No Cold Shutdown at Fukushima

Steam detected emanating from the refueling floor of Fukushima Dai-ichi Nuclear Power Station Unit 3 in July 2013 (source: TEPCO).

According to Hiroko Tabuchi's post with the headline "Steam Detected at Damaged Fukushima Reactor" published by The New York Times today, the operator of the stricken Fukushima Dai-ichi Nuclear Power Station Tokyo Electric Power Company (TEPCO) noticed steam emanating from the exposed refueling floor of Unit 3, the nuclear fuel of which melted down in the wake of the 2011 Great Tōhoku Earthquake and Tsunami and which was severely damaged by a violent hydrogen explosion.

As I discussed in my essay with the title "Fukushima: Fuel Meltdowns & Cold Shutdowns" posted Feb. 15, 2012, TEPCO assumed having reached temperatures below the boiling point of water, that is 100 °C, 17 months ago, using an improvised open-loop cooling water cycle (see IAEA news by Peter Kaiser with the title "Cold Shutdown Conditions Declared at Fukushima" dated Dec. 18, 2011). Reaching reactor pressure vessel temperatures below the boiling point of water with closed cooling water cycles after the shutdown of an intact nuclear reactor is known as cold shutdown, a mode TEPCO proclaimed to have achieved at the time.

TEPCO speculates the steam detected this week is generated by rainwater seeping into the reactor (see TEPCO's press release in Japanese dated Jul. 18, 2013).

Regardless of the source, steam emanating from the primary containment vessel implies that temperatures inside the vessel must be 100 °C or higher. The discovery of new steam proves the company's assertion of cold shutdown incorrect. TEPCO is preparing countermeasures for the possibility of a nuclear chain reaction. Follow the latest developments on simplyinfo.org.

 Related Posts

• Fukushima: Fuel Meltdowns & Cold Shutdowns

KitchenAid & Kitchen Damage

This summer we decided to remodel our kitchen. It is an intricate process, involving a contractor, an interior designer, builders, plumbers, electricians, tilers, cabinet installers, counter top installers, appliance installers and flooring layers. Inspectors must approve vital steps along the way. I developed deep respect for the contractor who forged this orchestra into a coherent ensemble.

The work was finished on time, taking roughly ten weeks. I must warn you that it takes adjustment to live without a proper kitchen for such extended time. Preparing meals for four on one hot plate can be taxing. I recommend an electric induction cooktop like the DUXTOP 1800-Watt Portable Induction Cooktop Countertop Burner 8100MC for cast-iron ware, but must admit that plenty pizza was ordered.

The work was finally finished. The day came to test the appliances. We use our old refrigerator and gas range. Their activation was uneventful. The new dish washer and microwave oven posed no problem either. However, when the brand new built-in KitchenAid^® Dual-Fan Convection Oven with Steam-Assist Technology (KEBU107SSS) was energized, trouble began. The high-end appliance is set into a large opening of one of the wonderful-looking wood-finish Merillat cabinets at upper body level. It needs a particular high amperage power line and a hose for filtered water. Immediately on activation, the oven's control panel displayed the error message:

F7-E2: Boiler NTC out of range.

The service center was consulted. The following week a subcontracted technician paid us a visit, connected his computer to the oven, checked its vital signs, and ordered one W10076760 sensor, one 9758598 boiler and one W10160958 cntrl-elec, worth roughly 450 dollars in toto, on warranty. The parts arrived on the door step two days later. On the third day, two other gentlemen arrived to install them and recheck the ovenly functions. The steam function seemed to work at 500° F.

Hooray, the great gadget finally seemed to work as it was supposed to without fail! Of course, the technicians did not bake anything in it. The first uses for the brand-new oven were merrily planned for the next day.

But fate had something else in store. Before we started cooking with the oven, I stepped down into our basement to retrieve the Christmas ornaments, only to find a small puddle of water on the floor encroaching on the cardboard boxes. First I thought our hot water boiler sprung a leak. But no, the water dribbled from above, exactly from the spot where the steam oven is located.

I ran upstairs, opened the doors of the cabinet beneath the oven. The pots and pans stored on the shelves were filled with water and had overflowed. Water was dripping from above. The laminated shelving was already crumbling. The wooden flooring in front of the cabinet showed signs of warping.

In the back, I saw the coupling between the water supply line and the oven line. I saw no drops of water on the tubing. I touched the coupling. It was dry.

No doubt, the water dribbled from the oven above. We could not see precisely where the source was, because a board blocks the view on the oven's underside.

I turned off the water supply. We removed the pots and pans, soaked up the water with rags, and called the service center.

