Astm stp 1270 1996

Topics include the effects of annealing on properties, properties of irradiated welds and specific reactor parts, conse- quences of flux, irradiation temperature and gamma radiation, int

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Printed in Ann Arbor, MI August 1996

Foreword

This publication, Effects of Radiation on Materials: 17th International Symposium, con-

tains papers presented at the symposium of the same name, held in Sun Valley, Idaho on 20-

23 June 1994 The symposium was sponsored by ASTM Committee E-10 on Nuclear

Technology and Applications David S Gelles of Pacific Northwest National Laboratory in

Richland, WA; Randy K Nanstad of the Oak Ridge National Laboratory in Oak Ridge, TN;

Arvind S Kumar of the University of Missouri in Rolla, MO; and Edward A Little of

University College in Swansea, United Kingdom presided as symposium chairmen and are

editors of the resulting publication

DEDICATION

Peter Hedgecock 1931-1992

Peter D Hedgecock contributed significantly to the success of ASTM Committee E-10 on Nuclear Technology and Applications Peter has been the Chairman of Subcommittee El0.02, on Radiation Effects on Structural Materials until the time of his sudden death His colleagues within ASTM acknowledge his high degree of professionalism, organization, and enthusiasm

Peter was trained as a metallurgical engineer at the University of London and was licensed in the United States as a metallurgical, corrosion, and nuclear engineer His knowledge and experience extended beyond that of nuclear structural materials, since he had extensive exposure in the aerospace industry and as an expert witness in accident recon- struction and component failures

Peter was a gentleman and a friend We will miss him

Contents

O v e r v | e w - - D s GELLES, R K NANSTAD, A E K U M A R , A N D E A L r I T L E xiii

MODELING OF CONTROLLING MECHANISMS IN R P V STEELS

Mechanisms Controlling the Composition Influence on Radiation Hardening

P r e s s u r e V e s s e l E m b r i t t l e m e n t P r e d i c t i o n s B a s e d o n a C o m p o s i t e Model of

C o p p e r Precipitation and Point Defect Clustering R E STOLLER 25

T h e B & W O w n e r s G r o u p P r o g r a m for Microstructurai Characterization and

V e s s e l S t e e l s - - R G LOTr AND P D FREYER 86

T h e Modeling o f Irradiation Embrittlement in Submerged-Arc W d d s - -

C J B O L T O N , J T BUSWELL, R B JONES, R MOSKOVIC, AND R H PRIEST 103

The Modeling o f Irradiation-Enhanced Phosphorus Segregation in Neutron

J VAN DE VELDE, J L PUZZOLANTE, T VAN R A N S B E E C K , A VERSTREPEN,

MICROSTRUCTURE STUDIES ON R P V STEELS

Electron Microscopy and Small Angle Neutron Scattering Study of

Radiation Damage Studies Using Small-Angle Neutron Scattering

A M K R Y U K O V , V I LEVIT, P A P L A T O N O V , A N D M A S O K O L O V 232

Microstructure and Mechanical Properties of WWER-440 Reactor Vessel

Metal After Service Life Expiration and Recovery A n n e a l - -

I V G O R Y N I N , E V NESTEROVA, V A NIKOLAEV, A N D V V RYBIN 248

A Microstructural Study of Phosphorus Segregation and lntergranular

C H A R P Y I M P A C T R E S P O N S E O F R P V S T E E L S

N u d e a r Power Plants R G E R A R D , A F A B R Y , J VAN DE VELDE,

J.-L P U Z Z O L A N T E , A VERSTREPEN, T VAN R A N S B E E C K , AND E VAN W A L L E 294

The Toughness o f Irradiated Pressure Water Reactor (PWR) Vessel Shell

Rings and the E f f e c t o f S e g r e g a t i o n Z o n e s N M BETHMONT, I.-M FRUND,

L o w Temperature Embrittlement of RPV Support Structure S t e e l - -

F M D B O Y D O N , R J McELROY, G GAGE, AND W J P H Y T H I A N 331

Effects of Neutron Flux and Irradiation Temperature on Irradiation

The Interpretation of Charpy Impact Test Data Using Hyper-Logistic Fitting

Uncertainty Evaluation in Transition Temperature M e a s u r e m e n t s - -

O n I m p a c t T e s t i n g of Subsize C h a r p y V-Notch T y p e S p e c i m e n s - -

R e c o n s t i t u t i o n : W h e r e Do We S t a n d ? m E VAN WALLE 415

T h e R e c o n s t i t u t i o n of Charpy-Size Tensile S p e c i m e n s m T VAN RANSBEECK,

E VAN WALLE, A FABRY, J L PUZZOLANTE, AND J VAN DE VELDE 442

Notch R e o r l e n t a t i o n of C h a r p y - V Specimens of the B W R P h i l i p p s b u r g 1

T h r o u g h R e c o n s t i t u t i o n - - E VAN WALLE, A FABRY, T VAN RANSBEECK,

J.-L PUZZOLANTE, L VAN DE VELDE, K TULKE, AND W BACKFISCH 458

V a r i a t i o n s in C h a r p y I m p a c t Data Evaluated by a R o u n d - R o b i n T e s t i n g

