The Fukushima accident was preventable

Abstract

The 11 March 2011 tsunami was probably the fourth largest in the past 100 years and killed over 15 000 people. The magnitude of the design tsunami triggering earthquake affecting this region of Japan had been grossly underestimated, and the tsunami hit the Fukushima Dai-ichi nuclear power plant (NPP), causing the third most severe accident in an NPP ever. Interestingly, while the Onagawa NPP was also hit by a tsunami of approximately the same height as Dai-ichi, it survived the event ‘remarkably undamaged’. We explain what has been referred to as the cascade of engineering and regulatory failures that led to the Fukushima disaster. One, insufficient attention had been given to evidence of large tsunamis inundating the region earlier, to Japanese research suggestive that large earthquakes could occur anywhere along a subduction zone, and to new research on mega-thrusts since Boxing Day 2004. Two, there were unexplainably different design conditions for NPPs at close distances from each other. Three, the hazard analysis to calculate the maximum probable tsunami at Dai-ichi appeared to have had methodological mistakes, which almost nobody experienced in tsunami engineering would have made. Four, there were substantial inadequacies in the Japan nuclear regulatory structure. The Fukushima accident was preventable, if international best practices and standards had been followed, if there had been international reviews, and had common sense prevailed in the interpretation of pre-existing geological and hydrodynamic findings. Formal standards are needed for evaluating the tsunami vulnerability of NPPs, for specific training of engineers and scientists who perform tsunami computations for emergency preparedness or critical facilities, as well as for regulators who review safety studies.

Tsunamis: bridging science, engineering and society

“…As the development of the design tsunami for the Fukushima NPP demonstrated [20], when absence of evidence of historic tsunamis is interpreted as evidence of absence, the results can be devastating. Given that most of the relative plate motion in the eastern Mediterranean is aseismic, 'the modern record of seismicity provides little or no information about the faults that are likely to generate large earthquakes'.…”

“…In the context of the Fukushima disaster, one perplexing aspect of the Okushiri event is discussed in this issue [20]. In its aftermath, Japan spent over US$600M (in 1998 $) to build an 11 m high seawall to protect about 20 km of coastlines and rebuilt the main town of Aonae.…”

“…Grilli et al [62] then applied it to the studies of the evolution of landslide waves. The comments of [20] regarding the futility of higher order numerical solutions in a physical problem where the uncertainties of the initial condition are far greater than differences in inundation estimates of different solution methods notwithstanding, FPNF represented a great step forward for routine application of nonlinear and dispersive long-wave models. We note that the first tsunami-relevant Large Eddy Simulation (LES) of the Navier-Stokes equations appears to have been that of Liu et al [63] in the context of simulating underwater solid block landslides.…”

The quest for wisdom: lessons from 17 tsunamis, 2004–2014

“…In conclusion, the 2011 Tohoku tsunami stands out as an example of catastrophic disaster, made significantly worse by inadequate, if not simply inept, mismanagement of its before-the-fact mitigation in the near field [113], and should earn a black star in this respect. However, in the midst of this despicable record, several glints of hope can be recognized.…”

“…As discussed in more detail by Synolakis & Kânoglu [113], the safety of the plant had been examined in two recent instances by scientific committees at the instigation of the plant's operator, the Tokyo Electric Power Company (TEPCO). As reported by the Washington Post [114] in the aftermath of the Tohoku disaster, during the first hearing in 2008-2009, a scientist had pointed out the so-called 'Jōgan' historical earthquake of AD 869 whose tsunami had inundated as much as 5 km into the Sendai plain [115], but his arguments had not been incorporated in the Committee's final report.…”