What should we learn from the nuclear accident in Japan?

There have now been three serious accidents at commercial nuclear reactors: Three Mile Island in 1979, Chernobyl in 1986, and Fukushima Daiichi in 2011. The Three Mile Island accident was largely the result of operator error, with very little release of radioactivity and no deaths as a result of the accident. Since this accident, the U.S. has significantly improved the operational procedures and safety design of its approximately 100 commercial reactors. The accident at Chernobyl was largely the result of operator error and an unsafe Soviet-era design without a containment structure. Despite the fact the reactor completely blew apart from a massive steam explosion and follow-on hydrogen explosions, the death toll was approximately 50. The Fukushima Daiichi reactor complex survived the magnitude 9.0 quake, but the tsunami that followed caused a common-mode failure of all emergency and back-up power systems. As a result, one or more of the reactors has experienced a core meltdown. But the vast majority of the radioactivity will remain within the reactor vessels, containment structures, and spent fuel pools. These reactors are all shutdown and the residual heat rates from the fuel rods are diminishing with time as the result of natural radioactive decay. The nuclear plant workers, Japan Defense Force, firefighters, and other emergency workers have been making a tremendous and courageous effort to restore cooling and stabilize the situation. There have been no deaths as a direct result of this accident, compared to the many thousands of deaths caused by the earthquake and tsunami.

For advanced societies that require large amounts of energy to remain advanced, the only viable sources of energy for the foreseeable future are nuclear power and fossil fuels. A sound energy policy would make use of both of these sources of energy to provide diversity and energy security. But clearly we should strive to make improvements in both nuclear technology and safety. Several advanced reactor concepts are being evaluated throughout the world for the next generation of nuclear energy. The U.S. Congress initiated the Next Generation Nuclear Plant (NGNP) project in 2005. Based on a systematic evaluation of several next-generation concepts, the Department of Energy (DOE) selected a Modular High Temperature Gas-cooled Reactor (MHR) as the concept for NGNP. A key design feature of the MHR is intrinsic safety. The MHR can survive a complete loss-of-coolant accident, including failure to insert control rods, without reliance on any emergency systems. As the reactor heats up, natural processes will shut it down. Because the reactor core and nuclear fuel are composed entirely of refractory and ceramic materials with capacity to absorb heat at high temperatures without structural degradation, there is no damage to the reactor, i.e., the reactor cannot melt down under any circumstances. No public evacuation is required, even next to the plant’s entrance gate. With its high temperature capability and efficient heat utilization, the MHR can generate electricity with high efficiency and displace fossil fuels for a number of petrochemical and industrial applications, including production of hydrogen for future clean fuel utilization. San Diego-based General Atomics (GA) is a pioneer of this technology. With partners from the U.S., Japan, and South Korea, GA is now completing the conceptual design of the NGNP demonstration plant for the DOE.

Japan has also been developing MHR technology on its own. Sitting above and just south of the small fishing village of Oarai, and about 100 miles south of the Fukushima reactor complex, is the Japan Atomic Energy Agency Oarai Research Establishment, which includes the High Temperature engineering Test Reactor (HTTR). The HTTR was commissioned in 1998 and is an operational, engineering-scale prototype of the MHR. The HTTR has been used to demonstrate the intrinsic safety characteristics of the MHR and has also demonstrated sustained operation with a 950C (1740F) coolant outlet temperature. By comparison, conventional water-cooled reactors operate with a 300C coolant outlet temperature, and are obviously not intrinsically safe.

The efforts in Japan should now be focused on helping the victims of the earthquake and tsunami and on stabilizing the damaged Fukushima reactors. But perhaps these events that occurred in Japan can also lay the foundation for developing, demonstrating, and commercializing a next generation of nuclear power with intrinsic safety. International collaboration among the U.S., Japan, and other nations on the MHR would provide a relatively quick path for achieving this goal.

Is it the same design as Chernobyl? Big difference.

Of course not. My point was that if a similar accident happened in Limerick, I'm a dead man. I'm speaking to the hysterical types. Things happen; we can't control the world. That's not to say we're helpless, one can do things to limit or learn lessons from unfortunate events.

In short, I'm not packing my bags.

Got some recent hard radiation readings in sea and air near plant 1 and 2.

Radiation measured in the waters and air (Fukushima Plant) April 4th 2011

They report seawater concentrations near plant #2 10 KM south of plant #1. So that gives an idea of dispersal. Also note Air reading of 790 microSv/h 500 meters nw reactor #2.

I have come to the conclusion..after reading up on TEPCO’s sordid past..such as keeping two sets of safety records..that I am not going to believe their data.

I want to see an independent source provide info.

I think the reason physicists are having a hard time analyzing info is because TEPCO isn’t telling the truth.

For example, if we see “X” we should be seeing “Y” but why don’t we... type of scenario.

In the internet age, I often wonder how much the Japanese really know about that Company as they suffer at the hands of an earthquake, tsunami, their government, and TEPCO.

There’s a book out (can’t remember the name) which documents the last day of the Chernobyl plant.
Truly fasinating read!

When the plant power spiked, they tried to do an emergency scram, the graphite tipped control rods caused an even bigger neutron spike and the entire thing blew up.

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