Wednesday, March 16, 2011

Energy Options for UK after Fukushima

Given the Japan situation, a knee jerk reaction seems to be that putting Nuclear Power Plants (NPPs) inland is a better option (where the coastal setting would be subject to some intermittent seismic disruption).


Has being 'Coastal' created the Fukushima situation or made it worse?

mainly NO. This is my opinion, and differs from the knee-jerk reaction I had, when I first started reading the headlines. Read on for explanation.


The situation at Fukushima - some cause and effect:

If my reading of the Japanese situation so far is correct (cursory reading) then:

(1) The earthquake effects on the plant where mostly 'indirect', in that, the main damage was caused by the loss of electrical grid power, and the consequent disorganisation in applying backup power systems*.

(2) An engineering failure in the high pressure injection system has left the plant vulnerable to overheating. It cannot restart the water systems which had [ rightly ] executed an 'automatic stop' during the earthquake.

(3) As the situation is now an 'advanced threat', the Japanese response is emergency cooling using seawater. Dangerous? Possibly. Avoidable? Probably not at this stage of management.

*Extract from Bloomberg.com
Back-up diesel generators that might have averted the disaster were positioned in a basement, where they were overwhelmed by waves.

NPPs in Earthquake zones require:
  1. Redundant cable feed electricity (this is rarely implemented)
  2. Yearly or twice yearly Disaster simulations where main power loss is realistically simulated.
  3. Backup power procedures that are regularly tested and improved, with the involvement of key workers (see simulations above)
The Bloomberg extract suggests 2 & 3 where not implemented at Fukushima, and I suspect 1 was not an implemented feature also.

But what about the Tsunami? Well it did have some effect, it flooded the basement where the backup generators lived. Also it did cause some other damage, however my impression* is this was less of an issue, than the lack of availability of backup generators.


*Engineers on the ground will have input into a report once the immediate disaster situation has been stabilised. Only then will it be made know how much each of the factors contributed to the situation becoming critical.


Coastal or Inland - Earthquake and Tsunami considerations:

International standard (IAEA) distance from active fault of 5km, does not sound very far really. Perhaps 30km or 40km is a figure the International body should be considering.
(Japan would probably have to ignore the 30km or 40km advice due to it's existing site investment, however the guidance might have some influence on future plans.)

Countries tend to always go 'coastal' by default, but there are obvious exceptions (Switzerland)

Engineering is practical to draw cooling water (and carry sanitized 'run off') the 30km or so to natural waterways, so perhaps more countries with moderate to high earthquake risks, could look at those engineering options.

An Extract from a Swiss "Earthquake Nuclear Safety" report:
An important feature of the Japanese earthquake safety concept is that all
NPPs are founded directly on hard rock.

Source: zlg.ethz.ch


For Japan being Coastal [ and in an earthquake zone ], seems to have been less of an issue, than the loss of grid electricity power, the injection control system restart failure, and the management issues in applying backup power systems.

Another element contributing to the risk in the current situation, is the practice of having 'spent fuel rods' hanging around within / around the main reactor structure.

The NPP managers have two 'cooling worries' instead of just focusing on the reactor itself.

Keeping 'cooling pools' of spent fuel rods in the immediate area of the main reactor, seems an economic practice (cost of transport / covered sealed tunnels), rather than a best practice based on disaster planning.

Strangely enough, having advanced to the situation of a possible overheat, having seawater readily available for pumping in, might prove to be a good thing.
( Whilst it is somewhat untried, and not good for the long term maintenance of the NPP, the seawater might in this case be the best thing about being coastal ) 


The style of Reactor at Fukushima Daiichi and General Electric:

One question I have not addressed much yet, is the question of Reactor design.
  • Japan did not design the reactor that is now having issues
  • The reactor is based on a General Electric (US) export design which was part of a new wave of 'lower cost' design choices pioneered in the 1960s
  • The United States invested heavily in the 1980s in retrofitted upgrades to NPPs using that design.

Some questions:
  • Did General Electric advise it's export partners of the retrofitted upgrades?
  • Is there even a requirement for notifying export partners about such things?
  • Were Japanese power generating companies advised / aware, but chose not to retrofit?

Reflecting on a 1980s quote from the Nuclear Regulatory Commission:
Mark 1 reactors had a 90 percent probability of bursting should the fuel rods overheat and melt in an accident.
Source: Ndtv.com - India

In particular Germany has just taken offline all pre 1980s NPPs, as a reaction to the experiences from Japan.


