Irradiation involves bombarding the ingots with neutrons for precise periods.
One in each billion silicon atoms in each ingot is changed to phosphorous. Therefore, the market for silicon irradiation is not huge, but it is significant financially. NTD occurs after silicon ingots have been lowered into the reactor's graphite reflector facilities, just outside its heavy water tank. Shin Etsu, Mitsubishi Materials Silicon Corporation, Komatsu Electronic Metals, Toshiba Ceramics and, more recently, Sumitomo Sitix Corporation. Feedback from all five client companies has been very positive.