Sunday, February 22, 2015

New Documentary on Fukushima

This brief but informative documentary (the first third of a program called VICE) points out that the radioactive water and soil are piling up with no plan in sight for disposal.   As Micho Kaku points out, we are 50 years into the nuclear power era, and we still don't know where to put the waste....

Saturday, August 16, 2014

ISIS has 40 kg of Uranium Compounds

After my last highly speculative post about ISIS, the terrorist group in Iraq, possibly acquiring Uranium, from used weapons, I researched breeder reactors more. I convinced myself that even possessing a large quantity of depleted (or natural) would not afford even a slight chance to the group to develop a nuclear weapon.  The main reason is that while the breeder reactor can create fissile Plutonium from standard or depleted Uranium, the task of separating it from Uranium is chemically very challenging.  

Never-the-less I thought it quite odd that 2 days after my post, stories came out reporting that ISIS had successfully obtained about 40 kg of "Uranium Compounds" from a lab in Mosul University.

Most reports (correctly, IMHO) dismissed the prospect of any fission weapon being made from this haul.  Some commentators threatened that this made a dirty bomb possible.   (Conventional explosives used to disperse somewhat radioactive compounds like U238).     I don't see how this "dirty bomb" scenario, even at its worst represents a significant threat by ISIS beyond their current capabilities (explosives and guns).   Since depleted uranium is scattered over the  country, left over from the US-Iraq war, adding some more doesn't seem like such a scary change.   Whatever harm scattering non-fissile Uranium around can cause, it has already happened.   The conventional explosives can clearly kill more people...not to mention guns and what ever other horrific methods that group may be using.

Sunday, July 6, 2014

Will ISIS use Depleted Uranium in Iraq?

Greetings.   I've decided to expand the purpose of this blog beyond scientific analysis of the nuclear issues associated with the Fukushima meltdowns to a general discussion of specific issues of public interest relating to nuclear physics.

My inspiration for today's post is the book I am reading "The Making of the Atomic Bomb" by Richard Rhodes...and excellent and very readable book.  I just read how nuclear scientists like Leo Szilard tried desperately to make the US government aware of the importance of the discovery of nuclear fission by Lise Meitner & colleagues.    A key factor is the difference in the way the two main isotopes of  Uranium react: the rare U235, and the heavier (and more common) U238.

This got me thinking about U238. It comprises ~99% of Natural Uranium, and to make bombs & reactors, natural Uranium is enriched until the ~1% of it that is U235 becomes 20% or even 99% (highly enriched, or weapons grade).  Nuclear bomb makers thus remove most of the less reactive U238.....but that doesn't mean they can't use the leftovers for weapons.  They can and they do.

This leftover "Depleted Uranium" is shaped into high density and very hard bullets and anti-tank shells,  which were used extensively both US-Iraq wars, and has, apparently caused serious health problems, including reproductive harm.   While U238 is not as radioactive is the U235 made for bombs, its radioactivity lasts a very long time.   Some 400 tons of DU was dropped on Iraq, of which most has not been cleaned up.

My goal here is to determine, via  a back of the envelope calculation if this reservoir of DU could be used by ISIS, to create a weapon that poses a general threat to human health.   ISIS  currently occupy what looks like about 1/3 of Iraq  (and a portion of Syria which is not of interest here).  So, with some rough assumptions, I calculate:

A.)  Of 400 tones of DU dropped on Iraq, 1/3 was in ISIS controlled territories.   (I'll decrease this to 1/4 since much DU was concentrated in South Iraq...but a lot was used in Falluja as well)

B.) Perhaps only 10% of DU is recoverable (eg. using Geiger counters).  The rest would be vaporized, too broken up to trace, or otherwise already cleaned up.   The figure could be lower than this.

This leaves about 40 tones, or 40,000 kilograms of pure Uranium 238 possibly under ISIS control.  What could they do w/ that amount?  Fortunately, one answer is NOT "immediately build a nuclear weapon".   While only 50 kg of U235 (a ball 4 inches in radius) is needed for a nuclear weapon, Depleted Uranium is pure U238 and has no critical mass, so cannot be "enriched" into U235.

But it can be transmuted into Plutonium 239 by means of what's called a breeder reactor.   That Plutonium 239 can be made into nuclear weapons, like the one that destroyed Nagasaki.  Basically a neutron source is required to add an extra neutron to U238 making Pu238 which Beta decays into Pu239.   Building a full fledged breeder reactor seems implausible to me given the current state of affairs in Iraq.

