London’s Secret Nuclear Reactor

Jul 30, 2018 0 comments

For more than 30 years, between 1962 and 1996, a nuclear reactor sat at the heart of London tantalizingly close to a busy thoroughfare and to people’s homes and public buildings. Its existence so close to the metropolis was kept a secret from the public, because to tell the truth would have been extremely controversial.

The reactor was located at the basement of King William Building at the old Royal Naval College in Greenwich. The Royal Naval College was established in 1873 and was housed in a 17th century building complex designed by the highly acclaimed English architect of the time, Sir Christopher Wren. The buildings originally housed the Greenwich Hospital—a retirement home for disabled sailors of the Royal Navy. The word “hospital” merely meant a place providing hospitality. After the hospital closed in 1869, these buildings became the Royal Naval College where navy officers were trained.


The Old Royal Naval College in Greenwich, the site of the world’s only reactor ever installed inside a Grade I-listed 17th-century building. Photo credit: Mark Ramsay/Flickr

In the beginning, the Royal Naval College was only a staff college where military officers were trained in the administrative duties of their profession. Later, with the transfer of the Royal Naval War College’s activities from Portsmouth to Greenwich in 1914, the Royal Naval College began to provide technical trainings in tactical and strategic naval warfare as well. As the years rolled by, these trainings became more and more sophisticated.

In the early 1960s, the Royal Naval College acquired a low-power nuclear reactor nicknamed JASON to educate and train military and civilian personnel involved in the naval nuclear submarine propulsion program. The Argonaut series 10 kW research reactor was previously operated by the Hawker Siddley Nuclear Power Corporation at Langley.

Compared to those in nuclear power stations, JASON was a small reactor measuring 12 feet high and was surrounded by more than 300 tons of steel and concrete cladding to prevent stray neutrons from escaping. Despite its small size, Jason was potent. According to the Independent, JASON used weapons-grade uranium 90 per cent enriched, which made it thirty times more radioactive than that used in commercial reactors. It was like a ticking time bomb. Surely, the Navy wasn’t going to tell Londoners they have a nuclear bomb for a neighbor. So JASON was kept a secret.


Control panel for the JASON nuclear reactor. Photo credit: Royal Naval College, Greenwich

“For a long while he was part-myth,” writes The Greenwich Phantom. “The weird thing is that I had heard from someone who worked with it directly (and who had no reason to lie) that it was just a model – that there was never any radioactivity in it, they just told the trainees there was to make them deal with it seriously.”

The funny thing is, Greenwich was declared, and continue to be a “nuclear-free” zone since 1963, a year after the nuclear reactor JASON went critical.

In 1996, the Navy decided to decommission the Naval College and hand the property over to civilian use, which meant that JASON had to go. But getting rid of him completely proved to be no easy task. First they had to disable the reactor itself and remove the operational equipment, which was the easy part and was completed swiftly. The hard part was removing the fuel, and dismantling the reactor and the concrete cladding that had become irradiated by neutrons over the years.

At that time, no nuclear reactor had ever been dismantled in Britain, so everything had to be learned from scratch.

In the end, which took three years, a total of 270 tons of nuclear waste was removed from the area. In November 1999, the Environment Agency finally gave the radiological clearance.

Today, live reactor training is carried out at the Imperial College Consort reactor at Ascot. The Royal Navy also uses simulators to impart education and training of military and civilian personnel in the naval nuclear propulsion program at the Royal Navy’s School of Marine and Air Engineering at HMS Sultan, Gosport, Hampshire.


The magnificent buildings of the Royal Naval College, now a UNESCO World Heritage Site, is a popular attraction in Greenwich. Pictured above is the interior of the Royal Naval College Chapel. Photo credit: Diliff/Wikimedia


One of the architectural highlights of the Old Royal Naval College, the Painted Hall, which was painted between 1707-1726 by Sir James Thornhill. Photo credit: Radek Lát/Flickr


The Painted Hall served as the dining hall for the Royal Naval College. Photo credit: kaysgeog/Flickr


Ceiling of the Painted Hall. Photo credit: Maciek Lulko/Flickr


The Royal Navy College cafeteria located in the basement under the Chapel. Photo credit: Nick Garrod/Flickr

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