As everyone knows, the 2011 earthquake and ensuing tsunami along the northeast coast of Japan swamped the 6 unit Boiling Water Reactor (BWR) complex in Fukushima causing the 3rd commercial power reactor meltdown in a single generation. This accident rates up there with Chernobyl in Russia and makes the Three Mile Island incident in the U.S look insignificant. Basically the earthquake was so powerful; it was outside the design safety basis of what the facility was engineered to withstand. However, the earthquake wasn’t what scuttled the safety systems or safe shutdown redundancy; it was the tsunami, also outside of the design safety basis. You see, when a nuclear power plant shuts down, there is a tremendous level of decay heat (heat from the radiological decay of fission daughter products within the fuel) contained within the core of the operating reactors, not to mention the decay heat from the expended fuel assemblies stored on site in vast pools from past operation and refueling cycles. The heat generated from the decay of the fission daughter products requires a substantial cooling system to remove the heat.
Removal of this decay heat requires pumps, piping, heat exchangers and most of all, electricity. The electricity for this particular nuclear function is provided by any or a combination of the following 3 sources; 1) the operating plant when at power and self sustaining, 2) from the electrical grid (other power plants, nuclear or otherwise) or 3) emergency diesel generators. In the case of the Fukushima facility, built on the ocean front for the convenience of an infinite heat sink (Pacific Ocean), the triple redundancy of emergency or shutdown power was inadequate; the tsunami swamped the facilities switchyard, the emergency diesels and took out the supplying power grid 20 miles or so inland. So with no electrical power for the cooling pumps and control systems to cool the units, the decay heat within existing core fuel assemblies and expended fuel assembles caused several breaches of that fuel, the reactor vessels and indirectly, the containment structures.
As I mentioned above, during the design and permitting of a nuclear power plant, a design safety basis that defines the facilities engineering rigor is developed and published by very smart and experienced engineers that work for the plant owner. The published design safety basis document is then approved by yet another group of very smart and experienced engineers that regulate construction and operation of nuclear plants. In the case of Fukushima, the Japanese Nuclear and Industrial Safety Agency was responsible for the review and approval of the design safety basis prior to permitting for design, construction and commissioning of the plants. Within the design safety basis, worse case scenarios that include earthquake (seismic), tsunami, tornado, crashing aircraft, high tide, red tide, fire, famine, locus infestation and just about any other improbable scenario of mother nature or humane caused aspect of mass destruction are evaluated to quantify the depth of design rigor and construction compliance to that design, that would be required to safely operate (including safe shutdown) under a worse case scenario. In other words, based on historical risk and hazards probability, e.g. experienced based evaluation, a facility would be designed and constructed robust enough to sustain the worst Mother Nature, a mad terrorist or the Israeli Air Force could throw at it.
The problem with the Fukushima facility is that they, the owners and their engineers and the regulators and their engineers and the managers, politicians and assorted other bureaucrats that are involved with permitting, did not pay attention to all of the historical lessons learned (experiences) associated with the area, namely the magnitude of a tsunami from an off shore seismic event. In fact, there was written warning, objective evidence of previous events, but it was not heeded. They DID NOT READ THE STONES.
READ THE STONES? Japan, as part of the Pacific Ring of Fire, is notorious for its earthquakes, volcanoes and other assorted seismic anomalies caused by the shifting of mother earth’s tectonic plates. It is common knowledge that it’s not an ‘if’ there will be an earthquake shaking up this island nation but ‘when’ and how powerful. In fact, these earthquakes and ensuing tsunamis have been occurring for millennia and the Japanese people that survived these past earthquakes have indeed provided warnings to future generations. They actually ‘Carved in Stone’ their warnings. Yes folks, hundreds of years ago (maybe even thousands) the people that survived past earthquakes and ensuing tsunamis laid out a series of Marked Stones along the northeast Pacific coast that basically stated, ‘if you build your house on the ocean side of these stones, it stands a good chance of being wiped out by a raging tsunami’. The New York Times did a great article on the subject and if you follow the link below, you’ll see that the ancestors of the Japanese people that live along the northeast coast new of the dangers.
http://www.nytimes.com/2011/04/21/world/asia/21stones.html?pagewanted=all&_r=1&
Now in a country whose industrial prowess is bases on the concept of ‘Continuous Improvement’, utilizing the past to improve the future, e.g. lessons learned, The Toyota Method, Kia Zen, the 5 S’s and are masters of Lean Management and Manufacturing ‘learn from the past’ concepts, why didn’t they READ THE STONES and build their 6 unit nuclear facility inland? They could have plumbed in water from the ocean for power production cooling or included cooling towers and man made reservoirs or even integrate purpose built cooling pools for a tsunami emergency. Here your ancestors blatantly stated and carved in stone, “Do Not Build Your Homes (and implied businesses) Below This Point” yet you did not learn; as an engineer, how arrogant can you be?
Also disturbing is the fact that Nuclear Power is a ‘compliance’ driven industry and the location of the facility was ‘out of compliance’ with the historical (experience) data. Nothing in the nuclear industry is designed, built, fixed, operated, modified, spit on or polished without a written document. Anyone that has ever worked in the nuclear industry knows that ‘verbatim compliance’ with an approved and officially released written document is the business norm. As a nuclear worker, you read everything, even the instructions on the toilet paper packaging that covers installation and use. The concept of working verbatim to approved and released documents is banged into our heads from day one. So in NOT READING THE STONES, a ‘carved in stone’ document that was truly approved in the blood of previous generations, the Japanese nuclear industry will always be tarnished. They failed to ‘read the instruction’; they missed a step in their procedure and paid dearly.
The moral of this story; read the instructions, look for and read warning signs, record and learn from past failures and always, always READ THE STONES, they are significant.
MMJennings
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