corrosion and erosion aspects in pressure boundary components of light water reactors

94 Pages·2010·2.3 MB·English

International Atomic Energy Agency IWGfRRPC-88-1
INTERNATIONAL WORKING GROUP
ON RELIABILITY OF REACTOR PRESSURE COMPONENTS
CORROSION AND EROSION ASPECTS
IN PRESSURE BOUNDARY COMPONENTS
OF LIGHT WATER REACTORS
PROCEEDINGS OF A SPECIALISTS MEETING
ORGANIZED BY THE
INTERNATIONAL ATOMIC ENERGY AGENCY
A N D HELD IN VIENNA, 12-14 SEPTEMBER 1988
INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1990
Infernafional Atomic Energy Agency IWG/-RPC-8-1
INTERNATIONAL WORKING GROUP
ON RELIABILITY OF REACTOR PRESSURE COMPONENTS
CORROSION AND EROSION ASPECTS
IN PRESSURE BOUNDARY COMPONENTS
OF LIGHT WATER REACTORS
PROCEEDINGS OF A SPECIALISTS MEETING
ORGANIZED BY THE
INTERNATIONAL ATOMIC ENERGY AGENCY
A N D HELD IN VIENNA, 12-14 SEPTEMBER 1988
INTERNATIONAL ATOMIC ENERGY A G E N C Y , VIENNA, 1990
EDITORIAL NOTE
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Authors are themselves responsible for obtaining the necessary permission to reproduce
copyright material from other sources.
CORROSION A N D EROSION ASPECTS IN PRESSURE BOUNDARY COMPONENTS
OF LIGHT WATER REACTORS
IAEA, VIENNA, 1990
IWG-RRPC-88-1
Printed by the IAEA in Austria
April 1990
F O R E W O R D
The purpose of the Specialists' Meeting was to
provide opportunities for discussion on recent achievements
in research of material behaviour affected by corrosion and
practical application of the results of research and
development works in the area to ensure safe operation and
high availability of nuclear power plants. This meeting was
considered as a continuation of the programme in the scope
of activities of the International Working Group on
Reliability of Reactor Pressure Components. In 1982 the
Agency convened an International Symposium on "Water
Chemistry and Corrosion Problems in Nuclear Power Plants and
the scope was large and included both fuel cladding and
reactor coolant systems and components. The IWG RRPC
decided that the topic could be narrowed and limited to
pressure boundary components and secondary systems such as
steam turbines and steam generators. The latter reflected
the scope of the Specialists' Meeting on "Corrosion and
Stress Corrosion of Steel Pressure Boundary Components and
Steam Turbines" which was held in Espoo, Finland from
22-24 November, 1983.
The conclusions of that Espoo meeting stated that the
reduction of plant availability or lack of capacity due to
corrosion problems had been considerable. The economic
penalties which resulted from the corrosion of plant
components might be so high that the question of prevention
or control of corrosion-erosion phenomena mast be regarded
as a major issue for the present and the future.
That Specialists' Meeting included considerations of
material selection, design and quality control, operational
procedures, effective techniques for reliable crack
detection, problems of repair and others. They also
recommended that future international cooperation,
coordination and exchange of information should continue
because it is seen as very valuable and beneficial.
In supporting those recommendations the IWG RRPC
decided to organise the specialists' Meeting on "Corrosion
and Erosion Aspects".
It was intended that the 1988 Vienna meeting should
deal with topics related to the safety and reliability
problems connected with the corrosion and erosion phenomena
experienced in pressure boundary components of LWR systems.
The topics to be covered would include the degradation of
the materials, influence of environment, mechanisms,
manufacturing practices, system design with regard to
thermohydraulics of the systems, the choice of materials,
surface conditions, radiation levels in connection with
maintenance and inspection, preventive and remedial
measures.
