Kathryn Higley, a radiation health physicist at Oregon State University in Corvallis, Oregon, comments on radiation from Tokyo Electric Power Co.’s damaged nuclear power plant in northeastern Japan.
Higley, who has worked on reactors and inspected nuclear power plants for emergency preparedness, spoke in a telephone interview today.
On rising levels of radiation around the plant:
“It’s very likely they have had fuel damage; they have released what are called the volatile radio nuclides -- the cesium and iodine that probably came out in those steam releases. Those are things that turn to gas in modest temperatures.
‘‘They were pumping water into the core, into the containment building. If you have any damage to the fuel, you are likely to be spreading some of that around.’’
Some radioactive cesium and iodine precipitates that weren’t emitted from the reactor in steam may wash into water being used to cool the reactor core, she said.
‘‘You mix that with water and it shouldn’t be a surprise to anybody that within that plant there’s going to be a lot of contaminated water.
‘‘As they start getting in there to try to remove the liquid, you’re probably going to see some localized spreading of contamination and maybe some puff releases if things are pressurized.
‘‘I haven’t yet seen evidence of plutonium and such outside of the plant. It wouldn’t surprise me when they start spraying stuff through the reactor system that they are moving bits of fuel into containment and possibly on the plant site.”
On levels of radioactive iodine in tap water in Tokyo:
“It dropped back down and they said keep young kids away from it. But it’s down in safe levels.
‘‘We know that kids’ thyroids are on overdrive and they’re more radio sensitive simply because they’re younger.
‘‘Unless you start your fission up again, they have probably released most of the volatile material when they had those original ventings.
‘‘It bears watching over the next week or so, but if it continues dropping, I wouldn’t expect to see any more elevated concentrations.’’
On whether the plant can be repaired:
‘‘When they made the decision to pump seawater in there, they pretty much decided those plants were done. There’s concern that the high temperature load may have deposited salt in the lines and done some corrosion. It’s not going to be practical” to repair the plant.
“There will need, more than likely, to be some sort of stabilization close in on the surfaces because you just want to keep the cesium largely from spreading any further.
‘‘You are probably going to see so many people aching to try their brand-new decontamination techniques to strip stuff off buildings. This will probably be a research park for the next 20 years.
‘‘There’s been huge development in techniques for decontamination as people keep expecting RDDs (radiological dispersal devices or dirty bombs) to happen. So the military has been coming up with lots of technologies to clean up. It wouldn’t surprise me if everyone wants to try their strippable coating and dry surfactants on buildings around the plant to help clean it up.’’
On entombing the plant:
‘‘They’ve got to make sure that the cores are stable -- that’s a tricky thing. They may find that the simplest thing is to entomb it and walk away from it for a few years. But they’re going to be very cognizant of the fact they could have another earthquake so any structure they put they will want to be robust enough to not cause another problem. It’s not a simple matter of pumping concrete in there and walking away. You don’t want to have a new little reactor cooking under the concrete you’re not aware of.”
On the plant’s future prospects:
“They’re going to make decisions on an acre-by-acre basis as to what’s going to happen to these facilities. The area around Chernobyl (in Ukraine, where a nuclear power disaster occurred in 1986) is now a nature park. When you move 100,000 people out of an area, nature does pretty well.
‘‘There certainly are going to have to be some decisions as to what they can do. All over the world people live in areas that are naturally radioactive.
‘‘You have to be really careful what you do because sometimes you can make problems worse by trying to do some of the surface remediation. They may find they are simply better off letting the cesium move down into the soil. It depends on the soil they have got there. And decay in places might be the most cost-effective technology. They will have a bit of time to sit back and think about it.’’