In early November I bought a Radex RD1212 radiation monitor from Amazon. The Radex is Russian made with an English menu. It’s simple ans seems to work fine. One feature of the unit is that it keeps a record of the time and strength of radiation it senses.
I used it daily at first to get an idea of what was normal here on Kauai. The unit measures in micro-sieiverts per hour. That’s a millionths of a sievert. As a reference;
- A person can safely be exposed to 3,650 micro-sieiverts in a year or .4 micro-sieiverts/hour.
- A radiation worker in the US is limited to a dose of 50,000 micro-sieiverts in a year.
- A person who absorbs 100,000 micro-sieiverts in a year is considered to have a clear increased cancer risk.
- A person absorbing 2,000,000 micro-sieiverts will suffer severe radiation poisoning that could lead to death.
Note: I believe the reference above is lowballing the risks to long tern exposure to nuclear radiation. The first source mentioned for the material is the U.S. Nuclear Regulatory Commission charged with licensing and regulating nuclear power plants… in other words keeping nuclear power plants going.
The Radex’s first time recording in my home were measurements of five minute averages for 15 intervals. The total average value was .08 micro-sieiverts per hour. That would convert to about 700 micro-sieiverts in a year. That’s much less than the 100,000 micro-sieiverts in a year considered to increase the likelihood of cancer.
The Radex is programmed to set off an alert when it measures over .3 micro-sieiverts per hour, or about 2,600 micro-sieiverts per year. That, depending on where you are, is about normal background radiation. Over the last two months I noticed a slight increase of background radiation from about .08 micro-sieiverts per hour to .09 micro-sieiverts per hour.
Sometime after lunch, the 27th of December, I turned the Radex radiation detector on and left it in the kitchen. Then I went back to work in my office.
I made a couple of phone calls on my wireless phone and noticed waves of static that occasionally almost obliterated my conversations. A bit later I turned on my FM radio and found the only Kauai station that came in without excess static was KKCR. All the KONG group stations were drowned out with static. I did not think much about that the radio signal – they often vary – but the wireless phone was almost alweays clear and without static.
Then about 1:50pm I heard a sound I thought was the electric inverter that provides power to my fridge. It’s on solar and can suck up a lot of power. I thought the beeper on the inverter was going off to tell me the batteries were getting low.
Then I noticed that the beeping was irregular. I went towards where I though I heard the sound and was led to my kitchen table where the Radex sat beeping away. When the unit gets to a measurement that would lead to .3 micro-sieverts/hour it makes a ping for each decaying betta or gamma particle that hits it. The Radex was crackling with pings.
The only time the Radex alarm had gone off since I bought it was when I moved it close to a wind-up travel alarm-clock I’d been given as a gift. It had once had a coating of radium painted on its hands a blob of radium at each hour. Much of the radium seemed worn away and there was just a greenish smudge that remained. But the Radex said it was a “hot” clock so I had to get rid of it.
The Radex alarm went on steadily. In the first of three five minute intervals starting a 1:50pm HST was .25 micro-sieverts/hour (almost three times higher than normal). Part of that time was less than .3 micro-sieiverts/hour but part was higher and that’s when the alarm pings went off. The second interval averaged 1.34 micro-sieiverts/hour.
By that time I was googling “Hawaii radiation alert” and visiting http://www.radiationnetwork.com/AlaskaHawaii.htm for a live reading of the Maui geiger-counter. It was at 39 counts per minute and was lit up orange (meaning trending up).
The third five minute interval was averaged 1.78 micro-sieiverts/hour. Somewhere early in that five minutes I noticed a reading above 3.0 micro-sieiverts/hour (over thirty times higher than average). I got a bit freaked out then. At a continuous dose that would be over 26,000 micro-sieiverts in a year (or more than half that the NRC is allowable for a worker in a nuclear plant.
I tried to call my wife Linda and alert her. But about as quickly as it began the radiation spike ended. The following interval was a steady .09 micro-sieiverts/hour. Now at 4:00pm HST it is still .09 micro-sieiverts/hour… but the the Maui geiger-counter is at 43 CPM.
I checked the weather and found that the wind was blowing from the North-West. That is unusual and might indicate situation in which the jet-stream from Japan was diverted further south than usual.
This event really spooked me. According to more than one source I found the level I was reading was dangerous. The readings I got put me momentarily in the brown range on Table 1 and in the red zone on Table 2.
Table 1 below indicates prolonged exposure at the spike level I measured could lead to a real risk of cancer if exposed to continuously in less than a year.
Table 2 below recommends that at the exposure spike I measured one should take shelter or leave the area.I believe this table was created from the table above as a source, but advises different actions.
This Fukushima thing has us on one nasty roller coaster ride.