P r o g r a m m A S u m m a r y - - A L LOWE, JR 487

T h e E m b r i t t l e m e n t Data Base 0EDB) a n d Its A p p l i c a t i o n s - - J A WANG,

Surveillance Programme for WWER-440/Type 213 Reactor Pressure

V e s s e l s - - S t a n d a r d P r o g r a m m e , R e - E v a l u a t i o n of Results,

S u p p l e m e n t a r y P r o g r a m m e - - M B R U M O V S K Y , P N O V O S A D , A N D J Z D A R E K 522

STRENGTH AND TOUGHNESS ISSUES IN RPV STEELS

A p p l i c a t i o n of M i c r o m e c h a n i c a i Models of Ductile F r a c t u r e I n i t i a t i o n to

R e a c t o r P r e s s u r e Vessel M a t e r i a l s m R CHAOUADI, P DE MEESTER

O n the Effect of Flux a n d C o m p o s i t i o n on I r r a d i a t i o n H a r d e n i n g at 6 0 ~

G R ODP,-IIE G E LUCAS, R D KLINGENSMITH, AND R E STOLLER 547

T h e D e p e n d e n c e of R a d i a t i o n H a r d e n i n g a n d E m b r i t t l e m e n t on I r r a d i a t i o n

T e m p e r a t u r e - - a B JONES AND T J WILLIAMS 569

HFIR Steels E m b r i t t l e m e n t : T h e Possible Effect of G a m m a Field

C o n t r i b u t i o n m t REMEC, J.-A W A N G , AND F B K K A M 591

T h e Influence of Metallurgical Variables o n the T e m p e r a t u r e D e p e n d e n c e of

I r r a d i a t i o n H a r d e n i n g in Pressure Vessel SteelswG R ODETrE,

Effects o f P r o t o n I r r a d i a t i o n on Positron A n n i h i l a t i o n a n d M i c r o - V i c k e r s

H a r d n e s s o f F e - C - C u M o d e l A l i o y s - - n SHIBAMOTO, K KOYAMA, H YUYA

M H A S E G A W A , A KIMURA, H MATSUI, AND S Y A M A G U C H I

Ductile F r a c t u r e M e c h a n i s m s in an A302B Modified R e a c t o r P r e s s u r e Vessel

SteeI L J CUDDY, M P M A N A H A N , G BRAUER, A N D J M A R T I N K O

F r a c t u r e T o u g h n e s s T e s t Results of T h e r m a l Aged R e a c t o r Vessel

A c t i v a t i o n M a r t e n s i t i c Steeis M VICTORIA, E BATAWl C BRIGUET,

D GAVILLET, P MARMY, J PETERS, AND F REZAI-ARIA

Influence o f T h e r m o m e c h a n i c a l T r e a t m e n t on I r r a d i a t i o n M i c r o s t r u c t u r e s in

an O D S F e r r i t i c SteeI E A LrrrLE

721

739

Effect of B o r o n on Post I r r a d i a t i o n Tensile P r o p e r t i e s o f R e d u c e d A c t i v a t i o n

F e r r i t i c Steel (F-82H) I r r a d i a t e d in H F I R - - K SmBA, M SUZUKI,

A, HISHINUMA, AND L E PAWEL

I r r a d i a t i o n Effects on Base M e t a l a n d Welds of 9Cr-lMo (EM10) M a r t e n s i t i c

S t e e l - - A ALAMO, J L SERAN, O RABOUILLE, J C BRACHET, A MMLLARD,

H TOURON, AND J ROYER

E v a l u a t i o n o f the U p p e r S h e l f E n e r g y for F e r r i t i c Steels f r o m M i n i a t u r i z e d

C h a r p y S p e c i m e n D a t a - - H KURISHITA I S H I B A H A R A , M NARUI, S MIZLTTA,

M i c r o s t r u c t u r a l E v o l u t i o n of AusteniUc Stainless Steels I r r a d i a t e d I n a Fast

R e a c t o r - - o v 8ORODIN, V V BRYK, V N VOVEVODIN, I M NEKLYLrDOV,

Swelling, M e c h a n i c a l Properties a n d S t r u c t u r e of Austenitlc High-Nickel

Alloy I r r a d i a t e d in a Fast R e a c t o r - - v K SHAMARDIN, V S NEUSTROEV

A V POVSTYANKO, T M BULANOVA, Z E OSTROVSKY, A A KUZNETZOV,

Effects of Metallurgical V a r i a b l e s o n Swelling of Modified 316 a n d H i g h e r Ni

Austenitic Stainless Steels I SHIBAHARA, N AKASAKA, AND S ONOSE 858

O n the F u n d a m e n t a l s of R a d i a t i o n Damage in F C C Materials: A R e v i e w - -

A n I n v e s t i g a t i o n of M i c r o s t r u c t u r e s a n d Yield S t r e n g t h s in I r r a d i a t e d

