Saturday, March 26, 2011

Plan B: Eject the Warp Core!

I don't often write off-topic, but the images coming from Japan are just too troubling. I am not sure which images trouble more - those coming from Fukushima, those that came from Chernobyl or this video from Swiss TV:

Einstein vom 24.03.2011

What would happen if something like Fukushima or Chernobyl happened here in Switzerland? 800'000 workers were needed to contain Chernobyl; 50'000 of them have died of radiation sickness. The radiation in the Chernobyl reactor was so intense that even the robots failed.

Switzerland's population is only 7.4 million, of whom 2.5 Million are adult males, aged 20 to 60. If an accident on the scale of Chernobyl happened here, that would mean more than 1 Swiss in 10 -- or more likely, 1 adult male in 3 -- would be called into service and around 1 adult male in 30 would die. An area nearly the size of Switzerland would be rendered uninhabitable.  Where would the rest of us go?

How can we expose ourselves to that kind of risk?

Either we need to get rid of nuclear power plants or we need a better Plan B.

Plan B

On the way home from work a few days ago, I was wondering how would Star Trek solve this problem? I could almost hear LaForge screaming "Captain, I have to eject the warp core!" How could a nuclear power plant eject its core?

Sending it into space is not option -- too dangerous -- and beaming doesn't work either. So there is only one direction available: Down. Fortunately that is relatively easy to do. Gravity will do most of the work for you. (You can demonstrate this by jumping from a diving board, throwing something off a tall building, or letting a ball roll down a hill).  You just need to prepare the reactor and path, so that the reactor core can fall or roll into a secure area on command.

The harder part is preparing the pathway and ensuring that there is enough material to isolate what is left of the reactor core and prevent the radiation and other products from contaminating our ecosystem. While this is not possible after a nuclear incident, an ejection could be prepared beforehand.

One approach for long term storage of radioactive materials is the so-called 'deep borehole.' The idea is to drop the waste down a very deep tube, say 5 km, then cap the tube with earth, rock and water to prevent leakage.  

Why not build the reactor directly over a borehole? In the event of an emergency, the reactor core could be separated from its mountings and allowed to fall into the tube. The deployment might look something like this (click to enlarge):


Would this be sufficient to safely dispose of a reactor core? There is a natural precedent. A mine in Oklo, Gabon had been site of a natural U235 reaction. The remains of that reaction are still radioactive, but the sandstone around the uranium deposit contains the radiation.

Can we build a suitable borehole? The current record for a deep boreholes extend over 12'000 meters into the earth's crust! Obviously, an eject borehole would need to be substantially wider than existing boreholes for pumping oil or scientific research. The final resting site probably should be below all aquifers.  And there are surely other issues and technical challenges. But there are precedents for the solution. And without a Plan B, nuclear power is just too dangerous.

Plan C

Would this Plan B have helped in Japan? I don't think so. An earthquake is liable to leave the boreholes blocked or otherwise unusable. Which brings us to Plan C: If there is no viable Plan B for securely and quickly shutting a reactor and isolating it from our ecosystem, then then nuclear power is just too dangerous. Shut it down or don't build it in the first place!

6 comments:

Daniel marbach said...

This is well thought off peter. But how do we fill in the need for energy? Don't get me wrong I also want to get rid of nuclear power but what kind of energy source is suitable?

Water power, wind power, solar power? The answer depends from country to country... What about in switzerland? Water power: plans in building more storage lakes or extending existing ones are blocked from nature activists because some rare specious need to be kept alive. wind power: were do you install these devices? They are huge. Rejections from alpinists, nature activists... Solar power: there is yet to find a better "wirkungsgrad" Or price to efficiency to square meter ratio and batteries

So where does this leave us? Reduce you amount of energy in your daily life! Change light bulbs, dont let the computer running, turn of your devices at night... If everyone reduces the intake about 30-40 % we dont need nuclear power!

Daniel

Peter said...

Hi Daniel,

I agree with you, the question is extremely difficult. What I have realized is that atomic power accumulates tremendous 'technical debt' - which will eventually have to be paid off.

