A Piece of the Sun by Daniel Clery

Author:Daniel Clery [CLERY, DANIEL]
Language: eng
Format: epub
Tags: SCI000000; SCI026000; SCI013000; SCI013060; SCI024000; SCI055000; SCI051000
ISBN: 9781468310412
Publisher: The Overlook Press
Published: 2014-07-29T00:00:00+00:00

The interior of JET, showing limiters on the central column, radio antennas on the outside wall and a divertor at the bottom.

(Courtesy of EFDA JET)

There was much to be done to get the reactor ready for D-T operation. The shielding had to be checked, the tritium handling tested, two of JET’s sixteen neutral beam sources had to be set up to fire tritium instead of deuterium, and the researchers had to work out what was the best kind of pulse to get the plasma to burn. They settled on a plasma current of 3 MA, a toroidal magnetic field of 2.8 tesla and 14 MW of neutral beam heating – experiments with deuterium showed that as soon as the heating beams kicked in this plasma swiftly went into H-mode and the number of neutrons produced from D-D fusions continued to grow. It was a time of high excitement: many of those who worked on JET had spent their entire working lives trying to make a plasma that would burn; now they were going to see if it was all worthwhile. Media organisations got a whiff that something was going on and asked if they could be present at the first burning plasma. Rebut thought about it and decided that the public had paid for it and so the public had a right to know what was going on. It was a potentially risky strategy, however, because it could fail to work. Fusion researchers had been burned before with ZETA and didn’t want the same thing to happen again.

On the appointed day, 9th November, 1991, hundreds of people crowded into the JET control room – researchers, officials, journalists. Getting the machine ready wasn’t a quick process. First the researchers did some shots with just deuterium to check they were still getting the plasma performance they wanted. Then they carried out some shots containing a trace of tritium, less than 1%, to test the diagnostics. Then the moment of truth arrived. The crowds in the control room craned to see screens that showed an image of what was going on inside the vessel. As the shot started they could see the diaphanous plasma form inside the vessel and when controllers switched on the neutral beams, including those firing tritium, the screens whited-out as neutrons flooded the camera. The control room erupted into applause. They had achieved the first controlled release of significant amounts of fusion energy.

The power had peaked for only around two seconds and reached a maximum value of 1.7 MW which amounts to Q=0.15, although this would have been Q=0.5 if a 50:50 D-T mixture had been used. JET was lauded in headlines and news bulletins around the world. Although the Culham researchers only performed two D-T shots, they had entered the era of burning plasma and they had done it before Princeton. But it would be a while before they would be able to do it again because JET was soon shut down to fit a divertor and the spotlight moved across the Atlantic.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.