“Among the more important problems of modern engineering science the utilization of energy of thermonuclear reactions is a problem of foremost significance. Physicists over the whole world are attracted by this extraordinarily interesting and very difficult task of controlling thermonuclear reactions.”

“In 1952 soon after experiments with pulsed discharges were started it was found that at sufficiently high currents the discharge in deuterium becomes a source of neutrons. (…) At the early stages of investigation it was quite natural to assume that the neutrons resulted from thermonuclear reactions in the plasma heated to a high temperature. This was exactly what was expected from the beginning and the fact that the effect was detected under conditions which completely corresponded to the a priori theoretical predictions seemed to speak in favour of this viewpoint. The behaviour of the neutron radiation (its dependence on pressure and current) observed in the first experiments qualitatively concorded with the assumption that the phenomenon was due to thermonuclear mechanism. However, very soon serious doubt concerning the correctness of this assumption began to appear.”

“On appraising the various approaches to the problem of obtaining intense thermonuclear reactions we do not deem it possible to completely exclude further attempts to attain this goal by using pulsed discharges. However, other possibilities must also be carefully considered. Especially interesting are those in which the idea of stationary processes may be used.”

From the address of I.V. Kurchatov: “On the possibility of producing thermonuclear reactions in a gas discharge” at Harwell on 25th April 1956 (printed as a bi-lingual report (10 MB) in Moscow, 1956.

In 1950s, in the period when thermonuclear fusion only began to be perceived as a potential source of safe energy, the world was divided into two rival social systems. Because of the newly developed nuclear weapons, their military industries worked under extremely secret conditions, and any nuclear research was by default believed to have important military consequences.

In this situation, scientists on both sides slowly realised that in the case of magnetically confined thermonuclear fusion there wasn’t actually any potential for military exploitation. Although this message seemed suspicious to any non-expert politician, scientists pushed it hard, knowing the strength of a free and broad international science collaboration.

In 1956, a Soviet delegation lead by Nikita S. Khrushchev (First Secretary of the Soviet Communist Party),  Nikolai A. Bulganin (Prime Minister of the USSR) and Academician Igor V. Kurchatov (leading Soviet atomic research physicist) visited the United Kingdom in an attempt to appease the cold war. On April 25,  I.V. Kurchatov read a lecture at Harwell. The Harwell site, located just a few miles from our Culham Science Centre, was then the leading research centre of the UK’s Atomic Energy Research Establishment (AERE).

picture of cover Kurchatov report

Front page of the bi-lingual report based on Kurchatov's lecture at Harwell

The lecture of Academician Kurchatov is remembered as a complete surprise with respect to its openness and deep insight into the problems of controlled thermonuclear fusion. Notice that it has even mentioned the extreme challenge of understanding the origin of measured neutrons - the very issue that would seriously hamper the fusion research at Harwell in 1957.

Partly under the influence of the lecture, in early 1957 the UK decided  to declassify thermonuclear research, and so did the USA. The US even organised a major exhibition on their fusion research within the second UN Conference on the Peaceful Uses of Atomic Energy in Geneva in 1958. Since this conference, where fusion research had its first plenary session, there have been no veils of secrecy over our research efforts. This openness enhances our scientific horizons and enforces our trust in the potential benefits of the project.