Naked Capitalism Link of the Day

There were several candidates today.  There is a story about honey made from the Manuka tree in New Zealand may be able to prevent the growth of the MRSA super staphylococcus.  There is a story about South Korean groundwater pollution from the mass graves of livestock from a foot and mouth disease outbreak last year.  There is a story comparing economic ideologies to religions, along with a commodity exporter's post with graphs blaming the Fed for commodity price increases. (I think this may be a feature for the Fed, and not a bug, looking to weaken the dollar and increase exports).  But the engineer in me chose this Atomic Power Review post about the problems and mistakes made at Fukushima, titled ARPA Special: Observations on Fukushima. An example of some of the design considerations which must be reassessed:

 Much has been made about the failure of the on site EDG units, which as we now know did run for about an hour between the time of the quake and the arrival of the tsunami. The fact that this natural disaster was of unprecedented scope and size somewhat eases any accusations of fault on the part of the operators. However, at an entirely different plant, much later, it was revealed after a near SBO event that two of the site's three EDG units were disassembled simultaneously for periodic inspections. The addition of this fact, coupled with the tsunami-related failure of all EDG units at Fukushima Daiichi now thrusts Japan's attitude about EDG units, SBO events and their relation to reactor and public safety squarely into the limelight. While staunch pro-nuclear advocates rightly point out the massive natural disaster that took out Fukushima Daiichi's diesels as off the top end of the scale as regards regulatory provisions for events to be protected against, the notion that a reactor plant could have two of three diesels simultaneously disassembled as a matter of normal, natural conduct of business is appalling.

Solutions to this set of problems include more diesels at each site, and placement, construction and water and shock proofing to guard against a duplication of the inundation-related loss of all onsite EDG capacity that occurred at Fukushima Daiichi. Specifically, it may be that diesels should be placed on the top of nearby hills, or placed several stories up and fully enclosed, and must be shock isolated. Further, as in primary equipment there should be the assumption that the first diesel to start fails, so that there must always be at least two available and set for auto start for every reactor plant.

Standardized external power connections are now a must. This situation is hampered a bit in Japan as some areas are 50 Hz and some are 60 Hz, but this is not a problem in terms of the provision of standard external connections and portable generating equipment.

REACTOR PLANT SITE DESIGN In the early days of commercial nuclear power plants, very rarely was consideration given to the idea that a particular site chosen for a nuclear plant might in the future accommodate further plants. Perhaps the first one that was designed this way was Indian Point; the initial plant built there, a Babcock & Wilcox PWR with separate two-unit oil-fired superheater, was not only enclosed in a partially below-grade vapor containment sphere but was also further enclosed by a reinforced concrete structure outside of the sphere to reduce personnel exposure on-site if other plants were built, both from an operating standpoint and from a future potential accident standpoint. (As we know, two further plants were in fact later built there.)
A number of factors led to the step to include multiple reactors at one site from the initiation of a plan to build a nuclear generating site. First, siting issues became complicated so that any one given utility company was not likely to find a multitude of possible sites; multi-reactor power stations helped solve that problem if they could be built far enough from population centers since multiple source terms for accidents had to be considered. Second, reactor plant technology progressed far enough that confidence in design and operability took this question out of the minds of investors and utility customers. Third, production of power at fewer sites made the design, construction and operation of the distribution system for electric power ('the grid') theoretically easier.

We then began to see, before the end of the 1960's, a number of multi-reactor sites being planned. In the United States, the maximum number of nuclear reactor plants operating on any one site is three. In many cases, the plants are very close to each other and in some designs (Browns Ferry) the reactor buildings are literally built in a large block, with no external space between, even though they are physically isolated from each other internally, sharing only the space above the refueling floor as common volume.