[Erw]

Oorspronkelijk geplaatst door patrickve

Die wanden werden wel degelijk gecontroleerd, maar niet met de nauwgezetheid die die nieuwere apparatuur toelaat. Bekijk het een beetje als medische analyse: hoe fijner uw analysetechnieken zijn, hoe meer potentiële ziektes je kan opsporen.

http://www.neimagazine.com/features/...und-at-doel-3/

Since 1982, when the reactor begun operation, several in-service inspections have been performed on the vessel. Different areas are inspected on each occasion, which means that after each period of ten years all the sensitive zones have been inspected. During the recent inspection, examination focused on zones prone to cracking, including weld zones (between the rings of the vessel) and duct tubes in the reactor circuit.

French company Intercontrole (a member of the AREVA group) conducted this and all prior vessel inspections at Doel 3. The company is also in charge of the same inspections at French reactors. During the recent outage, Intercontrole carried out an innovative ultrasonic inspection for Doel 3, aimed at detecting defects under the cladding; an approximately 7 mm thin stainless steel liner that protects the vessel from corrosion. (The vessel walls are up to 205 mm thick). A FANC spokeswoman said that the inspection technique was an immersion technology with pre-focus mono-crystal probes operating in pulse-echo mode in four directions with three focal depth zones. She also said that similar UT inspections of the RPV head and upper rings in the 1990s found only a few indications.

Concreet:
Men inspecteert enkel een "volgend" deel elke controle.
Deze keer (recent inspection).... FOCUSSED ON...zones.
Why the sudden FOCUS?
En bij aanbouw:

Inspections carried out during the fabrication stages of the vessels did not lead to detection of the flaws. This could be because the inspections, which involved UT controls and volumetric examinations as well as some other controls for welds, were performed manually and from the external surface of the vessel. The recent inspections were more sensitive and carried out from the inner surface of the vessel wall, according to FANC.

Dito bij de aanbouw.
Ze controleerden enkel de buitenwand.

Oorspronkelijk geplaatst door patrickve

Het zou zelfs kunnen zijn dat die openingen zelfs voordelen hebben, zoals het niet laten voortplanten van scheuren.

Er kan veel.
Dit is wat concreet is:

FANC said that the defects found in the Doel RPV “are usually associated with manufacturing and are not due to ageing.” It is ‘improbable’ that the flaws have evolved since their formation, according to Electrabel.

Metallurgical investigations support conclusions that the flaws appeared during fabrication, and principally due to high hydrogen content.

http://www.magnoxsites.co.uk/wp-cont...ft-15-5-14.pdf

Special Sizewell Stakeholder Group Meeting with Office for Nuclear Regulation held in public on 5th March 2014 to explain the technical review that was carried out by the Belgian nuclear regulator following the discovery of flaw indications in the reactor pressure vessels at Doel 3 and Tihange 2 and to explain how ONR used this international learning to assess if there were any implications for Sizewell

This, in case of the RPV, the Reactor Pressure Vessel – it involves moving sections of the core
and all the core internals, so you put people down and actually scan the inside of the pressure
vessel, so you will actually send people into the pressure vessel to take out the internals – or in
close proximity to the pressure vessel and not necessarily within it. The defects were found by
the Electrabel (Doel 3 and Tihange 2 Licensee) and their sub-contractor were looking at the
welds on that pressure vessel – because the ASME code does not specify that you look at the
forgings, the ASME code specifies that you only look at the welds during this ten yearly outage.
So they were looking at the welds – looking at a small section above and below as well – now
as they looked at the small sections above and below, they found some indications, and moving
on from that, they actually extended the inspections to cover the whole forgings and this is
when they found the forgings were quite heavily full of flaws –

Decennia lang hebben ze controles uitgevoerd.
Volgens de procedure (ASME code) moesten ze die "forged" (vervorming door druk) delen niet eens inspecteren, enkel de lassen.
En dat deden ze al de tijd.
En nu, een relatieve habbekrats voor de politiek geplande kernuitstap, controleren ze delen die ze voorheen nooit controleerden.
Daarom dat ik zei dat het leek alsof ze ernaar zochten haha.