Learning the true lesson of the Fukushima disaster

Due to design flaws, the Fukushima Daiichi nuclear plant was doomed when disaster struck. Manufacturers, utilities, regulators and politicians must protect the future of nuclear power by ensuring Generation III reactors are safe in practice, not just on paper.

In 1992 the British documentary maker Adam Curtis made the fascinating film A is for Atom, a history of civil nuclear power in the US, the UK and the USSR.

This hour-long film can be viewed in its entirety via the internet and, in light of Fukushima, it is essential viewing. Most relevant to the ongoing disaster in Japan is the film’s illuminating account of GE’s Mark I Boiling Water Reactor (BWR) ” the same design as used at the ill-fated Fukushima Daiichi facility.

In the early 1960s, GE took a gamble by offering utilities BWRs as loss leaders with the aim of building a nuclear bandwagon that in time would become a profitable business. It paid off in spades. By the end of the decade GE had sold dozens of BWRs at home and abroad.

GE’s Mark I BWR was derived from a nuclear submarine reactor and this design was pursued in part because it used a smaller containment structure. In order to be competitive with fossil fuels the BWRs had to become ever larger: 600″1000+ MWe, rather than the initial 100″200 MWe reactors. At these enlarged capacities, however, it was found that the Mark I containment vessel and pressure suppression system were unlikely to prevent a core meltdown and subsequent containment breach following a loss of reactor coolant.

Early on, the US Atomic Energy Commission (AEC), now known as the Nuclear Regulatory Commission, knew the Mark I containment vessel to be potentially dangerous. In 1966 the AEC’s Advisory Committee on Reactor Safeguards (ACRS) met with GE to force them to redesign the containment structures of the BWR. In A is for Atom, the then chairman of ACRS, Dr. David Okrent, claims GE refused as it would have been uneconomic to do so.

Concerned about increasingly large reactors planned for major cities like Chicago and New York, ACRS drafted a letter to AEC chairman Glenn Seaborg. The letter, which had to published by law, said ACRS would only agree to Indian Point 2, a 1020 MWe Westinghouse pressurized water reactor (PWR) located 39 km from New York City, if Westinghouse and GE agreed to make all future reactors safer.

Seaborg asked for the letter not to be published for fear of public alarm about the safety of nuclear power and subsequent damage to the nuclear industry. Instead, Seaborg dealt with the problem behind closed doors. Asked why AEC did not refuse to license such nuclear power plants and demand safer reactors, Seaborg said this was not a “feasible approach”.

As the plants ordered in the 1960s neared completion, nuclear engineers discovered for themselves the dangers of building large reactors with potentially inadequate safety measures. In 1971, the year that the first BWR was commissioned at Fukushima Daiichi, AEC conducted tests on emergency cooling systems by simulating accidents, such as pipe breaks.

In each case the systems worked but the water failed to fill the core, often being forced out under pressure. Robert Pollard, an AEC reactor engineer at the time, said: “We discovered that our theoretical calculations did not have a strong correlation with reality.

“We had no basis for knowing that the emergency cooling systems’ pumps and valves would actually prevent a reactor meltdown. But we just couldn’t admit to the public these safety systems might not do any good ” it would probably have been the end of nuclear technology.”

The warnings were ignored and it was only after a cooling system failure and partial reactor meltdown at Three Mile Island in 1979 that the existing Mark I BWR plants in the US were modified to meet newly introduced Nuclear Regulatory Commission standards.

A is for Atom does not condemn nuclear power. Rather, it highlights the potential for a compromised safety culture arising from economic expediency and a cosy relationship between manufacturers, regulators and politicians.

Curtis’ film ends with a quote from Valery Legasov, who led the investigation into the Chernobyl disaster of 1986. Legasov committed suicide two years after the explosion at Unit 4. “It is easy to imagine the enemy is the nuclear reactor, but the enemy is not technology,” he said. “I have come to the paradoxical conclusion that technology must be protected from man.”

Much has been learned about nuclear reactors since the 1960s. Many nuclear engineers still contend that the Mark I BWR was an excellent reactor design. Indisputably, GE’s pioneering technology has safely generated countless trillions of kWh around the world and continues to do so.

The current Generation III reactors promise enhanced safety systems, but in the drive to be more competitive they grow ever larger. Areva’s 1650 MWe European Pressurized Reactor (EPR), able to function with 100 per cent MOx fuel, is the largest reactor ever built. Having been criticized in some quarters for designing an over-engineered, overly-complex PWR, Areva now feels vindicated and sees an excellent business opportunity to sell EPRs around the world.

Areva is convinced that Fukushima would not have happened had the plant been an EPR. That is mere speculation. Larger, more efficient reactors with enhanced safety systems have greater advantages than older reactors, but in an accident the potential downsides are greater still.

It is imperative that manufacturers, regulators and utilities get the EPR and other new generation reactors right. A major accident with a Generation III reactor could deliver the nuclear power industry a blow from which it might never recover.

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