Thursday, September 22, 2011

Government Researchers: Hydrogen Gas Generation by Radiolysis In Reactor SFP May Have Led to Explosion

and as it was revealed at the fall conference of the Atomic Energy Society of Japan on September 20, the water had to be boiling for that to happen.

The article by Mainichi Shinbun on September 13 (linked below) summarizes the findings well enough. According to the article, the government researchers at Japan Atomic Energy Research and Development Agency and at Tokyo University announced the result of their analysis that the explosion of Reactor 4 reactor building at Fukushima I Nuclear Power Plant on March 15 may have been caused by a large amount of hydrogen gas produced by water radiolysis - dissociation of molecules by nuclear radiation in the Reactor 4 Spent Fuel Pool.

Here's from Mainichi Shinbun Japanese (9/13/2011):


An analysis by a team of researchers from Tokyo University and Japan Atomic Energy Agency shows that part of the reason for the explosion of Reactor 4 reactor building at Fukushima I Nuclear Power Plant was the large amount of hydrogen gas generated in the Spent Fuel Pool of Reactor 4. Radiation splits water and creates hydrogen. The analysis will be presented in the Atomic Energy Society of Japan's fall conference that will start in Kitakyushu City from September 19.


The Reactor 4 Spent Fuel Pool contained 1,535 fuel rods, the most in the reactors at Fukushima that broke down. At the time of the March 11 earthquake/tsunami, the reactor had been stopped for the regular maintenance. But the tunami knocked out the power supply, which caused the loss of cooling, and the reactor building exploded on March 15, 4 days after the quake.


In Reactors 1 and 3 which blew up in hydrogen explosions, it is considered that the fuel rods inside the reactors were damaged, which generated hydrogen. However, the fuel rods from Reactor 4 did not have noticeable damages. TEPCO suspects that hydrogen gas from Reactor 3, which shares the exhaust stack with the Reactor 4, flew through to Reactor 4, causing the explosion in Reactor 4.


However, the team of researchers from Tokyo University and JAEA looked at the 20-hour gap between the explosions of Reactor 3 and 4, and suspected there are some other causes for the explosion [of Reactor 4]. The team irradiated the water in a flask at room temperature, at 97 degrees Celsius, and at boiling temperature and measured the density of hydrogen generated. At 97 degrees Celsius, the density was 1.5 times as much as at room temperature, and at boiling temperature the density was 100 times as much as at room temperature.


If the density of hydrogen in the air exceed 4%, there's a danger of explosion. Vapor that went to the upper floors of the reactor building would have been cooled by the walls and condensed into water again, but hydrogen may have remained gaseous, increasing the ratio of hydrogen in the air.


Professor Yosuke Katsumura of Tokyo University (radiation chemistry), one of the team members, says "Water radiolysis may have happened in addition to the hydrogen flow from Reactor 3. We would like to test whether it can happen in an actual reactor building with a real-size spent fuel pool".


TEPCO says, "It is possible in theory, but we do not know whether a large enough amount of hydrogen is generated that way to cause an explosion".

There seem to be many interesting papers presented at the conference, highly scientific and technical, detailed insights into what may have happened and how at Fukushima I Nuke Plant. A nice departure from muddling through by TEPCO and NISA for the past 6 months. I only wish I had studied physics and chemistry more...


rtega said...

Any links to the papers themselves for readers with a scientific background?

arevamirpal::laprimavera said...

I'll ask around. May not have been published yet, and prelim abstracts only available to participants, and some data only disclosed in workshops.

Anonymous said...

Why have I only seen video footage of two reactor buildings blowing up at Fukushima? Namely,

- Unit 1, on March 12, 15:36 JST

- Unit 3, on March 14, 11:15 JST

(source for dates/times of explosions:

I have never seen footage of the following:

- the explosion in Unit 2, on March 15, 06:14 JST, which blew out a vent in one of Unit 2's walls (the vent appeared as a small square opening in center of the large expanse of one of Unit 2's walls)

- the explosion in Unit 4, which the Tokyo Univ/JAEA researchers say here occurred 20 HOURS AFTER UNIT 3 BLEW UP.

