Are the Japanese Nuclear plants melting down?

[Flyer_PE]

Found the following here.

UPDATE AS OF 9:15 P.M. EDT, THURSDAY, MARCH 17:
Tokyo Electric Power Co. said it hopes to activate the cooling system for Fukushima Daiichi reactor 2 "as early as Friday night" (Japan time). The company said it could restore power from the electric grid to reactor 2 by Thursday night (U.S. time).

The International Atomic Energy Agency reported that TEPCO completed connecting electrical cable from a makeshift transformer to reactor 2 at 4:30 A.M. EDT. Engineers were waiting to complete spraying sea water into the reactor 3 fuel pool before they restore power through the cable to the reactor 2 cooling system.

TEPCO says that if it can provide power supply to the other reactors, it could begin restoring some cooling functions. The company said that after fire trucks injected water into reactor 3's fuel pool, radiation levels at the plant's west gate dropped from 31 millirem per hour to 29 millirem per hour at 10:00 A.M. EDT.

To give a frame of reference, we were always told in the annual training that a chest x-ray was about a 50mr dose. The x-rays the dentist used to take of your teeth was about 10mr of exposure. A 30mr field all the way out at the gate is sobering but it's not a level that warrants mass hysteria.

Disclosure: 600mr lifetime accumulated dose from 8 years working at a BWR.

 

[navyasw02]

Found the following here.

UPDATE AS OF 9:15 P.M. EDT, THURSDAY, MARCH 17:
Tokyo Electric Power Co. said it hopes to activate the cooling system for Fukushima Daiichi reactor 2 "as early as Friday night" (Japan time). The company said it could restore power from the electric grid to reactor 2 by Thursday night (U.S. time).

The International Atomic Energy Agency reported that TEPCO completed connecting electrical cable from a makeshift transformer to reactor 2 at 4:30 A.M. EDT. Engineers were waiting to complete spraying sea water into the reactor 3 fuel pool before they restore power through the cable to the reactor 2 cooling system.

TEPCO says that if it can provide power supply to the other reactors, it could begin restoring some cooling functions. The company said that after fire trucks injected water into reactor 3's fuel pool, radiation levels at the plant's west gate dropped from 31 millirem per hour to 29 millirem per hour at 10:00 A.M. EDT.

To give a frame of reference, we were always told in the annual training that a chest x-ray was about a 50mr dose. The x-rays the dentist used to take of your teeth was about 10mr of exposure. A 30mr field all the way out at the gate is sobering but it's not a level that warrants mass hysteria.

Disclosure: 600mr lifetime accumulated dose from 8 years working at a BWR.

Still, I wouldn't want to hang out there. I think that's more in an hour than I got in a month on my dosimetry reports. What are the legal exposure limits? I cant remember those numbers off the top of my head anymore.

 

[Dleg]

Great info, guys. Keep it coming!

 

[Guest]

Found the following here.

UPDATE AS OF 9:15 P.M. EDT, THURSDAY, MARCH 17:
Tokyo Electric Power Co. said it hopes to activate the cooling system for Fukushima Daiichi reactor 2 "as early as Friday night" (Japan time). The company said it could restore power from the electric grid to reactor 2 by Thursday night (U.S. time).

The International Atomic Energy Agency reported that TEPCO completed connecting electrical cable from a makeshift transformer to reactor 2 at 4:30 A.M. EDT. Engineers were waiting to complete spraying sea water into the reactor 3 fuel pool before they restore power through the cable to the reactor 2 cooling system.

TEPCO says that if it can provide power supply to the other reactors, it could begin restoring some cooling functions. The company said that after fire trucks injected water into reactor 3's fuel pool, radiation levels at the plant's west gate dropped from 31 millirem per hour to 29 millirem per hour at 10:00 A.M. EDT.

To give a frame of reference, we were always told in the annual training that a chest x-ray was about a 50mr dose. The x-rays the dentist used to take of your teeth was about 10mr of exposure. A 30mr field all the way out at the gate is sobering but it's not a level that warrants mass hysteria.

Disclosure: 600mr lifetime accumulated dose from 8 years working at a BWR.

Good info.

Still, I wouldn't want to hang out there. I think that's more in an hour than I got in a month on my dosimetry reports. What are the legal exposure limits? I cant remember those numbers off the top of my head anymore.

When I was doing inspections, my limit was 5 mrem/hr total body count.

JR

 

[chaosiscash]

We're limited at the ACL to 1 rem (not mrem) a year. The DOE ACL is 2 rem and the DOE limit is 5 rem. Those are all whole body. The extremity limit is something like 50 rem and the pregnant female limit is much lower, although most pregnant women around here self-declare and are moved to a no dose area. Of course, those numbers are for Radworker II's. The limits for the general public are much, much lower. For a little perspective, the average annual dose for the general population from natural background and manmade sources is around 350 mrem. This includes medical x-rays, radon, etc.

Source: Just took my biannual Radworker II training a few days ago.

 

[Flyer_PE]

Typical limits for the nuclear utilities here are half the DOE/NRC limits. The max I've passed through was a 1R/hr field. I sure as hell wasn't loitering.

 

[Dleg]

I used to use Cesium 137 gamma ray sources and Americium 241-Beryllium neutron sources in the oil field, and as district radiation engineer, I got the honor (ahem) of being in charge of the wipe testing of all the sources we used. These were big well logging sources - way bigger than the typical civil engineering compaction tester sources. If I remember correctly, the cesium source was 1.7 curies, and the Am241Be was a whopping 16 Curies.

I did that for 4.5 years and walked away with a "lifetime" exposure of over 2,000 mrem. 1250 of that was "administrative" and not measured - some jackass left a cesium source out of its shield for three days in the shop, attached to the end of the handling tool in the back of his truck while we all worked. The CA NRC (or whatever CA called it) took all our badges and just assigned us a calculated, worst-case dose from the incident.

I've talked to nuclear submarine offices who are shocked at my exposure levels, even though they're way under the very conservative occupational limits. I guess a properly run nuclear power plant doesn't put out much radiation.

 

[Flyer_PE]

^It depends on what you're working on. Some of the instrument techs were up in the 5R range. Some of the vessel instrumentation was pretty hot. The stuff I mostly worked with was either in a 0-rad area (Batteries, switchgear, etc) or was only a radiation area when we were on-line (Main Turbine, Feedwater Heat/Reheat, etc). We didn't do much adjusting on the turbine and accessories when we were running.

 

[navyasw02]

I've talked to nuclear submarine offices who are shocked at my exposure levels, even though they're way under the very conservative occupational limits. I guess a properly run nuclear power plant doesn't put out much radiation.

When I was on a sub, I think my monthly doses were in the single digit mr range. I think I got less being underway than I did just by walking around and getting sunshine.

 

[cableguy]

So do you think the Japanese should make a deal something like this...

Take a prisoner, who's incarcerated for life with no chance for parole. Offer to pay them $100,000 if they'll work at the plant under 'dire' conditions (as in, they'll probably die from exposure), and offer to expunge their record (post-mortem) and give them a hero's funeral.

Think anyone would go for that? I think it'd be worth it to try. They essentially need some Kamikaze plant workers at this point... willing to "die for the greater good". Some of them may be at that point anyway.

 

[Guest]

A pretty good basis of information for the current status ...

http://www.jaif.or.jp/english/

JR

 

[willsee]

Update

http://bigthink.com/ideas/38924