{"id":17238,"date":"2025-12-19T20:47:14","date_gmt":"2025-12-19T18:47:14","guid":{"rendered":"https:\/\/www.beseit.net\/?p=17238"},"modified":"2025-12-19T20:54:25","modified_gmt":"2025-12-19T18:54:25","slug":"reactor-nuclear-de-sal-fosa","status":"publish","type":"post","link":"https:\/\/www.beseit.net\/?p=17238","title":{"rendered":"Reactor nuclear de sal fosa i Tori"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"721\" height=\"127\" src=\"https:\/\/www.beseit.net\/wp-content\/uploads\/2025\/12\/image-1.png\" alt=\"\" class=\"wp-image-17239\" srcset=\"https:\/\/www.beseit.net\/wp-content\/uploads\/2025\/12\/image-1.png 721w, https:\/\/www.beseit.net\/wp-content\/uploads\/2025\/12\/image-1-300x53.png 300w, https:\/\/www.beseit.net\/wp-content\/uploads\/2025\/12\/image-1-500x88.png 500w\" sizes=\"auto, (max-width: 721px) 100vw, 721px\" \/><\/figure>\n\n\n\n<p>En un <strong>reactor nuclear de sal fosa<\/strong> (del tipus <strong>MSR<\/strong>, <em>Molten Salt Reactor<\/em>), si es fa servir <strong>tori<\/strong> (Th) com a combustible nuclear, no \u00e9s el tori en si mateix el que sofreix fissi\u00f3, sin\u00f3 un is\u00f2top derivat: <strong>urani-233<\/strong> ((^{233}\\text{U})), que es produeix a partir del tori-232 ((^{232}\\text{Th})) mitjan\u00e7ant <strong>transmutaci\u00f3<\/strong>. A continuaci\u00f3 et detallo les reaccions nuclears principals que es produeixen:<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">1. <strong>Captura neutr\u00f2nica pel tori-232<\/strong><\/h3>\n\n\n\n<p>El tori-232, que \u00e9s f\u00e8rtil (no fissil), absorbeix un neutr\u00f3 t\u00e8rmic i es converteix en tori-233:<\/p>\n\n\n\n<p>[<br>^{232}\\text{Th} + n \\rightarrow ^{233}\\text{Th}<br>]<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. <strong>Desintegraci\u00f3 beta del tori-233<\/strong><\/h3>\n\n\n\n<p>El (^{233}\\text{Th}) \u00e9s inestable i es desintegra mitjan\u00e7ant <strong>emissi\u00f3 beta<\/strong> ((\\beta^-)) a protactini-233 amb una semivida d\u2019aproximadament <strong>22 minuts<\/strong>:<\/p>\n\n\n\n<p>[<br>^{233}\\text{Th} \\xrightarrow{\\beta^-} ^{233}\\text{Pa} \\quad (t_{1\/2} \\approx 22\\ \\text{min})<br>]<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. <strong>Desintegraci\u00f3 beta del protactini-233<\/strong><\/h3>\n\n\n\n<p>El (^{233}\\text{Pa}) tamb\u00e9 \u00e9s radioactiu i es desintegra a <strong>urani-233<\/strong> ((^{233}\\text{U})) amb una semivida d\u2019<strong>uns 27 dies<\/strong>:<\/p>\n\n\n\n<p>[<br>^{233}\\text{Pa} \\xrightarrow{\\beta^-} ^{233}\\text{U} \\quad (t_{1\/2} \\approx 27\\ \\text{dies})<br>]<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. <strong>Fissi\u00f3 de l\u2019urani-233<\/strong><\/h3>\n\n\n\n<p>L\u2019(^{233}\\text{U}) \u00e9s <strong>fissil<\/strong> i, quan absorbeix un neutr\u00f3 (especialment t\u00e8rmic), pot fissionar-se, alliberant:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Energia t\u00e8rmica (aprox. 200 MeV per fissi\u00f3),<\/li>\n\n\n\n<li>Neutrons addicionals (2\u20133 de mitjana),<\/li>\n\n\n\n<li>Productes de fissi\u00f3 (elements m\u00e9s lleugers com cript\u00f3, bari, estronci, etc.).<\/li>\n<\/ul>\n\n\n\n<p>Exemple simplificat de fissi\u00f3:<\/p>\n\n\n\n<p>[<br>^{233}\\text{U} + n \\rightarrow \\text{productes de fissi\u00f3} + 2\\text{\u2013}3\\,n + \\text{energia}<br>]<\/p>\n\n\n\n<p>Els neutrons alliberats poden:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mantenir la reacci\u00f3 en cadena,<\/li>\n\n\n\n<li>Ser capturats per m\u00e9s (^{232}\\text{Th}), produint m\u00e9s (^{233}\\text{U}) (breeding, o &#8220;cria&#8221; de combustible).<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Resum del cicle del tori en un MSR:<\/h3>\n\n\n\n<p>[<br>^{232}\\text{Th} \\xrightarrow{(n,\\gamma)} ^{233}\\text{Th} \\xrightarrow{\\beta^-} ^{233}\\text{Pa} \\xrightarrow{\\beta^-} ^{233}\\text{U} \\xrightarrow{\\text{fissi\u00f3}} \\text{energia + neutrons}<br>]<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Observacions importants en reactors de sal fosa:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>La <strong>sal fosa<\/strong> (normalment fluorurs com LiF-BeF\u2082, anomenat &#8220;FLiBe&#8221;) actua com <strong>refrigerant i portador del combustible<\/strong>.<\/li>\n\n\n\n<li>El tori i l\u2019urani es dissolen com a fluorurs (p. ex., ThF\u2084, UF\u2084).<\/li>\n\n\n\n<li>No hi ha &#8220;reaccions qu\u00edmiques&#8221; en el sentit convencional que alliberin energia; <strong>l\u2019energia prov\u00e9 exclusivament de reaccions nuclears<\/strong>.<\/li>\n\n\n\n<li>El disseny del MSR permet <strong>extreure en l\u00ednia<\/strong> productes de fissi\u00f3 i, opcionalment, el protactini-233, per evitar la seva captura de neutrons (ja que (^{233}\\text{Pa}) pot absorbir neutrons i convertir-se en (^{234}\\text{Pa}), que no dona lloc a (^{233}\\text{U})).<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h1 class=\"wp-block-heading\"><mark style=\"background-color:rgba(0, 0, 0, 0);color:#f51313\" class=\"has-inline-color\">Avantatges del cicle del tori en MSR:<\/mark><\/h1>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Abund\u00e0ncia del tori (m\u00e9s que l\u2019urani).