Dancing Sparks in ADITYA Tokamak(Nuclear Fusion Reactor)

This blog talks about how we started to notice sparks at different location on the top of machine, which had nothing to do with insulation failures but improper grounding and kept us clueless for long time.

Top View : ADITYA

This blog talks about how we started to notice sparks at different locations on the top of the machine, which had nothing to do with insulation failures but improper grounding and kept us clueless for a long time.

ADITYA Tokamak operations started to move in parameter space after we solved many problems affecting its performance. Please read these blogs to know about them:

All these helped us improve the machine parameters and make it operate at higher parameters. One day we suddenly notices a spark on the top of machine. We stopped the machine and examined in the area, if there were any insulation failure and subsequent burn in the area due to spark. We could not notice any such thing. We tested insulation again and it was all fine.

We started power supply again and after some time we noticed spark again as we moved to higher parameters. These sparks were not at the same location and used to dance around like a “Ghost”! We were clueless as to what was happening.

We put cameras and stood around the machine keeping safe distances. Some went on the top of crane platform with camera to record top view of the machine, where “action” was happening. It did not give any more info. Then we felt that it had nothing to do with insulation but most likely something to do with grounding system.

Grounding system in ADITYA was very complex. Machine was divided in three segments of 120 degree each. Each segment had to be electrically separated.When we started investigating, we found that only two segments were not electrically isolated. Investigating to find out the place where they were getting connected. Over several days, we kept removing various cables and others that were connecting to ground to some way in other. It was very frustrating to say the least. But after painstaking effort of several days, we had located the culprit and solution was trivial!

To connect the various components of machine to structure, a number of spacers along with nut bolts were used. Systematically some of them had a insulating block along with a metal block sandwiched together.Metal block was at the upper position. At one place where segments, that needed to be electrically separated, had the metal block touch across them as the block was put there. Everywhere else it did not matter but at the location, it simply connected the two segments and sorted them electrically. We simply had to reverse the block and electrical separation was achieved.
During assembly process, care should have been taken to keep checking the electrical isolation across segments but somewhere that protocol was not followed and whole assembly was done.

We reconnected everything and put the machine back to operation. Ghost sparks were no more visible!

Following protocol during assembly of such complex system and recording them as well is critical. In India, we tend to ignore such things in trying to rush but it costs a lot more in terms of time and money later on!

Author: Prabhat Ranjan

Prof. Prabhat Ranjan is Vice Chancellor, D Y Patil International University, Akurdi, Pune. He was heading India's Technology Think Tank, TIFAC(tifac.org.in) as its Executive Director since April 2013 to April 2018. Earlier he was Professor at Dhirubhai Ambani Institute for Information and Communication Technology, Gandhinagar (DA-IICT) since 2002. He was educated in Netarhat School(near Ranchi), IIT Kharagpur and Delhi University. He received his Ph D from University of California, Berkeley where he carried our research on “Nuclear Fusion” at Lawrence Berkeley Laboratory during 1983-86. He immediately returned to India after this and carried out research in Nuclear Fusion area at Saha Institute of Nuclear Physics, Calcutta and Institute for Plasma Research(IPR), Gandhinagar. He played a major role in India’s Nuclear Fusion program and was Project Leader of the largest operational Indian Fusion Reactor, ADITYA, at Institute for Plasma Research from 1996-2002. His current interests include applications of Wireless Sensor Network to Wildlife, Planetary Exploration (Chandrayaan mission), Nuclear Fusion, Healthcare, Agriculture etc. He has received National Science Talent Search Award, IBM Faculty Innovation Grant and HP Innovate 2009 award, NPEDP-Mphasis Universal Design Award 2012, Bihar Gaurav Samman 2012 etc.

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