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@radioguy ........

radioguy.. you can handle the new fabricated fuel elements with gloved hands... typically they are stored dry before being taken to the staging area when refueling

I saw those latest videos... seems interesting to me at least that we have been trying to determine if the top was blown off the #3 reactor but there seemed to be beams and things in the way... from verticle view and yest they seem to have gotten it with the remote heli... so.. is it our opinion that it was blown off.

Interesting paper on MOX in Japan following an accident in 1999 www.nci.org
Given the magnitude of the increased hazard associated with MOX use, one may well ask how prefectural and national regulatory authorities are able to justify this program. The answer can be found in the magazine Atoms in Japan, published by the Japan Atomic Industrial Forum (JAIF). According to the article entitled "MITI, STA Explain MOX Use in Fukushima,"

"a citizen attending a public forum on MOX use asked `is it true that an accident at a MOX-burning reactor would be four times worse than conventional ones?' The reply was that an accident would result in a large scale of damage only if fuel were scattered outside the plant. Since the MOX pellets are sintered, it would be virtually impossible for them to become powdered and be carried outside the site, meaning that the safety of MOX fuel in an accident was deemed to be the same as that as uranium fuel."

This response summarizes the flawed logic by which the Nuclear Safety Commission judged that utilities that planned to use MOX did not need to evaluate the consequences of accidents that would lead to plutonium releases off-site. It conveniently allows Japanese authorities to sidestep the serious safety issues associated with the vastly larger actinide inventories in MOX cores.

This reasoning, which is indefensible on a technical basis, is clearly a result of the same mindset that believed that criticality accidents at the uranium fuel processing plant at Tokai were also impossible. As explained above, MOX fuel, just like LEU fuel, can be dispersed in fine aerosol form in a severe accident with core disruption. One mechanism which has been under study in the U.S. is high-pressure melt ejection (HPME), in which the reactor vessel ruptures at high pressure after melting of the core. This causes the core to be ejected into the containment in the form of fragments, which rapidly heat the containment and in principle can cause it to fail, leading to radiological release.

@radioguy I am still trying to find you stuff @ukval if you see Jo can you point it out to him please

good update Nancy, by looking at the video of that area.. there are bolts or studs up on the side of the yellow top and too much of the side of it shows for a normal setting like the area around it is missing

elaine, with out looking at the physics it's a big question because with more Pu... the less the thermal margin and the closer they run to over heating and bad heat transfer... probably just another thing the NUCLEAR regulator allows

elaine.. where did you get that data may I ask?

Table II provides the results of a calculation, performed with the U.S. computer code MACCS2, of the consequences of such an accident within an area of 113 kilometers around a 870 MWe pressurized-water reactor similar the Takahama 4 plant. The release fractions used were taken from a recent U.S. NRC publication.[2] A population density of 550 persons per square kilometer was assumed, similar to the average population density within a 110 kilometer radius of Takahama.



The three cases evaluated, medium (M), high (H) and low (L), correspond to three different possible magnitudes of the plutonium release fraction. For each case, both a full MOX core and a one-quarter MOX core were considered. Kansai Electric Power Company (KEPCO) plans initially to use only a one-quarter core of MOX fuel, but intends to eventually reach a one-third MOX core. However, in the future, Japan intends to use full cores of MOX, and plans are proceeding to build an advanced boiling-water reactor (BWR) that will use a full MOX core in Aomori Prefecture.

elaine.. I think the japanese codes allow for less margin in safety, use different population densities per sq kilometer which allows they to use a higher enriched Pu...grrrrrrrr

Edano,, there have been links posted to explain nuclear glossary. all this information is used in the selection of fuels... poison material.. reflector material ect.. and in the end.. there are margins.. ie' safety factors that must be ensured to protect agains fuel clad failure...

Edan... after all the fuel and physics for operating is done then the radiological analysts take over to figure fractional releases for different accidents which postulates how many curies of istopes or.. percent fraction of the total inventory of source term in the reactor.. or canal will be released.... that level has to be with .. "site boundary " limits and a zone or aread from the reactor source... thus the 10 mile limit, 20 mile limit etc.. and those levels are what one has to back caluclate to make sure no limits are exceeded..