Press Talk - Workshop
Flaws in
reactor pressure vessels
of
Tihange 2 and Doel 3
Aachen (D) / Gemmenich (B) / Vaals (NL)
15.02.2013
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Agenda
Presentation (60 min.)
Break (15 min.)
Questions (60 min.)
Individual Talks (open end)
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Agenda
We introduce ourselves
Chronology
Evidence against further operation of Tihange 2 & Doel 3
Flaws origin
Structural integrity
Missing documentation
Hidden faults during quality assurance
Reports contain mistakes, contradictions, gaps and provisions for reduction of security-level
Nuclear-plant-tests: Neutral ?
Our questions to FANC
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We introduce our selves
Organisations
Aachener Aktionsbündnis gegen Atomenergie
Nucléaire, STOP !
Stop Tihange
Persons
Inge Gauglitz
Dieter Majer
Jörg Schellenberg
Walter Schumacher
Leo Tubbax
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Chronology
1985 Flaws during manufacture
2004 Cracks between cladding and basic steel material of the RPVs are found in Tricastin
06/07 2012 Investigations of Doel 3
09.08.2012 Reporting about flaws of RPV in Doel 3
09.08.2012 List of the 21 nuclear power plants, which may be affected worldwide as well.
16.08.2012 Tihange 2 goes into routine revision during this revision it should also be searched for supposed flaws.
13.09.2012 FANC reported similar problems in the RPV of Tihange 2
05.12.2012 Electrabel submitted its reports – published on 07.02.2013
19.12.2012 Electrabel submitted its Report on independent analysis and advice regarding the safety case – published on 07.02.2013
11.01.2013 Report of the National Scientific Expert Group – published on 07.02.2013
15.01.2013 International Expert Review Board report – published on 07.02.2013
15.01.2013 FANC requests more information from Electrabel
30.01.2013 FANC submitted its Provisional evaluation report – published on 07.02.2013
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Flaws
8707 findings in Doel 3 [S005]
2030 findings in Tihange 2 [S005]
Unknown characteristic - flakes, bubbles, cracks?
Unknown origin
Up to 24 mm in size (average size 10 mm) [S005]
Concentrated in specific areas e.g. upper core shell in Doel 3
Radial directed [S005]
Found between 20 to 100 mm (from the inner to the outer site) [S005]
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Origin of flawsdifferent point of views
Scientific Unknown but until proven otherwise it has to be assumed that they were evolved during operations because:
These flaws were not detected during manufacture even though methods were available at that time.
Characteristics of flaws can give a hint of their origin but● This can not be achieved with nondestructive methods● At present there is no recognized ultrasound testing to characterize
these defects in detail.
Electrabel During manufacture
“In the absence of any other explanation at this stage, the licensee supposes the presence of fabrication defects...” [S003]
FANC Follows Electrabel
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Different Consequences of flaws' origin
during manufacture
Hydrogen flakes are dangerous concerning structural integrity and “can cause unexpected serious failures” [S006]
Even if it were flakes with a homogeneous characteristic this flaws can be a starting point for cracks which evolves during operation.
during operation
The operation changes material properties. This process is evolutionary Extrapolation is not possible The RPV does not have sufficient resistance against the real
occurring loads (Belastungen).
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Structural integrity
In extreme situations the reactor pressure vessel does not provide the same level of resistance! → New reduced level of safety.
Especially in Doel 3 the flaws are located on the most stressed position. Following superposition of deflection (Biegung) and membrane.
Cracks can lead to spontaneous failure.
The following illustration is only one sample with the second moment of area (Flächenträgheitsmoment).
It should prove that the RPV with flaws is entirely a different mechanical system.
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Reactor Pressure Vessel (RPV)
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Cross section through RPV
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Cross section through RPV
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Cross section through RPV
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Disproportionate Representation of RPV Ring (thickness)
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RPV with and without flaws
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Idealized superimposed stripsdue to flaws
b 3 x 1/3 b
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Idealized superimposed stripsdue to flaws
b 3 x 1/3 b
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Second moment of area(Flächenträgheitsmoment)
J = 1/12
h b3
b
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Second moment of area(Flächenträgheitsmoment)
J = 1/12
h b3
b3
3 (1/3b)3
= 3/27
(b)3
=1/9 b3
==>
b
==> 1/9 of resistance
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A conservative approach
for static computation
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RPV section
200 mm
inner site outer site
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RPV sectionwith flaws
200 mm
inner site outer site
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RPV sectionwith flaws
100 mm
inner site outer site
100 mm
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RPV sectionremaining wall thickness for static computations
100 mm
inner site outer site
100 mm
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Lack ofdocumentation
Missing documentations about important manufacturing steps (What does missing mean? - Have never been there? - Have been lost? - Have been hidden or destroyed?)
