Why I am not worried about Japan’s nuclear reactors • Hacker News Board

Re: Why I am not worried about Japan’s nuclear reactors

#51

Post by cracki » Sun, Mar 13, 2011, 3:04 PM UTC

Kilimanjaro wrote: post #36

ugh wrote: post #32

Earlier quoted context omitted.

Can tidal power equipment survive a tsunami, though? Japan needs a stable energy supply – if only because they can’t just import power from one of their neighbors in a pinch (like, for example, most European countries can). I heard today that even wind turbines are not ideal for Japan because typhoons are common. Japan is in a pretty unique position – it’s certainly understandable why nuclear power is very popular th…

Earthquake destroys nuclear plant: thousands killed. Tsunami destroys tidal power plant: none killed. You are the PM of Japan, you make the call.

did the earthquake kill thousands, or did the total failure of a nuclear power plant kill them?

a tsunami can kill just as many people as an earth quake.

the subsequent deaths due to a destroyed power plant are another matter. from the article I get the impression that nuclear plants are built to withstand a lot of abuse and fuckups.

i see no reason to shy away from nuclear power. their power producing companies will know what kind of plants to run. we don't.

Re: Why I am not worried about Japan’s nuclear reactors

#52

Post by yummyfajitas » Sun, Mar 13, 2011, 3:05 PM UTC

ck2 wrote: post #40

ugh wrote: post #28

Earlier quoted context omitted.

That’s because hardly any radioactivity was released into the atmosphere during the Three Mile Island incident. It was mostly harmless.

I think you are missing some documentation http://www.southernstudies.org/images/sitepieces/wing_tmi_ca...

I don't know what the population density is, from your graph, it sure looks like Three Mile Island prevented a bunch of cancer. (Assuming of course you want to infer causality from one picture.) Look at all that dark green - those are areas with 50% less cancer than would be expected.

The wikipedia article suggests the science is very mixed, and there is no conclusive evidence one way or the other.

http://en.wikipedia.org/wiki/Three_Mile_Island_accident_heal...

So whatever the effects of TMI were, they are almost certainly small.

Re: Why I am not worried about Japan’s nuclear reactors

#53

Post by illumin8 » Sun, Mar 13, 2011, 3:07 PM UTC

radu_floricica wrote: post #39

veidr wrote: post #34

As a fellow Tokyo resident, newly-minted quake survivor, and even fellow UFC aficionado, I found this guy's reprinted letter of explanation quite comforting. We've been kind of worrying about the nuke meltdown scenarios, and wondering if maybe we should find some pretext for a quick trip abroad in the next couple days. And so I read this post, and nodded, and though 'Hmm, ok, good... OK, sounds reasonable. Oh, I see,…

There is a reason I feel much relieved after reading this. Pretty much everything I've read so far implied that once there is a meltdown, all bets are off. We'll have radioactive material boiling in open air, and all the "good" things that come with it. Which sounded very suspicious to me... I mean, isn't containment designed to prevent exactly that? Once the fuel melts, it just makes a hole on the bottom of the cont…

Except that "Fukushima Dai-ichi No.1 Reactor does not have a concrete containment dome. This reactor was built before the now familiar reinforced concrete dome became mandatory for most reactors. Instead, the reactor has a much smaller steel containment vessel around the reactor vessel."

This was from a Slashdot comment, so I trust it about equally to a newly minted blog with only a single post: http://slashdot.org/comments.pl?sid=2033910&cid=35463272

Someone with more knowledge of nuclear power history could surely cross reference the dates here for us and confirm/deny the existence of the 3rd containment layer:

Fukushima Daiichi Unit 1

- 439 MWe BWR, 1971

- Automatically shut down

- Water level decreasing

- Pressure release implemented

- Explosion observed

- Containment believed intact

- Seawater injection has started

- Radiation levels did not rise after explosion

Unit 2

- 760 MWe BWR, 1974

- Automatically shut down

- Water level lower but steady

- Preparations for pressure release

Unit 3

- 760 MWe BWR, 1976

- Automatically shut down

- Preparations for pressure release

Unit 4

- 760 MWe BWR, 1978

- Shut for periodic inspection

Unit 5

- 760 MWe BWR, 1978

- Shut for periodic inspection

Unit 6

- 1067 MWe BWR, 1979

- Shut for periodic inspection

Re: Why I am not worried about Japan’s nuclear reactors

#54

Post by borism » Sun, Mar 13, 2011, 3:24 PM UTC

lispm wrote: post #27

Wow, such a denial of reality. 'in control'? If anything I saw in the last hours, the thing is not in control. Diesel generators failed, a building exploded, core meltdowns going on, restoring of electricity failed, seawater used for cooling (how were they pumping it and are the pumps powerful enough to provide cooling over a longer period of time like days). Valves are not working, measurement of pressure is not pos…

the lack of communication between TEPCO, Japanese govt and IAEA is a cause of serious concern as well, IMHO.

Re: Why I am not worried about Japan’s nuclear reactors

#55

Post by lemming » Sun, Mar 13, 2011, 3:26 PM UTC

benohear wrote: post #47

vdbnnss wrote: post #38

Earlier quoted context omitted.

Thank you for reminding us of how much of a non-event the Chernobyl accident was for you in Switzerland, a few thousand miles away. While you're at it, don't forget tell those wimps in Belarus to shut up and stop whining about this non-event.

