{"id":104,"date":"2015-11-03T15:30:58","date_gmt":"2015-11-03T15:30:58","guid":{"rendered":"http:\/\/johnbrear-plantintegrity.com\/?page_id=104"},"modified":"2019-01-18T20:48:53","modified_gmt":"2019-01-18T20:48:53","slug":"residual-element-limits-for-pwr-pressure-vessels","status":"publish","type":"page","link":"https:\/\/johnbrear-plantintegrity.com\/?page_id=104","title":{"rendered":"Residual element limits for PWR pressure vessels"},"content":{"rendered":"<figure id=\"attachment_71\" aria-describedby=\"caption-attachment-71\" style=\"width: 342px\" class=\"wp-caption alignright\"><img fetchpriority=\"high\" decoding=\"async\" src=\"http:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2015\/01\/nuclear-pressure-vessel-weld.jpg\" alt=\"Nuclear pressure vessel weld\" width=\"342\" height=\"601\" class=\"size-full wp-image-71\" srcset=\"https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2015\/01\/nuclear-pressure-vessel-weld.jpg 513w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2015\/01\/nuclear-pressure-vessel-weld-171x300.jpg 171w\" sizes=\"(max-width: 342px) 100vw, 342px\" \/><figcaption id=\"caption-attachment-71\" class=\"wp-caption-text\">Trial PWR pressure vessel weld<\/figcaption><\/figure>\r\n<p>PWR pressure vessel weld[\/caption]On the decision to move towards a PWR programme in the UK, it was realised from previous experience that structural and cladding welds in the pressure vessels could be subject to various forms of embrittlement.  The nozzle-ring and belt-line areas were seen to be particularly critical.&#160; A joint working-group involving the utility, the construction consortium, government institutions and the statutory body was established to address this.<\/p>\r\n<p>A significant task was to identify achievable residual-element limits for base metal and weld consumables, so as to reduce the susceptibility to stress-relief, temper and irradiation embrittlement to tolerable levels.  The work involved extensive mechanical testing of controlled-purity alloys and commercial steels from a range of manufacturers, welded to various procedures.  Detailed metallography \u2013 including Auger analysis \u2013 was performed on the test-pieces.  Mechanistic models of the different degradation processes were developed, allowing quantification of the effects of each impurity element on each embrittling mechanism.  Thence the kinetics of in-service embrittlement could be determined.<\/p>\r\n<p>The work resulted in an agreed residual element specification for the selected steels, recommendations as to construction and fabrication routes, and a proposed monitoring programme using surveillance specimens.<\/p>\r\n<h4>Publications based on this work include:<\/h4>\r\n<p>Brear, J.M. <br \/>\r\n\u201cApproaches to predicting the kinetics of grain boundary segregation in ferritic steels\u201d <br \/>\r\nInst Metals Conf `Intergranular Failure Mechanisms in Steel\u2019, London, March 1988<\/p>\r\n<p>Brear, J.M. and King, B.L.,<br \/>\r\n\u201cAn assessment of the embrittling effects of certain residual elements in two nuclear pressure vessel steels (A533B, A508)\u201d,<br \/>\r\nConf \u2018Residuals, Additives and Materials Properties\u2019, Royal Society, May 1978, Phil Trans R Soc, London, A295, 1980, p.291<\/p>\r\n<p>Brear, J.M. and King, B.L.<br \/>\r\n\u201cReheat cracking in nuclear reactor pressure vessel steels\u201d<br \/>\r\nInt J Pressure Vessels and Piping, Vol 7, 1979, pp.339-40<\/p>\r\n<p>Brear, J.M. and King, B.L.<br \/>\r\n\u201cStress relief embrittlement in Mn-Mo-Ni  pressure vessel steels\u201d<br \/>\r\nInst Metallurgists, Spring Residential Conf \u2018Grain Boundaries\u2019, Jersey, 1976, pp.C13-18<\/p>","protected":false},"excerpt":{"rendered":"<p>PWR pressure vessel weld[\/caption]On the decision to move towards a PWR programme in the UK, it was realised from previous experience that structural and cladding welds in the pressure vessels could be subject to various forms of embrittlement. The nozzle-ring and belt-line areas were seen to be particularly critical.&#160; A joint working-group involving the utility, &hellip; <a href=\"https:\/\/johnbrear-plantintegrity.com\/?page_id=104\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Residual element limits for PWR pressure vessels<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":107,"menu_order":7,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-104","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/104","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=104"}],"version-history":[{"count":8,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/104\/revisions"}],"predecessor-version":[{"id":535,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/104\/revisions\/535"}],"up":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/107"}],"wp:attachment":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}