Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
×
Japan Power

Japan Says Seawater Radioactivity Below Limits Near Fukushima (reuters.com) 113

Reuters reports: Tests of seawater near Japan's Fukushima nuclear power plant have not detected any radioactivity, the environment ministry said on Sunday, days after authorities began discharging into the sea treated water used to cool damaged reactors.

Japan started releasing water from the wrecked Fukushima plant into the Pacific Ocean on Thursday, sparking protests in Japan and neighbouring countries, in particular China, which banned aquatic product imports from Japan.

Japan and scientific organisations say the water is safe after being filtered to remove most radioactive elements except for tritium, a radioactive isotope of hydrogen. Because tritium is difficult to separate from water, the Fukushima water is diluted until tritium levels fall below regulatory limits.

The ministry's tests of samples from 11 points near the plant showed concentrations of tritium below the lower limit of detection — 7 to 8 becquerels of tritium per litre, the ministry said, adding that it "would have no adverse impact on human health and the environment". Monitoring would be carried out "with a high level of objectivity, transparency, and reliability" to prevent adverse impacts on Japan's reputation, Environment Minister Akihiro Nishimura said in a statement.

This discussion has been archived. No new comments can be posted.

Japan Says Seawater Radioactivity Below Limits Near Fukushima

Comments Filter:
  • Tritium (Score:5, Informative)

    by Xardion ( 215668 ) on Sunday August 27, 2023 @02:48PM (#63801762)

    Luckily tritium has a really short half-life (about 12 years), so it's pretty much a non-issue at the concentrations they're maintaining.

  • Of course it is (Score:5, Informative)

    by bradley13 ( 1118935 ) on Sunday August 27, 2023 @02:50PM (#63801772) Homepage
    This is such a non-issue. Eco-freaks never took science, or else didn't pay attention.
    • Re: Of course it is (Score:5, Informative)

      by pollarda ( 632730 ) on Sunday August 27, 2023 @02:58PM (#63801800)
      Yes. People forget or are too clueless to know that two of the best shields for radioactivity are salt and water. Also, there are approximately 4 billion tons of uranium already dissolved in the worldâ(TM)s oceans.

      One of the best ideas Iâ(TM)ve seen on what to do with nuclear waste was published in Scientific American in the early 1980â(TM)s. They found an area of seabed that was geologically stable where nothing has happened there in hundreds of thousands of years. The area has hundreds of feet of silt as well. They proposed putting it in containers under a few hundred feet of silt where it will sit there undisturbed for another few hundred thousand years.

      • by hdyoung ( 5182939 ) on Sunday August 27, 2023 @03:25PM (#63801836)
        What century do you live in? Listening to scientists and experts is sooooo 1900s.
      • Even air provides plenty of protection from tritium.

        It decays to He3 by emitting an 18.6 KeV electron.

        Many power stations run at higher voltages than that.

        • Air is moderately good protection from such a low energy beta decay, and your clothing is even better protection from beta particles. But all this assumes you haven't ingested tritium.

      • Throwing it in the silt in a deep ocean also ensures that some future civilization will have to have some tech savvy in digging it up. It won't just come out of a cave, be brought to the local village and kill everyone.

        • by wagnerer ( 53943 )

          With a 12.3 year half-life I assume you mean future civ as in 100 years? After 123 years the activity will be down by a factor of 1024. Far less than one atom decaying in a liter of water per second.

          • by pjt33 ( 739471 )

            The "bury it in the silt" proposal is for general nuclear waste, not specifically tritium.

      • Yes. People forget or are too clueless to know that two of the best shields for radioactivity are salt and water.

        Huh? Not really much better than anything else.

        Pretty much any mass between you and the beta emitter is effective shielding. Water, dirt, aluminum foil, old copies of the New York Times, whatever.

        The main point is that there is very little tritium, and millions of tons of water, so it's diluted into levels less than the natural radiation that's around us anyway..

        • *pshaw*

          Is water a good blocker of radiation? [calpoly.edu]
          Currently, NASA and other space agencies plan on using water as a shield against radiation since it is already necessary for human missions. Water has been tested thoroughly and has been proven to be effective.

          Does water block radiation? [quora.com]
          Saying hydrogen is a good moderator means that the hydrogen nuclei in water scatter fast neutrons elastically and so reduce their energy very effectively. In fact, both ordinary hydrogen and oxygen can scatter fast neutrons elastic

          • Different radiation.

            We're talking here about blocking radiation from tritium, which is beta radiation: relatively low-energy electrons. The first article is about blocking space radiation, primarily protons (trapped particles) and high-energy heavy nuclei (cosmic rays)... but the actual tests were against blocking gammas. In any case, none of them were shielding against beta radiation. And water was not "one of the best," but was right in the middle of the materials he tested.

