Wednesday, March 23, 2011
Metropolis Magazine - Japanese English Language Info
There is an IT guy in Japan who is doing a great job of taking readings around Tokyo with a scintillation detector and a G-M tube type detector. He is blogging the results here. For any Health Physics folks - we are having a small albeit interesting discussion on the comments section. Some of the folks in Japan are perfectly safe-feeling at 2.2 uSv / hr general area gamma readings in Tokyo (about 220 microR / hr). Shows you some perspective I guess.
Site shows radiation readings in Tokyo
Here is a site with a webcam showing constant readings in Tokyo. Very interesting.
Thursday, March 17, 2011
Yes - It CAN happen here....
The issue we have been asked about most often is - could this happen here? The answer is a most definite YES.
The main problem the Japanese are experiencing now has less to do with the actual reactors and much more to do with a problem very common to every nuclear plant in the United States. The problem is what to do with spent fuel (used up fuel rods).
When a civilian nuclear plant "refuels", the plant workers change around the configuration of the fuel rods in the reactor and replace the oldest rods with new fuel rods. The spent fuel rods are highly radioactive and extremely dangerous. In the U. S. we have never reached a consensus as to how to dispose of or store these rods so all U. S. plants have a spent fuel pool along with a spent fuel storage building (most) where the rods sit. These spent fuel rods require cooling water just like the reactor core except in many cases, the spent fuel is not stored in facilities anywhere near as robust as the actual core. In the BWR's in Japan (and several of which I am familiar in the U. S.) the spent fuel actually sits in a pool ABOVE the reactor.
Once the cooling flow is lost to the spent fuel pool and the fuel is uncovered, regardless of any other situations, the buildings become too dangerous to approach much less to work in. Exposure to spent fuel rods would cause very quick death. The protective suits you see workers wearing on the photos and videos coming out of Japan do not provide ANY protection from this type of radiation - only from contamination (see earlier post). There is NO suit or other magical device which can make it safe for humans to get near these reactors once the fuel is uncovered.
So what can they do now? I am not familiar with any remote systems which might be able to mitigate the damage by flooding the fuel and reactor but most of the actions you may have seen are what we would call "hail mary passes". If luck doesn't turn for the Japanese, a large swath of the country may be uninhabitable for many many years.
The main problem the Japanese are experiencing now has less to do with the actual reactors and much more to do with a problem very common to every nuclear plant in the United States. The problem is what to do with spent fuel (used up fuel rods).
When a civilian nuclear plant "refuels", the plant workers change around the configuration of the fuel rods in the reactor and replace the oldest rods with new fuel rods. The spent fuel rods are highly radioactive and extremely dangerous. In the U. S. we have never reached a consensus as to how to dispose of or store these rods so all U. S. plants have a spent fuel pool along with a spent fuel storage building (most) where the rods sit. These spent fuel rods require cooling water just like the reactor core except in many cases, the spent fuel is not stored in facilities anywhere near as robust as the actual core. In the BWR's in Japan (and several of which I am familiar in the U. S.) the spent fuel actually sits in a pool ABOVE the reactor.
Once the cooling flow is lost to the spent fuel pool and the fuel is uncovered, regardless of any other situations, the buildings become too dangerous to approach much less to work in. Exposure to spent fuel rods would cause very quick death. The protective suits you see workers wearing on the photos and videos coming out of Japan do not provide ANY protection from this type of radiation - only from contamination (see earlier post). There is NO suit or other magical device which can make it safe for humans to get near these reactors once the fuel is uncovered.
So what can they do now? I am not familiar with any remote systems which might be able to mitigate the damage by flooding the fuel and reactor but most of the actions you may have seen are what we would call "hail mary passes". If luck doesn't turn for the Japanese, a large swath of the country may be uninhabitable for many many years.
Tuesday, March 15, 2011
Article by Marvin Resnikoff
Here is an article on the front of the Huffington Post by Marvin Resnikoff. I have known Marvin for many years - he is highly sought for his expertise in the field. Worth a read.
Contamination and Radiation - WTF????
There is much confusion in the news media about radiation and the long term consequences of the Japanese plant disasters. There are many issues but one of the more confusing ones is why we are worried about the wind patterns and fallout. I have heard talking heads say, "I thought radiation was like light?"
The simple answer is as follows:
The immediate concern is the very high levels of gamma radiation coming from the plant itself. Presently plant workers are not able to get anywhere near the plant to assist in cooling the cores. Big problem.
The long term problem is the contamination that will result from the radioactive material (contamination) being blown around the local area and (ultimately) ejected into the atmosphere.
Radiation is emitted from the contamination. Think of contamination in the simplest terms as being a big pile of dog crap. The smell coming from the pile would be the "radiation". As long as the pile is sitting around it will continue to smell and irradiate. It will spread, dry out, blow around, etc. Eventually the smell goes away (in this case it will take hundreds of years for the "smell" to go away on it's own). The key to cleaning up after a radioactive accident is to contain the contamination as soon as possible, clean it up and put it in a safe place. Where that will be with these cores I am not sure.
Each of these explosions carries the danger of spewing radioactive contamination across a large area. Fortunately the contaminants become more diffuse as they spread although this is of little comfort to anyone in their path.
For now, all anyone can do is hope the cores cool fast - build a sarcophagus - and begin a detailed clean up of the area surrounding the plants.
