South Korea To Restart Its Oldest Nuclear Reactor 129
ananyo writes "South Korea's oldest nuclear reactor is set to restart after a four-month closure, despite strong opposition from local residents and activists. The Kori-1 reactor in Busan was shut down on 13 March, after it was revealed that the reactor and its emergency generator had temporarily lost power during routine maintenance the month before, causing the coolant temperature to rise. The power failure did not cause an accident, but a report by the International Atomic Energy Agency in Vienna discovered that senior engineers from Korea Hydro and Nuclear Power, which runs the reactor, had neglected the safety problems for more than a month after the loss of power. In June, after a safety check, the IAEA gave the green light for Kori-1 to resume operation. Korea's Nuclear Safety and Security Commission (NSSC) approved the restart on 4 July, but activists and local residents remain strongly opposed to restarting the reactor. At first, the Korean Ministry of Knowledge Economy, which oversees energy policy, had said that the restart would be delayed to alleviate anxiety. But the government changed its mind as a result of a nationwide heatwave that has put a strain on the country's electricity supply in recent days."
Re:Safety? (Score:5, Informative)
... thought that all modern reactors were protected by passive safety mechanisms ...
Kori-1 is a PWR from 1978 and like most reactors currently in service, it is a generation II design. These have many passive safety features, but they are generally not fully passively safe.
Some Gen-III reactors (1990s tech) and most Gen-III+ reactors (2000s tech) have full passive safety, in addition to many other safety improvements like simplified designs, better containment, better redundancy, etc. Gen-IV designs (future) step it up to inherent safety - for example pebble beds (meltdown is impossible because thermal expansion stops the reaction even if all cooling strategies fail) or my favorite, the LFTR [wikipedia.org] (liquid fuel - you can't melt down when you're already melted, and thermal runaway just drains it into a basin in a noncritical configuration; and it's an unpressurized design, which eliminates tons of problems).
So does this actually pose a safety risk?
Yes - like everything worth doing in life, there is always risk. In this case the risk is that the reactor requires water to be actively pumped for a while after shutdown. The risk is generally acceptable: a failure like the one that happened a few months back doesn't cause a sudden catastrophic failure. There is considerable thermal mass in the water inside the reactor so the temperature rise is gradual. In event of a failure you have days to get some power back online. In the case of the failure a few months back, the power was back within minutes and there was little chance that they wouldn't be able to manage it in time. The incident wasn't an acute safety risk; but it was a failure that shouldn't have happened in the first place, so it's somewhat worrying.
The problem is if you have a disaster like the Japan earthquake: if the power is knocked out and all your infrastructure is too crippled to fix the grid or truck in some generators; then things go sideways. These are low frequency events, but they happen, which is why in my opinion we need to start building modern reactors so we can decommission these old Gen-II relics.
Re:The needs of the few (Score:5, Informative)
Re:Safety? (Score:5, Informative)
Actually, the Gen III+ is Soviet 1980ies tech, but don't let Westinghouse hear that. The Soviet Union published its AES-88 design in 1988 and handed it over for review in Germany - after Chernobyl, this was called for. The AES-88 is a passive design and predates the AP-600 by 10 years. There were several other designs as well all designed until about the time of the break-up of the Soviet Union. (After this some 2-3 million people starved/froze to death or otherwise perished in the worst economic crisis the world has never heard of. Life expectancy in Russia dropped to levels not seen since a certain Josef Stalin. In short: They had other problems.)
More designs followed much later. The latest being the AES-2006. Which adds a core catcher and is more economical than the AES-88, without sacrifying the passive safety, as it was in the AES-92. The AES-92 had a large pool of cooling water to provide emergency cooling without electricity for 12 hours or so, but no heat removal systems to recondense and recycle the cooling water. AFAIK those that have been build were refitted since, but I might be wrong. The AES-2006 also has hydrogen catalyzers by design, I'm not sure if this was the case in the older ones.
(Please note: Russian designes distinguish between the reactor/power system and the power plant design as a whole. The AES-2006 design is implemented in all of the VVER-1200 power stations, for example.)
Better still are the breeder reactors, which are fully passive by design. The BN-600 is still operating, three BN-800 are under construction, two in China, one in Russia. The main problem is, of course, the flamable coolant (sodium). A lead cooled commercial reactor is supposed to be finished in 2017.
To make a long story short: If you're looking for the latest in nuclear power, look at Russia. (And yes, this came as a surprise to me as well.)
Re:The needs of the few (Score:5, Informative)
I understand what you're saying, but you are very much scaremongering here.
The differences are:
o The US reactor is not on in a tsunami zone.
o The US reactor is geologically stable.
o The US reactor's batteries are above sea level.
o The US reactor's generator is above sea level.
o The US reactor has at least three generators, shared between several other reactors, available on call.
o The IAEA repeatedly gave bad marks to the Japanese reactor, for all of the elements which failed. They have given good marks to the US reactor.
Basically, while it certainly is a reactor to keep our eye on simply because of its age, it has none of the risks which directly and/or indirectly initiated and exacerbated the situation in Japan. Basically they are the same design but the US reactor not only has none of the same risks, all of the known risks have been intelligently mitigated. Whereas in Japan, they were literally ignored.
As such, a comparison without providing such details only serves to spread Fear, Uncertainty, and Doubt and scaremonger without any rational justification whatsoever.