Fukushima Vs Chernobyl - Compare And Contrast

Zero Hedge predicted from the very beginning that unfortunately Fukushima would end up being an as serious, if not more so (just consider the extremely high concentration of human and other capital in proximity to Fukushima: unlike the USSR there is little to none displacement capacity) catastrophe than Chernobyl. Yesterday's final hike in the incident severity level, which started at 4 and hit the highest , 7, is simply yet another confirmation of this although in absolute terms Fukushima still has a ways to go before surpassing the Soviet accident:
Choernobyl leaked a total of 5.2 million terabecquerels of radioactivity, Fukushima has so far leaked 500,000 terabecquerels. In the meantime what little progress is being made is promptly shadowed by all the incremental bad news that keep being disclosed (the most recent debacle is the discovery of extremely radioactive strontium just off the plant). Yet to be sure, there are differences between the two situation. Courtesy of Reuters, here are the key comparisons and differences between the two.

From Reuters

Here are the main points of how the two accidents differ.


Unit 4 at Chernobyl was a water-cooled and graphite-moderated reactor -- a combination that can and did yield a runaway chain reaction. A series of gross errors and misjudgment by operators resulted in an explosion and fire that catapulted radioactivity into the upper atmosphere.

The resulting release of radiation has been compared to 10 times that released by the 1945 U.S. nuclear bomb attack on the Japanese city of Hiroshima.

The boiling water reactors at Fukushima do not have a combustible graphite core. The nuclear fuel in reactors No. 1, No. 2 and No. 3 was allowed to melt at least partially, but operators have since succeeded in cooling both the reactors and the spent fuel pools and no chain reaction is happening now.

As long as cooling operations continue and Japan can prepare tanks fast enough to store the contamination overflow, Japan can still hope to buy time to figure out how to bring the reactors to a cold shutdown.


Chernobyl had no containment structure and nothing stopped the trajectory of radioactive materials into the air.

Fukushima's reactors are built on granite foundations and are surrounded by steel and concrete structures. The reactor vessels and containment structures, as well as some of the pipes leading from the reactors, are likely to have been damaged by the March 11 tsunami and recurring earthquakes. But with radiation levels now down to a sliver of what they were at the peak, experts say that the structures are still holding.

Chernobyl contaminated an area as far as 500 km (300 miles) from the plant, and an area spanning 30 km (18 miles) around the plant is still an exclusion zone and uninhabited.


At Fukushima, there have been no deaths so far due to radiation. Eight people have been injured. More deadly have been the 9.0 magnitude quake that hit on March 11 and the aftershocks that have rocked the site while workers tried to bring the plant under control. Two have died and three have been critically injured.

At Chernobyl, the initial explosion resulted in the death of two workers. Twenty-eight of the firemen and emergency clean-up workers died in the first three months after the explosion from acute radiation sickness and one died of cardiac arrest.


Bungling, yes. Disorganised, incoherent and sometimes contradictory, yes. But it is difficult to accuse Japanese officials or TEPCO of intentionally covering up information, with round-the-clock updates and a steady stream of data.

Chernobyl was initially covered up by the secretive Soviet state, which remained silent for two days. But authorities, obliged by huge radiation releases throughout Europe, gradually disclosed details of the accident, showing unprecedented Soviet-era openness.


It's not over yet. One month since the March 11 earthquake and tsunami, workers still have to inject water into the reactors, creating more contaminated water that is hampering the restoration of power to pumps to cool the reactors and bring them to a cold shutdown.

The situation led a frustrated and demoralised TEPCO spokesman to say that the total fallout could exceed that of Chernobyl. Fukushima involves loss of control at four reactors and potentially more radioactive material, that could continue to seep, leak or burst into the environment.

Officials have said that if power cannot be restored to the cooling pumps, there are other measures, such as air cooling, and that in a worst-case scenario, they could try water entombment in the reactors whose containment structures are sound.



And another key difference: with Chernobyl, even under utmost secrecy, the government moved fast, sacrificing many people, but only to prevent a far greater damage in the long run. In other words, the polar opposite of TEPCO (at least so far). And as this report from Yomiuri confirms, it was TEPCO's "tardiness" that has been the primary reason for much of the escalation.

From Yomiuri:


Prime Minister Naoto Kan's blood must have run cold around 10 p.m. on March 11, the day of the Great East Japan Earthquake, when he received the first report on the terrible situation at the Fukushima No. 1 nuclear power plant.