CONTENTS
Opening Remarks 7
V. Lyssakov
Experiences in the in-situ corrosion deposit measurements of the primary system
at Paks nuclear power plant 9
T. Sztaricskai, P. Raics, T. Pinter, P. Ormai
Technology development by the U.S. industry to resolve erosion-corosion 14
B. Chexal, N. Dietrich, J. Horowitz, W. Layman, G. Randall, V. Shevde
Flow asisted corosion in power plants — Part I: The EDF research programe 19
M. Bouchacourt
Flow asisted corosion predicting method and mechanical consequences 27
F.N. Remy
Erosion by cavitation on safety-related piping systems of French PWR units 31
G. Thoraval
Pipe wal thining in U.S. light water reactors 41
P.C.S. Wu
Thickness measurements of pipes submitted to erosion and corrosion problems in the steam,
fedwater and condensate systems of the Doel 1 and 2 power plants 43
J. P. Goffin
Erosion corrosion in power plant piping systems — calculation code
for predicting wal thining 49
W. Kastner, M. Erve, N. Henzel, B.Stelwag
Asesment and avoidance of erosion-corosion damage in PWR fedpipework 60
IS. Woolsey
Experience of erosion and erosion-corosion in nuclear steam turbines 6
M. Hedstrdm
Corosion fatigue aspects of VER-40 reactor materials 70
T. Saario, K. Torronen, R. Ahlstrand, V. Ignatov, V. Fedorova, V. Rybin, B. Timofeev
Special aspects of localized corosion proceses on austenitic stel at elevated temperatures 7
G. Lehmann, K. Mummert, M. Uhlemann, F. Schneider
Conclusions and Recomendations 89
Glosary 91
List of Participants 91
OPENING R E M A R K S
V. Lyssakov
Division of Nuclear Power
International Atomic Energy Agency
Vienna
It's my pleasure to greet all of you here at the Agency's Headquarters as
participants to the Specialists* Meeting on "Corrosion and Erosion Problems of
Pressure Boundary Components of LWRs".
This meeting is convened in the framework of the activities of the
Agency's International Working Group on Reliability of Reactor Pressure
Components and represents an up-dating event which covers one of the regular
topics within the framework of the activities of the IWG-RRPC. The idea to
hold this meeting was approved by the IWG-RRPC after the meeting with the
similar title which was held in Finland in the year of 1983.
That particular meeting was devoted to corrosion-erosion problems and
included a number of specific problems like corrosion and stress corrosion in
different environments typical to LWR environments, strain induced corrosion
cracking, hydrogen embrittlement of steels typical for RPV's, effects of
metallurgical variables on stress corrosion cracking of different RPV steels
and many others.
It should be noted that the Agency pays a great deal of attention to
different problems of reliable and safe operation of NPP's. Due to this fact
the Agency has recently launched a programme which deales with problems of
ageing of NPP components and their life-time extension. This particular
programme has been elaborated for all-time-dependant factors affecting
degradation of properties of material used as structural materials in NPP's
systems and components. It is understood that corrosion/erosion problems
could be considered both as degradating and time depending factor influencing
the reliability and safety of NPP's component performance.
The reduced plant availability or loss of capacity in modern NPP's today
can be significantly attributed to corrosion/erosion problems. The economic
penalties that can result from this aspect show clearly that a prevention or
regular monitoring could be an effective tool to handle the issue both now
and in the future.
The latter shows an importance of the understanding of the mechanisms
causing the phenomena. Taking into account the complexity of factors
influencing corrosion/erosion processes one should thoroughly consider full
interaction of parameters involved in the process and clearly define how to
monitor every separatly taken factor in order to prolong the life-time or
replace/repair a component on the economically favourable basis.
Though the corrosion problems have not so far been thought to cause any
serious safety problems they still are considered as economically serious
especially in the case of steam-generator performance.
7
Up to date it should be recognized that there are still many questions
left unanswered and practical solutions to be found regarding
corrosion/erosion problems.
Variety of materials used combined with environments and loading
conditions require a long term programme which could give a clear answer
regarding the interaction of parameters involved and how one could monitor
these parameters in order to achieve a longer safe and reliable pressure
boundary component service.
Solutions to this problem could be different but the most important task
is still existing: we should clearly definy what the mechanism is and how it
could be deseribed qualitatively and quantitatively with regard of materials
used, environmental and loading conditions.
The correspondens of those factors*could provide operators with valuable
information allowing to initigate the influence' of corrosion/erosion phenomena
on availability of NPP's.
The last meeting on the topic has recommended to develop and investigate
some measures which should be developed to achieve concrete results. They
have included proposals for more stringent material specifications, design
improvements to reduce local stresses, improved quality control of materials
and manufacturing processes, smooth operational procedures and conditions,
development of effective techniques to provide early corrosion crack detection
and sizing, accumulation of experimental data for reducing uncertainties,
suggestions for safe repair techniques of corrosion cracks and failures and so
on.
It is expected that this meeting will serve as a practical tool for
increasing the body of knowledge in the above mentioned area.
Presentations to be made at the meeting will serve as an updated
information exchange in the area concerned, and could be used internationally.
Before I give the floor to Mr. M.L. Davies who will serve as Chairman of
the meeting I would like to wish you useful and fruitful work which would
hopefully provide you with some new ideas for your future research work.
