Skip to main content

Evening Report

From NEI’s Japan earthquake launch page:

UPDATE AS OF 7:00 P.M. EDT, MARCH 24

Restoration of electric power at reactors 1, 2 and 4 at the Fukushima Daiichi nuclear power plant has led to the reconnection of important reactor instrumentation, the International Atomic Energy Agency said.

Cooling water continues to be injected into reactors 1, 2 and 3. Reactors 5 and 6 at Fukushima Daiichi remain safely shut down. Both reactors were undergoing maintenance at the time of the earthquake.

Radiation dose rates inside the containment vessels of reactors 1 and 2 have decreased slightly, IAEA said.

External power has been reconnected to the common used fuel storage pool at the plant and cooling started on March 24 at 5:05 AM EDT, according to Japan’s Nuclear and Industrial Safety Agency.  About 60 percent of the used uranium fuel rods at Fukushima plant are stored at this facility.

Radiation monitoring continues

Air samples collected at on-site monitors at the Fukushima Daiichi plant March 19-23 show that only iodine-131 was found to be in excess of Japanese government limits. Radiation dose rates measured on site March 21-23 have decreased from 193 millirem to 21 millirem per hour. Radiation dose rates at the plant’s site boundary ranged from 1 millirem to 3 millirem per hour on Thursday.

At distances between 34 and 73 kilometers to the west of the Fukushima Daiichi nuclear power plant, the dose rate ranged from .06 millirem to .69 millirem per hour.

Considerable variation in the levels of reported iodine-131 and cesium-137 continues in 10 prefectures, IAEA said. Food, milk and drinking water sampling has been most thorough and extensive in the Fukushima and Ibaraki prefectures, IAEA said.

Seawater samples collected at several points 30 kilometers from the coastline near the Fukushima Daiichi nuclear power plant found measurable concentrations of iodine-131 and cesium-137, IAEA said. The iodine concentrations were at or above Japanese regulatory limits. The cesium levels were well below those limits.

For more information on iodine-131, see NEI’s fact sheet Health Impacts of Iodine-131

Comments

Martin Burkle said…
"Radiation dose rates inside the containment vessels of reactors 1 and 2 have decreased slightly, IAEA said."
Why would we care what the radiation level in the containment vessel is?
I think the containment vessel is a place where no one would be. Doesn't the reactor vessel vent to the containment vessel and the containment vessel vent to the suppression torus or optionally to the area under the roof (or the outside is the roof is gone)?
Unknown said…
What are the normal levels?

"At distances between 34 and 73 kilometers to the west of the Fukushima Daiichi nuclear power plant, the dose rate ranged from .06 millirem to .69 millirem per hour."

0.06 mr/hr. What is the normal background level and variation?

How can these help the public put it into perspective?
Unknown said…
Regarding the I-131 fact sheet, every bit of news coming out of Japan is reporting dose in Seiverts and activity in Becquerels - why is NEI sticking to rem and picocuries??

Please consider changing your base units, or at least including both side by side.
Karen Street said…
I want to second Peter's recommendation. Being American means having to memorize two sets of numbers. We can use some help here. Yes, I know the conversion is easy.
David Bradish said…
To help put the radiation doses in perspective, check out page 7 in this pdf. One x-ray is 10 millirem, US background radiation is 300 millirem per year. 0.06 mrem/hr works out to 526 mrem/year. I talked with our radiation folks and the Japanese numbers are assumed to include their background radiation but we haven't seen numbers from what they were before the accident.

From searching news articles, it looks like the background radiation at Wako city next to Tokyo is 0.04 micro Sieverts/hr which works out to 0.004 mrem/hr. The average US background dose is 0.04 mrem/hr (310 mrem/8,760 hours in a year) so it looks Tokyo has quite a bit less background radiation than the US does.

As to why NEI is sticking with rem and picocuries, it's because the US hasn't adopted the SI system so that's why the NRC, EPA and industry use those numbers.

I recommend checking out our page on Japan's radiation. A lot of questions here about radiation can be found on that page.
David Bradish said…
correction: on page 7 of our sheet that I pointed folks to above, it should be Dose at the top of the table and not Annual Dose.
D Kosloff said…
Martin,
There is radiation measuring equipment inside containments. Variations in containment radiation levels provide information that may be useful in evaluating reactor conditions. For the Japanese BWRs no one would be in the primary containment because it is filled with inert gas (nitrogen). The area under the roof is the secondary containment. Reporters generally do not know that there are two containments for each plant.
Karen Street said…
Dave, we all know that Americans use international units to send people to the moon and American units to talk to one another and two sets of tools so that we can fix either bike. But would it be unAmerican to include international units in ()? If we can see temperatures in °F and °C without violent protests, I'm thinking two sets of units, while a pain, would make life easier for us. And yes, I know the conversion is easy.

Also, I understand the premise behind not going to km from miles (it's too hard to change), but I would think that a fair percentage of those who rattle on and on and on about mrem could handle the shift to SI units. Probably not your decision.

Popular posts from this blog

An Ohio School Board Is Working to Save Nuclear Plants

Ohio faces a decision soon about its two nuclear reactors, Davis-Besse and Perry, and on Wednesday, neighbors of one of those plants issued a cry for help. The reactors’ problem is that the price of electricity they sell on the high-voltage grid is depressed, mostly because of a surplus of natural gas. And the reactors do not get any revenue for the other benefits they provide. Some of those benefits are regional – emissions-free electricity, reliability with months of fuel on-site, and diversity in case of problems or price spikes with gas or coal, state and federal payroll taxes, and national economic stimulus as the plants buy fuel, supplies and services. Some of the benefits are highly localized, including employment and property taxes. One locality is already feeling the pinch: Oak Harbor on Lake Erie, home to Davis-Besse. The town has a middle school in a building that is 106 years old, and an elementary school from the 1950s, and on May 2 was scheduled to have a referendu

Why Ex-Im Bank Board Nominations Will Turn the Page on a Dysfunctional Chapter in Washington

In our present era of political discord, could Washington agree to support an agency that creates thousands of American jobs by enabling U.S. companies of all sizes to compete in foreign markets? What if that agency generated nearly billions of dollars more in revenue than the cost of its operations and returned that money – $7 billion over the past two decades – to U.S. taxpayers? In fact, that agency, the Export-Import Bank of the United States (Ex-Im Bank), was reauthorized by a large majority of Congress in 2015. To be sure, the matter was not without controversy. A bipartisan House coalition resorted to a rarely-used parliamentary maneuver in order to force a vote. But when Congress voted, Ex-Im Bank won a supermajority in the House and a large majority in the Senate. For almost two years, however, Ex-Im Bank has been unable to function fully because a single Senate committee chairman prevented the confirmation of nominees to its Board of Directors. Without a quorum

NEI Praises Connecticut Action in Support of Nuclear Energy

Earlier this week, Connecticut Gov. Dannel P. Malloy signed SB-1501 into law, legislation that puts nuclear energy on an equal footing with other non-emitting sources of energy in the state’s electricity marketplace. “Gov. Malloy and the state legislature deserve praise for their decision to support Dominion’s Millstone Power Station and the 1,500 Connecticut residents who work there," said NEI President and CEO Maria Korsnick. "By opening the door to Millstone having equal access to auctions open to other non-emitting sources of electricity, the state will help preserve $1.5 billion in economic activity, grid resiliency and reliability, and clean air that all residents of the state can enjoy," Korsnick said. Millstone Power Station Korsnick continued, "Connecticut is the third state to re-balance its electricity marketplace, joining New York and Illinois, which took their own legislative paths to preserving nuclear power plants in 2016. Now attention should