Austenitic Stainless Steels Using Small S p e c i m e n T e c h n i q u e s - -

M B TOLOCZKo, G E LUCAS, G R ODETIE, R E STOLLER, AND M L HAMILTON

I r r a d i a t i o n H a r d e n i n g a n d Loss of Ductility of T y p e 316L(N) Stainless Steel

Plate M a t e r i a l Due to N e u t r o n - I r r a d i a t i o n - - M G HORSTEN AND

M I DE VRIES

902

919

F a t i g u e C r a c k P r o p a g a t i o n by C h a n n e l F r a c t u r e In I r r a d i a t e d 316 Stainless

S t e e i m s JrrSUKAWA, A HISHINUMA, AND M SUZUKI 933

F r a c t u r e T o u g h n e s s of I r r a d i a t e d C a n d i d a t e M a t e r i a l s for I T E R First Wall/

B l a n k e t S t r u c t u r e s - - D J A L E X A N D E R , J E P A W E L , M L GROSSBECK,

I r r a d i a t i o n B e h a v i o r of W e i d m e n t s of Austenitic Stainless Steel M a d e by

V a r i o u s W e l d i n g T e c h n i q u e s - - K SHIBA, T SAWAI, S JITSUKAWA,

H e l i u m Effects o n the Reweldability a n d Low C y d e F a t i g u e Properties of

Welded J o i n t s for T y p e C r l 6 N i l l M o 3 T i a n d 316L(N) Stainless

S t e e l s - - s A FABRITSIEV AND J G VAN DER L A A N 980

D a t a Collection o n the Effect of I r r a d i a t i o n o n the M e c h a n i c a l P r o p e r t i e s of

Austenitic Stainless Steels a n d Weld MetalS A.-A TAVASSOLI, C PICKER,

O T H E R M A T E R I A L S

Bubble M l c r o s t r u c t u r e Evolution a n d H e l i u m B e h a v i o r in He + I m p l a n t e d Ni-

Base AIIoys B A KALIN, I I C H E R N O V , A N K A L A S H N I K O V , AND

S a t u r a t i o n of Swelling i n N e u t r o n I r r a d i a t e d P u r e Nickel a n d Its D e p e n d e n c e

o n T e m p e r a t u r e a n d S t a r t i n g Dislocation M i c r o s t r u c t u r e - -

Effect of I r r a d i a t i o n in a Spallation N e u t r o n E n v i r o n m e n t on Tensile

P r o p e r t i e s a n d M i c r o s t r u c t u r e of A l u m i n u m Alloys 5052 a n d 6 0 6 1 - -

J A DUNLAP, M J BORDEN, W F SOMMER, AND J F STUBBINS 1047

C o r r e l a t i o n Between S h e a r P u n c h a n d Tensile D a t a for N e u t r o n - I r r a d i a t e d

A l u m i n u m Alloys M L H A M I L T O N , M B T O L O C Z K O , D L EDWARDS,

W F SOMMER, M J BORDEN, J A DUNLAP, J F STUBBINS, AND G E LUCAS 1057

Effect of D y n a m i c a l l y C h a r g e d H e l i u m o n Mechanical Properties of

V a n a d i u m - B a s e A l i o y s - - a M CHUNG, B A, LOOMIS, AND D L SMITH

Swelling a n d S t r u c t u r e of V a n a d i u m - B a s e Alloys I r r a d i a t e d in the D y n a m i c

H e l i u m C h a r g i n g E x p e r i m e n t - - H M CHUNG, B A LOOMIS, AND D L, sMrm

A c t i v a t i o n - - K EHRLICH, S W CIERJACKS, S K E L Z E N B E R G , AND A M O S L A N G 1109

C h a r a c t e r i z a t i o n of I r r a d i a t i o n - I n d u c e d Precipitates by Small Angle X-Ray

a n d N e u t r o n S c a t t e r i n g E x p e r i m e n t s - - M GROSSE, F EICI~ORN,

V a r i a b l e E n e r g y P o s i t r o n M e a s u r e m e n t s a t Nitrogen I o n B o m b a r d e d Steel

The Seventeenth International Symposium is distinguished by the very large attendance attained One hundred seventy-seven abstracts were submitted for presentation at the sympo- sium, and 104 are now being published in the combined proceedings of the symposium The size of this publication effort has proven to be too large to fit in an ASTM STP, and therefore, it was necessary to split the publication between two publishers The basis chosen for the split was relevance to ASTM standards, with the underlying intent to include in each publication examples of the wide range of topics covered As a result, the papers being published in this volume represent the full range of topics covered at the symposium, but emphasize those topics that are most closely related to ASTM standards

The papers published in this STP have been organized into eight sections The first four sections are devoted to behavior of low alloy reactor pressure vessel steels Papers on pressure vessel steels constituted approximately half of the papers submitted, and topics range from discussions of modeling and mechanisms, to microstructure and welding effects, but the greatest number describe mechanical property response or mechanical property data base intbrmation The next two sections describe research on two other major classes of material: ferritic and martensitic steels and austenitic steels and the seventh section includes papers on the remaining materials of interest The final section contains papers concerning special procedures, such as development of low long-term activation steels for fusion applications, and special techniques, such as positron measurements, laser extensometry, and small angle neutron scattering measurements