Important documentation must be available!
FANC never demand a full documentation for relevant parts like the reactor pressure vessel!
The documentation of the flaws findings during final testing at manufacture is missing ...
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Lack of quality during manufacture
Missing dehydrogenation during manufacture.
But it is the task of FANC to ensure that relevant steps of manufacture like dehydrogenation has been performed!
If flaws arose during manufacture they should have been found during quality testing. As stated earlier possible methods do exist at that time.
There are elements in favour of the hypothesis that this report, currently filed with the upper core shell, would be in fact related to the lower core shell, where a large number of indications were found in 2012. [S010]
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Different publicationof amounts of flaws
Reactor pressure vessel components
Number of flaws in the reactor pressure vessels
Tihange 2 Doel 3
12.10.2012 30.01.2013 03.09.2012 30.01.2013
Vessel head flange 0 5 ./. 3
Vessel flange 19 19 ./. 2
Nozzle shell 0 0 ./. 11
Upper core shell 1931 1931 931 857
Lower core shell 80 80 7776 7205
Transition ring 0 0 ./. 71
[S003, S004, S010]
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Flaws
Analysis of the character of the "flaws"
History of the „flaws“
...
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Reports contain
Mistakes Contradictions Gaps Provisions for reduction of security-level
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Evidences of Electrabel likea house of cards
Unknown origin of flaws
Unknown characteristic of
flaws
Missing documentation
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Evidences of Electrabel likea house of cards
Unknown origin of flaws
Unknown characteristic of
flaws
Missing documentation
Material properties
Non representative
sample
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Evidences of Electrabel likea house of cards
Unknown origin of flaws
Unknown characteristic of
flaws
Missing documentation
Material properties
Non representative
sample
Structuralintegrity
&Evolution
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Evidences of Electrabel likea house of cards
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Recommendationof reducing loads
“Continuing respectively introducing a neutron fluence reduction program to minimize further materiel embrittlement until clarification is achieved on the other issues” [S008]
“For Doel 3 and Tihange 2, the licensee will reduce the authorized heat-up and cool-down gradients during start-up and shut-down operations. According to the licensee, this will further reduce the thermal and pressure loadings on the reactor pressure vessels during normal operation.” [S010]
→ If normal loads have to be reduced the RPV may not be able to bear loads during accidents which can be significantly higher.s
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Contradictions
“The indications have not grown significantly in 30 years the plants were in operation and will not grow significantly in the future under normal operation conditions.” [S008]
→ It is not possible to see an evolution by a one-time exploration.
→ Previous citation recommend a reduction of load (thermal and neutron bombardment)
→ Again, if already normal conditions have to be reduced. Can load induced by extreme situation be handled?
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Current parameters are ignored
“The effect of thermal ageing should be taken into account in the structural integrity assessment” [S008]
→ An assessment on structural integrity can not be done reputably without ageing effects have been taken into account(e.g. thermal shocks and nuclear embrittlement).
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Contradiction in the choice of a conservative value for RT
NDT
“In view of the potentially large increase in RTNDT
that may be
revealed by the tests just described, the Board recommends that before restart, a sensitivity study be performed using a RT
NDT shift
up to 100 °C (instead of 50 °C used in the current calculations) to take into account the uncertain effect of the segregation of chemical impurities and other uncertain effects.” [S008]
vs.
“However, the shift in RTNDT
of 50°C considered in the analysis
provides a significant safety margin.” [S009]
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Corresponding safety margins unknown
“The significant conservatism inherent to this procedure (over-estimating the applied stress intensity (K
applied) factor by at least 1.7-
times) was demonstrated by 3D finite element analysis of a number of the most critical indication groupings.” [S008]
→ Complies this safety margin with underlying standards?