            The second article you quote

      • by e3m4n ( 947977 )
        for beta particles (tritium) that's only 11mm. People also freak out with words ending in -ium. We use tritium all the time in things that need to glow at night time such as the Cammenga 3H lensatic compass, or the Trijicon 4x32 ACOG our us marines use for std issue. hell the tritium itself doesnt even glow, its a beta emitter (electron). Stage 2 of the glow factor is phosphor that glows as it absorbs the electrons. The thing about charged particle radiation like alphas and betas is that it cant penetrate v
    • Re:Of course it is (Score:4, Interesting)

      by DrunkenTerror ( 561616 ) on Sunday August 27, 2023 @04:21PM (#63801894) Homepage Journal

      shitty people are shitty, damnation to the science. this week china banned japanese seafood [msn.com] and japanese establishments in china are facing harrasment & vandalism [nhk.or.jp]

    • By getting excited about this issue, the green campaigners will get money into their bank accounts. Some of them might even feel guilty at deceiving the scientifically illiterate public over the issue, but will probably argue that if their organisation didn't do this campaign, another one would and they'd get the money instead of my organisation. 'Of course my organisation will spend this money on projects that are fully justified by the science...' will also be offered as a means of self justification.

    • Re: (Score:2, Informative)

      by hey! ( 33014 )

      While I happen to believe the IAEA evaluation that this will pose no significant risk to people or ecosystems, no amount of general science background can allow you to make a reliable snap judgment about a thing like that. Details and specifics matter. A lot of the high school science reasoning people use to leap to conclusions one way or the other is actually faulty, although of course it always sounds "scientific".

      For example you often hear that because tritium is a beta emitter, and beta particles are s

      • It can, for example, bioaccumulate after being converted into organically bound tritium by plants and algae.

        Tritium occurs naturally so if tritium bio-accumulation was a problem then we'd have likely detected that by now. Because this has not been seen yet it is far more likely that with time the tritium will dilute in the sea, and the sea is a large place for artificially produced tritium to hide among naturally occurring tritium.

        • It can, for example, bioaccumulate after being converted into organically bound tritium by plants and algae.

          Tritium occurs naturally

          Not enough to matter.

          A trivial amount of tritium can be produced by cosmic rays, but the amount is pretty much too small to measure.

        • Re: (Score:2, Insightful)

          by hey! ( 33014 )

          Tritiated water occurs naturally as a result of cosmic radiation, but in negligible quantities -- about 1 in 10^18 water molecules is naturally tritiated. If OBTs *did* bioaccumulate, you wouldn't expect to see significant effects *because there's not enough tritium in the system to produce those effects before the tritium leaves the food chain*, either by nuclear decay or biochemical processes.

          We're talking about tritium levels 10,000x the natural baseline. That's still not very much, but you can't safel

      • by Vihai ( 668734 )

        Tritium is almost chemically indistinguishable from hydrogen. A biological process that would be able to separate and accumulate tritium is very, very improbable.

      • You don't even have to give numbers per se. There are multiple reactors in Korea and China that release more tritium/year than this will. It is a normal byproduct and safety limits are well established. This information is in the IAEA slide deck, and the press just ignores it. The tritium release is totally safe. The only issue worth talking about is ensuring appropriate monitoring so that everything else is definitely removed to planned limits. That China doesn't negotiate on testing requirements jus
    • their thoughts before quickly trying to get the first post.
      Even checking wikipedia could be elevating for some commenters here.

    • You only hear from the ones who didn't.

      They wont listen to the ones who did. Ask me how I know.

  • How can you trust a country that still kills whales while saying it's for "research"? Call a donkey a donkey, don't slap another label on it to confuse people. That said, they might mean something else by saying "safe" in this context.

    • by ceoyoyo ( 59147 )

      You know the US still hunts whales right?

    • How can you trust a country

      No one is trusting a country. The release of the waste water is done under the approval and supervision of the IAEA. No one country is involved here, and no one country is being trusted here.

      I'll leave it to someone else to point out your entire post is a strawman fallacy, but even if it weren't, it's just silly.

    • I can't tell if you're being silly or not. Besides the fact that these things have NOTHING to do with each other, directly, tangentially, or even emotionally, pointing out that "a country" does any one thing as a cohesive unit is inherently... dumb. There's no need to extend your logic any further to reach a conclusion that no country can be trusted on any topic, ever. How can you trust the Canadians on maple syrup production? Some of their Inuit population kills baby seals.

      I think it's unlikely in the extr

  • ... about dumping all that tritium. We could have had a great supply for pistol sights.

    • The price is like $30,000 per gram and it still wasn't profitable to extract? That is a really low concentration.

      • by jcochran ( 309950 ) on Sunday August 27, 2023 @09:59PM (#63802466)

        $30,000 per gram? That's rather impressive. So if they managed to extract all the tritium from that contaminated water, they could sell it for an astounding $63,000. The issue is that the total amount of tritium there is only 2.1 grams, which can produce 14 mL of pure tritiated water, which in turn is mixed with 860,000 cubic meters of water. Yea, not economically viable to extract.

    • Analog watches too.

  • The complaints about this action are not coming from scientific analysis, and because of that, they cannot be swayed by it. It's an emotional objection, and honestly from that perspective it's an understandable one. Lots of people find the idea of drinking recycled, purified sewage water upsetting, no matter how clean you prove that water to be.

    So, pay "some" attention to providing enough details to assuage the fears of those who are on the fence... but write off the people who won't be convinced no matter

  • ...based on the amount of tritium at Fukushima, if they dump it all, the concentration of naturally-occurring tritium in the ocean will increase by 1e-10 percent. And that increase will have a half-life of only 12 yrs. Compared with the amount of cosmic-ray-produced tritium raining down from the sky into the ocean each year, this is a non-event.
  • NRC tests are never random. Radioactivity tests always taken exact same location. More good news for you

Any programming language is at its best before it is implemented and used.

Working...