Ikuo Kondo

A four-pellet pneumatic injection system in the JT-60

Abstract A four-pellet pneumatic injection system has been developed for plasma fueling of the JT-60. The JT-60 pellet injector is capable of accelerating separately four cylindrical pellets 3.0 mm in diameter × 3.0 mm long for two pellets and 4.0 mm in diameter × 4.0 mm long for the remaining two. The JT-60 pellet injector was installed on the JT-60 tokamak machine at the end of 1988. Obtained pellet velocity was higher than 2300 m/s by propellant gases of up to 100 bar and the pellet fueling efficiency achieved was around 70% for both dimensions of pellets. This paper describes the design, injection operation and performance test results of the JT-60 pellet injector.

Experimental evaluation of fission spectrum averaged cross sections of 93Nb(n, n′)93mNb and 199Hg(n, n′)199mHg reactions

Abstract The fission spectrum averaged cross section of the 93 Nb(n, n′) 93m Nb reaction has been performed to obtain (125 ± 28) mb. The value is about 15% larger than that calculated from the Hegedus cross section data. For the 199 Hg(n, n′) 199m Hg reaction, (252 ± 20) mb has been obtained.

SYSTEM DESIGN OF ZENKEI, THE CENTRAL CONTROL SYSTEM OF JT-60

ZENKEI, the central control system of JT-60 is in the final design stage. Since the last report we have been extending the system to make it possible to control the plasma parameters such as density and temperature. This paper gives a brief description of the most recent design, especially those of the modification of the discharge control system. An additional computer and dual port memory with D-port were adopted. For event-oriented control of plasma discharges, the timing system was improved.

SAFETY DESIGN OF THE JT-60 CONTROL SYSTEM

The control system of JT-60 consists of several computer-CAMAC combinations, timing systems and hard-wired interlock systems. The functions of the control system are roughly represented by discharge control including real-time feedback control, plant operation support and safety interlock.

DESIGNING & DEVELOPMENT OF THE REAL-TIME CONTROL SYSTEM FOR JT-60 PLASMA DISCHARGE

Real-time plasma control is planned to be executed in JT-60 experiments. The object of which is to obtain the Q=l plasma, protecting the JT-60 machine from the electromagnetic force, heat load, etc. In this report we present the design of this control system.