→ Have different standards been mixed?
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UT not calibrated
“The licensee performed the on-site inspection with an inspection technique that was not fully calibrated.” [S009]
→ This is the basis for all further estimations and conclusions
→ Calibration is a state that can be true or false but not half – what means “fully”?
→ Without a calibrated basis for UT results can not be accepted as valid.
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Samples for testing structural integrity are not representative
“Moreover, the investigation could not be carried out on material that can be proven to be fully representative for the materials in the region of the indications, and the effect of thermal ageing has not been accounted for.” [S008]
They can be considered as representative to a certain extent rather than fully representative, since there are differences in the fabrication process for the AREVA shell and no hydrogen flakes are present in the Doel 3 nozzle cut. [S010]
→ Testing on samples which do not reflect the situation in Doel and Tihange totally can not be used!
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Search of flaw can not take place at the whole RPV
“AIB-Vinçotte notes that there are some non-inspectable areas (i.e. under the radial keys) in the reactor shells of Doel 3 and Tihange 2. AIB-Vinçotte asks the licensee to demonstrate that no critical hydrogen flake type defects are expected in the non-inspectable areas (short-term requirement).” [S010]
→ There is no guarantee that flaws are not located here. The density of flaws might even be higher in this regions!
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Structural assessment failed
“Bel V remarks that the analytical evaluation procedure as provided in the current section XI of the ASME B&PV code fails to address the fitness-for-service of a component affected by clustered flaws. Hence, Bel V considers that the structural assessment should be founded on the safety objective of ensuring the safe performance of the reactor pressure vessels rather than on the compliance with Section XI of the ASME B&PV code. Bel V considers that the objective of the safety demonstration is to show that the hydrogen-induced degradation does not affect significantly the safety level of the RPV that was expected after the fabrication.” [S010]
→ See following ...
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Electrabel introduced own modellingto solve issues
“When possible, the licensee performed the analysis in accordance with the ASME Section XI procedure. However, due to the high density of discovered indications, the ASME XI procedure cannot be applied integrally, motivation the development of a new procedure by the licensee. … The proposed solution was not experimentally validated” [S009]
→ If safety can not be proven by ASME XI procedure, the nuclear power plant can not be restarted!
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Possible loads are not considered
“Regarding the transients, Bel V reminds that a conservative fracture mechanics flaw assessment requires that the most penalizing transients under all the specified plant operating conditions (levels A/B and levels C/D) be considered and that, for each of those transients, the most penalizing applied loadings for the considered application be defined. Applying that statement to the transients involving injection of cold water, the potential detrimental effect of non-axisymmetric distribution of the thermal loads around the RPV shell (“plume effect”) needs to be investigated. Electrabel provided Bel V with information allowing concluding that the “plume effect” may be neglected.” [S010]
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Nuclear-plant-tests: Neutral ?
Our check of the FANC report
How truly neutral
is the authority FANC ?
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Nuclear-plant-tests: Neutral ?
FANC ( Federal Agency for Nuclear Control) is Governmental Belgium authority supervisory authority for Nuclear Systems, responsible for Monitoring of nuclear power plants
under construction and in operation
1. FANC enforces checks for Tihange-2 and Doel-3
2. The results force a closer examination!
3. The interim result of this examination was published on 30.01.13
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Nuclear-plant-tests: Neutral ?
Jan Bens he is the new director of FANC since 1/2013
By chance we „found“ his CV:
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Nuclear-plant-tests: Neutral ?
Details in the CV of Jan Bens:
1979-87: Safety Engineer at Doel
1988-90: Data Analysis at Electrabel
1991-96: Head of Technology in Doel
1997-2004 various foreign activities
2004-07: Director of Doel
2007-12: Highest-Saftey Chief (WANO)
since 1/2013 Chief of the FANC:
Is this the independent superintendent of the Doel studies?
(By the way: He is married, has no children.)
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Nuclear-plant-tests: Neutral ?
The FANC has set up several commissions for the investigation report:
BEL V AIB-Vinçotte Scientific Council International review board
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Nuclear-plant-tests: Neutral ?
