Thermal pollution

[BYRPV@ccmail.ceco.com]

Subject: Re: "POLLUTION FREE"
Author:  David F. Gilmore
Date:    11/30/95 4:11 PM

David wrote:

Excuse me, but what about thermal pollution?  I don't know much about 
nuclear power, but aren't large amounts of water needed for cooling 
purposes with resulting elevation of temperature in the receiving 
waters?  Temperature changes can cause population changes in various 
organisms, from microbes on up.



The generation of waste heat at a nuclear power plant 
is no different than that from any fossil fuel plant.  
When liquid water is boiled to produce steam, 540 
calories of thermal energy are required per gram of 
water.  This is latent heat of vaporization.  After the 
energy is spent in the steam as its pressure is reduced 
across the turbine, it is then condensed back into 
liquid water.  During the condensation, the latent heat 
is released into the cooling water.  This represents 
about 2/3 of the thermal energy put out by the reactor. 
The efficiency of a fossil plant is a little higher 
because the steam is superheated therefore a larger 
percentage of the energy is transfered to the steam 
itself.

Thermal pollution is minimized in cases of river 
discharge by first allowing the heat to dissipate into 
the atmosphere via cooling towers or a cooling lake.

Paul Vitalis
Health Physicist
Byron-"Real Nukes Have Cooling Towers"-Station
byrpv@ccmail.ceco.com