Let us assume we applied airplane crash liability standards to those 50'000 people who would die fighting a meltdown. $5'000'000 per person or so. Multiply those figures together and you get a very big number. Add in the costs of relocating 2/3rds of Switerland's population and businesses abroad, value of property lost, etc, and my guess is that would add 1 to 2 CHF/KWh to the price of nuclear-generated power. Would nuclear power be attractive if those costs were priced into the power generated?

But those are just numbers. In Chernobyl, the toll is comparable to the aftermath of an atomic bomb. It just happened more slowly, without the bang. Who would be willing to accept an atomic bomb going off in Switzerland someday to have a wide-screen TV in their living room?

Personally, I'm OK with Plan B. Given the choice between Plan A or Plan C (Chernobyl-style cleanup or not operating nuclear power plants), I would prefer Plan C.

Despite how much I love my computer, wide-screen TV and other electronic toys, I just can't warm up to idea of having a 1 in 3 chance of being called up as a liquidator.

Given that we have Plan A right now, perhaps it is time for a 2 CHF per KHw tax on atomic power. This would build up the necessary financial reserves to pay for the disaster ...and encourage people consume less energy!

And yes, last year I replaced most of the bulbs in our apartment with energy savers and replaced a number of gadgets whose standby power consumption was > 1 watt.

Cheers, Peter

Bradley said...

"800'000 workers were needed to contain Chernobyl; 50'000 of them have died of radiation sickness."

Where are you getting this figure? 31 people died working on Chernobyl. These are the only deaths directly related to the accident.

Peter said...

Hi Bradley,

The figures I cited were reported in the video from SF (Swiss Television), between 2:30 to 2:40 into the report.

Where do you get your statistics from?

Best regards,
Peter

Peter said...

Hi again, Bradley

A google for cherbobyl deaths produces among other things:

A list of 31 people who deaths were "directly attributable" to Chernobly. Most of these people died of acute radiation poisoning.

A 2005 paper by the World Health Organization entitled "Chernobyl: the true scale of the accident", which attributed 50 deaths, but also estimated a total of "as many as 4000" deaths and many other physiological, psychological and social consequences of the accident and ensuing (forced) migration.

A 2006 Greenpeace report estimated "a quarter of a million cancer cases and nearly 100,000 fatal cancers."

A 2010 book from the New York Academy of Sciences estimated a total 1'000'000 deaths caused by the accident. This book was based on an extensive survey of Slavic language literature. Among their findings: "by 2005, between 112,000 and 125,000 liquidators had died." What I found even more depressing: "The proportion of children considered healthy born to irradiated parents in Belarus, the Ukraine, and European Russia considered healthy fell from about 80 percent to less than 20 percent since 1986."

My conclusion: Figures don't lie, but liars can figure. An estimate of 31 to 50 deaths 'directly attributable' to Chernobyl strikes me a someone's attempt at whitewash. The consequences of a Chernobyl-like catastrophe are terrible and far-reaching, regardless of what numbers you attach to them.

Best regards,
Peter

Tony said...

Alas just because liars can figure doesn't mean all estimates are of equal worth.

On Chernobyl, I believe the UNDP (United Nations Development Programme) report is right. A short summary of its findings is here.

Key sentences are:
There has been real suffering, particularly among the 330,000 people who were relocated after the accident. About that there is no doubt. But, for the five million people living in affected regions who are designated as Chernobyl “victims,” radiation has had no discernable impact on physical health.

This is because these people were exposed to low radiation doses that in most cases were comparable to natural background levels. Two decades of natural decay and remediation measures mean that most territories originally deemed “contaminated” no longer merit that label. Aside from thyroid cancer, which has been successfully treated in 98.5% of cases, scientists have not been able to document any connection between radiation and any physical condition.

Where a clear impact has been found is mental health. Fear of radiation, it seems, poses a far more potent health threat than does radiation itself. Symptoms of stress are rampant, and many residents of affected areas firmly believe themselves to be condemned by radiation to ill health and early death.

The longer more technical report is here.

One should note, writers of reports such as these who don't echo the fears of millions have a thankless job. But science is more important than opinions of millions. If that weren't so, we'd still be in the dark ages.

Disclaimer: I was a student with Ms. Vinton, the UNDP representative to the Ukraine and Belarus, in a summer program when we were in high school. A bio of her is here and is impressive.

Tony

( see you in DC, Peter! I signed up. Best wishes )