FAST FREEZING 10 BARREL HYDROGEN PELLET INJECTOR (POROUS SLEEVE)

EXPORTED TO: Japan, NIFS National Institute for Plasma Physics, Toki

The injector is a pneumatic type 10-barrel system for injection of frozen hydrogen or deuterium pellets into plasmas. All the barrels can operate independently. Every barrel has its own helium heat exchanger, fast valve for propellant gas admission and gate valve for pellet production. The pellet formation time is reduced from 3-5 minutes in a routine pipe-gun injector to a few seconds due to a new technique using a porous sleeve. A pre-frozen solid fuel is melted inside the porous unit by means of a heat pulse of a propellant gas moving through the injector barrel and after that the liquid is re-frozen in the barrel. This technique provides a continuous steady-state pellet formation and injection of an unlimited amount of pellets. Cryogenic system is based on a helium flowing cryostat.

Propellant gas

He

Gas pressure

8 MPa

Pellet material

hydrogen, deuterium

Pellet size

2 barrels: Ø 1.5 mm × 1.5 mm (L)

3 barrels: Ø 2 mm × 2 mm (L)

3 barrels: Ø 3 mm × 3 mm (L)

2 barrels: Ø 3.8 mm × 4 mm (L)

Pellet velocity

1.4 km/s

Repetition rate

0.3 Hz from every barrel