scientific memorandum
associatedPerson Henry Tizard
James Chadwick
Mark Oliphant
associatedWith University of Birmingham
author Otto Frisch
Rudolf Peierls
catalyzed systematic British research into nuclear weapons
commissionedBy Rudolf Peierls (self-initiated with Otto Frisch)
contrastedWith earlier estimates requiring tons of uranium
countryOfOrigin United Kingdom
dateWritten March 1940
documentFormat written report
era early nuclear age
geopoliticalImpact contributed to Allied decision to pursue atomic weapons
historicalSignificance first detailed technical argument that a small, practical uranium bomb was feasible
key early step in Allied nuclear weapons development
influenced British atomic bomb program
MAUD Committee
Manhattan Project
language English
mainSubject atomic bomb design
nuclear fission
nuclear weapons feasibility
uranium-235
proposedBombMass on the order of kilograms of uranium-235
proposedIsotope uranium-235
proposedWeaponType uranium-based atomic bomb
purpose to assess feasibility of an atomic bomb
to inform the British government about nuclear weapons potential
relatedEvent World War II
relatedField nuclear physics
weapons research
securityStatusAtTime classified
statedProperty a compact fission bomb could produce extremely large explosive yields
a small critical mass of uranium-235 could sustain a fast neutron chain reaction
a uranium-235 bomb could be delivered by aircraft
industrial-scale isotope separation would be required
no known defense would be effective against such a bomb
submittedTo British government scientific authorities
Henry Tizard
typeOfAnalysis assessment of production requirements
estimate of explosive yield
theoretical calculation of critical mass
year 1940


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