Two weeks ago there was a power failure at the Fukushima Daiichi nuclear power plant (here). The spent fuel pools of reactors 1, 2, 3 and 4 lost their cooling systems for more than 24 hours (apparently a radioactive rat chewed through some cables). The Tokyo Electric Power Company (TEPCO) said that there was no radiation release, and temperatures in the fuel pools would have remained at safe levels for at least four days. Whilst it’s correct that they could have gone for four days before pool water started boiling and the fuel rods began burning, during the more than 24 hours the cooling systems were out of action the temperature of the water would have risen considerably, resulting in a radiation release from evaporation. The main point, though, is that two years after the Fukushima disaster began, TEPCO still don’t have a back-up for these crucial cooling systems. Ironically, as I type this the BBC are reporting that there’s been another power failure at the Fukushima plant, and the cooling system for spent fuel pool No.3 is not working (here). It’s unusual for the BBC to report anything about Fukushima, and when they do it’s not very accurate, so before I go on I just want to correct something that the BBC has said:
The spent fuel remains in the ponds for a year or more.
Spent fuel rods need to have circulating cooling water for up to five years, and they are kept in the pools indefinitely, because no one knows what else to do with them. There are 8,800 highly radioactive fuel rods in these four fuel pools, and there’s also 6377 fuel rods in what’s called the ‘common pool’ (40 years worth), containing, for example, cesium that is equivalent to thousands of atomic bombs. If even one fuel pool catches fire, the radiation released would seriously contaminate the entire northern hemisphere; yet at Fukushima we have a corrupt and incompetent corporation, TEPCO, handling the disaster management. It’s a bit like Carry On Splitting Atoms.
Of most concern is fuel pool No.4, which I’ve written about at length here. The plants at Fukushima are Mark 1 Boiling Water Reactors (BWR), designed 40 years ago by General Electric. The design of these BWRs has the fuel pool suspended about 60 feet/20 metres above the ground, and it doesn’t have any kind of proper containment structure (brilliant, Watson!). No.4 reactor building was badly damaged by an explosion in the early days of the disaster, and the fuel pool is in danger of collapse. If it does collapse, and all cooling is lost, the fuel rods will catch fire, resulting in the aforementioned catastrophic release of radiation. TEPCO’s plan is to take the fuel rods out of pool No.4 and put them in dry cask storage (which once again will still be stored on site, because they don’t know what else to do with it – here). I won’t go into the technical details, but will just say that this is a major engineering feat, that has to be carried out in an extremely hazardous environment, and the last I heard was that TEPCO reckon the job won’t be completed for another two years yet (cue the Sid James chuckle).
I won’t go into how patently crazy it is to build nuclear plants in an area of very high seismic activity (or indeed how criminal it is), yet if there’s another big earthquake in the next two years, fuel pool No.4 could collapse and it’s goodnight Vienna. TEPCO say that they’ve shored-up fuel pool No.4 and it can withstand a big earthquake. Hmm, only this week there was a magnitude 6.1 earthquake off the coast of Fukushima (here) and last December there was a 7.3 earthquake. In fact, Japan has large earthquakes on a daily basis (check out the Japan Meteorological Agency)
The issue here is one of trust, because the only information that we get about Fukushima comes from TEPCO and the Japanese Government, and they have lied consistently since the start of this nightmare (ie, we now know that it wasn’t the tsunami, knocking out cooling systems, that caused reactors 1, 2 and 3 to go into complete meltdown, it was the earthquake itself). At the very least they should bring in military resources to help get the fuel rods out of No.4 pool (TEPCO, being a big corporation, is using cheap and largely unskilled labour). Instead we get Carry On Splitting Atoms, whilst those who get past the media blackout look on with bated breath.
Editing in: shortly after I made this post today, TEPCO held an emergency press conference. It relates to the fuel pool situation, and is another example of just how badly the Fukushima disaster is being handled…