Michele Kearney's Nuclear Wire

Sunday, March 20, 2011

The nuclear crisis in Japan grew more troubling Sunday as efforts to control the Fukushimi Daiichi nuclear power facility continued to hit unexpected roadblocks. But Energy Secretary Steven Chu says Americans "are in no danger" from radiation.

Figures Released On Fukushima-Daiichi Seismic Design Reference Values

THE NUCLEAR COMMUNICATIONS NETWORK

Japan Update / Brief No. 75 / 20 March 2011

Figures Released On Fukushima-Daiichi Seismic Design Reference Values

20 Mar (NucNet): The maximum ground acceleration near unit 3 of the Fukushima-Daiichi nuclear plant from the earthquake that struck northern Japan on 11 March 2011 was 507 gal – or 507 centimetres per second squared – which is above the plant’s design reference values of 449 gal, the Japan Atomic Industrial Forum (JAIF) said today.

It was also announced that the University of Tokyo has re-evaluated the maximum height of the tsunami wave and it had a peak height of at least 23 metres when it hit Miyagi and Fukushima prefectures. The plant design reference value was 10 metres.

Meanwhile, external power is available onsite at the plant and teams from the Tokyo fire service and national Self-Defence Force are continuing to pump seawater into the reactor pressure vessels (RPV) and primary containment vessels (PCV) at units 1, 2 and 3 in an effort to cool the nuclear fuel.

The International Atomic Energy Agency said workers were continuing efforts to restore plant systems at units 1, 2 and 3.

At unit 2, external power has been established to the control room meaning essential surveillance and control systems are again operational, Japan’s Nuclear and Industrial Safety Agency (NISA) said.

NISA said workers were preparing to connect an external power supply to the residual heat removal systems of unit 2 and then unit 3. If the systems have not been damaged, this will allow cooling and feeding of the reactors and the spent fuel pools (SFPs).

Seawater spraying into the SFP at unit 3 has begun and while the pressure in the PCV went up early today, it was not sufficiently high to justify venting. The local dose rate close to this unit is decreasing At unit 4, where there is no fuel in the reactor, seawater spraying of the SFP started today at 09:40 Japan time (01:40 central European time). An external power supply connection is being prepared, NISA said.

At units 5 and 6, diesel generators were repaired yesterday and there is now enough power available to each unit for the residual heat removal system pumps. NISA said the temperature has fallen in both SFPs and the units were now in cold shutdown. Workers were today preparing to connect an external power supply to both these units.

Cold shutdown means the reactors are in a safe mode, with cooling systems stable and under control, and with low temperature and pressure within the reactor.

Air Sample Analysis

Plant operator Tokyo Electric Power Company (Tepco) said today it made the first spectral analysis of air samples taken on the Fukushima-Daiichi site at noon on Saturday local time and found volatile iodine and particulate caesium isotopes as follows:

Iodine-131: 5900 becquerel per cubic metre (Bq/cubicm), above the limit of 1000 Bq/cubicm;

Iodine-132: 220 Bq/cubicm, below the limit of 70,000 Bq/cubicm;

Cesium-134: 22 Bq/cubicm, below the limit of 2000 Bq/cubicm;

Cesium-137: 24 Bq/cubicm, below the limit of 3000 Bq/cubicm.

The limits are for air being breathed by workers under surveillance, but Tepco said workers were wearing charcoal masks and no internal contamination is expected.

Environmental Radiation Monitoring

The Ministry of Education, Culture, Sports, Science and Technology (MEXT) has published updated data from its surveillance network of automatic measurement posts (MPs) at a distance of more than 20 kilometres from the plant site. Inside the 20 km zone, Tepco is responsible for the network, but under NISA’s surveillance.

The downward trend of all measurements has continued since yesterday.

Today (Sunday), the highest dose rates were measured at the north-eastern Fukushima Mountains (summit 864 m, 30 km from the plant site), with values between 45 and 110 microsieverts per hour (microSv/hr) at 12:00 noon Japan time today in comparison with 60 to 170 microSv/hr on Thursday.

In the valleys, where most people live, the readings range from 1 to 6 microSv/hr in a distance of 35 to 60 km from the plant site. This is 25 percent less than on Thursday.