Recent improvement in our understanding of reactor pressure vessel steel embrittlement has advanced rapidly, so that this proceedings contains seven papers in section one that describe mechanisms controlling behavior and model the processes of radiation embrittle- ment and segregation Section two focuses on the precipitation process that controls embrit- tlement, including reports on electron microscopy and small angle neutron scattering, and the improvements available from annealing procedures to recover properties by altering precipitate distributions Section three includes thirteen papers that expand and organize the mechanical properties data base on irradiation embrittlement Topics include the effects of annealing on properties, properties of irradiated welds and specific reactor parts, conse- quences of flux, irradiation temperature and gamma radiation, interpretation of data by

xiv OVERVIEW

specialized data analysis procedures, use of small specimen technology and reconstitution, and data base summaries including round robin test results Section four expands the mechanical properties data base on reactor pressure vessel steels, providing six papers with improved understanding of irradiation hardening, one paper concerned with ductile fracture mechanisms and finally four important papers on fracture toughness results including new techniques used to understand the fracture process in these steels

Section five provides a shift in attention to steels with higher chromium levels for use at higher temperatures Papers include development of Martensitic steels for fusion, effects of radiation on the microstructure of an oxide dispersion strengthened alloy, and four papers on the mechanical properties of this class of steels Section six is concerned with austenitic ferrous alloys, with four papers covering microstructural response, a paper on the fundamen- tals of radiation damage in this class of materials, six papers on mechanical properties, and one paper concerned with development of a materials data base Section seven includes two papers on microstructural evolution in nickel, two papers on mechanical properties of aluminum alloys, two papers on helium effects in vanadium, one on microstructure, the second on mechanical properties, and finally a paper on corrosion of a zirconium alloy The last section includes four specialized papers on development of structural materials for fusion to avoid long-term radioactivity, and on use of neutron scattering for precipitate characterization, positron measurements, and laser extensometry

It should also be noted that this proceedings contains a series of excellent papers con- cerned with the development of small specimen technology and understanding of fractographic information for assessment of fracture toughness response Papers on these topics are included in sections three, four, and five Together, they demonstrate that our understanding of the propagation of a crack tip is increasing rapidly

A photograph of attendees is provided in Fig 1

Finally, in order to be fair to those authors at this symposium whose papers could not be

FIG 1 Symposium attendees

OVERVIEW XV published in this volume, we have provided the following section that lists authors and titles

of papers that have appeared in the companion volume of this proceedings, Volume 225 of

the Journal of Nuclear Materials

Symposium Cochairman and Editor

Ted A Little

Dept of Materials Engineering University College, Swansea, UK Symposium Cochairman and Editor

Volume 225, 1995

C a l c u l a t i o n of R a d i a t i o n - I n d u c e d Creep a n d Stress R e l a x a t i o n - - J NAGA~WA, p 1

C o r r e l a t i o n Between Void Swelling a n d SIPA C r e e p - - c H WOO, p 8

T h e Effect of Swelling o n SIPA I r r a d i a t i o n C r e e p - - v A BORODIN, p 15

Critical P a r a m e t e r s C o n t r o l l i n g I r r a d i a t i o n Swelling in B e r y l l i u m - - v L DUatNKO AND

V R BARABASH, p 22

T h e o r y of I r r a d i a t i o n Swelling in Materials with Elastic a n d Diffusional A n i s o t r o p y - -

v L DUBINgO, p 26

T h e Effect of I n t e r n a l Stress Fields on F r a c t u r e of S t r u c t u r a l M a t e r i a l s u n d e r I r r a d i a -

t i o n - - v M MANICHEV AND V A BORODIN, p 33

F A GARNER, T MUROGA, AND N YOSHIDA, p 76

R a d i a t i o n - E n h a n c e d Diffusion in Nickel-10.6% C h r o m i u m A l l o y s - - M Gn~a, t NEmCK AND W, scmn~E, p 85

Dependence of Radiation-Induced Segregation on Dose, T e m p e r a t u r e and Alloy Com- position in Austenitic Alloys D L DAMCOTr, T R ALLEN, AND G S WAS, p 97

A Model for Radiation-Induced Segregation in F C C Binary AIIoys T HASHIMOTO,

Y ISOLE, AND N SHIGENAKA, p 108

Quantification of Defect-Solute Coupling from Inverse-Kirkendall S e g r e g a t i o n - -

E, P SIMONEN, L A CHARLOT, AND S M BRUEMMER, p 117

M i c r o s t r u c t u r e of C o p p e r and Nickel I r r a d i a t e d with Fission Neutrons Near 2 3 0 " C - -

S J ZINKLE AND L L SNEAD, p 2 3

Low A c t i v a t i o n B r a z e J o i n t of D i s p e r s i o n - S t r e n g t h e n e d C o p p e r - - S CHEN AND B.A CHIN, p 132

M i c r o s t r u c t u r e and Tensile Properties of Neutron I r r a d i a t e d Cu and Cu-5Ni Contain- ing Isotopicaily Controlled Boron T MUROGA, H WATANABE N YOSHIDA, H KURISHITA, AND M L HAMILTON, p 137

