Leslie Shepherd (physicist)
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Leslie Shepherd | |
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| Born | 23 November 1918 Pontycymmer, Wales |
| Died | 18 February 2012 (aged 93) |
| Alma mater | |
| Known for | Dragon reactor |
| Scientific career | |
| Institutions |
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| Thesis | Magnetic Spectrometer Studies on Radioactive Isotopes (1948) |
Leslie Robert Shepherd (23 November 1918 – 18 February 2012) was a Welsh nuclear physicist. He was involved in the design and operation of the experimental Dragon reactor, which used helium as a coolant. He was also an advocate of space exploration, serving as the president of the British Interplanetary Society and the International Astronautical Federation.
Leslie Robert Shepherd was born on 23 November 1918, in Pontycymmer, Wales, where his father, William Shepherd, was a station master. Although his family moved to London when he was a teenager, he retained a Welsh accent. When he was six years old he suffered an infection that left him deaf in his left ear. He entered University College, London, where he studied physics. On the outbreak of the Second World War he drafted into the British Army, serving in the Royal Corps of Signals, but was allowed to return to University College to complete his degree.[1] He graduated in 1940 with a BSc with first-class honours.[2]
During the war he worked at the Mond Laboratory at the University of Cambridge, where he was engaged in testing electronic fuses for naval guns. After the war ended Sir Arthur Vick persuaded him to remain at Cambridge and pursue postgraduate studies at St Catharine's College, Cambridge. He married Elsie Lodge in 1947; they had one son. He completed his PhD in 1948, writing his thesis on "Magnetic Spectrometer Studies on Radioactive Isotopes".[1][2]
Nuclear reactors
In 1948, Shepherd joined the Atomic Energy Research Establishment at Harwell, Oxfordshire. In 1956, he was deputy head of the group that developed the Dragon reactor, an experimental high temperature gas-cooled reactor that investigated the use of helium as a coolant. Construction commenced in 1959 at Winfrith in Dorset, and the reactor became operational in 1965.[1] In addition to the use of helium, Dragon incorporated many groundbreaking technologies. Efficiency was improved by omitting the metal cladding on the fuel elements, with the idea that gaseous fission products could be removed with filters. It was found that most were retained within the fuel elements, resulting in the development of a new coating for fuel pellets. It also investigated the thorium fuel cycle, which held great promise.[3]
Shepherd became the chief executive of the project three years later, and remained in the job until the project was cancelled in 1975. This came as a grave disappointment to Shepherd, who was convinced of the safety, efficiency and commercial viability of the helium-cooled reactor design. After a sabbatical in the United States, Shepherd returned to Winfrith in 1978, and remained there until he retired in 1983.[1]