The simple answer is as follows:
The immediate concern is the very high levels of gamma radiation coming from the plant itself. Presently plant workers are not able to get anywhere near the plant to assist in cooling the cores. Big problem.
The long term problem is the contamination that will result from the radioactive material (contamination) being blown around the local area and (ultimately) ejected into the atmosphere.
Radiation is emitted from the contamination. Think of contamination in the simplest terms as being a big pile of dog crap. The smell coming from the pile would be the "radiation". As long as the pile is sitting around it will continue to smell and irradiate. It will spread, dry out, blow around, etc. Eventually the smell goes away (in this case it will take hundreds of years for the "smell" to go away on it's own). The key to cleaning up after a radioactive accident is to contain the contamination as soon as possible, clean it up and put it in a safe place. Where that will be with these cores I am not sure.
Each of these explosions carries the danger of spewing radioactive contamination across a large area. Fortunately the contaminants become more diffuse as they spread although this is of little comfort to anyone in their path.
For now, all anyone can do is hope the cores cool fast - build a sarcophagus - and begin a detailed clean up of the area surrounding the plants.
Are Japanese and US reactors the same?
Yes and No. In the US we have both Boiling Water Reactors (BWR) and Pressurized Water Reactors (PWR). The reactors in Japan where the releases have occurred are US designed BWR's.
BWR's (as the name implies) boil water IN the reactor and send the radioactive steam into a turbine building where the steam turns turbines to create electrical power. These reactors are more efficient than PWR's but have some (now) obvious inherent flaws. I was never comfortable with the idea being an ex-Navy guy where all of the reactors are of the PWR variety.
PWR's use a closed-loop system. All of the radioactive stuff stays in the containment. Sort of like your car's cooling system where the coolant is separated from the oil. The "hot" loop (very hot and radioactive water) is circulated through heat exchangers which heat non-radioactive water which is then turned to steam and turns a turbine in another building to create electricity.
In Louisiana we have both types of reactors. Waterford III near New Orleans is a PWR while Riverbend near St. Francisville is a BWR.
BWR's (as the name implies) boil water IN the reactor and send the radioactive steam into a turbine building where the steam turns turbines to create electrical power. These reactors are more efficient than PWR's but have some (now) obvious inherent flaws. I was never comfortable with the idea being an ex-Navy guy where all of the reactors are of the PWR variety.
PWR's use a closed-loop system. All of the radioactive stuff stays in the containment. Sort of like your car's cooling system where the coolant is separated from the oil. The "hot" loop (very hot and radioactive water) is circulated through heat exchangers which heat non-radioactive water which is then turned to steam and turns a turbine in another building to create electricity.
In Louisiana we have both types of reactors. Waterford III near New Orleans is a PWR while Riverbend near St. Francisville is a BWR.
What is REALLY going on in Japan??
I decided to start this blog today to provide some information to our clients and anyone interested. Our company (Radiation Technical Services, Co.) is one of only a handful of firm's licensed to perform Decontamination and Decommissioning on old radioactive waste sites. We have listened to the news with alarm as have many of you. Unfortunately many of the media outlets have resorted to using unqualified news people to discuss the situation in Japan. Yesterday CNN had their weatherman talking about the issues of fallout.
Reading today's report from the IAEA (International Atomic Energy Agency) was particularly alarming. The IAEA reported front gate readings had fallen from 11.9 milliSievert / hr to 0.6 milliSievert / hr. If this report is correct, the problem is much greater than anyone is reporting and would indicate serious, serious fuel problems. To understand these numbers consider that 11.9 milliSieverts / hr would be the radiation exposure rate a worker INSIDE the reactor building might expect to encounter working in the worst of conditions. In very, very simple terms, gamma radiation from a point source reduces at an inverse square of the distance it travels. For instance, if you were to measure 100 milliSievert / hr at 1 foot from a point source, you would generally expect the levels to be reduced to 10 milliSievert / hr at 2 feet. In the simplest terms, the levels in and around the actual reactor MUST be in the many hundreds of Sievert per hour (or likely thousands). Those kind of doses can kill very quickly. I assume (always dangerous to do) that the gate is a significant distance from the reactor building.
These reactors are much closer to Chernobyl type problems than Three Mile Island. TMI was a minor issue which worked itself out with safety systems and some dumb luck. The Japanese were hit with a number of events which overwhelmed even their many redundant systems.
Reading today's report from the IAEA (International Atomic Energy Agency) was particularly alarming. The IAEA reported front gate readings had fallen from 11.9 milliSievert / hr to 0.6 milliSievert / hr. If this report is correct, the problem is much greater than anyone is reporting and would indicate serious, serious fuel problems. To understand these numbers consider that 11.9 milliSieverts / hr would be the radiation exposure rate a worker INSIDE the reactor building might expect to encounter working in the worst of conditions. In very, very simple terms, gamma radiation from a point source reduces at an inverse square of the distance it travels. For instance, if you were to measure 100 milliSievert / hr at 1 foot from a point source, you would generally expect the levels to be reduced to 10 milliSievert / hr at 2 feet. In the simplest terms, the levels in and around the actual reactor MUST be in the many hundreds of Sievert per hour (or likely thousands). Those kind of doses can kill very quickly. I assume (always dangerous to do) that the gate is a significant distance from the reactor building.
These reactors are much closer to Chernobyl type problems than Three Mile Island. TMI was a minor issue which worked itself out with safety systems and some dumb luck. The Japanese were hit with a number of events which overwhelmed even their many redundant systems.
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