flaws in reactor pressure vessels of tihange 2 and doel 3

Press Talk - Workshop

Flaws in

reactor pressure vessels

of

Tihange 2 and Doel 3

Aachen (D) / Gemmenich (B) / Vaals (NL)

15.02.2013

15.02.2013 Flaws in reactor pressure vessels of Tihange 2 and Doel 3 of 60

Agenda

Presentation (60 min.)

Break (15 min.)

Questions (60 min.)

Individual Talks (open end)


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


We introduce our selves

Organisations

Aachener Aktionsbündnis gegen Atomenergie

Nucléaire, STOP !

Stop Tihange

Persons

Inge Gauglitz

Dieter Majer

Jörg Schellenberg

Walter Schumacher

Leo Tubbax


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


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]


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


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).


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.


Reactor Pressure Vessel (RPV)


Cross section through RPV


Disproportionate Representation of RPV Ring (thickness)


RPV with and without flaws


Idealized superimposed stripsdue to flaws

b 3 x 1/3 b


Second moment of area(Flächenträgheitsmoment)

J = 1/12

h b3

b


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


A conservative approach

for static computation


RPV section

200 mm

inner site outer site


RPV sectionwith flaws

200 mm



RPV sectionwith flaws

100 mm


100 mm


RPV sectionremaining wall thickness for static computations

100 mm


100 mm


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 ...


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]


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]


Flaws

Analysis of the character of the "flaws"

History of the „flaws“

...


Reports contain

Mistakes Contradictions Gaps Provisions for reduction of security-level


Evidences of Electrabel likea house of cards

Unknown origin of flaws

Unknown characteristic of

flaws






flaws


Material properties

Non representative

sample





flaws


Material properties

Non representative

sample

Structuralintegrity

&Evolution


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


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?


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).


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]


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?


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.


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!


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!


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 ...


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!


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]



Our check of the FANC report

How truly neutral

is the authority FANC ?



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



Jan Bens he is the new director of FANC since 1/2013

By chance we „found“ his CV:



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.)



The FANC has set up several commissions for the investigation report:

BEL V AIB-Vinçotte Scientific Council International review board



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



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)



Advertising of IMSETHC



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.


Our questions to FANC

We send 48 questions to FANC

only some are answered.


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.


Thank you!

Questions?

[email protected]://www.anti-akw-ac.de


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

http://www.milquet.belgium.be/sites/default/files/CV-Jan%20Bens.pdf


http://www.fanc.fgov.be/nl/news/doel-3-de-internationale-deskundigen-belast-met-de-revisie-van-het-dossier-zijn-gekend/555.aspx


http://www.greens-efa.eu/fileadmin/dam/Documents/Studies/Comments_on_flaws_Doel_3.pdf

http://www.afcn.fgov.be/GED/00000000/3300/3379.pdf





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


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