You're right. For them it was an absolute tragedy. I wasn't implying otherwise. But the premise of the OP was some Australians that were freaking out because of the events in Japan. It's a similar situation.

From the comments looks like the OP lives in Japan, hence his family's concern.

Re: Why I am not worried about Japan’s nuclear reactors

#56

Post by radu_floricica » Sun, Mar 13, 2011, 3:39 PM UTC

eliasmacpherson wrote: post #16

radu_floricica wrote: post #11

It was very interesting to read the wikipedia page for INES. Turns out we never heard about the most serious incidents except Cernobyl http://en.wikipedia.org/wiki/International_Nuclear_Event_Sca...

Interesting also that in the INES pdf on that site, the requirement for INES4 is at least one death from radiation. Perhaps the declaration of INES level four was in error, or the requirement is not strict. Another interesting link just found: http://en.wikipedia.org/wiki/List_of_civilian_nuclear_accide...

There is one confirmed death (a crane operator, but I didn't find any clear cause of death) and several injuries.

Re: Why I am not worried about Japan’s nuclear reactors

#57

Post by neutronicus » Sun, Mar 13, 2011, 3:43 PM UTC

The article is mostly correct, but a few corrections from a nuclear engineer:

1. What he refers to as "moderator rods" are actually control rods. The term "moderator" refers to a material that is unlikely to absorb neutrons, but likely to scatter them. This helps lower the average neutron speed inside the reactor, which actually increases the fission rate. Since water serves this purpose just fine, most reactors do not have specific "moderator rods", although BWRs actually run pipes of liquid water through the fuel assemblies for additional moderation.

2. BWRs are not run all-rods-out, like he claims. BWRs are generally run with significant control rod insertion, so that the water stays liquid for a greater portion of the height of the core.

3. He doesn't quite explain that the source of the hydrogen is a replacement reaction where zirconium and water react to create zirconium oxide and hydrogen gas.

4. Xenon-135 is a fission product, not produced by neutron activation, and neutron activation of coolant is nothing to sneer at (the half-life of tritium is 12.3 years).

Re: Why I am not worried about Japan’s nuclear reactors

#58

Post by illumen » Sun, Mar 13, 2011, 3:49 PM UTC

cracki wrote: post #51

Kilimanjaro wrote: post #36

Earlier quoted context omitted.

Earthquake destroys nuclear plant: thousands killed. Tsunami destroys tidal power plant: none killed. You are the PM of Japan, you make the call.

did the earthquake kill thousands, or did the total failure of a nuclear power plant kill them? a tsunami can kill just as many people as an earth quake. the subsequent deaths due to a destroyed power plant are another matter. from the article I get the impression that nuclear plants are built to withstand a lot of abuse and fuckups. i see no reason to shy away from nuclear power. their power producing companies will…

This is a company that has been caught falsifying safety reports, and had resignations because of it. I would not trust them to choose in the interest of everyone - but instead in the interest of the company.

Re: Why I am not worried about Japan’s nuclear reactors

#59

Post by neutronicus » Sun, Mar 13, 2011, 3:50 PM UTC

lispm wrote: post #31

lispm wrote: post #27

Wow, such a denial of reality. 'in control'? If anything I saw in the last hours, the thing is not in control. Diesel generators failed, a building exploded, core meltdowns going on, restoring of electricity failed, seawater used for cooling (how were they pumping it and are the pumps powerful enough to provide cooling over a longer period of time like days). Valves are not working, measurement of pressure is not pos…

The reactor 3 at the first Fukushima plant is not just using Uranium. It uses MOX fuel. So what the author ('expert???') wrote is already useless, he does not even know what the reactors are using as fuel. Japan Today: http://www.japantoday.com/category/technology/view/mox-fuel-... From August last year: MOX fuel loaded into Tokyo Electric's old Fukushima reactor Sunday 22nd August, 05:36 AM JST FUKUSHIMA — Tokyo Ele…

Honestly, whether the fuel is UOX or MOX is not particularly relevant at this point, since the primary differences between those fuels are neutronic, not thermal, and even there they are qualitatively very similar.

I'm pretty sure the author is not an 'expert', exactly, because he seems unfamiliar with some of the nuances of BWR operation, but his summary is generally correct.

Re: Why I am not worried about Japan’s nuclear reactors

#60

Post by [deleted] » Sun, Mar 13, 2011, 4:00 PM UTC

neutronicus wrote: post #59

lispm wrote: post #31

Earlier quoted context omitted.

The reactor 3 at the first Fukushima plant is not just using Uranium. It uses MOX fuel. So what the author ('expert???') wrote is already useless, he does not even know what the reactors are using as fuel. Japan Today: http://www.japantoday.com/category/technology/view/mox-fuel-... From August last year: MOX fuel loaded into Tokyo Electric's old Fukushima reactor Sunday 22nd August, 05:36 AM JST FUKUSHIMA — Tokyo Ele…

Honestly, whether the fuel is UOX or MOX is not particularly relevant at this point, since the primary differences between those fuels are neutronic, not thermal, and even there they are qualitatively very similar. I'm pretty sure the author is not an 'expert', exactly, because he seems unfamiliar with some of the nuances of BWR operation, but his summary is generally correct.

[deleted]