The PXE is located near the premier missile trial centre Integrated Test Range (ITR).
Panic stricken staff ran out to the beach and 13 fire engines were pressed into service; no one was injured. Explosions were heard from a distance and all roads to the facility have been closed.
DRDO spokesperson Dr Ravi Gupta said that the fire is fully contained. An inquiry has been ordered, he said.
Different shells and ammunition of various artillery systems, including the 155 mm Bofors field guns are brought to the PXE for test, the officials said, adding that Pinaka rockets are also test-fired from PXE complex.