EXPERT ADVICE FOR EXTERNAL HAZARD ASSESSMENT

摘要

The Fukushima nuclear accident following the Great Tohoku earthquake and tsunami in March 2011 has raised concern about the adequacy of expert advice on external hazards such as earthquakes, tsunamis and extreme weather events. Consequently, the adequacy of the process by which that expert advice is commissioned and accepted is also inherently of concern. A review of the events at Fukushima establishes that expert advice was flawed. Historical evidence of large tsunamis does not appear to have been accounted for in the design basis. Based on the issues raised in the discussions a process for the use of expert advice for external hazards has been outlined. This aims to provide a framework that should be followed to ensure that due diligence has been demonstrated. This process is generic and is therefore applicable to any external hazard. An example can be provided in the context of the United Kingdom. It is not sufficient to describe the UK seismic risk as low and to assess this purely from the historical record. The acceptance process should confirm that probability of very low frequency events has been correctly addressed. When expert advice is commissioned, there are four fundamental quality checks that lie within the due diligence responsibility of the commissioning authority. These are accreditation of the expert(s), validation of advice against real world evidence, peer review and due consideration of dissenting advice. As a more detailed level of examination of a method for quantifying a hazard, a well-established procedure for rating completeness of an engineered system can be adapted to assess fitness for purpose of a theoretical model or analytical system. The engineering procedure is the Technology Readiness Level system, believed to have originated in NASA. The Model Readiness Level version identifies two points of failure in setting of the design basis seismic threat to Fukushima.