“The government would like to show it is doing whatever it can do,” said Masahiro Horie, the dean of international affairs at Japan’s National Graduate Institute for Policy Studies, who worked for 35 years in the government. “It’s natural that they try to keep people calm, do everything possible and not give any information that might cause a panic.”

The Japanese are not alone, of course, in having to improvise on the run. Last summer, Americans could only watch as BP and a host of oil industry experts tried — and repeatedly failed — to get control of a gushing well on the floor of the Gulf of Mexico. BP officials initially thought they could seal the well in a way that would let them save it. When that proved impossible, they resorted to more drastic steps, including pumping in cement to seal the well — nearly five months after the rig explosion that created the spill.

A solution to the Fukushima catastrophe remains elusive. After failing on their own, Tepco officials have been forced to seek help outside the company. Having the police, firefighters and the Self-Defense Force join the effort has reassured some people, but others consider those moves as signs that the emergency is spiraling out of control.

On Friday, the Japanese nuclear safety agency raised its assessment of the problem’s severity — ranked on a 7-level international scale — to 5 from 4. Level 4 denotes incidents with local consequences; Level 5 indicates broader consequences. For comparison, the partial meltdown of the reactor at Three Mile Island near Harrisburg, Pa., in 1979 was rated a 5.

“Some people might think the arrival of the Self-Defense Forces and helicopters mean that strong measures are being applied, but I think it’s the opposite,” said Tadae Takubo, who taught international politics and national security at Kyorin University in Tokyo. “They seem like desperate measures to me. It’s all too late.”

Some of the Tepco workers, police officers and others who have fought to cool the reactors may have been exposed to high levels of radiation. In a nation that values selflessness and determination, it is not surprising that they have been praised in Japanese news reports as heroes for their willingness to sacrifice their health for the sake of the nation.

Though their efforts have yet to succeed, the fact that someone is doing something — anything — is reassuring to some.

“I don’t know — I’m a little skeptical about dropping water out of a helicopter,” said Akiko Sato, 28, an office worker who was shopping in Tokyo’s Ginza district. “But I like to think what they’re doing with the water cannons might be useful. I think they’re really trying.”