I have put my submission to Mike Weightman on the web
My articles on nuclear subjects are marked with an asterisk on
The submission follows:-
The Areva EPR, the Toshiba-Westinghouse AP1000 PWR and Fukushima
The Fukushima incident
Assuming that the control rods were fully lifted – they come up from under the reactor in the case of the BWR - and had there been a means of residual heat removal there might have been no severe consequences of the earthquake and tsunami. Under normal circumstances there would have been no need for the standby generators as there would always have been one at least operating reactor able to maintain supplies to others shutdown and to maintain a filtered, cooled circulation of the spent fuel ponds. There may have been only one standby generation system for the entire complex.
The loss of station power and of the standby diesel generation backup, not just for an emergency shutdown, but also during a routine fuel change must therefore be a concern for the UK new build. But the release of hydrogen and the consequent explosions when venting the reactor vessels because of a rising and dangerous build up of pressure is the main concern.
The route of a release from the reactor vessel pressure relief valve is not shown and the valve may vent into the containment. It would be advisable to vent the release externally as it could contain hydrogen. At Fukushima the overpressure was vented into the building and considerable damage to the building and the spent fuel ponds was caused.
The APEX-1000 test facility
Assuming that the control rods were fully lifted, had there been a means of residual heat removal there might have been no severe consequences of the earthquake and tsunami. Under normal circumstances there would have been no need for the standby generators as there would always have been one at least operating reactor able to maintain supplies to others shutdown and to maintain a filtered, cooled circulation of the spent fuel ponds. There may have been only one standby generation system for the entire complex.
The loss of the standby diesel generation must therefore be the principle concern for the UK new build. I note that in the case of the EPR there are two separate diesel generator facilities, sited at opposite sides of the reactor. It is claimed that the AP1000 passive core cooling safety system is independent of ac standby supplies or dc batteries for its operation, but which is taken up as an issue above. But external supplies or standby generators would be needed for the spent fuel pond cooling..
However, what is of concern in regard to any type of reactor associated with the new build is the situation at the end of the claimed operational life of 60 years. Assuming that some of the new build is commissioned in 2020, then 60 years takes the decommissioning to commence in 2080. Thereafter residual heat removal will be needed, but the main problem will be the maintenance of cooling and filtering the contents of the spent fuel ponds for a further 10 to 20 years. Depending on how long it takes for the last spent fuel to be cool enough to be transferred to the dry casks, there could be a need to require an alternative electricity supply or standby generation to be available until the turn of the century in 2100.
BP's Statistical Review of 2010 recorded a global peak in "all-oils" production in 2008, while the normal "swing" producer, Saudi Arabia experienced its national peak in 2005, so the availability of diesel fuel in the near future, let alone in 2080, must be a cause of concern. It means that because, as in the case of Fukushima all available normal supplies were lost, the fuelling of the standby generators needs consideration by your good self.
The situation exigent at the time of the closure of the new build is indeterminable. Ageing may not allow the operation to endure for the claimed 60 years without substantial component renewal, but even if just the 40 years current lifespan is attained, it is still over-optimistic to be able to determine the situation in 2060.
In short the inability to determine the fate of the new build from 2060 to 2080 and beyond is reason enough for the new build to be abandoned. The insecurity of the LWR coolant containment and the potential for a hydrogen explosion and core meltdown adds another more compelling reason for its abandonment.