Loss of Blade Accidents Revisited

[SAFarberMSPH@CS.COM]

Radsafe:


Sandy Perle posted a nuclear items update today which included in part the 

following note on North America's largest windmill soon starting up in 

Canada.  A while back I posted my 1981 satire on Radsafe about the "most 

dreaded of all power generation accidents - the  LOBA [loss of blade 

accident]" which leads me to pose a question.


Does anyone know how close to Pickering's turbine hall this new windmill is 

located? A 384 foot tall windmill with 128 foot blades weighing many tons 

each, could release a blade or blade element that could feather a great 

distance in the event of a windmill LOBA. Is it possible a blade or blade 

fragment from this particular windmill could strike anything onsite such as a 

major transformer,  power lines, diesel backup generator, turbine,  outside 

waste storage tanks, etc. causing damage and an impact on plant 

operations/safety? Just a question.


I recall during the early site study and plant layout for a PWR nuclear plant 

in the US in which I was involved at the time as Staff meteorologist, it was 

necessary for the architect-engineer to change the orientation of the turbine 

hall and reactor building due to a concern raised about "turbine missiles" 

such that a radial failure and release of a turbine blade or fragment could 

not strike the reactor building, with the possibility I was told of damage 

inside containment.


The concern was that the failure of an electric generating steam turbine in a 

real LOBA which happens occasionally sometimes leading to catastrophic 

failure of all  turbine blades as fragments sweep through the turbine  [of 

course a steam turbine is turning at 3600 rpm, but with much, much  smaller 

blades than the windmill] and the generation of "turbine missiles" could 

cause damage to a reactor building internals since the kinetic energy of the 

turbine blade missile fragments was so great. 


Any information on the questions above about proximity of this new windmill 

to Pickering or any other windmills near nuclear plants would be appreciated.


Please respond directly to me unless you think this might be of interest to 

others on the list.


Stewart Farber

Public Health Sciences

172 Old Orchard Way

Warren, VT 05674

email: SAFarberMSPH@cs.com


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EXCERPT FROM EARLIER POST BY S. PERLE:

"Ontario opens North America's biggest windmill


TORONTO, Aug 22 (Reuters) - Ontario Power Generation was set on 

Wednesday to put the finishing touches on what it claims is the 

tallest wind turbine in North America as it looks to develop more 

"green" energy. 


The turbine, with a capacity of 1.8 megawatts -- or enough to power 

for about 600 homes -- is located beside the utility's Pickering 

nuclear power station, just east of Toronto. 


Manufactured in Denmark, the turbine stands 117 meters (384 feet) 

tall, with 39-metre (128-foot) blades. It is part of a C$50 million 

($33 million) strategy by the provincially owned company to develop 

new sources of renewable energy as it prepares for deregulation of 

the Ontario power sector. 


"We are very serious with our green energy program because we know 

that the people of Ontario see it as a market that they would like to 

tap into," said spokesman John Earl.