Bear in mind that the German move may well be political, but also, that the position might well be rather different, if Germany exported Nuclear technology.

( Germany does some great Engineering, particularly Space and Aerospace, however Nuclear technology seems to be their bogey. )


Spent Fuel Rods - on the roof, onsite, offsite - the choices:

Offsite, Offsite, Offsite. Repeating might make the message stick!

Taking spent Fuel rods by train, to an inland reprocessing or triage area, is in my opinion the best option.

Yes, the facility would have to be well guarded and secure. Many countries have these facilities and manage them well.

Yes, there is a cost. However in a disaster situation, you are then not worrying about 'reactor cooling' and exposure from 'spent fuel' at the same site.

Disaster management (as the Japanese situation is demonstrating), is much more difficult to get right when you have multiple risks to address.

The practice of keeping the spent fuel on the roof of the main reactor sounds like something out of a comic book to me. (I can only assume that this is a useful technique from a containment point of view).

However it takes back as much as it gives...

What seems like a convenience (in terms of containment), actually creates an opportunity for inertia in moving the now cooled 'spent rods', away from the critical superstructure of the main reactor.

It may be necessary to keep spent fuel onsite for a short time whilst transit is arranged, however there should be a mandatory time limit on this sort of temporary storage.

There is a writeup of thoughts on Japan and the spent fuel situation here [ Ndtv.com ]


Would future UK reactors be safe?:

Plans were agreed last year for 8 new UK NPPs

Those designs would certainly not be based on 1960s 'lower cost' designs.

The new designs will have to be robust, and designed with the intention of being primarily MOX fuelled.

Certainly worth reviewing disaster recovery procedures, and ensuring nuclear facilities are required to have 'cooling pools' for spent fuel away from the main superstructure of the reactor.

Mandatory limits on keeping spent fuel rods on site, need to be strictly enforced with random visits from the nuclear safety agencies, and suitable financial and personal liability penalties for those involved in breaching the rules.


MOX fuel - new technology and the blame game

The UK future nuclear plans are to produce and use mixed-oxide (MOX) fuel.

Instead of a 'cost burden' associated with deep earth disposal and/or long term storage, a new approach to dealing with highly enriched plutonium has emerged in the last 10 years.

One attraction of MOX fuel is that it is a way of disposing of surplus weapons-grade plutonium, which otherwise would have to be disposed as nuclear waste, and would remain a nuclear proliferation risk.

It should not be assumed that all reactors are capable of using MOX fuel, and each country goes through it's own review and certification process.
( See this Wikipedia article for the quote used above and the detail of the review and certification process country by country )

New NPPs should certainly be built, with designs capable of, an intake of traditional 'low enriched uranium oxide' plus the newer MOX fuel.

Nuclear material (like Coal and Oil) is not an endless resource. This is why the term 'renewable' is not applied to Nuclear.


Who is using MOX fuel today?
30 thermal reactors in Europe (Belgium, Switzerland, Germany and France) are using MOX and a further 20 have been licensed to do so.
Source: Wikipedia


Delays in agreement for new UK NPPs and how this might be a benefit:

Now that Europe is committed to an urgent review of plans for all new NPPs, the UK can benefit from the oversight this will bring.

Instead of 'convincing' the UK about the safety of the new designs planned for the 8 NPPs, that process will now come in for wider scrutiny.

I feel confident that should the new designs meet UK and European safety regulation, then they will have passed some important tests on the way to future safe operations.


Japan and Disaster relief - a time for compassion

During this article I have been focusing on just one part of the current Japanese crisis.

The bigger part of things, is the tragedy of Earthquake and Tsunami, which has already claimed many lives.

Disaster relief is essential at this time and, hopefully, all countries will do their part in supporting Japan during this time.


Notes and Further Reading:

How do I personally feel about NPPs? I think they are an important plank of our Energy system.

They are not 'renewables'. Neither are they cheap. However it will take another 10->30 years of investment for the 'renewables' industry to be fully developed.

As a worldwide population we seem to have little appetite for, reducing the amount of energy we consume. So in my book NPPs still have a role to play.

Should NPPs be subject to stringent safety oversight, giving 'low cost' options some balance. Certainly.



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