8
EXPERIENCES IN THE IN-SITU CORROSION DEPOSIT d e t e r m i n a t i o n o f t h e a c t i v i t i e s o f t h e c o r r o s i o n d e p o s i t s a l o n g
MEASUREMENTS OF THE PRIMARY SYSTEM AT PARS t h e p i p e l i n e s o f t h e p r i m a r y c o o l i n g l o o p s o f t h e r e a c t o r s . A
NUCLEAR POWER PLANT* p o r t a b l e s m a l l v o l u m e h i g h p u r i t y g e r m a n i u m g a m m a - s p e c t r o m e t e r
w a s s e t u p i n D e b r e c e n f o r t h e i n - s i t u m e a s u r e m e n t s o f t h e
T. SZTARICSKAI, P. RAICS
r a d i a t i o n f r o m t h e a c t i v a t e d c o r r o s i o n d e p o s i t s o n t h e i n t e r n a l
Institute of Experimental Physics,
w a l l o f t h e m a i n p r i m a r y p i p e l i n e s . T h e o p t i m a l g e o m e t r y f o r t h e
Debrecen
c o l l i m a t o r a n d t h e m e a s u r i n g s e t u p h a v e b e e n d e t e r m i n e d i n
T. PINTER, P. ORMAI
c a l c u l a t i o n s a n d t e s t e d e x p e r i m e n t a l l y . A s e t o f 1 0 i n - s i t u
Paks Nuclear Power Plant,
m e a s u r e m e n t s w a s c a r r i e d o u t in t w o - t w o p o s i t i o n s o n t h e h o t
Paks
a n d t h e c o l d l e g s a t e a c h o f t h e s i x p r i m a r y c o o l i n g l o o p s o f
Hungary t h e f o u r r e a c t o r s i n e v e r y y e a r d u r i n g t h e r e f u e l l i n g s h u t - d o w n .
T h e r e s u l t s w e g o t b y t h e i n - s i t u m e a s u r e m e n t s w e r e e v a l u a t e d
Abstract a n d a n a l y s e d .
U s i n g t h e p o r t a b i l i t y o f s m a l l s i z e H P G e s p e c t r o m e t e r s s
m e t h o d w a s d e v e l o p e d f o r t h e d e t e r m i n a t i o n o f t h e s u r f a c e a c t i -
EX P E R I M E N T A L M E T H O D
v i t y o f c o r r o s i o n d e p o s i t s o n t h e p r i m a r y c o o l i n g l o o p s o f t h e
f o u r V V E R - 4 4 0 r e a c t o r s o f P a k s N P P . T h i s m e t h o d a l l o w s t h e f a s t
T h e H P G e d e t e c t o r o f a b o u t 0 . 5 c c m v o l u m e w a s p l a c e d i n a
m a p p i n g o f t h e c o r r o s i o n d e p o s i t a l o n g t h e p i p e l i n e s d u r i n g t h e
l e a d c o l l i m a t o r , l o o k i n g a t t h e t u b e o f t h e p r i m a r y p i p e l i n e s .
a n n u a l r e f u e l l i n g s h u t - d o w n s . T h e r e s u l t s o b t a i n e d i n t h e
A n a c c u r a t e e f f i c i e n c y c a l i b r a t i o n p r o c e d u r e w a s c a r r i e d o u t f o r
i n - s i t u m e a s u r e m e n t s w e r e c o m p a r e d w i t h t h e d a t a f r o m t h e d i r e c t
t h e d e t e r m i n a t i o n o f t h e o p t i m a l g e o m e t r y of t h e p r i m a r y
s a m p l i n g . T h e a c t i v i t i e s o f t h e c o r r o s i o n p r o d u c t s a f t e r t h e
t u b e - c o l l i m a t D r - d e t e c t o r s y s t e m . I n a m o d e l e x p e r i m e n t , u s i n g a
a n n u a l s h u t - d o w n s a r e c o m p a r e d a n d a n a l y s e d . T h e g a m m a - s p e c t r o -
s p a r e p r i m a r y t u b e it w a s t e s t e d t h e c a l c u l a t i o n o n t h e g e o m e t r y
m e t r i c m e t h o d h a s a l s o b e e n u s e d f o r t h e s t u d y o f t h e s a t u r a t i o n
a s w e l l a s t h e r e a l a b s o r p t i o n o f t h e t u b e w a l l , t h e c o o l a n t a n d
of t h e i o n - e x c h a n g e r c o l u m n o f t h e r e a c t o r s .
