Japan's operating rate for commercial reactors sank to a record low of 23.7 percent in fiscal 2011, the Japan Atomic Industrial Forum said in a recent report.

The operating rate, which is also known as the capacity utilization ratio, is defined as the amount of power actually produced divided by the total power capable of being generated by all of the nation's reactors.

The fiscal 2011 rate is the lowest since comparable data became available in fiscal 1971. In fiscal 2010 it was 67.3 percent.