Nuclear reactor damaged in Japan during the quake.

[nighthawk]

Okay guys how can Ex-Rad help those that have been exposed?

Seems to be some debate as to whether it functions better as a prophylactic or an actual cure in regards to radiation damage to living cells.

I also agree that this is an excellent discussion of the topic with all sides bringing up really good points. One of my favorite movies is called Trinity and Beyond. It really does not delve too much into the physics of splitting the atom as it does the arms race to build bigger, more powerful nukes. The movie to me drives home the huge difference between splitting the atom in peaceful applications vs splitting the atom to make war on a devastating scale.

One thing we have to face is that older design or new nuclear power is here to stay. After 9/11 there were up grades implemented at our U.S. plants to address deficiencies that were thought could make the plants vulnerable to attack. The afore mentioned upgrade to the cooling systems was one of them that I was told about. I also know that the civil support things were upgraded. Things like improved automated civil alert sirens, stockpiles of iodine to protect the thyroid at shelters and other public places, updated evacuation procedures, more classes and drills for emergency responders in the vicinity of the plants....

It was needed. We will learn. Like it or not we need nuclear power.

[rizeye]

I should of added a referance for dose. I am more comfortable using the rad and rem terms which is the US system, the Gy and Sv are SI (System International) system. For general purposes 1 rad = 1 rem. the 2 terms are related as a rad is a measure of the energy absorbed by a material, a rem is the amount of biological damage done by that energy. rad and rem are not equal for alpha, neutron, and very high energy cosmic radiations.

Background radiation dose in the US averages about 0.5 rem. A chest x-ray is about 0.02 rem, spinal x-ray 0.2 - 0.3 rem, a CT is about 1 rem. astronauts in earth orbit get about 0.02 rem per day. radiation worked are allowed to receive 5 rem per yr.
the following are acute radiation damage due to receive the following dose over a very short period of time. a short time is less than 3 weeks.
minor cell damage starts at about 20 rem, skin burns start at 100 rem, intestinal failure at 250 rem, 50% chance of death at 500 rem, nervous syatem colapse at 3000 rem.

I hope this helps put some things into perspective.

[nighthawk]

It does and thank you. It appears as if the worst fears are now being realized at the plant. Reports are that the reactor core has melted through the bottom of the vessel and is in contact with the concrete floor:

http://www.foxnews.com/world/2011/03...r-expert-says/

Can you imagine the tremendous amount of heat it took to do that? Did it actually melt through the graphite in the bottom of the reactor case or did it run around it like it did at Three Mile Island? Reports that the fuel rod temps are still in the 700f range.

What do we do now with all the contaminated water that was pumped in to cool the core? It says they are running out of holding space for it so they may be forced to dump it directly into the ocean! Yikes! What an ecological and human tragedy we have here!

I pray for the workers that were soaked with radioactive water!

[rizeye]

These reactor, nor any in the US use graphite in the reactor. some older models in russia still have the old graphite reactors. here is pic of the type of reactor japan has. it's called a boiling water. seems like the fuel melted through the core vessle and is sitting on the floor of the primary containment.

bfndiag.jpg

[nighthawk]

I knew they were a boiling water pressure vessel but I was led to believe they still used graphite as a lining at the bottom of the vessel or on the containment floor. Makes sense if they don't though because that would just be a waste of money.

My understanding is once they start the meltdown the best ways to get them under control are with massive amounts of fresh water (Three Mile Island) or concrete (Chernobyl).

Pretty grim situation no matter how one looks at it. I am trying to remember where the core from TMI was removed to. I think it went out west somewhere so I searched the net and found this:

http://www.ans.org/pi/resources/spto...i/cleanup.html

Interesting stuff.

[rizeye]

the reason they use water is just to kool the fuel. the fission reaction produces massive amounts of energy and heat. after the fission reaction terminates, the FP produce enough heat to melt steel and the fuel rod cladding just by the energy released during decay. it's jsut the nature of the physics. as for the concrete used for chernobyl, it was used to build a containment structure because there was none at chernobyl. the core was completely destroyed and the graphite was burning out of control. the concrete was used to smoother the fire and stop the release of radioactivity to the environment and to reduce the radiation levels in the immediate vicinity. actually the introduction of concrete was a remarkable achievment. eventually all that and the area needs to be properly cleaned. that's a process that can be started now. but who knows if the russions will do the right thing.

[Steve Molcsan]

rizeye

Have an updated perspective based on the elapsed time..?

Its good to put things in perspective..

Be safe