However, there are many types of neutron source, with different neutron fluxes, ranging from the old fashioned Radium+Beryllium sources used by fission pioneers such as Otto Hahn (Nobel Prize winner, not to be confused with David Hahn, the "Radioactive Boy Scout" who also used this same type of neutron source) to home made & commercially available "Fusors"......It is difficult to calculate what neutron flux is needed to transmute appreciable U into the required 10 kg of Pu, using neutron reflectors and neutron moderators (eg. Heavy Water) to improve the process.

One report makes such transmutations sound easy, given the right facilities; but according to this website its well nigh impossible (but it does not consider the prospect of a large quantity of free DU).     I'll have to leave that calculation until later...if you have any thoughts feel free to chime in in the comments.   How could we tell if ISIS were doing this:   look out for large purchases of Geiger counters, Heavy Water, smoke detectors, etc.

Ostensibly it is unlikely that any viable attempt at nuclear weapons will made by non-state entities, so there probably is nothing to worry about.  ...After all, isn't it safe to assume that if the US military invades a country they will have thought through any of the adverse consequences like this?

Thursday, June 19, 2014

Its been a long time since I posted any updates on Fukushima.   I wanted to note two important recent stories.  The first, in the NY Times:

Is ostensibly about an intriguing new technology, muon imaging, that may enable clean up crews to peer into the reactor buildings.   But the most important part of the story comes in the first two paragraphs:

Nobody really knows, because nobody has yet examined many of the most important parts of the wreckage. Though three and a half years have passed, it is still too dangerous to climb inside for a look, and sending in a camera would risk more leaks. 

This has been the first point I make when people ask me about Fukushima: nobody has looked at the problem yet.   Imagine if you had a massive leak in the pipes of your house.   Your first goal might be to switch off the main water supply, and remove excess water.  But if, after 3 years nobody had taken a look at the damage caused or the cause of the leak, where would that leave you?     To clean something up, you need to look at it first.   No one has done that, and until they do, we can say that there is currently no (credible) plan to clean up Fukushima.

The other article shows the failure of the "Frozen Wall" plan...a dubious plan from the start in my mind.

Apparently its just not so easy to make a huge block of soil freeze solid.    I remember in geology class learning that each kilometer down you dig, the temp. of the Earth increases by a certain amount  (hence mines are very hot).   I'm sure they are fighting this and many other factors.   Since the "China Syndrome" has, effectively, happened, perhaps we should revisit the article, written by a Manhattan Project veteran, in which the term was coined.   Actually, another blogger has already done so:

Sunday, December 8, 2013

25 Sieverts/Hour! Highly Lethal radiation found OUTSIDE reactors.

NKH Has  reported detection of radiation in a duct outside the reactors at the level of 20 Sieverts per hour.

This is typical of the radiation levels INSIDE a reactor!   It can kill a human in about 20 minutes.  One obvious, unasked question is: who made this measurement, and how close did he get to make the measurement?  I would be concerned for the health of that worker.

Speaking of workers,  this article reports that the workers who built the tanks storing millions of tons of radioactive water were hired in very suspicious and possibly illegal ways.

Of greater importance to me are the reports that they tried to report the shoddy construction of the tanks but were ignored.   One worker appears to have been payed hush money to keep the shoddy work secret.  The tanks later failed and leaks thousands of gallons of radioactive water.

Friday, December 6, 2013


A few headlines from a few weeks ago.

NY Times:   "Tainted water still flowing"

It appears that TEPCO tore down a cliff that would have protected the reactors from the tsunami to build Fukushima:

Fuel is being removed from Reactor 4.  That this is possible is a good sign.  However it could be a risky endeavor.

Tuesday, October 22, 2013

Once again fission Nuclear power proves too expensive to insure.     India refuses to buy US reactors unless they come with warrentees from manufacturers that include full liability.   Of course the producers of nuclear plants (eg GE, Westinghouse) don't have to pay for defects in their products in the US per US Federal Law, so why should India want these US companies to be held accountable?

There is, of course one obvious reason they may want US companies to agree to be accountable for their plants:  Bhopal.

In related news, the ex. PM of Japan just came out for completely eliminating nuclear plants form Japan  calling nuclear power: