• Research
  • Emissary
  • About
  • Experts
Carnegie Global logoCarnegie lettermark logo
DemocracyIran
  • Donate
{
  "authors": [
    "James M. Acton"
  ],
  "type": "legacyinthemedia",
  "centerAffiliationAll": "dc",
  "centers": [
    "Carnegie Endowment for International Peace"
  ],
  "collections": [],
  "englishNewsletterAll": "ctw",
  "nonEnglishNewsletterAll": "",
  "primaryCenter": "Carnegie Endowment for International Peace",
  "programAffiliation": "NPP",
  "programs": [
    "Nuclear Policy"
  ],
  "projects": [],
  "regions": [
    "East Asia",
    "Japan"
  ],
  "topics": [
    "Nuclear Policy",
    "Nuclear Energy"
  ]
}

Source: Getty

In The Media

Japan's Nuclear Situation Takes 'Grim Turn'

While substantial core melting in the Japanese nuclear reactors damaged by the earthquake and following tsunami may create the risk of a large release of radiation into the environment, it is also possible that any amounts of radiation released would be relatively small.

Link Copied
By James M. Acton
Published on Mar 14, 2011
Program mobile hero image

Program

Nuclear Policy

The Nuclear Policy Program aims to reduce the risk of nuclear war. Our experts diagnose acute risks stemming from technical and geopolitical developments, generate pragmatic solutions, and use our global network to advance risk-reduction policies. Our work covers deterrence, disarmament, arms control, nonproliferation, and nuclear energy.

Learn More

Source: NBC

BRIAN WILLIAMS, Anchor: And we have more now on this nuclear risk. And beyond the immediate area in Japan, a lot of Americans are asking a lot of questions. To that end, with us here in our New York studio tonight, physicist James Acton with the Carnegie Endowment.

Thank you very much for being with us. Let's talk about the risks and consequences, because we are starting to throw around terms like meltdown. What does that mean in terms of danger to humans, both in the area and a great distance away?

JAMES ACTON, Carnegie Endowment for International Peace: Well, good evening, Brian. And when Americans have been looking at the wind maps over the Pacific and they see that the wind blows from Japan to the United States, it's understandable that they get worried. But what they have to remember is two things.

Firstly, as the radiation gets taken and blown out, it gets more and more dilute. And secondly, we are also subject to radiation the whole time. It's in the air, it's in the rocks around us. So whereas this is a very serious situation, the White House has announced today that based on its modeling it doesn't believe there's a threat to people in the United States, and I have no reason to doubt that conclusion.

WILLIAMS: And when you hear they're pouring seawater on a core to cool it down, that's obviously the last resort. They've decided this is just going to become a hot tomb. For how long does that just have to stay inert, untouched?

ACTON: Well, a lot is going to depend on the scale of damage in the core. But you see, as soon as the reactors were shut off, they continued to produce heat. And over the last three days, the engineers running the plant have been in a desperate race to cool those reactors down. And the news for reactors one and three looks like they might, and I stress might, be coming through. But reactor two still appears to be in significant trouble.

WILLIAMS: So a worst-case scenario here, if we lose one, two or, God forbid, all three of these, this remains a deeply local crisis; but thankfully, in a hyper-prepared nation where people have gotten away from the immediate area and now must stay away for a long period of time, I'm guessing.

ACTON: I think that's right. I mean, if there is--if there is substantial core melting, then there is the risk of a large release of radiation into the environment. There's no certainty of a large release of radiation. At Three Mile Island there was extensive core melting and relatively small release of radiation into the environment.

But if there is a large release of radiation into the environment, then the Japanese really have done everything they can. Everybody has been evacuated from around the site, so the immediate injuries due to radiation should be relatively low. The real long-term problem, if there is a large release of radiation, is in long-term illnesses, particularly cancers.

WILLIAMS: All right, James Acton with Carnegie, thank you very much for answering our questions tonight.

ACTON: Thank you.

About the Author

James M. Acton

Jessica T. Mathews Chair, Co-director, Nuclear Policy Program

Acton holds the Jessica T. Mathews Chair and is co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace.

    Recent Work

  • Other
    Unpacking Trump’s National Security Strategy
      • Cecily Brewer
      • +18

      James M. Acton, Saskia Brechenmacher, Cecily Brewer, …

  • Commentary
    Trump Has an Out on Nuclear Testing. He Should Take It.

      James M. Acton

James M. Acton
Jessica T. Mathews Chair, Co-director, Nuclear Policy Program
James M. Acton
Nuclear PolicyNuclear EnergyEast AsiaJapan

Carnegie does not take institutional positions on public policy issues; the views represented herein are those of the author(s) and do not necessarily reflect the views of Carnegie, its staff, or its trustees.

More Work from Carnegie Endowment for International Peace

  • Commentary
    Emissary
    In Its Iran War Debate, Washington Has Lost the Plot in Asia

    The United States ignores the region’s lived experience—and the tough political and social trade-offs the war has produced—at its peril.

      Evan A. Feigenbaum

  • apan's 8,900-ton Maritime Self-Defense Force supply ship Oosumi leaves Muroran port escorted by the 4,550-ton destroyer Murasame bound for Kuwait February 20, 2004 in Muroran, Japan.
    Article
    Japan’s Security Policy Is Still Caught Between the Alliance and Domestic Reality

    Japan’s response to U.S. pressure over Hormuz highlights a broader dilemma: How to preserve the alliance while remaining bound by legal limits, public opinion, and an Asia-centered security agenda. Tokyo gained diplomatic space through an alliance-embracing strategy, but only under conditions that may not endure.

      • Ryo Sahashi

      Ryo Sahashi

  • Implementing the Biden Administration’s China Strategy
    Report
    Implementing the Biden Administration’s China Strategy

    At the heart of Biden’s approach to China was the consolidation of a framework for strategic competition with an eye toward coexistence.

      • Senkai Hsia

      Christopher S. Chivvis, Senkai Hsia

  • apan's Prime Minister Sanae Takaichi (L) reacts as US President Donald Trump delivers a speech in front of US Navy personnel on board the US Navy's USS George Washington aircraft carrier at the US naval base in Yokosuka on October 28, 2025.
    Article
    Takaichi’s Security Agenda After the Landslide Election

    Backed by a new LDP supermajority, Prime Minister Takaichi aspires to revise Japan’s long-standing security doctrine. Ahead of her visit to Washington, she faces fiscal hurdles for her proposed defense spending while needing to navigate President Trump’s request for naval assets to the Strait of Hormuz.

      • Harukata Takenaka

      Harukata Takenaka

  • Japanese Prime Minister Sanae Takaichi delivers a speech during the graduation ceremony at the National Defense Academy of Japan on March 14, 2026 in Yokosuka, Kanagawa Prefecture, Japan.
    Article
    Revisiting Japan’s Non-Nuclear Principles: Between a Nuclear Allergy and Umbrella

    Japan’s prime minister, Takaichi Sanae, may kickstart a discussion on Japan’s non-nuclear principles.

      Shizuka Kuramitsu

Get more news and analysis from
Carnegie Endowment for International Peace
Carnegie global logo, stacked
1779 Massachusetts Avenue NWWashington, DC, 20036-2103Phone: 202 483 7600Fax: 202 483 1840
  • Research
  • Emissary
  • About
  • Experts
  • Donate
  • Programs
  • Events
  • Blogs
  • Podcasts
  • Contact
  • Annual Reports
  • Careers
  • Privacy
  • For Media
  • Government Resources
Get more news and analysis from
Carnegie Endowment for International Peace
© 2026 Carnegie Endowment for International Peace. All rights reserved.