M i c r o s t r u c t u r e Investigation of C r and Cr Alloys I r r a d i a t e d with Heavy I o n s - -

V V BRYK, V N VOYEVODIN, L M NEKLYUDOV, AND A N, RAK1TSKIJ, p 146

Swelling and Dislocation Evolution in Simple F e r r i t i c Alloys I r r a d i a t e d to High Fiuence in F F T F / M O T A - - Y KATOH, A KOIJVAMA, AND D S GELLES, p 154

Void Swelling in Binary Fe-Cr Alloys at 200 d p a - - D , s GELLES, p 163

Microstructure-Mechanical Properties Correlation of I r r a d i a t e d Conventional and Reduced-Activation Martensitic Steels R L KLUEH, J.-J KAI, AND D J ALEXANDER, p

175

Hardness of 12Cr-8Mo F e r r i t i c Steels I r r a d i a t e d by Ni Ions T OWrA, T OHMURA,

K KAKO, M, TOKIWAI, AND T SUZUKI, p 187

Experimental Evidence of Several Contributions to the Radiation Damage in F e r r i t i c AUoys M AKAMATSU, t C VAN DUYSEN, P PAREIGE, AND P AUGER, p 192

I r r a d i a t i o n - I n d u c e d M i c r o s t r u c t u r a l Changes, and Hardening Mechanisms, in Model

P W R R e a c t o r Pressure Vessel Steels J T BUSWELL, W.J PHYTHIAN, R, I McELROY,

S DUMBILL, P H N RAY, J, MACE, AND R N SINCLAIR, p 196

C h a r a c t e r i z a t i o n of Phosphorus Segregation in N e u t r o n - I r r a d i a t e d Russian Pressure Vessel Steel W e l d - - M K MILLER, R JAYARAM, AND K F RUSSELL, p 2 1 5

A P F I M Investigation of Clustering in N e u t r o n - I r r a d i a t e d Fe-Cu Alloys and Pressure Vessel Steeis p AUGER, P PAREIGE, M AKAMATSU, AND D BLAVETYE, p 225

Effect of Specimen Size on the I m p a c t Properties of Neutron I r r a d i a t e d A533B S t e e l - -

L E SCHUBERT, A S KUMAR, S T, ROSINSKI, AND M L HAMILTON, p 231

Size Effects on the U p p e r Shelf Energy of a Neutron I r r a d i a t e d Pressure Vessel Weld

OVERVIEW xvii

Microstructurai Aspects of Accelerated Deformation of Zircaloy Nuclear Reactor

Components During Service M GRWFr~S, R A HOLT, AND A ROGERSON, p 245

Tensile Behavior and Microstructure of Neutron-Irradiated Mo-5% Re A l l o y - -

A HASEGAWA, K ABE, M SATOU, AND C NAMBA, p 259

Change in Physical Properties of High Density lsotropic Graphites Irradiated in the

" J O Y O " Fast Reactor L MARUYAMA, T KA1TO, S ONOSE, AND I SHIBAHARA, p 267

Radiation Damage of Graphite and Carbon-Graphite Materials YAISHTROMBAKH,

Inert Gas Release from Metals and UO2 During High Temperature Annealing: The

Role of Thermal Vacancies J n EVANS p 302

A Mechanistic Model for Radiation-Induced Crystallization and Amorphization in

Effect of Irradiation on the Mlcrohardness of the LEC Grown Semi-InsulaUng GaAs

Single C r y s t a i s - - M UDHAYASANKAR, S ARULKUMARAN I AROKIARAJ, P SANTHAN-

ARAGHAVAN B SUNDARAKANNAN, I KUMAR, P RAMASAMY, K G M NAIR, P MAGUDAPATHY,

N S THAMPI, AND K KRISHAN, p 314

S t r u c t u r a l Damage in Spinel After I o n l r r a d i a t i o n - - N BORDES K.E SICKAFUS,

C A COOPER, AND R C EWING, p 318

Optical Properties in Fibers During Irradiation in a Fission Reactor T SHIKAMA,

T KAKUTA, M NAMI T SAGAWA, AND H KAYANO, p 3 2 4

Radiation Induced Conductivity in Alumina c PATUWATHAVITHANE, W Y WU, AND

R H ZEE, p 328

Modeling of Controlling Mechanisms in

RPV Steels

V A Nikolaev I and V V Rybin 2

MECHANISMS CONTROLLING THE COMPOSITION INFLUENCE ON

RADIATION HARDENING AND EMBRITTLEMENT OF IRON-BASE ALLOYS

REFERENCE: Nikolaev, V A and Rybin, V V., "Mechanisms Controlling the

Composition Influence on Radiation Hardening and Embrittlement of Iron-Base

Alloys," Effects of Radiation on Materials: 17th blternational Symposium, ASTM

STP 1270, David S Gelles, Randy K Nanstad, Arvind S Kumar, and Edward A

Little, Eds., American Society for Testing and Materials, 1996

ABSTRACT: Classification and ranking of the solid solution on thier reaction to the

irradiation is suggested on the basis of binary system structure controlling by mixing

enthalpy sign, melting temperatures relation of components and solidus curves slope

