Saturday, March 26, 2011

Don't Like It

According to yesterday's release from NISA, the Japanese nuclear safety agency :

a) hefty chunks of the fuel rods are exposed to the air in reactors 1, 2 and 3

b) there's no information on spent fuel pool temperatures in reactors 1, 3 and 4 (2 is OK at 28C).

c) there seems to be uncertainty about the sources of the smoke observed at all four reactors. Yesterday 1, 2 and 4 were all emitting, 3 was emitting the day before.

d) pressure in #1 is far higher than in 2 or 3.

NHK reports that there's highly radioactive water in the basements of 1 and 3 - not totally surprising given they're being sprayed. TEPCO's latest assessment of the reactors says that the company believes of reactors 4, 5 and 6 that "we do not consider any reactor coolant leakage inside the reactor happened", while remaining silent on 1, 2 and 3. Some are interpreting the radioactive water as the result of a possible breach.

"Water was also discovered in Units 2 and 4, and the company said it suspects that, too, is radioactive. Officials acknowledged the water would delay work inside the plant.

Plant officials and government regulators say they don't know the source of the radioactive water discovered at Units 1 and 3. It could have come from a leaking reactor core, associated pipes, or a spent fuel pool. Or it may be the result of overfilling the pools with emergency cooling water."

I get the impression that the 'injection' of water and seawater into the cores is not accompanied (deliberately, at any rate) by removal of hot water from the cores. Looks like they're just pumping more in. I can see that will reduce pressure in the short term as the temperature drops, but surely that can't go on indefinitely? Yet apparently the fuel is still exposed - where's all the water going? Hopefully not the basement.

Looks like the struggle continues, with number 3 being the beast to tame, because of the plutonium hazard. Best of luck, lads (and lasses - there's at least one woman on the team).

Tuesday, March 22, 2011


Last week, as the reactor problems piled up for Japan's embattled TEPCO company, the Guardian tried a new initiative.

How would you solve Fukushima?

Use the comments to leave your suggestions on how to tackle the Fukushima reactors

Commenters immediately split into three camps.

Some took the mick :
a) never build the damn thing in the first place

b) see above

"Attach several long cables to each reactor, tow them to the Marianas trench, cut cables."

Some thought the idea tasteless, while a minority were upset or outraged :

I think this entire thing is in incredibly bad taste and frivolous. This isn't some party game for educated liberals, is it?

"I am Japanese and am currently trying to live through all this.
And I would just like to say that I fnd this whole idea of inviting your readers to try and "solve" Fukushima in extremely bad taste.
This is not a puzzle or a quiz---well, it isn't for us, nor is it for the workers and others who are risking their lives on site."
"It would be one thing to solicit opinions from nuclear scientists and engineers, but I fail to see the benefit of asking for solutions from people with no practical knowledge whatsover. All it does is make a mockery of a very bad situation."

Now this was in the Guardian the day after helicopters had dropped four bags of water - a few tons - over the reactors - the vast majority of which missed the target. The cooling ponds should contain hundreds of tons of water. When people saw this on video they reasoned - rightly IMHO - that the guys on site were starting to clutch at straws. The problems which were preventing them getting cooling water to the ponds were as much engineering issues as nuclear ones. You didn't need nuclear physics to realise that the issues involved getting a lot of water from A to B - where B is in a damaged building with high radiation levels.

So out came the third camp with their suggestions. Some were eccentric but still perhaps possible :

"Use water balloons... instead of trying to drop water by itself. Also it sounds stupid, but if there's something sold and wet to throw, then something like a trebuchet might be able to do it at much longer range than either a helicopter or a fire truck - they have a range of potentially several hundred metres, and it's a large target to hit."

Some were frankly insane as well as not addressing the problem :

"Subject all new models to standardized stress tests of operational full-sized plants recreating the actual effects of earthquakes, floods, and military attacks, singularly and as multiple events."
Hmm. A working, full-size nuclear reactor, and as a safety test you'll subject it to multiple military attacks? And you'll simulate a 9-scale earthquake how exactly?

"It just requires really big laboratories to contain the effects."

But there were a lot of possible ones. Why not attach a hose to a tethered blimp, and keep it suspended above the reactor with multiple guys ? Add cameras too. What about the giant construction cranes Japan has so many of - couldn't you get one over the reactors ? Firefighting boats attacking from seaward. Address the power shortage with a ship's generators.

"Surely they could rig some fire trucks to drive up and pump water"
"Drones for inspection - the US ones are pretty good"
"I would suggest using hydraulic concrete pump trucks to flood the spent fuel rod pools. They can be operated from ground level and reach a long distance both up and over."
And it came to pass :

"Six SDF fire engines resumed blasting the reactor with water shortly before 2 p.m. Friday and worked for about 45 minutes, the Defense Ministry said... Meanwhile, the Tokyo Fire Department dispatched 139 firefighters to the nuclear plant Friday with 30 vehicles, including ladder trucks and chemical fire engines, to aid the SDF's mission."

"A Global Hawk drone flew over Japan’s crippled Fukushima Dai-Ichi nuclear plant today to collect data and imagery for the Japanese government, said U.S. Air Force Chief of Staff General Norton Schwartz. "

"A vehicle with a long spraying arm injected water into the No.4 reactor at the troubled Fukushima Daiichi nuclear power plant for about 3 hours on Tuesday. The vehicle, owned by a construction firm in Mie Prefecture in central Japan, began the operation at 5:17 PM Tuesday at the request of the Tokyo Electric Power Company. The vehicle is used in construction of high-rise buildings, and is capable of extending its arm more than 50 meters to pour concrete.

TEPCO says 2 other similar vehicles are ready to join the water-spraying operations. "
The drone was deployed the same day as the Guardian piece, the firetrucks a few days later, the concrete pump only today. Whether anyone in Japan was reading the Guardian or not, the commenters there seem to be at least as good as TEPCO when it comes to bright ideas.