Tokyo, Japan (CNN) -- Two of the damaged reactors at the crippled Fukushima Daiichi nuclear power plant in Japan may be riddled with holes, according to the facility's owner.
The holes may be as big as 7 to 10 centimeters ( 2.8- 3.9 inches), Tokyo Electric Power Co. said in a 225-page document submitted to Japan's Nuclear and Industrial Safety Agency.
In the report, Tokyo Electric says the containment vessel of reactor No. 1 may have developed a hole as big as 3 centimeters in diameter 18 hours after the quake.
Fifty hours after the quake, the hole may have widened to 7 centimeters, the report said.
In reactor No. 2, the containment vessel may have developed a hole as wide as 10 centimeters 21 hours after the quake.
The nuclear plant has suffered cooling problems and radiation leaks since a March 11 earthquake and tsunami.
The hydrogen explosion four days after the crisis began may have led to the formation of a second hole in reactor No. 2, as wide as 10 centimeters in diameter.
"This report is not conclusive. No one has entered these areas and we cannot confirm this as fact," TEPCO said, adding that the report is making preliminary assumptions about what happened inside the reactors.
A hole in the reactor's containment vessel means there is a high probability of the leakage of radioactive material into the reactor building.
The amount of radioactive material in all three of the reactor buildings has hampered TEPCO's ability to build an effective cooling system. TEPCO says a cooling system is a critical step to leading to a cold shutdown, still estimated to be five to eight months away.
Nuclear experts and scientists have long suspected this sort of damage to the containers of the reactors at the crippled plant, as well as a full meltdown of the fuel rods in reactors 1, 2 and 3.