Spreading radiation and suspected new leaks are plaguing the ongoing disaster site of the Fukushima nuclear power plant on Monday, while the head of Japan's nuclear regulatory body warned that there may be no other option than to dump radioactive waste water into the Pacific.

The new warnings come after a weekend in which plant operator TEPCO revealed that the radiation levels around the plant were 18 times higher than it previously reported, and that it had patched a leaking pipe with plastic tape.

In July, TEPCO admitted that contaminated groundwater was leaking into the ocean, up to 300 tonnes a day, and may have been doing so ever since the disaster began in March 2011. Apart from that leaking water, as Reuters reports,

Tepco has been pumping water into the reactors to keep the damaged cores and stored fuel from overheating. But that emergency step has created a secondary crisis of how to manage the contaminated water that is pumped back out.

"I'm afraid that it is unavoidable to dump or release the water into the sea," Shunichi Tanaka, head of Japan's Nuclear Regulation Authority, said on Monday.

"If we decide to discharge water into the ocean, we will use various methods to ensure that radiation is below accepted levels," Tanaka told reporters in Tokyo. "We will have to dispose of it eventually, but we are committed to reducing or removing radioactive materials.

Also on Monday, the Japan Times reported on further evidence that the storage tanks used to hold contaminated water are prone to leaks. 

An unnamed worker who built storage tanks in the H4 area two years ago warned late last month that the storage tanks were hastily built. “We were told to put priority on making the tanks, rather than quality control. There were fears that toxic water may leak.”

Though the worker said that they didn't "cut any corners constructing the tanks," he warned, “All of the tanks are makeshift. So more toxic water may leak as they deteriorate.”