{"id":4042,"date":"2025-08-21T09:37:01","date_gmt":"2025-08-21T08:37:01","guid":{"rendered":"https:\/\/blogg.lnu.se\/unesco\/?p=4042"},"modified":"2025-09-11T09:18:07","modified_gmt":"2025-09-11T08:18:07","slug":"beyond-a-million-years","status":"publish","type":"post","link":"https:\/\/blogg.lnu.se\/unesco\/?p=4042","title":{"rendered":"Claudio Pescatore: The Deep-Time Reality of Nuclear Waste"},"content":{"rendered":"\n<p>Claudio Pescatore explains why high-level waste still needs shields\u2014and memory beyond a million years:<\/p>\n\n\n\n<p>When it comes to high-level waste repositories, the old reassurance \u2014 \u201c<em>radioactivity falls back close to or below natural levels<\/em>\u201d \u2014 is misleading. Yes, if you total up all the radioactivity in a repository and compare it to the original ore, the <em>sum<\/em> may look modest after ten to a hundred thousand years, depending on waste type. But people (and animals) don\u2019t meet sums. They meet <em>things<\/em>: individual containers, cores, and fragments that concentrate radioactivity. What matters\u2014ethically and practically\u2014is the radiation dose at the surface of each piece as time rolls on.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"974\" height=\"650\" src=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/Picture1.png\" alt=\"\" class=\"wp-image-4055\" style=\"width:529px;height:auto\" srcset=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/Picture1.png 974w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/Picture1-300x200.png 300w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/Picture1-768x513.png 768w\" sizes=\"auto, (max-width: 974px) 100vw, 974px\" \/><figcaption class=\"wp-element-caption\"><em><em>Total radioactivity vs original uranium ore in Swedish spent fuel. (Report SKB-TR-97-13)<\/em><\/em><\/figcaption><\/figure>\n\n\n\n<p>A new paper looks squarely at that reality. Rather than only computing dose, a concept for radiation specialists, it asks a tangible question: how thick must a shield be to meet modern radiation protection limit not just now, but at one million years and beyond? Using concrete as the reference, the answer comes in units anyone can picture: roughly <strong>50<\/strong>\u2013<strong>90 cm<\/strong> <strong>at a million years<\/strong>, depending on the waste and the protection target.<\/p>\n\n\n\n<p><strong>At one million years <\/strong>(and ignoring any container):<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Spent fuel (SF) requires a<\/strong>bout <strong>67\u201393 <\/strong><strong>cm<\/strong> of concrete for a representative multi-ton package<\/li>\n\n\n\n<li><strong>Vitrified high-level waste<\/strong> <strong>(VHLW) <\/strong>requires about <strong>53\u201372 cm <\/strong>of concrete for a full-size cylinder.<\/li>\n<\/ul>\n\n\n\n<p><strong>Beyond one million years<\/strong>, uranium-238 \u2014 lasting billions of years \u2014 makes the shielding requirement essentially constant: without containers, concrete thicknesses range from <strong>7\u201342 cm<\/strong> for vitrified-waste cylinders and <strong>62\u201387 cm<\/strong> for spent fuel.<br><br><strong>Smaller isn\u2019t safer<\/strong>. Even drill cores (say, 40 cm tall by 10 cm wide) or fragments still need shielding on the same order, because near-surface dose depends on what\u2019s inside, not the item\u2019s size. At a million years, unshielded drill cores still translate into <strong>about<\/strong> <strong>48\u201367 cm<\/strong> of required concrete for vitrified waste and <strong>about<\/strong> <strong>46\u201372 cm<\/strong> for spent fuel.<br><br><strong>Scale matters<\/strong>. Numbers per item are only half the story. Program scale multiplies these requirements: for example, Sweden plans roughly <strong>6,000<\/strong> spent\u2011fuel canisters. In France, there will be more than <strong>50,000<\/strong> vitrified-waste cylinders.