The lady from the other side of the globe was friendly. After she verified our coordinates, I explained what happened. She told me that the next appointment with a service technician was available in eight days. I replied that this was no case for a service technician, but for an adjuster to strike up a damage report.

After a little silence, the sweet voice suggested a service technician one more time. I did not dare turn down her offer in the hope that somebody would show up in the flesh eventually. Furthermore, I asked her to kindly inform her superviser of the water damage to the kitchen.

One day later, we have yet to hear from the superviser. In my opinion, our KitchenAid^® steam oven is deeply flawed. It was supposed to be a brand-new, high-end appliance and should have worked right out of the box. Sadly, it never ran properly even after massive repairs. Moreover, it severely damaged a brand-new kitchen cabinet.

It is beyond my expertise to judge whether the manufacturer or the service company are responsible for the damage. Regardless in what fashion this journey will end, the consumer experience has been catastrophic from the beginning. I wonder how the KitchenAid^® brand manages to survive against its competitors with such abysmal record.

Addenda

• A team of experts has visited our home to investigate the cause of the accident. The installation guide for the oven suggests copper tubing for the water supply. The gentlemen divined that the coupling between the copper tubing and the oven had sprung the leak, when the service technicians moved the oven back into the cabinet after the repair. This may happen, I was told, because the copper tubing is stiff and prone to kink. The gentlemen also noted that the technicians had installed only one of the three spare parts that were ordered (12/21/2012).
• Two days ago, the kitchen cabinet furnisher delivered a replacement for the damaged cabinet housing the steam oven and a new appliance. The company had both installed yesterday. An expert was called in to connect the water line. Another shut-off valve was placed beneath the oven between the piece of copper tubing connected to the oven and the plastic tubing connected to the water filter. This morning, I checked the cabinet beneath the oven for traces of water and was happy not to find any. This afternoon, we tested the new oven's steam function, baking French bread. The oven was preheated to 450° F. The steam function was activated, and the loaves were placed on the rack. The convection fans in the oven's back spun with unbearable noise. The first oven's fans ran quietly during the technician's brief test. Despite, the oven kept working without error messages. The bread rose. Its crust turned nicely brown. About 15 minutes into the process, when the bread was almost ready, the oven stopped with the warning:
  
  F7-E0: Water is not high enough.
  We checked the cabinet beneath the oven. Plenty water was dribbling from above, accumulating on the shelves. We closed the new shut-off valve and mopped up the spill as much as possible. The bread turned out great (12/29/2012).
• Today experts visited us to look after the new oven. They attested that electrical wiring behind the convection fans supplying a water level gauge was improperly fastened, allowing one wire to rub against the spinning fans. The rubbing had caused the noise we heard. Once the wire's insulation had been shaven away, the water level gauge failed. The gauge failure apparently allowed the feedwater to flow uncontrolled, spilling into the cabinet below. Because we noticed the leak immediately and shut off the water supply, no water damage to the cabinet could be found this time. The experts repaired the faulty gauge and tested the oven at 300° F for 20 minutes. No malfunction occurred. Regardless of this progress, two brand-new defective ovens in a row provide disconcerting evidence that KitchenAid^® needs to urgently improve quality control. Whoever assembled and tested these ovens should feel profoundly embarrassed for their shoddy workmanship (01/10/2013)!
• We have been baking delicious breads four times to date.
  
  The appliance performed well, though a relay seems to stick on occasion, producing a soft vibratory sound. No further leaks sprang up. Other than an urgent review of quality control, I may suggest two additional safety features that may help avoid water leaks. First an expansion joint between the oven pipe and the feedwater pipe may help prevent the coupling between the two pipes from leaking because of potential unequal metal expansion owing to differing temperatures at the terminations. Moreover, an external solenoid-operated stop-check valve should be installed in the feedwater line. The valve ought to fail close on power loss or on error signals from the oven's control board (01/20/2013).
• Recently, we had another kitchen appliance-related experience of note. When we bought the steam-assist oven, we also purchased a kitchenaid gas range with a double oven. After the range broke on average once a year because the igniters, the convection fan and the emergency gas shutoff valve failed, we decided to go for a Bosch model from a nationwide retailer that contracts out delivery and installation to different contractors. Delivery took a week. The installer did not arrive for three weeks. When we complained to the retailer in person, the installer played cat and mouse with us. After four weeks we returned the uninstalled appliance at full refund. We bought the same model at a different store, where delivery and installation are carried out by the same company on the same day within five business days at half the cost. Buyer beware! Some retailers have implemented better business models than others (06/25/2016).