t h e t h e r m a l i n s u l a t i o n . T h e c h a n g e f o r t h e g e o m e t r i c a l
e f f i c i e n c i e s f o r c a s e s w h e n t h e a x i s o f t h e c o l l i m a t o r d o e s n o t
i n t e r s e c t t h e a x i s o f t h e t u b e w a s s t u d i e d c a r e f u l l y . T h e
c o l l i m a t o r c h a r a c t e r i s t i c s w e r e d e t e r m i n e d b y p o i n t a n d l a r g e
IN T R O D U C T I O N
s u r f a c e s o u r c e s a s w e l l . T h e s p e c i f i c a c t i v i t y f o r a g a m m a - l i n e
of e n e r g y E , i n t e n s i t y y c a n b e c a l c u l a t e d b y t h e f o r m u l a :
T h e s t u d y o f t h e c o r r o s i o n p r o d u c t t r a n s p o r t r e l a t e d t o t h e
P a k s N u c l e a r P o w e r P l a n t , i n s p i t e o f t h e r e l a t i v e l y s h o r t
o p e r a t i o n t i m e o f t h e P a k s IIPP, h a s s o m e r e s u l t s ( 1 , 2 ) . T h e
i n - s i t u m e a s u r e m e n t o f c o r r o s i o n d e p o s i t s b y C E A ( 3 ) w a s t h e
*f CTT,(E)-K(R) - i ( R A
r e a s o n t o d e v e l o p a p o r t a b l e m e a s u r i n g s y s t e m f o r t h e
w h e r e I : t h e m e a s u r e d p h o t o p e a k i n t e n s i t y , C : t h e c o r r e c t i o n f a c t o r
* This work was supported in pan by the Hungarian Research Foundation under contract 259
and the Paks Nuclear Power Plant. f o r r a n d o m p i l e - u p an d d e a d t i m e l o s s e s , : t h e e f f i c i e n c y f o r
,5
0 K> 20 30 «> M U 10
F i g . 2 T h e d i s t a n c e d e p e n d e n c e o f t h e d e t e c t o r e f f i c i e n c y
t h e i n p u t p l a n e o f t h e c o l l i m a t o r a t e n e r g y E , K: t h e d i s t a n c e
f u n c t i o n f o r t h e e f f i c i e n c y . F u n c t i o n i ( R , E ) i n c l u d e s a l l t h e
g e o m e t r i c a l e f f e c t s c o n n e c t e d t o t h e t u b e p a r a m e t e r s a n d t h e
a b s o r p t i o n , k a c c o u n t s f o r t h e c o n d i t i o n of t h e t u b e : f i l l e d
w i t h c o o l a n t o r e m p t y , w i t h o r w i t h o u t t h e r m a l i n s u l a t i o n :
F i g . 3 T h e l a y o u t o f t h e t e s t p o i n t s a r o u n d t h e p r i m a r y
w r a p p e d o r b a r e . T h e e n e r g y d e p e n d e n c e o f t h e d e t e c t o r
c o o l i n g s y s t e m
e f f i c i e n c i e s i s s h o w n i n F i g . l . T h e e f f i c i e n c y v s t u b e - d e t e c t o r
d i s t a n c e f u n c t i o n i s i l l u s t r a t e d i n F i g . 2 . T h e s e l a s t c u r v e s -
MEA S U R E M E N T S A N D E V A L U A T I O N
v e r i f i e d b y e x p e r i m e n t s - s h o w b r o a d m a x i m a . S u c h a f e a t u r e c a n
b e e x p l a i n e d b y t h e c o l l i m a t o r - t u b e g e o m e t r y r e l a t i o n s . T h e
T h e g a m m a - s p e c t r a f r o m t h e c o r r o s i o n d e p o s i t s o n t h e i n t e r n a l
b r o a d m a x i m u m i s v e r y i m p o r t a n t f o r m i n i m i z i n g t h e r a n d o m
w a l l o f t h e p r i m a r y p i p e l i n e s w e r e c o l l e c t e d b y a S e r i e s 2 0
u n c e r t a i n t i e s o f t h e e x p e r i m e n t a l s e t - u p at t h e p r i m a r y l o o p s
C A N B E R R A M C A a n d w e r e r e c o r d e d b y c a s e t t e r e c o r d e r . T h e
of t h e r e a c t o r s . T h e l a y o u t o f t h e m e a s u r i n g p o i n t s a r o u n d t h e
b a c k g r o u n d r a d i a t i o n f r o m t h e e n v i r o m e n t of t h e d e t e c t o r w a s
p r i m a r y c o o l i n g l o o p s i s s h o w n i n F i g . 3 .
t a k e n i n t o a c c o u n t p u t t i n g a 5 c m t h i c k l e a d b r i c k b e t w e e n t h e