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"550\" src=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-1024x550.png\" alt=\"\" class=\"wp-image-4060\" style=\"width:479px;height:auto\" srcset=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-1024x550.png 1024w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-300x161.png 300w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-768x413.png 768w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-1536x825.png 1536w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/shielding_thickness_1Myr_title_removed-2048x1100.png 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><em><strong><em>Concrete shielding thickness at one million years<\/em><\/strong><em> for spent fuel (full canister and drill core) and vitrified high-level waste (full cylinder and drill core). Results are shown for two protection targets: 0.02 mSv\/h (brief, one-hour exposure) and 0.002 mSv\/h (background-like)<\/em>\u2014<strong><em>ballpark<\/em><\/strong><em> in the absence of project-specific requirements<\/em><\/em><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">What this means in human terms<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Heritage, not waste alone.<\/strong> If descendants encounter these materials\u2014by curiosity, drilling, erosion, or chance\u2014they won\u2019t face a vanishing hazard but an enduring one, beyond legal timeframes and planning horizons. Our commitment to protect future people \u201c<em>to levels comparable to today<\/em>\u201d becomes concrete\u2014literally\u2014in centimeters of real shielding.<\/li>\n\n\n\n<li><strong>Justice and foresight.<\/strong> Thinking \u201c<em>per item<\/em>\u201d reframes responsibility. Are we designing containers\u2014and contingencies\u2014that keep each piece safe, including broken pieces? The ambition is that we should.<\/li>\n\n\n\n<li><strong>Design humility.<\/strong> Landscapes move; encounters may occur. The ethical stance is not to promise a perfect fortress forever, but to equip future people with buffers that still work: robust, intelligible, possibly maintainable shields\u2014and the <strong>memory provisions<\/strong> (institutional handovers, markers, archives, &nbsp;time capsules) to keep that knowledge alive. Also, <em>acknowledge that these wastes never become harmless<\/em>.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">&nbsp;So what now?<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Build for fragments.<\/strong> Don\u2019t just model intact packages; assume cores, partial breaches, and erosion-revealed segments\u2014and assign them shielding, too.<\/li>\n\n\n\n<li><strong>Specify the long-lived drivers.<\/strong> Make a standard reporting of the deep-time isotopic loadings, because they determine both the danger and the shield.<\/li>\n\n\n\n<li><strong>Design the message with the material.<\/strong> If safety demands 50\u201390 cm at a million years, our markings and archives should be designed to last\u2014and be rediscoverable\u2014on comparable horizons. <em>Or that should be the ambition<\/em>.<\/li>\n\n\n\n<li><strong>Expand the lens.<\/strong> Apply similar analyses to other long-lived wastes that carry significant uranium-238 loadings.<\/li>\n<\/ol>\n\n\n\n<p><strong>Takeaway:<\/strong> this isn\u2019t a new fear; it\u2019s a clearer ethic. We owe the future not only sealed vaults and clever signs, but <strong>credible buffers<\/strong>\u2014thicknesses you can measure with a ruler\u2014matched to how matter behaves over time. &nbsp;<strong><em>The shield is not a metaphor; it\u2019s a promise we can make, and keep.<\/em><\/strong><\/p>\n\n\n\n<p>Further reading<\/p>\n\n\n\n<p>Claudio Pescatore, <em>Beyond a million years: Robust radiation shielding for high-level waste<\/em> Nukleonika, 70(3): 87-93.<\/p>\n\n\n\n<p><a href=\"https:\/\/sciendo.com\/article\/10.2478\/nuka-2025-0009\">https:\/\/sciendo.com\/article\/10.2478\/nuka-2025-0009<\/a> (open access)<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"984\" src=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-1024x984.jpg\" alt=\"Claudio Pescatore\" class=\"wp-image-3804\" style=\"width:422px;height:auto\" srcset=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-1024x984.jpg 1024w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-300x288.jpg 300w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-768x738.jpg 768w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-1536x1476.jpg 1536w, https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2024\/11\/Claudio-P-2024-2048x1969.