Wednesday, August 27, 2014

Molten Salt Reactor Not Good To Go

Subtitle: Extolling Virtues and Ignoring Faults is Deceptive 

A laughable post appeared today at WattsUpWithThat, titled "A Universally Acceptable and Economical Energy Source?"    The article describes, in over-the-top glowing terms, a molten salt nuclear reactor to produce commercial power.    Apparently the author, and those who commented on the post, have not read my article 28 on TANP from July 20, 2014 in which the multiple drawbacks of a MSR (molten salt reactor) are provided.   Nothing has changed since July, however, nuclear cheerleaders continue to sell, sell, sell the gullible, the ill-informed, their desperate message of Nuclear Is Cheap!  Nuclear Is Safe!    Nothing could be farther from the truth.     Link here to my earlier article on MSR. 

To recap the many drawbacks:

MSR will have much more expensive materials of construction for the reactor, steam generator, molten salt pumps, and associated piping and valves, compared to the PWR design.   There will be no cost savings, but likely a cost increase.  That alone puts MSR out of the running for future power production.  

The safety issue is also not resolved, as pressurized water leaking from the steam generator into the hot, radioactive molten salt will explosively turn to steam and cause incredible damage.  The chances are great that the radioactive molten salt would be explosively discharged out of the reactor system and create more than havoc.  Finally, controlling the reaction and power output, finding materials that last safely for 3 or 4 decades, and consuming vast quantities of cooling water are all serious problems.  

The greatest problem, though, is likely the scale-up by a factor of 250 to 1, from the tiny project at ORNL to a full-scale commercial plant with 1500 MWth output.   Perhaps these technical problems can be overcome, but why would anyone bother to try, knowing in advance that the MSR plant will be uneconomic due to huge construction costs and operating costs, plus will explode and rain radioactive molten salt when (not if) the steam generator tubes leak.    There are serious reasons the US has not pursued development of the thorium MSR process. 

The WUWT article actually states some laugh-out-loud aspects of the "new" design.  First, the "new" design supposedly uses zero cooling water.   At the same time, the author claims higher efficiency.  Any decent process engineer will tell the author that waste heat must be dissipated to some heat sink, either cooling water or ambient air.  Cooling water is the usual choice because it is usually colder than air but more importantly, the capital cost of a water-cooled heat exchanger is far less than a comparable air-cooled heat exchanger.   A water-cooled exchanger is also far more compact, has fewer operating problems, and is not subject to serious control issues that air-cooled exchangers have.  

Next, the author claims the near-zero, or low pressure, for the molten salt as a safety feature.  As shown above, and in the TANP article 28, materials leak when tubes corrode, and the leak is from high-pressure into the low-pressure molten salt. 

Finally, the author claims a 500 MWe plant will cost only $2 billion and require only 36 months to construct.   That is approximately 1,500 MWth output.  That is indeed laughable, to have such a very low cost.  But then, nuclear advocates are very prone to hawking low-balled construction cost estimates, then blaming anyone but themselves for cost over-runs.  We see this time and again.   

The final point, and one that shall always be the deal-killer:  if the MSR reactor system was any good at all, why has it not already been developed, designed, tested, constructed, operated at larger and larger scales, and completely dominated the commercial power industry?   The answer is, of course, that MSR has insurmountable engineering issues, which are well-known to those in the industry.  

A version of the MSR is being built, we are told, in China.  Perhaps economics does not matter to them.  Perhaps operating problems also do not matter to them.  Perhaps the state-run media will refuse to report on the plant explosions and other serious upsets that will inevitably occur.  

Roger E. Sowell, Esq.
Marina del Rey, California

Copyright (c) 2014 by Roger Sowell  -- All rights reserved  

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