Chernobyl Vs. Pt. Lepreau

 

Dear Editor,

 

In a recent letter (Chernobyl… March 7, 2005) Larry Lack presents his view on the UNSCEAR report on the radiological health effects of the Chernobyl accident.  To quote Mr. Lack, “The result is a systematic U.N. cover-up and denial of what is actually happening in the large area affected by the Chernobyl accident.”

 

This accusation ignores the fact that while the report was done on behalf on the United Nations it was the conglomeration of research from hundreds of scientists, most of whom had no relation to any United Nations body.  While it is one thing to bring forth a conspiracy theory against the U.N. it is another entirely to accuse hundreds of professional scientists. 

 

Mr. Lack then interprets his conspiracy theory in such a way that nuclear power is not worth the risk involved.  This he does without consideration of the circumstances that led to the accident.  A combination of poor design and criminally negligent human actions is what led to the Chernobyl disaster and each is tackled at Point Lepreau by the concept known as “defence in depth”.

 

Point Lepreau has two completely independent digital control computers.  Under most circumstances these computers and the Reactor Regulating System (RRS) they control are capable of bringing the reactor to a safe state.  In the certain circumstances when this is not possible it has two completely independent special safety systems.  One is spring assisted “shut off rods” and the other the “Liquid Injection Shutdown System”. Each is controlled separate from the RRS and is tripped automatically by computer and will shutdown the reactor within two seconds.  At Chernobyl the RRS and the shutdown system were one in the same, they needed to be tripped manually and took 18 seconds to operate.  Furthermore, the design of the rods inserted “positive reactivity” into the core for a short period of time.  This is exactly the opposite of what they need to do!

 

Of course these are only a few of the high level safety systems.  There are many more and each is supported by several levels of redundant equipment which ensure defence in depth is maintained even if equipment brakes or people make mistakes.

 

Perhaps the most telling distinction between Chernobyl and Pt. Lepreau is the moderator.  This is the entity in a nuclear reactor which “thermalizes neutrons” and allows a controlled reaction to be sustained.  In Chernobyl it was solid graphite, in Lepreau it is liquid water.  The major spread of radioactivity in Chernobyl occurred when the moderator caught on fire.

 

Pt. Lepreau avoids three million tonnes of air pollution and greenhouse gases every single year.  This prevents both global warming and the health effects related to burning fossil fuels.  In the words of eminent environmentalist Prof. James Lovelock, “civilization is in imminent danger and has to use nuclear - the one safe, available, energy source - now or suffer the pain soon to be inflicted by our outraged planet.”