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Nidec ASI SpA (former Ansaldo Si- Experimental Reactor, and the Development of Fu-
stemi Industriali SpA), with legal he- sion Energy). The QPCs will be then transferred to
adquarters in Milan and six facilities their final destination in Japan, in the frame of a
in Italy and over 150 years of combi- “Procurement Arrangement” between F4E and the
ned experience in the energy, metal, Japan Atomic Energy Agency (JAEA). In 2010, the
environmental, marine and industrial contract for the QPC procurement (including de-
sign, manufacturing, testing, transportation, instal-
markets, has the experience to deliver process- lation, commissioning and final test) was entrusted
by Consorzio RFX to Nidec ASI. .
oriented power quality and control solutions, from Nidec ASI endorsed the QPC reference scheme
indicated in the Technical Specifications, previously
components to engineering and is a global supplier studied and tested by Consorzio RFX; it was based
on a Hybrid Circuit Breaker (HCB) composed of a
of power electronics equipment and systems, as mechanical ByPass Switch (BPS), in parallel to a
Static Circuit Breaker (SCB) for current interruption.
well as of electric motors and generators, and sy- Nidec ASI developed the detailed executive design.
It was the first time such advanced hybrid circuit
stem automation. breaker technology was used in industrial applica-
tion for so high current and voltage ratings. there-
Nidec ASI has always played an important role in fore a full scale prototype both of the PFC and the
TFC QPC was developed in the frame of the con-
the field of Research and can count on an impres- tract, to perform a wide range of type tests to check
the design choices, to characterize the operation
sive number of collaborations both in international and to verify the performance, before starting with
the production of the final equipment. Type tests on
and national projects. Nidec ASI is the technologi- the individual components were carried out at the
manufacturer premises, while the test campaigns
cal partner of many important research institutes at full power on the whole TFC and PFC QPC pro-
totypes were performed at Consorzio RFX.
to develop special power electronics equipment The manufacturing and testing of the 13 QPC units
started in 2012 just after the completion of type
for nuclear fusion experiments, plasma and wind tests and, after the delivery in Japan, their instal-
lation started in December 2014, representing the
tunnels, laboratories, and test facilities. In a context first occasion of activities directly performed by Eu-
ropean personnel at Naka Site for JT-60SA: a spe-
where technology and customization are needed, cial VISA dedicated to Broader Approach Activities
was issued by Japanese government for the Eu-
high expertise and solution-oriented approach are ropean personnel involved in the QPC installation.
After the completion of commissioning activities
the keys to satisfy such demanding applications. in February 2015, the final acceptance tests were
successfully performed in June 2015, allowing the
In the field of “environmentally clean” nuclear rese- closure of the QPC procurement activities on 31
July 2015, according to the original schedule.
arch, Nidec ASI brings as a reference a thirty-years
The Quench Protection Circuit
presence in projects like RFX, JET and similar,
The quench protection circuit has an important
always acting as a primary role supplier. Particu- safety function in the JT-60SA machine: super-
conducting coils are needed to confine the fusion
larly, Nidec ASI partnership in the RFX project da- plasma, but if, for whatever reason, the coils stop
being superconducting, it is necessary to immedia-
tes back in the 80’s, when the project started, and tely discharge them to avoid damage from overhe-
ating.
continued in the new Millennium (2000) with the This protective function is performed in JT-60SA by
the 13 QPC units that, when operated, allow ra-
supply of the new power supply systems for po- pidly dissipating the huge magnetic energy stored
in the coils (> 2.3 GJ in total) into a set of discharge
loidal and toroidal circuits of the RFX experiment. resistors. The quench protection system interrupts
dc currents of more than 25 kA withstanding reap-
In the last few years, the design and construction of plied voltages of about 4.2 kV. Large design margin
was taken to improve reliability.
a new plasma experimental device (Satellite Toka-
mak) named JT-60SA has been launched in Naka,
Satellite Tokamak Japan in the framework of the Broader Approach
JT-60SA agreement between Europe and Japan. JT-60SA
is a tokamak with superconducting Toroidal Field
Coils (TFC) and Poloidal Field Coils (PFC) capable
of confining high tempera-
In the last few years, a new plasma ture plasmas (current up
to 5.5 MA) for 100 s with
experimental device (Satellite Tokamak) heating and current drive
named JT-60SA has been installed power up to 41 MW. The
in Naka, Japan in the framework of majority of the new power
the Broader Approach agreement supplies are provided by
between Europe and Japan. JT-60SA Europe: among them,
the “Quench Protection
is a tokamak with superconducting Circuits” (QPC), aimed at
Toroidal Field (TF) and Poloidal Field protecting the supercon-
(PF) magnets capable of confining high ducting magnets in case
temperature plasmas (current up to 5.5 of loss of their supercon-
MA) for 100 s with heating and current ductive status (quench),
drive power up to 41 MW by quickly dissipating the
stored energy.
The QPC are procured by
Consorzio RFX, acting on
behalf of the Italian Research Council (CNR) in the
frame of an “Agreement of Collaboration” with Fu-
sion for Energy (F4E: the European Union’s Joint
Undertaking for ITER, International Thermonuclear
Impiantistica Italiana - Settembre-Ottobre 2015 57
