in memory of the work of Dr John Large, consulting nuclear engineer
Initiating Request to ONR on HPC HIC components, 27 January 2017
EmailAutomated Response from ONR with due date of 24 February 2017, 27 January 2017
EmailInitiating Request to ONR on ONR Acceptance of le Creusot Forge, 2 February 2017
EmailFollow Up Request to ONR on ONR Acceptance of le Creusot Forge, 23 February 2017
EmailAt Leibstadt, the planned 2 August 2016 partial refuelling outage was originally scheduled to end on 27 August, was first extended by a further 8 weeks until 29 October, but is now projected to last through to February 2017.
The reason for this extended outage is damage to the nuclear fuel pin cladding, now acknowledged to be due to an in-core phenomenon referred to as ‘dryout’ dating back to the 2012-2013 fuel core cycle. It is now reported that similar levels of fuel pin surface scarring arose in subsequent fuel core cycles.
For the 2015-16 fuel cycle Axpo put in place specific measures to eliminate what it believed to be the root cause triggering dryout but examination of the 2015-16 fuel core fuel removed in mid-August revealed the problem persisting with similar area of fuel pin dryout surface scarring developing during the fuel cycle. In other words, the root cause solution implemented by Axpo did not address and rectify the dryout phenomenon.
In order for Leibstadt NPP to be allowed to start up again, ENSI has stated (20 December 2016) that “. . .the fuel core loading and reactor operation must be such as to exclude dryout during normal operation, in the event of operational malfunctions and in accident categories 1 and 2 of the design basis accidents”. Preparations towards satisfying this ENSI requirement seems to have been the reason why a normally 3 to 4 week refuelling outage of 2016 has now been extended indefinitely until at least February 2017 (24 weeks+).
ReviewPROTECTED
Office of Nuclear Regulation FOI – Internal Review ‐ IR201610587ofEIR201609529
Internal ReviewThis work follows on the French nuclear debacle of flawed JCFC and, possibly, JSW steam generator Class 1 components entering the French Nuclear Equipment Supply Chain that has directly resulted in 12 French nuclear power plants being shut down for further investigation.
The premise is that, first, since it is irrefutable that macrosegregated, excess carbon components were wholly manufactured in the JCFC Japanese works and, second, since these manifestly flawed parts were somehow about to leave the JCFC works without detection, the only remaining safeguard to stop similarly flawed components entering the Japanese supply chain would have been the then (1990 to 2000) much discredited Japanese nuclear safety regulator NISA – of course, in France this final barrier, ASN, failed to safeguard the French nuclear power plants.
Part I Review Press Part II & III Review JapaneseForged components of the Flamanville 3 NPP reactor pressure vessel were first manufactured in 2005-06. These end caps or heads were then welded into the RPV assemblage, the whole machined into the finished RPV that was finally installed into the reactor pit in the primary containment dome and, finally connected to the other components of the primary coolant loop. Then in 2014 AREVA first informed the nuclear safety regulator ASN that weaknesses in the material toughness of the cap components had been discovered.
This LargeAssociates comprehensive review explores the developing situation relating to the Flamanville 3 NPP project and considers the nuclear safety implications for certain operational NPPs in France that are also afflicted with much the same safety related defects.
Summary Étude PressUS nuclear safety regulator NRC casts doubts on adequacy of AREVA EPR Control and Instrumentation systems – Nucleonics Week 11 July 2013 – confirming findings of LargeAssociates.
Reviewnot challenged by Office for Nuclear Regulation’s Response Letter
Response Lettersee also later LargeAssociates reporting on Carbon Anomaly at Flamanville 3 RPV
NoteTerms of Reference for ONR’s aircraft crash TAP will not include for NPP containment damage severity, release inventory and radiological consequences of potential release scenarios.
Review