If Unit 3 blew up at 11:15 JST on March 14, then - 20 hours later - Unit 4 exploded some time around 07:00 JST on March 15. (Wikipedia is silent on this point.)

Where is the footage of Unit 4 blowing up in the early morning of March 15?

Has anyone ever seen it?

Or am I missing something really obvious here?

Anonymous said...

".. and measured the density of hydrogen generated. At 97 degrees Celsius, the density was 1.5 times as much as at room temperature, and at boiling temperature the density was 100 times as much as at room temperature."

I trust that concentration of hydrogen is not a normal effect upon the boiling of water?
A short removal from design parameters and the stuff is literally tearing the place down?

Too dangerous for an error-prone world. For a world with too many agendas, too many intrigues, too many grievances powered by cynicism.


Anonymous said...


"...I only wish I had studied physics and chemistry more..."

That is your +positive side: Because if u had, u would not be writing theses sceptic theses seeking for facts - but would happily sing along with the brainwash... ...err... "educated" and MSM.

Thks for all that!

Another viewpoint into this issue is the propaganda all nuclear physics have eaten fully: the periodic table of uranium contains 13 nuclei - a hidden hoax bigger than vatican itself. All physics books had it right before 1945 - somehow now vanished, only 12 to be found today ... itching fact: 500kg of fuel 'vanishes' yearly from these BWR reactors ... and no explanation for that.

Psst, IAEA runs scared, it has leaked out: direct radiation


Anonymous said...


Seems evident the imperialists various Really do not like each other.

Anonymous said...

"1,535 fuel rods"

...or assemblies?

Depending on source, Typical GE BWR Reactor contains 131 - 151 tons uranium; up to 20% plutonium mix (MOX) ... UO2,UO2-Gd2O3 maybe 746 assemblies.
Mystique: Fukushima internal papers show reactors having 116 fuel 'slots'.

9x9 rod array Assembly weight is said to be 190kg. But is it?
- One pellet, 3.0wt% 235U; 10×10.3 mm
- Zirkonium Zr-lining, diameter 12.3 mm; 0.86mm (Zr-lining 1.0mm); one rod has 3.7m pellet ‘stack’
- Total 8x8 (or 9x9 !?) assembly weight 192kg (or 246kg!?)
- as one assy weight more than 1000kg, the latter fits the 4 x 9x9 -pattern.

Taking into account 6 reactors and 40 yrs usage, maximum (capacity for Fukushima Daichii is) 9600 (12.300!?) tons of plutonium/uranium waste/fuel.

What is the actual amount? And I dont mean the TEPCO handout fuku... Has anybody the real number?

They will still all blow out: See this 2002 revelation:

Anonymous said...

There is a likelihood that some hydrogen leaked from Unit 3 to Unit 4 as TEPCO has previously shown evidence by analyzing the filters. However, the amount that flowed was insufficient to blow up Unit 4 by itself or else there would not have been a delay between Unit 3 blowing up and Unit 4 blowing up. The amount of hydrogen generated by the irradiated boiling water in SFP 4 may not have been enough to cause the explosion by itself without the added amount that flowed in from Unit 3. Again, a confluence of factors.

Anonymous said...

The problem with hydrogen production at boiling reactors caused accidents 2001 at Hamaoka-1 and Brunsbüttel. The detonation caused pipes to explode. The problem where researched worldwide at that time. Later some studies was done to estimate the production of hydrogen at boiling reactors.

However, it seams that less attention is spent on the pool with used nuclear fuel.

Anonymous said...


Did I really just read the following in your link?

From the present investigation it may be concluded that

�� The future disaster of TEPCO's making at Fukushima will make it abundantly evident that the proper response is to dump massive, massive quantities of borax on the coriums, as Elvis is ever of the mischief."

Most prescient of them to include that in their study's report.


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