Several combinations of these characteristics permit to pick out three groups of

substitutional elements capable to form the vacancy-solute atom complexes either

low-mobile or fast-mobile ones as compared to monovacancies migration The

radiation hardening (and embrittlement) of binary alloys should be intensified

respectively either due to heterogeneous point defect clusters nucleation on solute

traps or due to solute atom clusters/precipitate formation A local cohesion decrease

may also occur especially if low-melting elements (characterized by low surface

energy) are segregating on internal sinks or grain boundaries The predicted specifics

of diffrent alloy group under irradiation and during post-irradiation annealing were

experimentally examined using a wide set of Fe-base alloys A good agreement was

find between expected and really observed behaviour of alloys

KEYWORDS: radiation, hardening, embrittlement, defect, cluster, solid solution,

segregation, annealing, iron, binary alloy

1 Binary Alloys Classification On Their Possible Reaction On Irradiation

Simplified qualitative models of the point defect - solution atom complex

formation and migration were analysed to build a classification and ranking of the Fe-

Laboratory Chief, CRISM "Prometey", St.petersburg, Russia

2 Department Chief, CRISM "'Prometey", St.Petersburg, Russia

4 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

alloys on their sensitivity to radiation hardening and embrittlement [1 ] Some

thermodynamic characteristics of the binary systems and individual element

properties were suggested as prediction parameters, namely:

- a sign of partial enthalpy of mixing

AU=UAB- I/2(UAA-kUBB)

where UAA, UBB,UAB are energies of the paired interaction of A and B (solute)

element atoms:

- a relation of melting temperatures of B and A a t o m s %=TmB/TmA;

- a solidus parameter 0=(dTJdCB) - (TmB-TmA),

where (dTs/dCB) is the slope of the solidus curve at B element content, CB, equal to

zero;

- a dimension misfit factor, 6, of atoms A and B

Three groups of substitutional elements were picked out from the position of

their predicted behaviour under irradiation

Group 1 AU<0, Z>I In these systems the solute atoms are capable to trap the

migrating vacancies forming the low-mobile complexes (as compared with

monovacancies migration) The heterogeneous point defect cluster nucleation should

lead to the growth of radiation hardening and, respectively, barrier-induced

embrittlement of similar alloys The irradiation temperature elevation should decrease

this effect The post-irradiation annealing should completely recover alloys properties

after defect annihilation In the case of the Fe-base systems the following elements

are appertained to this group: Hf, Ta, Nb, Zr, Ti, W, Mo The order in row of these

elements corresponds to parameter 0 decrease pointing to the direction of the effect

weakening

Grouo 2 AU>0, Z<I This type of binary systems is predisposed to the solid

solution separation or to precipitation of the structurally free phase The solutes in

such alloys should form the fast-mobile vacancy complexes The latter should

enhance the radiation hardening (embrittlement) due to clustering of the solute atoms

or mixed defect-solute cluster formation The irradiation temperature elevation and

annealing treatment can either weaken or enhance second component influence

depending on its content in relation to the solubility limit The following elements

belong to this group in Fe-base systems: Au, Cu, Mn, Ni (for the latter AU>0

condition is valid just in the case of BCC modification) This series of elements is

arranged for the parameter Z growth and solubility increase

Grouo 3 IUAAI>>IUBBI, Z << 1 This is a group of especially low-melting and

low surface energy elements The atoms of these elements can also form fast-mobile

complexes despite of AU sign Their segregation on internal sinks or grain boundaries

NIKOLAEV AND RYBIN ON RADIATION HARDENING 5

should cause a local decrease in cohesion and thereby will lead to the embrittlement

effect out of direct connection with the barrier-induced hardening The effects of

irradiation temperature and annealing should depend on individual element properties

and solution concentration For Fe-base alloys this group can be presented by the

following elements: P, Sb, Sn, As, Ga, Zn The arrangement in the series corresponds

to the parameter 0 diminution Phosphorus takes also especial place in this row being

only element that has a smaller atom size than iron This feature makes it capable for

fast diffusion on mechanisms of mixed dumbbell migration

Thus, the experimental observation of specifics of radiation induced changes

in mechanical properties and following behaviour of alloys during the post-irradiation

annealing enables to reveal a meaningful difference in their nature and to get the

described concept confirmation (or to refuse it)

2 Experimental Study of Iron Model Alloys

2.1 Experimental Procedure

Model alloys were melted under laboratory conditions using high purity iron

(0.003% C, 0.008% Si, 0.00t7% P, 0.005% Mn, 0.015% Cu, less than 0.002% Ni, Cr,

Mo, V) Alloying additions were made to the furnace in the form of pure elements

with increasing concentration during overflow The concentration of the second

component, CB, varied with regard to its solubility, but was no more than 3 at.% The

alloys contained nitrogen (0.01 0.03% by weight) which was present either in the

completely bound condition (in alloys with Ta, Ni, Ti) or partially in the solid

solution which was controlled by the effect of dynamic strain ageing In order to

evaluate the possible secondary influence of the dissolved nitrogen in the Fe-Cu

alloys, one of the two serieses was melted with addition of about 0.15% Ti for

bonding the nitrogen A total of about 50 alloys and l 2 binary systems were prepared

