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Thursday, April 05, 2012

Professor Bernard L Cohen - R.I.P

  On 17th March Professor Bernard L Cohen died.

  I first read of Professor Cohen in the late Professor John McCarthy's site when he reported on his calculation of the amount of usable uranium available from seawater.
Cohen calculates that we could take 16,000 tonne per year of uranium from seawater, which would supply 25 times the world's present electricity usage and twice the world's present total energy consumption. He argues that given the geological cycles of erosion, subduction and uplift, the supply would last for 5 billion years with a withdrawal rate of 6,500 tonne per year. The crust contains 6.5x10^13 tonne of uranium.

He comments that lasting 5 billion years, i.e. longer than the sun will support life on earth, should cause uranium to be considered a renewable resource.

  I personally made use of this in a speech to the LibDems. In fact this calculation is most useful in making the point simply. The amount of radioactives in the ground enormously exceeds that in the sea it is simply that the seawater calculation is indisputable as is the fact that it can be recovered. Thus there is no possibility of the human race running out of power, unless we deliberately decide to do so.

   Professor Cohen was also responsible for the largest statistical study of background radiation levels across the US, compared with health, which thoroughly and apparently successfully (nobody has suggested other factors which could account for it)  disproved the radiation LN theory & found a positive effect from radiation of roughly half the negative effect of smoking.
...We compiled hundreds of thousands of radon measurements from several sources to give the average radon level (r) in homes for 1729 US counties, well over half of all US counties and comprising about 90% of the total US population
We see a clear tendency for m [age adjusted lung cancer rates] to decrease with increasing r [radon level], in sharp contrast to the increase expected from the supposition that radon can cause lung cancer, shown by the line labelled "theory". ...

Since no other plausible explanation has been found after years of effort by myself and others, I conclude that the most plausible explanation for our discrepancy is that the linear no-threshold theory fails, grossly over-estimating the cancer risk in the low dose, low dose rate region. There are no other data capable of testing the theory in that region.
   He also wrote this book, The Nuclear energy Option, on the history of the nuclear power industry. I have several times quoted from it here, particularly Chapter 9 on how the costs of reactors were artificially raised, as much as 13.6 times by regulatory Luddism
Some plants completed in the late 1980s have cost as much as $5 billion, 30 times what they cost 15 years earlier. Inflation, of course, has played a role, but the consumer price index increased only by a factor of 2.2 between 1973 and 1983
  And there is the instance of him, when Ralph Nader described plutonium as "the most toxic substance" of him challenging Nader to eat as much caffeine as he would plutonium oxide. That indicated not just knowledge but personal bravery. Nader, presumably knowing that he had lied, refused the challenge which, in a world where the news media were interested in facts or simply human interest news rather than false scare stories would have been much more widely reported and permanently discredited him.
Ralph Nader, noted activist and lawyer, once claimed that plutonium was “the most toxic substance known to mankind.”
Other writers and scientists, often with far less publicity, have published detailed analyses of these claims and used statistics and experience to prove them totally false. One man, Dr. Bernard Cohen, went so far as to volunteer to eat as much plutonium as Ralph Nader would caffeine in an attempt to demonstrate the folly of the severe toxicity claims.
Mr. Nader refused the challenge.
   It would be overstating to equate Professor Cohen with Dr Semmelweis, since the former has not been alone in his path, but his place as a significant figure in the history of human progress is assured.

  Wkiipedia entry

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