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Thursday, August 23 3:02 AM SGT

Japan developing micro nuclear reactor for apartment blocks

PARIS, Aug 22 (AFP) -

Japan is developing a tiny nuclear reactor designed to generate power in the basement of an apartment block, despite widespread public concern over the country's nuclear safety record, New Scientist says.

The 200-kilowatt micro-reactor, Rapid-L, measures just six metres (20 feet) high and two metres (6.5 feet) wide and was initially conceived as a plug-and-play source of power for lunar colonies.

Although colonisation schemes have long been shelved, scientists at Japan's Central Research Institute of Electrical Power Industry (CRIEPI) have revived plans for the Rapid-L, believing it could be a handy source of power for an office building or apartment block, the report says.

It would be located in the building's basement, surrounded by a solid containment structure for safety reasons. "In the future it will be quite difficult to construct further large nuclear power plants because of site restrictions," Mitsuru Kambe, head of the research team, told the British science weekly.

"To relieve peak loads in the near future, I believe small, modular reactors located in urban areas such as Tokyo Bay will be effective," he said. Kambe added, however: "The success of such a reactor depends on the acceptance of the public, the electricity utilities and the government."

In the past few months, Kambe's team have been testing a fail-safe mechanism to close the reactor down in the event of overheating, the report says in next Saturday's issue of New Scientist. The work is being financed by the Japan's Atomic Energy Research Institute.

Unlike conventional reactors, the Rapid-L would have no control rods to regulate the nuclear reaction, the goal being to remove a mechanical source of potential malfunction. Instead, it would use reservoirs of molten lithium-6, an isotope that is effective at absorbing neutrons. The reservoirs areconnected to a vertical tube that runs through the reactor core.

During normal operation the tube contains an inert gas. But as the temperature of the reactor rises, the liquid lithium expands, compressing the inert gas and entering the core to absorb neutrons and slow down the reaction. The reactor would run at about 530 C (986 F), cooled by liquid sodium.

Malcolm Grimston, a nuclear expert at the Royal Institute of International Affairs, doubted whether the Japanese public could be persuaded that the reactor was safe, given a string of incidents at large nuclear plants in recent years.

In the worst case, two workers died at a uranium processing plant in Tokaimura in 1999, more than 400 other people were exposed to radation and at least 300,000 people were forced to shelter indoors for more than a day.

"There's nothing wrong with the (Rapid-L) concept," Grimston told New Scientist. "But if the Japanese public won't now accept big reactors for safety reasons, then you have to wonder what the response would be building lots of small reactors in the middle of cities."

-- Swissrose (cellier3@mindspring.com), August 23, 2001

Answers

I've made sarcastic remarks before about nuclear power. I'm sure the Japanese came make a micro reactor safe but we NEVER can make the waste product safe and it remains unsafe for untold thousands of years by which time the storage receptable has cracked and its leaking into our water supply. Oh what the hell, we'll just ship it to Russia, they know what to do with it.

-- Guy Daley (guydaley1@netzero.net), August 23, 2001.

I'd like to see some more details: -the reactor is 2m by 6m, how long is it? -what temperaturedoes liquid lighium-6 have to be to melt? -how is the liquid sodium kept in that state? How is it cooled so it can remove heat from the reactor? -what kind of maintenance will the reactor require and who will be certified to do it? Who will monitor the function? -lets say the reactor is down for refueling or repair? Who will supply electricity?

-- John Littmann (johntl@mtn.org), August 23, 2001.

This is madness. Wilhelm Reich discovered in 1940 that nuclear reactions drive away the life force "orgone" for a fifty mile radius. He later died in prison. All of his work was ordered destroyed. We, the public, were denied his discovery of this universal medium, that connects all living matter.

Try to live as far away from these things as possible.

-- Ken (n4wind@sonic.net), August 24, 2001.