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><em>Claudio Pescatore is a member of the UNESCO Chair on Heritage Futures at Linnaeus University<\/em><\/figcaption><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Claudio Pescatore explains why high-level waste still needs shields\u2014and memory beyond a million years: When it comes to high-level waste repositories, the old reassurance \u2014 \u201cradioactivity falls back close to or below natural levels\u201d \u2014 is misleading. Yes, if you total up all the radioactivity in a repository and compare it to the original ore, [&hellip;]<\/p>\n","protected":false},"author":932,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,28256],"tags":[72334,28301,72371],"class_list":["post-4042","post","type-post","status-publish","format-standard","hentry","category-blogg","category-research-results","tag-long-term-thinking","tag-nuclear-waste","tag-radioactivity"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\r\n<title>Claudio Pescatore: The Deep-Time Reality of Nuclear Waste - UNESCO<\/title>\r\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\r\n<link rel=\"canonical\" href=\"https:\/\/blogg.lnu.se\/unesco\/?p=4042\" \/>\r\n<meta property=\"og:locale\" content=\"en_US\" \/>\r\n<meta property=\"og:type\" content=\"article\" \/>\r\n<meta property=\"og:title\" content=\"Claudio Pescatore: The Deep-Time Reality of Nuclear Waste - UNESCO\" \/>\r\n<meta property=\"og:description\" content=\"Claudio Pescatore explains why high-level waste still needs shields\u2014and memory beyond a million years: When it comes to high-level waste repositories, the old reassurance \u2014 \u201cradioactivity falls back close to or below natural levels\u201d \u2014 is misleading. Yes, if you total up all the radioactivity in a repository and compare it to the original ore, [&hellip;]\" \/>\r\n<meta property=\"og:url\" content=\"https:\/\/blogg.lnu.se\/unesco\/?p=4042\" \/>\r\n<meta property=\"og:site_name\" content=\"UNESCO\" \/>\r\n<meta property=\"article:published_time\" content=\"2025-08-21T08:37:01+00:00\" \/>\r\n<meta property=\"article:modified_time\" content=\"2025-09-11T08:18:07+00:00\" \/>\r\n<meta property=\"og:image\" content=\"https:\/\/blogg.lnu.se\/unesco\/wp-content\/blogs.dir\/209\/files\/sites\/209\/2025\/08\/Picture1.png\" \/>\r\n<meta name=\"author\" content=\"Helena Ryd\u00e9n\" \/>\r\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\r\n<meta name=\"twitter:creator\" content=\"@UnescoChairLNU\" \/>\r\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Helena Ryd\u00e9n\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\r\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/blogg.lnu.se\/unesco\/?p=4042\",\"url\":\"https:\/\/blogg.lnu.se\/unesco\/?p=4042\",\"name\":\"Claudio Pescatore: The Deep-Time Reality of Nuclear Waste - UNESCO\",\"isPartOf\":{\"@id\":\"https:\/\/blogg.lnu.se\/unesco\/#website\"},\"datePublished\":\"2025-08-21T08:37:01+00:00\",\"dateModified\":\"2025-09-11T08:18:07+00:00\",\"author\":{\"@id\":\"https:\/\/blogg.lnu.se\/unesco\/#\/schema\/person\/de31efdae235c3484e09113eebd40318\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/blogg.lnu.se\/unesco\/?p=4042\"]}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/blogg.lnu.se\/unesco\/#website\",\"url\":\"https:\/\/blogg.lnu.se\/unesco\/\",\"name\":\"UNESCO\",\"description\":\"Chair on Heritage Futures\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/blogg.lnu.se\/unesco\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/blogg.lnu.se\/unesco\/#\/schema\/person\/de31efdae235c3484e09113eebd40318\",\"name\":\"Helena Ryd\u00e9n\",\"description\":\"Assistant to the UNESCO Chair on Heritage Futures\",\"sameAs\":[\"https:\/\/lnu.se\/en\/unescochair\",\"https:\/\/twitter.com\/@UnescoChairLNU\",\"@HeritageFutures\"],\"url\":\"https:\/\/blogg.lnu.se\/unesco\/?author=932\"}]}<\/script>\r\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Claudio Pescatore: The Deep-Time Reality of Nuclear Waste - UNESCO","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/blogg.lnu.se\/unesco\/?p=4042","og_locale":"en_US","og_type":"article","og_title":"Claudio Pescatore: The Deep-Time Reality of Nuclear Waste - UNESCO","og_description":"Claudio Pescatore explains why high-level waste still needs shields\u2014and memory beyond a million years: When it comes to high-level waste repositories, the old reassurance \u2014 \u201cradioactivity falls back close to or below natural levels\u201d \u2014 is misleading. 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