The arguments against nuclear power are nothing new but they are misconceptions despite being popular ones.
Disposal of the waste is not a technical problem and never has been one. Yes, the solution is to bury it, once the initial high levels of radioactivity have dwindled. Contrary to popular opinion, this happens quickly. Three hours after being removed from the core, spent fuel has only half the energy output that it had when first removed. After 5 years, the output has dropped 99.96%. This is because short-lived radioisotopes are most the intense, but these decay extremely quickly. If the waste is buried, after 500 years it is no more radioactive than the ore bodies from which the uranium that comprised the original fuel was mined. The fact is that the ground beneath us is inherently radioactive due in the main to uranium, thorium, potassium (K-40, present to the extent of 0.0118% in all potassium is a radioactive isotope), rubidium and carbon-14.
People like to claim that buried radioactive waste poses some particular hazard, but in reality this is not true. If some of the sequestered waste was to be extracted from the ground in 500 years time, it would only be hazardous if ingested which is somewhat improbable since it is a hard, refractory and insoluble ceramic material. Long lived radioisoptopes, far from posing any hazard, are benign and we are surrounded by them in any case. Because they are long lived they decay very slowly and emit very little radiation.
As to the three sites mentioned:
1. Chernobyl. In essence this blew up because of a combination of design failings. These were well known in the west, and in 1976 the UK Atomic Energy Authority published a list of seven design deficiencies which would prevent the RBMK series reactor being licensed in the west. Such reactors exist only in Lithuania, the Ukraine and Russia. The Chernobyl explosion, which took place on 26 April 1986, occurred because:
(a) The power levels were run down during a foolhardy experiment;
(b) The RBMK reactor is inherently unstable below 20% output power, that is, around 700 MWt;
(c) At one stage, the reactor was running at just 30 MWt;
(d) Emergency cooling weas disconnected by the operators.This is not possible in a western reactor;
(e) The reactor featured water cooling in conjunction with graphite moderation -- moderation slows "fast" neutrons emerging from nuclear fission so that they are "thermal" and thermal neutrons are far more efficient at generating further fission, so the more moderation, the faster the reaction runs. This led to a situation where the nett effect of the water was to absorb neutrons, which had the implication that as water was boiled off, the reaction would run hotter. This is termed a positive void coefficient, and is dangerous because the reactor runs faster and faster as the coolant boils away. It is not allowed in the west. By contrast, the light water PWR and BWR reactors, and the heavy water Candu reactor have self-levelling operation as when coolant is boiled off, the reaction slows down;
(f) When it was desired to shut down the reactor, the neutron absorbing control rods had displacer blocks composed of graphite attached to them, and these sat 1.25 metres above the base of the channels. This meant that in the event of a scram an emergency shut down) the effect would be an actual increase in reactivity low in teh channels when the desired effect was entirely the opposite. it is a bit like fighting a fire by throwing gasoline over it;
(g) The scram procedure was very slow;
(h) There was no secondary containment. In a Candu reactor an explosion, even one as powerful as the Chernobyl explosion, would have been entirely contained within the secondary containment;
(i) The combination of graphite moderation in conjunction with water cooling led to the formation of explosive water gas -- hydrogen plus carbon monoxide, and it was this that caused the second explosion that breached the reactor vessel and released radioactive material offsite;
(j) Civil defence was inadequate and very slow, meaning that many nearby populations were needlessly exposed and not treated for contamination by iodine-131 when they could have been;
(k) The controlling computer, Scala, was inaccurate and too slow;
(l) Instead of admitting that there had been a problem, the authorities responded to the incindent with obfuscation and denials.
In the end there were 31 deaths, and there have been predictions of further deaths from late-occurring cancers etc, amounting to up to 6,942 people in total. Many exaggerated and unproven claims of widespread birth deformities and cancer deaths have been made, and people have even blamed bad backs and other quite unrelated ailments on the disaster. However, the fact is that the endemic chemical pollution and other problems in the area are almost certainly responsible for many of these things and Chernobyl is merely a convenient scapegoat -- not that any of this in any way excuses the event.
Anything else anyone wants to know about Chernobyl?
2. Three Mile Island
On 26 March 1979, owing to equipment malfunction and operator error, a partial core melt occurred, but a trifling 20 curies of radioactive material was released offsite, there were no deaths or injuries and the secondary containment worked as intended. A comprehensive review of ewuipment and procedures resulted in improvements to other PWR reactors to ensure the likelihood of a similar incident in the future was greatly reduced. A great deal of hysteria and anti-nuclear agitation followed, but most of this was extremely shallow on technical rigour and long on hype. A lawsuit brought against the utility was dismissed when the defendant applied for and was granted summary judgment against the plaintiffs; a sure sign that there was absolutely no merit in their claims.
3. Sellafield
There are several issues that may potentially be raised under this head. I am assuming that we are discussing the most recent issues, which are claims of leukemia clusters associated with the nuclear facilities there, and the claims that radioactive materials are dumped into the Irish Sea.
The leukemia clusters have now been proven to have no association or correlation with nuclear activities. It has been shown that these are apparently randomly distributed throughout various communities in the UK and there is no connection with nuclear activities whatsoever. The latest theory is that a virus is responsible.
The cliams of radioactive materials being dumped into the Irish Sea are false. It must always be remembered that there is a natural background radiation dose and that this varies depending on place, altitude and various other circumstances.
I trust this shed some light on this subject. As far as I am concerned, nuclear power is a valuable, useful, and environmentally-friendly method for the generation of baseload electricity and it ought to make up more of the world's generation mix.
Philip Ross
Chairman
NZ Atomic Energy Advocacy Council
http://www.saveguard.co.nz/atomic
Note: this is slightly different to the reference given by an earlier contributor.