The report from the Nuclear and Industry Safety Agency of the Economy, Trade and Industry Ministry predicted reactor cores at the nuclear power plant--where power and all functions to cool the reactors were lost in the quake and tsunami--would be exposed to air, and that extreme heat generated by fuel rods would damage their encasing tubes later that night.

Fuel rods would melt down, and the following morning the pressure inside the reactors' containment vessels would reach the maximum allowed for by the facilities' designers, the report predicted.

Kan and everyone at the Prime Minister's Office understood the seriousness of the situation described by the report.

There were only two options that might prevent a meltdown of the reactors--either restore the plant's power supply and cooling functions immediately, or pour water directly into the reactors. If neither course of action could be taken, the pressure inside the reactors would become so great that they would be destroyed.

The report concluded that valves in the containment vessels would have to be opened, to release radioactive steam and reduce the pressure inside.

However, opening the valves was considered a last resort. Although it could prevent the reactors from breaking apart, it would release steam with high levels of radioactive materials into the atmosphere.

Such a step had never been taken at a nuclear power plant in Japan.


Countdown to power loss

The Prime Minister's Office, the nuclear safety agency and even Tokyo Electric Power Co., the operator of the Fukushima plant, were filled with relief immediately after the earthquake. They had been told backup diesel generators would provide sufficient support to stabilize the Nos. 1 to 3 reactors, which were in operation when the quake hit.

However, subsequent tsunami destroyed 12 of the 13 emergency generators.

"Round up all the power-supply cars and send them to the plant right now!" shouted a TEPCO supervisor at the utility's head office in Tokyo.

Nuclear reactors have emergency cooling systems that channel water into the reactor, using a turbine that can be powered by residual heat. However, the systems rely on emergency batteries to power the water intake valves.

The emergency batteries at the Fukushima plant were expected to run out of power around midnight.


Options exhausted

TEPCO dispatched power-supply vehicles from various power stations around the country to the crippled nuclear plant. However, the vehicles had to travel very slowly because of damage to roads in northeastern Japan. The first power-supply car did not reach the plant until 9 p.m. on March 11.

Once at the site, the lack of preparation became apparent. Cables needed to connect the vehicles' high-voltage electricity to plant facilities were not long enough. TEPCO immediately ordered additional cables, but precious time had been wasted. Power would not be restored at the plant by midnight.

The pressure inside the containment vessels rose above the maximum allowed for by the facilities' design, and radiation levels at the plant increased sharply. No option was left but to open the valves.


Anger rose as TEPCO dithered

TEPCO began preparations for opening the valves around 7 p.m. on March 11. Pressure inside the No. 1 reactor was particularly high.

"Soon, the reactor won't be able to withstand the pressure," said an official of the accident headquarters at the plant, which was keeping in touch with TEPCO's head office via video phone. "We have to vent the pressure immediately."

"Pressure inside the containment vessel of the No. 1 reactor has gone up dramatically," the agency told Banri Kaieda, economy, trade and industry minister, at 12:45 a.m. on March 12. In fact, it had reached 1.5 times the designed maximum, meaning the condition of the reactor was critical.

"To get things under control, we have to pour water into the reactors and then vent the steam that is generated," Haruki Madarame, chairman of the Cabinet Office's Nuclear Safety Commission, told Kaieda.

At 1:30 a.m. on March 12, Kan, Kaieda and Madarame gathered at the crisis management center in the basement of the Prime Minister's Office.

The three urged TEPCO officials to vent the steam as soon as possible. But TEPCO officials said there was no way of opening the valves because there was no power supply.

Exasperated, Kaieda called the utility's head office in Tokyo and the accident headquarters at the plant every hour, pressuring them to open the valves immediately.

TEPCO workers tried to open the valves by manually overriding the automatic system, but struggled to make progress because they had to work in darkness.

At dawn, pressure inside the No. 1 reactor was more than twice the designed maximum.

Eventually, at 6:50 a.m., the government ordered the utility to open the valves under the Nuclear Reactor Regulation Law.

When Kan visited the accident site shortly after 7 a.m. and found TEPCO had not opened the valves yet, he reprimanded company officials. The officials replied they would like to have another hour to make a decision on what to do.

Kan blew his stack.

"Now's not the time to make such lackadaisical comments!" the prime minister told the TEPCO officials.

Yet even still, the utility spent three more hours discussing the matter before finally opening the valves at 10:17 a.m.

Five hours after that, a hydrogen explosion occurred at the No. 1 reactor, blowing apart its outer building.


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