There is major idiocy being spouted over the situation in Fukushima. Most of all, there are a lot of ‘ifs’. I find the speculation/analysis on the internet is becoming too much with most analyses low on actual hard facts.
This video, however, from NHK Japan is a summary of the events at the stricken plant. It goes back as far as the earthquake and the tsunami itself and uses 3D animations to explain what has happened at each of the reactors.
In Reactor 3, for which there is no specific animation, the explosion had identical causes to that in Reactor 1; due to the greater damage I assume it was simply a larger explosion. The highest levels of radiation are coming from Reactor 3 which has been the focus of cooling efforts today, and Reactor 4, where levels have been too high to allow aerial drops of water. I have been trying to find footage from NHK that I watched live today where they explained the dangers of the aerial operations, again using an animation. The drops from 90 metres were far from ideal. They explained that radiation at the preferred height of 30m was ~250 milliSieverts/hr, but at 90m it was 87 mSv/hr (note how quickly that level falls off with distance). From Wikipedia on radiation dosage:
- Lowest clearly carcinogenic level: 100 mSv/year
- Elevated limit for workers during Fukushima emergency: 250 mSv/year
The helicopters (CH-47 Chinooks) have been adapted with additional lead shielding on the floor to protect from radiation, and are advised not to hover. Each run can carry up to 7.5 tons of seawater; they are restricted to flights of 40 minutes in the area to reduce exposure to radiation.
CNN two days ago (link here) talked to a former GE design engineer who resigned in 1975 over what he saw as critical design flaws in the ‘Mark 1’ reactors. He and others were bothered that the Mark 1 containment design had not taken into account all of the loads that could be experienced in an accident that resulted in loss of cooling (a ‘large loss of coolant’ accident such as coolant pipe breakage in the reactor primary system and a release of steam into the containment system itself). In the designs, the steam released was supposed to be condensed to water in the suppression pool (the large torus structure around the reactor base); the designers’ concern was if the structure failed this would mean loss of containment and loss of the source of cooling water for reactor core; therefore there would be the potential for core meltdown.
At Fukushima the cause was different – the loss of back-up power from water inundation and (both ‘drowning’ the back up electrical systems and washing away fuel storage tanks for the diesel generators) – but the effect is the same that operations are unable to cool system in the way it was designed.
Tonight, an electrical cable is reported in place so there is hope of easing the situation:
Japanese authorities have informed the IAEA that engineers were able to lay an external grid power line cable to unit 2. The operation was completed at 08:30 UTC.
They plan to reconnect power to unit 2 once the spraying of water on the unit 3 reactor building is completed.
What about some of that ‘nonsense’. Well, there’s the concern over the “government coverup” over radiation reaching the US (e.g. here). Then there’s the “all nuclear is bad” and then the counter of “look how much these plants can take”: e.g. The Register: “Fukushima is a triumph for nuke power: Build more reactors now!”. Um – just how can the explosions and events in Fukushima be considered ‘a triumph’? That’s just egregious nonsense bordering on pro-nuclear propaganda.
There is a much more considered piece here: After the Quake: A Reappraisal of Nuclear and LNG Option
After the triple blow of a massive earthquake, aftershocks, and a tsunami, much of the infrastructure in northeast Japan is reeling, and the energy sector is descending into a significant crisis.
Already, a casualty has emerged: The resurgence of nuclear power as an alternative energy source worldwide has taken a direct hit.
Meanwhile the MSM in the UK has been wheeling out the Government’s Chief Scientific Officer Professor Sir John Beddington for his opinions on the safety of the radiation levels. Now this is where we think ahead a bit. The UK needs nuclear. The government knows this and has committed to it. At some point it will need Prof Beddington to come out and say that the new reactors that will be built in the UK will be inherently safe. No doubt he will announce a review and the appointee will be his choice. So – the question is – who will it be? Perhaps he can ask pal Lord Oxburgh to play another blinder ;-)