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Friday Update

From NEI’s Japan Micro-site

Contaminated Water Levels Beginning to Drop at Fukushima Daiichi

July 8, 2011

Plant Status

• Tokyo Electric Power Co. is continuing preparations to stabilize Fukushima Daiichi’s reactor 3 primary containment vessel. The company is using a robot-mounted camera to check whether a penetration joint is suitable for nitrogen injection that will help stabilize conditions inside the reactor vessel. TEPCO is also checking radiation levels, which have decreased by up to half after installing steel plates on the floor of the working area inside the reactor building. However, radiation levels in the building are still high—up to 5 rem per hour.

• TEPCO is making headway in reducing the volume of contaminated water on site. In the last week, the new water filtration system has treated more than 13,000 tons of water. Recycling the treated water into the plant cooling systems also began last week, and the rate of water accumulation is now being reversed. The company says water levels in the basements of the reactor buildings could drop by more than three feet by next month. About 120,000 tons of water have accumulated in basements at the facility and in storage facilities. Also, the company has installed steel plates at the seawater intake structures for Fukushima reactors 1 through 4, closing off a path for leakage of contaminated water from the reactors to the ocean.

• TEPCO will add 12 more on-site monitoring locations at Fukushima Daiichi to sample for airborne radiation around the reactor buildings. Plant officials believe that dust and contaminated steam leaking from the reactors continue to contribute to contamination off site. A lightweight cover for reactor 1 is being built and should be in place by September. Similar covers will be installed on reactors 2-4.


Industry/Regulatory/Political Issues

• The mayor and town assembly of Genkai have retracted their approval for the restart of Genkai nuclear reactor after the central government announced that European Union-style “stress tests” should be conducted to assess the safety response of all Japanese nuclear plants to severe accidents. Mayor Hideo Kishimoto criticized the government for imposing the tests as a condition for restarting plants after he was assured that Genkai was safe to restart.

• Radioactive cesium levels in processed tea made in Tochigi City, about 100 miles from Fukushima Daiichi, are three times higher than the provisional government limit. Tochigi prefecture officials asked that farmers temporarily stop shipments of the tea.

• The Nuclear and Industrial Safety Agency has found that some electrical equipment at the Tokai Daini nuclear plant in Ibaraki prefecture does not meet industry seismic standards. The plant operator will strengthen the seismic resistance of the equipment during the NISA inspection period.

New Products

• NEI’s new website provides information about nuclear safety, security and measures to protect public health.

Upcoming Events

• The Senate Appropriations Energy and Water Development Subcommittee will hear Fukushima-related testimony at a July 14 hearing on small reactor designs. Marvin Fertel, NEI’s president and chief executive officer, will testify at the hearing.

• The NRC task force reviewing agency processes and regulations in light of the accident at Fukushima will brief the commissioners on the report at a public meeting July 19. NRC Chairman Gregory Jaczko will speak at the National Press Club in Washington, D.C., on July 18.

Comments

D Pulaski said…
I have a question.

Does anyone know why is the limit for cesium 137 in tea, a concentrated product, is the same as in beef, 500 becquerels per kg?

227 g of tea represents 100 tea bags (referring to my Red Rose tea box in the pantry), which means 1 kilogram of tea can make approximately 440 ten-ounce mugs of tea. I doubt even that dedicated tea tippler, fence post man, can drink more than 20 mugs of tea a day, consequently 1 kilogram is at least a 22 day supply. Furthermore, surely some percent of the cesium 137 will remain in the teabag/tea-ball.

On on the other hand, surely an exclusive beefeater like fence post man could easily consume one kilogram of beef in one day. If he broils his beef, and doesn't brine it first, he will ingest all the cesium.

I do not see why the same limit is applied for the two products, and I hope someone will explain it to me.

D. P. Pulaski
D Pulaski said…
I see that green tea continues to have high concentrations of cesium-I suspect because green tea is strictly the youngest leaves and shoots, and then the tea is dehydrated, so the effective concentration is higher than it was in the original leaves.

I have a question. Why do beef and tea have the same limit for cesium 137, 500 becquerels per kilogram?

Tea is a concentrated product. According to my Red Rose tea box, 227 grams of tea is equivalent to 100 tea bags. Consequently, one kilogram of tea can be used to make 440 ten-ounce mugs of strong tea. Even that dedicated tea-tippler, fence-post person, surely cannot consume more than 20 mugs of tea a day, so one kilogram represents no less than a 22 day supply. Furthermore, since the leaves themselves are not consumed, some percentage of the cesium probably remains in the tea bag or tea ball after brewing.

On the other hand, a dedicated beef eater like fence post person, should easily be able to consume one kilogram of beef in 3 meals (1 day). If he broils the beef, and does not brine it first, he will surely ingest almost all of the cesium.

I don't at all see why these two products should have the same regulatory limit. Does anyone know whether there is any scientific justification for this?

D. P. Pulaski

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