BUCHANAN, N.Y. (AP) -- The Indian Point nuclear power plant's sometimes iffy emergency siren system has gotten good marks in a quarterly test.

Nuclear Regulatory Commission spokesman Neil Sheehan says only two of the 156 sirens malfunctioned during Wednesday's test. He says audio sensors didn't register the sirens, but observers reported hearing them.

The results exceeded the 94 percent average needed under NRC rules.

The sirens are intended to alert residents to any serious problem at Indian Point, on the Hudson River 35 miles north of midtown Manhattan.

The sirens have had various troubles in recent years. They are set to be replaced by a new siren system that also proved problematic in some early tests. Originally due in January 2007, the new system now is supposed to be running by mid-August.