{"id":816,"date":"2023-07-25T20:32:35","date_gmt":"2023-07-25T20:32:35","guid":{"rendered":"https:\/\/wp.ccnr.org\/?page_id=816"},"modified":"2025-02-19T15:34:39","modified_gmt":"2025-02-19T15:34:39","slug":"do-radioactive-wastes-produce-heat","status":"publish","type":"page","link":"https:\/\/wp.ccnr.org\/fr\/do-radioactive-wastes-produce-heat\/","title":{"rendered":"Do Radioactive Wastes Produce Heat?"},"content":{"rendered":"
\n

Do Radioactive Wastes Produce Heat?<\/strong><\/span><\/h2>\n

A background piece by Gordon Edwards, July 12, 2011<\/strong><\/em><\/p>\n

Once radioactive materials have been created, nobody
\nknows how to shut off the radioactivity. \u00a0Radioactivity is
\ncaused by the spontaneous disintegration of unstable
\natoms; in fact the unit of radioactivity is the “becquerel”
\nwhich indicates that one disintegration is taking place
\nevery second. \u00a0If we knew how to shut off radioactivity,
\nthere would be no nuclear waste problem.
\nIn a nuclear reactor, under normal operation, more than
\n90 percent of the heat \u00a0is produced by splitting uranium
\natoms — this process is called\u00a0nuclear fission, and it CAN
\nbe stopped. That’s why every\u00a0reactor has control rods
\n(for slow shutdown) and shut-off\u00a0rods (for fast shutdown).
\nBut the broken pieces of uranium atoms — the fragments that
\nare left when uranium atoms have been split — are extremely
\nradioactive, and that radioactivity cannot be shut off. So even
\nafter the fission process has been totally stopped (no more
\nsplitting of atoms), a lot\u00a0of heat is still being\u00a0produced
\nby the disintegrating atoms of the\u00a0radioactive waste
\nmaterials in the core of the reactor.<\/p>\n

This “unstoppable” heat, due to radioactivity alone,
\nis called “decay heat”.<\/p>\n

For example, in a 1000 megawatt reactor, immediately
\nafter shutdown the decay heat would be about 200
\nmegawatts. \u00a0And if the pumps do not keep pumping
\nwater through the core to remove that decay heat,
\nthe fuel will get hotter and hotter as more and more
\nheat is added, so the temperature will rise higher and
\nhigher until the\u00a0fuel itself begins to melt at about 2800
\ndegrees celsius.<\/p>\n

The radioactive wastes inside a nuclear reactor are
\nnot just hot, but they actually GENERATE heat — like
\na furnace that just never stops burning. \u00a0So there is
\nreally no limit as to how hot the surroundings can get
\nif that heat is allowed to keep building up. \u00a0The wastes
\nfrom the core of a nuclear reactor that has recently
\nbeen\u00a0shut down generate so much heat that they will
\neventually melt through any container they are in, unless
\nthere is\u00a0a method for removing the heat as it is being
\nproduced. \u00a0That’s why nuclear reactors need to keep
\npumping coolant through the core of the reactor for
\ndays and weeks after shutdown.<\/p>\n

Because of the decay heat, the irradiated fuel that is
\nremoved from the core of the reactor after it is “used
\nup” or “spent” has to be stored in a deep pool of
\ncirculating water which is used to cool the fuel for at
\nleast\u00a07 to 10 years. \u00a0If the fuel is uncovered during the
\nfirst few years it will slowly overheat and eventually
\ndamage its metallic container at hundreds of degrees
\ncelsius and release a lot of radioactive gasses and
\nvapours\u00a0into\u00a0the air.<\/p>\n

The problem is that even though the fuel is “spent”
\n(meaning the fission process no longer\u00a0works well)
\nit still contains an enormous quantity of radioactive junk
\n(mostly the unstable broken pieces of atoms that were
\ncreated when the atoms were split — these are called
\nthe “fission products”) and that’s where the heat comes
\nfrom — from the unremitting and unstoppable disintegration
\nof trillions and trillions of unstable atoms.<\/p>\n

AECL has produced graphs showing how the decay
\nheat from buried spent fuel will heat up the underground
\nrock formations, which will finally return to their “ambient
\nlevel” of temperature\u00a0after about 50,000 years.<\/p>\n

This graphic is taken from one of the technical appendices of\u00a0AECL’s
\nEIS for the Geologic Disposal Concept.\u00a0The dark horizontal layers
\nrepresent underground rock strata, whereas the brightly coloured
\nportion in the first graphic represents the buried spent fuel. \u00a0Colours
\nare used to indicate temperatures. \u00a0The decay heat from the spent fuel
\nraises the temperature of the surrounding rock strata for thousands of
\nyears, because the heat cannot escape. \u00a0However the heat output does
\ndecrease over time, so the temperatures will eventually return to more
\nnormal levels, close to the “ambient temperature” they started with.<\/p><\/blockquote>\n

\"This<\/p>\n

Gordon Edwards, Ph.D., President,<\/p>\n

Canadian Coalition for Nuclear Responsibility.<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Do Radioactive Wastes Produce Heat? A background piece by Gordon Edwards, July 12, 2011 Once radioactive materials have been created, nobody knows how to shut off the radioactivity. \u00a0Radioactivity is caused by the spontaneous disintegration of unstable atoms; in fact the unit of radioactivity is the “becquerel” which indicates that one disintegration is taking place …<\/p>\n

Do Radioactive Wastes Produce Heat?<\/span> Lire la suite\u00a0\u00bb<\/a><\/p>","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-816","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/pages\/816","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/comments?post=816"}],"version-history":[{"count":7,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/pages\/816\/revisions"}],"predecessor-version":[{"id":3719,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/pages\/816\/revisions\/3719"}],"wp:attachment":[{"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/media?parent=816"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/categories?post=816"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.ccnr.org\/fr\/wp-json\/wp\/v2\/tags?post=816"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}