Members of the International review board (start 13.9.2012)
Pr. André PINEAU, École des Mines, Frankrijk
Dr. Helmut SCHULTZ, ex-GRS, Duitsland
Tim WILLIAMS, ex-Rolls Royce, Verenigd Koninkrijk
Dr. Mark KIRK, Nuclear Regulatory Commission, Verenigde Staten
Pr. Kim WALLIN, VTT Technical Research Centre, Finland
Dr. Stefan VODENICHAROV, Directeur van het Institute of Metallography Science, Bulgarije
-----
Pr. Pierre-Étienne LABEAU (ULB), Voorgezeten
Benedikt MARTENS (SCK•CEN), Wetenschappelijk secretariaat
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Nuclear-plant-tests: Neutral ?
For example:
Dr. Stefan VODENICHAROV, Bulgaria
Professor (Sofia)
President of the Bulgarian Academy of Sciences
Director of a weapon-producing-company IMSETHC (Institute of metal science, equipment and technologies with hydroaerodynamics centre), producing high-tech security and defence systems, Bulgaria
Education Minister of Bulgaria (since 31.01.2013)
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Nuclear-plant-tests: Neutral ?
Advertising of IMSETHC
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Nuclear-plant-tests: Neutral ?
Details to Dr. Stefan VODENICHAROV
These jobs doesn’t lesson his skills.
But he could not speak out against Doel and Tihange because he was a highly pronounced advocate for the Bulgarian nuclear plants „Kozloduy 3 and 4“, who are from the same type as Tihange and Doel.
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Our questions to FANC
We send 48 questions to FANC
only some are answered.
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Our Conclusion
A restart of Tihange 2 and Doel 3
is irresponsible by the current published studies.
Without doubtless clarification of all open issues
Tihange 2 and Doel 3 must not be restarted.
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Thank you!
Questions?
[email protected]://www.anti-akw-ac.de
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Sources Book
S001 – curriculum vitae of Jan Bens Head of FANC - http://www.milquet.belgium.be/sites/default/files/CV-Jan%20Bens.pdf
S002 – OECD Nuclear Energy AgencyS003 – Flaw indications in the reactor pressure vessel of Doel 3 (03.09.2012) -
http://fanc.fgov.be/GED/00000000/3200/3288.pdfS004 – Membership of international group of experts (13.09.2012) -
http://www.fanc.fgov.be/nl/news/doel-3-de-internationale-deskundigen-belast-met-de-revisie-van-het-dossier-zijn-gekend/555.aspxS005 – Flaw indications in the reactor pressure vessels of Doel 3 and Tihange 2 (12.10.2012) -
http://fanc.fgov.be/GED/00000000/3300/3323.pdfS006 – Flawed Reactor Pressure Vessels in Belgian Nuclear Plants Doel‐3 and Tihange‐2 - Some Comments - Ilse
Tweer - http://www.greens-efa.eu/fileadmin/dam/Documents/Studies/Comments_on_flaws_Doel_3.pdfS007 – Flaw indications in the reactor pressure vessels of Doel 3 and Tihange 2 (01.02.2013) -
http://www.afcn.fgov.be/GED/00000000/3300/3379.pdfS008 – Doel 3 – Tihange 2 RPV issue - International Expert Review Board - Final Report (15.01.2013) -
http://fanc.fgov.be/GED/00000000/3300/3393.pdfS009 – Report of the National Scientific Expert Group on the RPVD3T2 (11.01.2013) -
http://fanc.fgov.be/GED/00000000/3300/3392.pdfS010 – Doel 3 and Tihange 2 reactor pressure vessels: Provisional evaluation report (30.01.2013) -
http://fanc.fgov.be/GED/00000000/3300/3391.pdf
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20 further possibly affected NPP
Active
Borssele (NL)
Cofrentes (SP)
Ringhals 2 (S)
Leibstadt (CH)
Mühlberg (CH)
Atucha 1 (ARG)
Catawba 1, McGuire 2, Nord-Anna 1, Nord-Anna 2, Quad Cities 1, Sequoyah 1, Sequoyah 2, Surry 1, Surry 2, Watts Bar 1 (USA)
Source: S002
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20 further possibly affected NPP
in permanent shutdown
Brunsbüttel (D)
Philippsburg 1 (D)
Dodewaard (NL)
Santa María de Garoña (SP) (unexpectedly in permanent shut down since December 2012)
Source: S002