To use only 100G ports, switch PIC 0 (where the 100G ports are) to the desired mode, and turn off PIC 1 (where the 10G ports are).

vitalvas@mx204-city17# show chassis
fpc 0 {
    pic 0 {
        pic-mode 100G;
        tunnel-services;
    }
    pic 1 {
        number-of-ports 0;
        power off;
    }
}
network-services enhanced-ip;