<\/li>\n\n\n\n<li>Menor producci\u00f3 de <strong>act\u00ednids menors<\/strong> (residus de llarga vida).<\/li>\n\n\n\n<li>(^{233}\\text{U}) t\u00e9 bones propietats neutr\u00f2niques en espectre t\u00e8rmic.<\/li>\n\n\n\n<li>El tori no \u00e9s directament utilitzable per armes nuclears (encara que (^{233}\\text{U}) s\u00ed que \u00e9s armable, normalment est\u00e0 contaminat amb (^{232}\\text{U}), que emet radiaci\u00f3 gamma intensa, dificultant el seu \u00fas clandest\u00ed).<\/li>\n<\/ul>\n\n\n\n<p>Si tens inter\u00e8s en aspectes qu\u00edmics de les sals (com la corrosi\u00f3, estabilitat dels fluorurs, etc.) o en el tractament de residus, tamb\u00e9 puc ampliar la informaci\u00f3.<\/p>\n\n\n\n<p>Els <strong>reactors nuclears de sals foses (MSR)<\/strong> tenen diversos <strong>avantatges respecte als reactors convencionals d\u2019urani<\/strong> (com els d\u2019aigua lleugera). Els principals s\u00f3n:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">? Seguretat<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>M\u00e9s segurs intr\u00ednsecament<\/strong>: funcionen a pressi\u00f3 atmosf\u00e8rica, reduint el risc d\u2019explosions.<\/li>\n\n\n\n<li><strong>Refredament passiu<\/strong>: si hi ha un problema, el combustible es pot drenar autom\u00e0ticament a un dip\u00f2sit segur on la reacci\u00f3 s\u2019atura.<\/li>\n\n\n\n<li><strong>No hi ha fusi\u00f3 del nucli<\/strong>: el combustible ja \u00e9s l\u00edquid.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u267b\ufe0f Gesti\u00f3 de residus<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Menys residus radioactius a llarg termini<\/strong>.<\/li>\n\n\n\n<li>Poden <strong>reutilitzar residus nuclears existents<\/strong> com a combustible.<\/li>\n\n\n\n<li>Especialment eficients si utilitzen <strong>tori<\/strong>, que genera residus menys perillosos que l\u2019urani.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u26a1 Efici\u00e8ncia<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Major efici\u00e8ncia t\u00e8rmica<\/strong>: operen a temperatures m\u00e9s altes.<\/li>\n\n\n\n<li>Millor aprofitament del combustible (menys urani o tori per la mateixa energia).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">? Impacte ambiental<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Menor necessitat de mineria<\/strong>.<\/li>\n\n\n\n<li>Menor risc de contaminaci\u00f3 massiva en cas d\u2019accident.<\/li>\n\n\n\n<li>Emissions indirectes de CO\u2082 molt baixes.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">? Operaci\u00f3 i manteniment<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Disseny m\u00e9s simple<\/strong> (sense sistemes de pressi\u00f3 elevats).<\/li>\n\n\n\n<li>Possibilitat de <strong>funcionament continu<\/strong>, ja que el combustible es pot processar sense aturar el reactor.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">? Proliferaci\u00f3 nuclear<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>M\u00e9s dif\u00edcils d\u2019usar per a armes nuclears<\/strong>, especialment els reactors de tori.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u26a0\ufe0f Inconvenients (per context)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Tecnologia encara <strong>poc desenvolupada comercialment<\/strong>.<\/li>\n\n\n\n<li>Problemes de <strong>corrosi\u00f3<\/strong> dels materials per les sals calentes.<\/li>\n\n\n\n<li>Cost inicial elevat de recerca i desenvolupament.<\/li>\n<\/ul>\n\n\n\n<p>Si vols, puc fer una <strong>taula comparativa<\/strong>, explicar-ho de manera <strong>m\u00e9s divulgativa<\/strong>, o enfocar-ho des del <strong>punt de vista del tori vs urani<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>En un reactor nuclear de sal fosa (del tipus MSR, Molten Salt Reactor), si es fa servir tori (Th) com a combustible nuclear, no \u00e9s el tori en si mateix el que sofreix fissi\u00f3, sin\u00f3 un is\u00f2top derivat: urani-233 ((^{233}\\text{U})), &hellip; <a href=\"https:\/\/www.beseit.net\/?p=17238\">Continua llegint <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":3167,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-17238","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bloc-de-notes"],"_links":{"self":[{"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/posts\/17238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.beseit.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=17238"}],"version-history":[{"count":3,"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/posts\/17238\/revisions"}],"predecessor-version":[{"id":17243,"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/posts\/17238\/revisions\/17243"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.beseit.net\/index.php?rest_route=\/wp\/v2\/media\/3167"}],"wp:attachment":[{"href":"https:\/\/www.beseit.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.beseit.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.beseit.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}