Source: Nikkei Asian Review
October was an extraordinary month in Japan. A record five typhoons hit, with a near miss by a sixth. A 7.1-magnitude earthquake struck off the coast of Fukushima Prefecture on Oct. 26, just as one of the storms was arriving.
A worried world focused on the possible effects of all this on the Fukushima Daiichi nuclear power station. And indeed, although the earthquake did no further damage to the stricken plant, the heavy rainfall contributed to more contaminated water flowing into the facility’s port area.
According to the Japan Meteorological Agency, an average of one to two typhoons approach Japan in October. And since 1996, Japan has had an average of one earthquake greater than 7.0 every five months, or about two per year.
We would be correct in saying that a month with five typhoons, one near miss and a 7.1 quake was an unexpected confluence of unlikely events. But are all unlikely events really unlikely? Is there any way to expect — and guard against — the unexpected?
Unlikely yet likely?
Let us look at nuclear power generation and the possibility of a core damage accident. Over the years, the International Atomic Energy Agency and most regulators have endorsed several safety goals. Two such goals stipulate that reactor operators should ensure that for each unit, the likelihood of a core damage accident is no greater than one per 10,000 years; the likelihood of a large release of radiation should be no greater than one time every 100,000 years.
These seem like pretty unlikely events, right?
Let me put this in perspective. As of March 10, 2011, there were 438 commercial nuclear power generating units around the globe. If each unit was operating 70% of the time, and each one was safe according to the goals I have just described, the likelihood of a core damage accident somewhere on the planet was about three times every 100 years.
So a core damage accident, although unlikely in a single nuclear reactor, does not seem so improbable if we look worldwide. In fact, in my lifetime there have been such accidents at three commercial reactor sites: Three Mile Island in the U.S., Chernobyl in Ukraine and Fukushima Daiichi.
Now, core damage accidents do not necessarily result in radiation releases. At Three Mile Island, no radiation escaped. If we use the same reasoning for large releases of radiation, then we should expect a Fukushima-like accident about once every 330 years.
Please remember, too, that I am only talking about the likelihood of an accident, not the consequence that people will get sick or die from one. The contamination surrounding Fukushima Daiichi is measurable, but according to the United Nations Scientific Committee on the Effects of Atomic Radiation, the disaster is unlikely to cause any health effects in the future among the general public and the vast majority of workers.
Still, consider this: In the next 15 years, the number of new nuclear units will increase significantly worldwide. Therefore, we should expect the odds of core damage accidents to increase worldwide as well. In Asia alone, China has 29 reactors under construction, adding to 15 operational units.
So here is my question to you: Can you accept this risk?
Keep in mind that energy-related risks will not disappear if we abandon nuclear power. Look at all of the gas, oil, and liquefied natural gas tanks on the coasts of almost every Asian country. We have done studies on how large earthquakes, tsunamis, and typhoons could impact the chemical, oil and gas industries. Believe me, there are accident scenarios with environmental, social and economic consequences that could approach those of Fukushima.
The Fukushima accident has clearly shown that nuclear power inevitably carries risks. It is time to change the terms of the debate from the oversimplified safe/unsafe dichotomy to an honest and open discussion of what the risks are and what is being done to mitigate them.
In this context, the risks of nuclear power have to be considered in a balanced comparison with other risks. At the end of the discussion, the public and the leaders they have elected — rather than technical experts — should make the final decision.
Woody Epstein serves as manager of risk consulting at Lloyd’s Register Consulting Japan. From 2011 to 2012 he was also a visiting scientist at the Ninokata Laboratory of the Tokyo Institute of Technology, where he was involved in analyzing the Fukushima disaster. The opinions expressed in this regular column do not reflect those of his employers, their affiliates or clients.