The resulting alloys in the form of blanks (bars and plates) were treated on a

solid solution with heating to 925~ (for alloys with Ta and Nb up to 1225~ with

subsequent cooling in water (for supersaturated alloys) or in air

The tensile properties were mainly defined at room temperature on 3 mm dia

specimens In order to determine T t shift the sub-size Charpy type specimens were

used (5x5x27.5 mm) The electrical resistance measurements were fulfilled also for

some alloys using flat 0.2 mm thick specimens

The specimens were irradiated by neutrons predominantly at temperature of

the coolant of reactor WWR-M (50~ or in some cases in the range of 250-300~

The fluence of fast (E>0.5 MeV) neutrons in several experiments was within the

range of 3 5x10 23 m 2

2.2 Effect of Solute Concentration on Radiation Hardening and Embrittlement

6 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

The test results were treated in the form of dependence of concentration of the

irradiation-induced increase in yield stress z~O-y and its AT t (Fig 1) We will discuss the

experimental data that characterize the behaviour of the alloys with elements

belonging to each classification group

Group I Alloys with elements o f this group have radiation hardening

dependence similar to those o f radiation embrittlement The sharpest rise in the

quantities ACyy and T t with rise in concentration of the second component is observed

in alloys Fe-Ta and Fe-Nb (Fig 1) Alloys Fe-Ti and Fe-W occupy an intermediate

position Alloys of the latter system even for the content of 3 at.% W do not reach a

hardening level essential alloys Fe 0.25 at %Ta and Fe - 0.35 at %Nb Alloys Fe-Mo

in the interval of concentrations studied show very weak dependences of radiation

hardening and radiation embrittlement on dissolved element content

As it follows from a comparison of Figs 1 a,b, the effectiveness of elements in

the I group on radiation hardening and radiation embrittlement o f alloys actually is

controlled by parameter 0 One can be qualitatively convinced o f this after comparing

Figs la, b with Fig lc which shows the solidus curves of the same binary systems

The order o f arrangement o f the curves in these pictures essentially coincides Only

curves for pairs o f elements W-Mo and Nb-Ta change places These discrepancies are

explained by the fact that the order of arrangement of curves Ts(CB) are determined

by the slope dT s / dCB, while curves Am.(Cn) are determined by parameter 0 The

.~ B A

latter differs from dTs/dC a by the quantity T m - T rn, which for W and Ta is

especially great

The type of concentration dependence ACyy(CB) and ATt(CF3 ) obtained from the

experiment agrees well with the predictions [1] With small C B the dependence o f

radiation hardening and radiation embrittlement on concentration is close to linear

The linearity interval is conditioned by the vacancy-solute atom complex binding

energy, i.e., the value 0 Therefore, in alloys of the system Fe-W an approximately

linear relationship is revealed A(yy(CB) and ATt(CB) in the range o f concentrations

studied, while for alloys Fe-Nb and Fe-Ta, only at the initial section o f curves

A~y(CB) At C a > 2xl0 -3 the corresponding relationship is described better by the

formula o f type AO'y-CB 0"4, which does not contradict to the permissible interval o f

change in the exponent, which changes from 1 to 0.33 in the case o f three-

dimensional clusters l1 ]

Group IL For two series of copper-containing alloys with dissolved nitrogen

(further called Fe-Cu-N) and with addition of 0.15% Ti the results of several

independent experiments (each point at 50~ corresponds to the main result o f an

individual experiment) shows (Fig 2) an essentially linear dependence of Ac~y and ATt

on concentration in limits up to 1.2 at.% In this case the slope o f the curves for alloys

o f the series Fe-Cu-0.15 Ti is considerably steeper

With a rise of the irradiation temperature up to 250~ the linear relationship is

preserved, moreover, the slope of the corresponding curves for alloys o f the series Fe-

NIKOLAEV AND RYBIN ON RADIATION HARDENING 7

Fig 1 Effect of the refractory element content on radiation hardening (a),

embrittlement (b) and solidus curve slope (c) of binary iron alloys

8 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

NIKOLAEV AND RYBIN ON RADIATION HARDENING 9

Cu-0.15 Ti Thus, in the nitrogen-free solid solution the influence of copper reveals

weak sensitivity to the change in irradiation temperature in the studied interval This

relationship is explicitly impacted by the presence of dissolved nitrogen, apparently

because of bonding of the vacancies

The linear relationship ACry(CB), according to the analysis [ 1 ], is possible in

the case of a mechanism similar to solid-solution hardening, or under the influence of

