reactors & fuelrod pools closeup

8-8-13   LANL researcher, Haruo Miyadera, said that the muons are scattered more strongly by high-Z materials, such as uranium fuel in Fukushima’s reactor.

He further added that by measuring the scattering angle and understanding the physics of Coulomb multiple scattering, one can assess the locations and amount of the melted fuel in the reactor.

This new technique offers significant advantages over traditional muon imaging.

It measures muon trajectories both before and after the object. By combining the incoming and outgoing trajectories, one can more accurately specify the location of the scattering, yielding a clearer image.

Meanwhile, the access inside the Fukushima reactor pressure vessel has been very limited due to high radiation.

However, the LANL team plans to install detectors in front of the reactor building and on the 2nd floor of the turbine building, so that their muon scattering technique can assess the damage without direct access to the reactor building.

A few months of measurement will reveal the distribution for reactor core fuel and will accelerate the planning and execution of reactor dismantlement, potentially reduce the overall project span by years, reduce overall worker radiation doses, and help Japan and the nuclear power industry in the recovery process from this catastrophic event, Miyadera said.   http://zeenews.india.com/news/science/muon-imaging-technology-can-help-calculate-fukushima-damage-study_867624.html

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The Fourth Reactor at Fukushima on February 20, 2012. The yellow area is the containment vessel. –The Asahi Shimbum Digital

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10-25-2011   Because of the serious nature of this threat, it would be wise for the Japanese Government to call in experts from other countries to assess the structural integrity of the spent fuel pool in Unit 4 and to recommend measures that can be taken to strengthen it.  It is imperative that the spent fuel pool and its supporting structures are capable of withstanding the most severe imaginable aftershock.  -Dr. Gordon Edwards  http://akiomatsumura.com/2011/10/447.html

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Most nuclear engineers and nuclear regulators have developed a “blind spot” about the catastrophe potential associated with the spent fuel bay because of years of neglect. Such considerations have never played a significant role in their training as nuclear engineers or in their many subsequent years of experience in the field of nuclear safety analysis.

As a result we have backup pumps, backup electrical supply systems, and backup cooling systems for the core of the reactor, but no backup pumps or electrical supply or cooling system for the spent fuel bay. We have extravagant containment systems for the core of the reactor, but no comparable containment systems for the spent fuel pool.

This absence of backup systems for the spent fuel pool is testimony to the lack of effort and lack of forethought that has been devoted to the spent fuel bay….

The overheating of the spent fuel in the pool can be exacerbated by the intense exothermic reaction between the zirconium cladding and the steam produced from the overheated water, and can even result (at around 1000 degrees C) in a very intense zirconium fire which can result in tiny particles of intensely radioactive spent fuel being liberated into the atmosphere….

In addition to the possibility of zirconium fires (which have for a long time been almost completely overlooked by nuclear engineers and regulators) there is another, even more dangerous possibility.  An alteration in the geometry of the spent fuel in the pool, by which the separation between the spent fuel rods is slightly but significantly reduced, can lead to re-initiation of the chain reaction in the pool.

This “accidental criticality” will not only drive the temperature up rapidly, but will also replenish the supply of short-lived heat-producing fission products, accelerating the damage to the fuel, magnifying the heat loading, increasing the probability of a fuel pool meltdown, and vastly increasing the atmospheric releases of radioactivity.

It has been a standard practice in the nuclear industry to avoid consideration of all of these possibilities, based on the assumption that there will be “lots of time” to react to any emergency involving the spent fuel pool, as it will normally take days for the spent fuel to reach the melting point and it will be a “simple matter” to refill the pools with water if necessary.

This ignores the fact that major structural damage may make it impossible to approach the spent fuel pool due to the lethal levels of gamma radiation emanating from the spent fuel once the protective shielding of the water is gone.  -Dr. Gordon Edwards  http://akiomatsumura.com/2012/01/lack-of-training-on-the-catastrophic-accident-potential-at-spent-fuel-pools.html

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 July 2013      Unit 4’s fuel pool has the most fuel and the hottest fuel. It was recently (before March 2011) changed out. So a loss of cooling in the unit 4 fuel pool can still lead to a fuel pool fire and contamination of vast amounts of the country. The chance of a fuel pool fire diminishes with time because the fuel becomes cooler. It’s not there yet but it is approaching the point where if the pool were to lose water, it’s likely that the fuel would not catch on fire. That assumes the fuel stays intact. If the earthquake is significant enough to distort the fuel and cause it to collapse, all bets are off and you can still get heating to the point of creating a fire if the fuel were to break and not be cooled. But the third thing, Akio, is what you referred to as the unit 3 problem. Unit 3 has less fuel in it than unit 4. That’s good. The bad news, though, is that unit 3 is much more severely damaged than unit 4. So if unit 4 could ride out a Richter 7 earthquake, it’s likely unit 3 will not. So the risk of a structural failure in unit 3 is higher, although there’s somewhat less nuclear fuel in the fuel pool, it still presents in my mind now rapidly becoming the single biggest risk on the site is a structural failure of the unit 3 building because of all the damage from the massive detonation shockwave that hit the building. The magnitude of this problem is huge. It’s as if we – the Japanese should be fighting this as if it were a war. And you don’t fight a war on a budget. And I think that’s what’s happening in Fukushima. Tokyo Electric has minimal funds and they’re doing the best they can with minimal funds. And the Japanese government, it’s easier for them to blame the problems on Tokyo Electric rather than face the fact that at the root of this problem is that there’s not enough money being spent. So if you’re going to solve the biggest industrial accident in history, you’re going to need the funds required to do that. And I don’t think either party – Tokyo Electric or the Japanese government – want the Japanese people to understand just how deeply in debt the Fukushima Daiichi disaster has put them. I think it’s about a half a trillion to three quarters of a trillion dollars in debt to clean up the site and to clean up the prefecture.          -A. Gundersen    http://fairewinds.org/media/fairewinds-videos/forty-good-years-and-one-bad-day

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Conference reveals faltering US-Taiwan ties

10-1-13   For the second year, both the US Department of State and the Department of Defense have failed to provide senior officials to speak at the conference although both have sent delegations.  http://www.taipeitimes.com/News/taiwan/archives/2013/10/01/2003573428/1

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9-26-13     TAIPEI — The new government of Australia has said it is willing to begin free trade talks with Taiwan, a sign that the new administration will be more friendly toward Taiwan than its predecessor, a senior official of the Ministry of Foreign Affairs (MOFA) said yesterday.   http://www.chinapost.com.tw/taiwan/foreign-community/2013/09/26/389822/Aussie-new.htm

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