All these readings refer to an area north-west of the plant. This was the direction in which prevailing winds were blowing during the first days of the accident when the main releases occurred.

In the Tokyo area, the dose rate stayed very low at 0.05 microSv/hr. Yesterday the government’s chief cabinet secretary Yukio Edano said radiation exceeding the government-set radiation level was detected in sampled milk in Fukushima Prefecture and in six samples of spinach in neighbouring Ibaraki Prefecture.

He said the radiation measured from the samples posed “no immediate threat” to health.

Stabilization at Fukushima Daiichi

Stabilisation at Fukushima Daiichi

20 March 2011

FIRST PUBLISHED 2.05pm GMT
UPDATE 1: 2.56pm GMT Units 5 and 6 in cold shutdown, tsunami heights
UPDATE 2: 3.30pm GMT IAEA graph of fuel pond temperatures

Workers on site have succeeded in increasing the stability of the Fukushima Daiichi reactor units with units 5 and 6 now in cold shutdown. Pressure built up within unit 3 but a more significant venting does not seem necessary now.

External power has now been connected to unit 5 and 6, allowing them to use their residual heat removal systems and transfer heat to the sea. This has been used to cool the fuel ponds and bring the units to cold shutdown status, meaning that water in the reactor system is at less than 100ºC.

This graph from the International Atomic Energy Agency illustrates how
fuel pond temperatures have dropped at units 5 and 6 since the
connection of external power and use of the residual heat removal
system was restarted

An extended operation to refill the fuel pond took place at unit 3, with the Hyper Rescue crew spraying for over 13 hours. Radiation levels 500 metres north of the reactor showed a decrease from 3.44 millisieverts per hour to 2.75 millisieverts per hour, indicating a measure of success in refilling the pond. A similar operation is planned for later today at unit 4 and the surface temperatures of the buildings appear to be below 100ºC.

At units 1 and 2, external power has been restored. Tokyo Electric Power Company (Tepco) said it would restore functions in the central control room shared by the units so that accurate readings could again be taken from the reactor system. Next, workers will check the condition of the water supply systems to the reactor and the used fuel pond. With luck these will be able to go back into operation as they had been immediately after the earthquake on 11 March.

External power for units 3 and 4 should be in place 'in a few days time', said Tepco.

Tsunami data

The Fukushima power plants were required by regulators to withstand a certain height of tsunami. At the Daiichi plant the design basis was 5.7 metres and at Daini this was 5.2 metres.

Tepco has now released tentative assessments of the scale of the tsunami putting it at over 10 metres at Daiichi and over 12 metres at Dainii.

The plant sites were inundated, causing the loss of residual heat removal systems at both sites as well as emergency diesel generators at Daiichi.

During the day, the company had noted a pressure increase within unit 3, warning that venting may be required. Preparations were underway to open the relief vale on the torus suppression chamber, or if that had proven full of water, another valve on the reactor containment. These operations had been expected to release a more significant amount of radioactivity than earlier venting, but Tepco has since said the higher pressure is stable and it does not need to vent.
Radiation monitors in the area near the plant have shown gradually decreasing readings since spikes on 15 March following the loud noises and apparent rupture of the torus of unit 2. While levels were above natural background radiation they have not posed a threat to public health. Most people within 20 kilometres were evacuated before that time and people in a further ten-kilometre radius has been warned to stay indoors. Evacuation centres have been supplied with potassium iodide tablets that would protect people's thyroid glands in the case of a serious release of radionuclides from the reactor cores.

Despite contradictory comments by the US Nuclear Regulatory Commission to US politicians and media, most observers in nuclear industry and regulation consider the measures taken by Japanese authorities to be prudent.

Strategy Document for anti-nuclear activists

Update to Information Sheet Regarding the Tohoku Earthquake The Federation of Electric Power Companies of Japan (FEPC)

The original from FEPC included two PDF files with current radiation readings. These files are available for your reference at JAIF (Japan Atomic Industrial Forum) has been posting the translation of news reports on their website.

