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November 2012

November 2012 Summary : Bad Luck and Trouble

Lucky Contract Worker

A contract worker was ordered to cut a plastic pipe with a hand saw. He did what all contract workers do, he followed the order though he did not have the lightest idea what he was doing. He had bad  luck: Inside th plastic pipe was a high power electric cable unter tension. The action resulted in a heavy short circuit, flames and smoke. The contract worker was lucky, the saw handle was isolating. The only consequence was that TEPCO had to file lengthy accident reports. The figure from the accident report illustrates what has happened.

Unlucky Contract Worker

A contract worker was ordered to insulate a pipe system outside the reactor buiding with insulating foam: Winter and cold is coming to Fukushima. He did what all contract workers do, he followed the order though he did not have the slightest idea what he was doing. There were some valves with handles and some instruments. While working he inadvertantly moved the wheel of the flow rate adjustment valve for the external injection of coolant into the reactor pressure vessel. He was lucky: Nobody around noticed it and cautiously he tried to bring the wheel back into the original position or what he thought the original position was.

The next day the alarm went off and TEPCO engineers started to jump in circles. For no evident reason the external injection into unit 3 had increased substantially. TEPCO had to file lengthy reports on the findings and also started an intensive search for the potential cause. Some sceptics already suspected the restart of the chain reaction and asked for Xenon measurement. However, soon they found the wheel of the valve had been moved and from earlier fotos it was concluded this was changed during the installation of the insulation. The subcontract worker was unlucky: He was identified and confessed his attempt to cover up the changing of the wheel position. TEPCO had to file more lengthy reports: The figure from one of these reports illustrates the incident.

The fate of the unlucky worker was not reported.

Actual injection rates:
Unit 1: 2.5 m³ feed water, 2.0 m³ core spray, unit 2: 1.9 m³ feed water, 3.9 m³ core spray, unit 3: 2.1 m³ feed water, 4.0 m³ core spray

Lessons Learned from Fukushima in Japan

Anybody  who has read the ENSREG stress test for European NNPs has learned that little or nothing can be learned for the safety of European and especially German NPPs, at least according to the government experts who have prepared the German stress test report. From the German Stress Tests it can be learned that German NPPs are the safest in the world - believe it or not - at least in view of the official German safety experts.Quite astonishing in view of the fact that all German NPPs have substantial safety deficits, e.g. in the protection againt the crash of a large commercial airliner or the preparations for external mobile injection (see "Die Sicherheitslücke").

In sharp contrast to the official European nuclear experts findings, Japanese safety experts have identified safety deficits and are adding new safety features to the Japanese power plants. Some are quite interesting and are shown on the figure below in the report dating from 2012.10.14.

A new report shows a new surprising proposal: A truck with two pumps and an heat exchanger.

This proposal indicates that the injection of sea water and other untreated water has caused more problems than TEPCO has admitted. In the mobile injection planned in German NPPs this kind of interface between the cooling water and the external water taken from rivers or other storages is not foreseen. Obviously the Japanese experience shows that such an interface should be provided and implemented. One favorable result from the use of this heat exchanger is that the borated water firstly injected into the system is not diluted and the borate concentration is kept up. This adds to the margin of safety from inadvertant re-criticality.

NHK addresses potential lack of man power for Fukushima clean-up

In one of its regular reports on Fukushima, NHK TV station has addressed the problem that the Fukushima will require thousands of workers on the contaminated accident  site for 40 years and the more difficult problems of the clean-up are still to come. This might lead to the problem of a substantial lack of workers willing to work on the contaminated accident site and take the health risks even if adequate monetary recompensation is offered.

Basically, working in a contaminated environment leads to a restriction on the time of employment. In a well organised society a worker who is reaching the allowed radiation dose can no longer work there and he has to find a new job or work somewhere else for his company. This is the reason why most of the work in a NPP is carried out by contract worker who work there on a time limited basis and can easily be hired and fired. NPPs prefer contract workers which are on site for a limited time only to do the work which may lead to substantial radiation exposure. The idea is that it is easier to replace unskilled contract worker that to replace the company's specialists.

Evidently the workers from the subcontracters are persons who are too old or unskilled and have difficulties to find other employment. This explains why more than two workers died during work simply by exhaustion being to old for the hard work under full scale protection. The problem to find workers who are willing to work on site for a limited period is connected with the pay. People are always willing to take risks if they obtain a reasonable recompensation.

Bottom Line: The admin thinks that NHK has identified a problem but this problem can be easily solved with money and to the best of scientific knowledge there is no real health risk if the workers are exposed to radiation below the dose limits.

2012.11.19     Restoration works halfhearted and uninspired

Tepco has not implemented a feasible solution to cope with the water ingress into the basements of the reactor and turbine buildings. The amount of contaminated treated water is increasing steadily and has reached about 325.000 m3 by now. The figure illustrates the situation.

The good news is the level of radioactivity in the water has decreased by a factor of 10 during the last year. Basically TEPCO is washing cesium from the reactor and the basement,  is  filtering it out and storing it in the sludge vessels. At the end of the day, all radioactivity will be transferred in this way into the sludge vessel which means hot waste storage on the plant site. If TEPCO is continuing this process long enough the radioactivity level will be low enough to allow the water to be dumped into the sea. This might be the secret behind TEPCO's reluctant and uninspired approach to the problem.  

2012.11.4     Slow or no progress at Fukushima Daichi

Tepco is reporting on a regular basis on the works performed and the progress made. During October 2012 there was no substantial progress nor any milestone achieved.
The makeshift emergency equipment shows the well-known failures: leackages and electical problems: smoke coming out of motors and cables, leackages from pipes, valves and piping typically found by some workers from subcontractors stupid enough not to keep away from potential radiation sources. This causes TEPCO a lot of paper work and a lot of explanations.
The lack of real news has led to the curious situaton that some experts tried to dramatize TEPCO's finiding on the contamination of shell and shellfish caught off the Fukushima shore.
TEPCO has been catching fish and shellfish off the Fukushima shore since May 2012 and has been reporting the radiation levels. Clearly, the values found are random caused by the random nature of catching fish. What is bothering some experts is the fact, that there is no tendency in the data as one would expect the contamination levels should go down following the radioactive decay.
On second thoughts it is clear that these "experts" are no experts for this issue as more factors contribute to the actual radiation levels:
- the contamination of the ocean water and soil
- the amount and period of intake by fish and shellfish
- the increase of contamination by river water from contaminated land areas.
Taking these different mechanisms into account it is obvious that one cannot expect a decreasing tendency and there is no reason to suspect radioactive leackage from the Fukushima plant covered up by TEPCO.