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

Update to Information Sheet Regarding the Tohoku Earthquake

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office

As of 11:00PM (EST), March 20, 2011

Radiation Levels

At 07:00PM (JST) on March 20, radiation level outside main office building (approximately 1,640 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 2,623 micro Sv/hour.
Measurement results of ambient dose rate around Fukushima Nuclear Power Station announced at 4:00PM and 7:00PM on March 20 are shown in the attached two PDF files respectively.
For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.

Fukushima Daiichi Unit 1 reactor

At 3:00PM on March 20, pressure inside the reactor core: 0.187MPa.
At 3:00PM on March 20, water level inside the reactor core: 1.7 meters below the top of the fuel rods.
At 3:00PM on March 20, pressure inside the primary containment vessel: 0.17MPaabs.
As of 6:00PM on March 20, the injection of seawater continues into the reactor core.
As of 7:00PM on March 20, activities for recovering the external power supply are underway.

Fukushima Daiichi Unit 2 reactor

At 3:00PM on March 20, pressure inside the reactor core: -0.016MPa.
At 3:00PM on March 20, water level inside the reactor core: 1.4 meters below the top of the fuel rods.
At 3:00PM on March 20, pressure inside the primary containment vessel: 0.125MPaabs.
At 3:05PM on March 20, injection of seawater into the spent fuel storage pool has begun, until 5:20PM (total about 40 tons)
As of 3:46PM on March 20, the distribution board began to receive the external power.
As of 6:00PM on March 20, the injection of seawater continues into the reactor core.

Fukushima Daiichi Unit 3 reactor

At 4:00PM on March 20, pressure inside the reactor core: 0.119MPa.
At 4:00PM on March 20, water level inside the reactor core: 1.65 meters below the top of the fuel rods.
At 4:00PM on March 20, pressure inside the primary containment vessel: 0.290MPaabs.
As of 6:00PM on March 20, the injection of seawater continues into the reactor core.
As of 7:00PM on March 20, about 2,605 tons of water in total has been shot to the spent fuel storage pool.
As of 7:00PM on March 20, activities for recovering the external power supply are underway.

Fukushima Daiichi Unit 4 reactor

At 8:20AM on March 20, 10 Self Defense Force vehicles began to shoot water aimed at the spent fuel pool, until 9:29AM.
As of 7:00PM on March 20, about 83 tons of water in total has been shot to the spent fuel storage pool.
As of 7:00PM on March 20, activities for recovering the external power supply are underway.

Fukushima Daiichi Unit 5 reactor

At 2:30PM on March 20: cold shutdown
At 4:00PM on March 20, the temperature of the spent fuel pool was measured at 95.2 degrees Fahrenheit.

Fukushima Daiichi Unit 6 reactor

At 10:14PM on March 19, ump for Residual Heat Removal (RHR) started up and cooling of spent fuel storage pool has started.
At 4:00PM on March 20, the temperature of the spent fuel pool was measured at 82.4 degrees Fahrenheit.

Fukushima Daiichi Common Spent Fuel Pool

At 09:00AM on March 19, the temperature of the spent fuel pool was measured at 134.6 degrees Fahrenheit

Our official sources are:

Office of The Prime Minister of Japan
Nuclear and Industrial Safety Agency (NISA)
Tokyo Electric Power Company (TEPCO) Press Releases
Ministry of Education, Culture, Sports, Science and Technology (MEXT)

The Facts about the Japanese Fukushima Daiichi Nuclear Power Plant

The Facts about the Japanese Fukushima Daiichi Nuclear Power Plant

Date: Tuesday, March 22nd 2011

Time: 2:00 pm – 3:00 pm

Call-in Number: 614-384-5247 Pin Code: 029468#

Streaming Webcast: http://InstantTeleseminar.com/?eventID=18477552

Areva sents its third shipment of radiation supplies to Japan Friday

AREVA in Richland sent its third shipment of radiation-protection supplies to Japan Friday.
Masks, coveralls, gloves, shoe coverings and filter cartridges for respirators were sent at the request of Tokyo Electric Power Co., which operates the damaged nuclear reactors in Japan.
The company has been contacting AREVA to let it know what it needs and then items are flown out of Richland to Seattle and then Japan, said Anna Markham, spokeswoman for AREVA A fourth shipment is planned for Tuesday.
Areva’s Richland plant manufactures fuel assemblies for nuclear power production.