"vacancy pump" The last case corre~pcmds tO the critical nucleus of the cluster made

of 2 - 3 atoms of copper

The results of testing the Fe-Ni and Fe- Mn alloys are presented in Fig 3 in the

form of concentration dependence of the increment in ~y and T t for irradiation

temperature of 50~ The findings unequivocally indicate that with a rise in the

content of nickel and manganese in the studied interval of concentrations, changes in

t~y and T t rise by linear law At this temperature of irradiation the influence of these

elements is essentially equivalent since the slope of the curve is almost the same (it is

noticeable smaller than the alloys Fe-Cu)

The interrelationship between radiation hardening and radiation embrittlement

for alloys Fe-Ni and Fe-Nn at an irradiation temperature of 50~ is confirmed as for

alloys Fe-Cu by the same type of relationships ACry(CB) and ATt(CB) and

approximately the same ratio of angular coefficients of the corresponding curves

Increase in irradiation temperature to 250C means that the influence of the nickel

content is significantly weakened The influence of manganese to the contrary rises

The last effect that was not predicted beforehand but correlates with the behavioural

features of alloys detected in anealing experiments

Group III Concentration dependences for alloys Fe-P, -Sb, -Sn, -Ga and -Se are

shown in Fig 4 It is clear from these data that starting from a certain concentration

the alloys with phosphorus, antimony and tin are severely embrittled Additions of

phosphorus are especially deleterious With a content of 0.3 at.%, the magnitude of

ATt exceeds 300~ A similar effect is observed for alloys Fe-Sb and Fe-Sn, but with

concentration 0.5 and 0.6 at.% respectively For alloys Fe-Ga and Fe-Se the

dependence of values AT t on the content of the second component in the studied

concentration interval of 0 1 at.% has not been revealed

Comparison shows that in this group of alloys mutual arrangement of the

curves ATt(CB) correlates with that for the family of solidus curves (Fig 4c), i.e., the

solidus criterion in this case correctly ranks the relative effectiveness of the elements

It is indicative that the only element with small atomic diameter, phosphorus, for

which the theory predicts the possibility of segregation due to diffusion by the

mechanism "relay-race" interstitial migration is not isolated by its position among the

remaining elements characterized by the parameter AE > 0, and therefore potentially

prone to migration by the vacancy mechanism This fact indicates the high diagnostic

rank of the parameter 0

As for the influence of the III group on hardening, for alloys Fe-P one can

indicate a weak tendency for intensification of radiation hardening with concentration

10 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

Fig 3 Effect of nickel and manganese content on radiation embrittlement and

hardening o f binary iron alloys

NIKOLAEV AND RYBIN ON RADIATION HARDENING 11

Fig 4 Effect of the refractory element content on radiation hardening (a),

embrittlement (b) and solidus curve slope (c) of binary iron alloys

12 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

in the interval 0 - 0.5 at.% (Fig 4b) but this does not at all explain the sharp

concentration relationship of their embrittlement For alloys of the series Fe-Sb the

dependence o f A~yy o n concentration is altogether missing Thus, the fact of disruption

in proportionality between he quantities A~y and A T t as a classification sign of

elements of the III group is fairly clear

2.4 Post-Irradiation Annealing

The recovery of mechanical properties o f alloys has been studied during

isochronal annealing during 1 h after irradiation at the temperature o f 50~ The

results o f experiments on recovery of the yield stress and T t o f alloys o f the I group

presented in Fig 5 agree well with the theory In fact, for alloys o f the system Fe-Nb, -

Ta, -Ti for which this study was made it was found that the recovery begins at the

temperature about 170 ~ and with T a = 350 ~ (-0.35 T m of iron) the process ends

completely The residual effect of hardening or embrittlement after annealing at

temperatures above this is missing One should note a certain slowing down in the

recovery for alloy Fe - 1.1 at.% W compared to the remaining materials, which is

linked to the presence o f free nitrogen in the solid solution

The experiments on isochronal annealing o f irradiated Fe-Cu alloys revealed

complex kinetics for changes in the increment in the yield stress depending on the

annealing temperature, T a (Fig 6a) Its main feature is that the beginning of softening

is preceded by an additional increase in the yield limit, the effect o f radiation-thermal

hardening, especially noticeable in alloys Fe-Cu-N This process is observed in the

temperature region o f 175 325~ i.e., it occurs simultaneously with annealing o f the

radiation defects In order to separate these effects, for alloys o f the series Fe-Cu -

0.15 Ti differential (in relationship to the curve for iron) curves were constructed

(Fige 6b) They obviously confirm both the actual existence o f radiation-anneal

hardening in the temperature range of 175 - 325~ and its dependence on copper

concentration

Another not less important fact is that after high-temperature annealing (T a =

500~ the initial strength level o f the alloys is not reached In this case the residual

effect of hardening is essentially proportional to the copper concentration (Fig 7)

The solubility limit o f copper in iron at 450~ amount to 0.15 at.% [2], thus,

both radiation-thermal hardening and residual hardening and brittleness of alloys at

the annealing temperature o f 500~ is naturally explained by the precipitation o f

copper atoms from the supersaturated solid solution during irradiation and subsequent

annealing The hardening peak is reached at the annealing temperature of 325~

while at T a = 450~ the alloys are already in overaged condition Similar processes

occur under the initial conditions as well, but for equal concentrations, the magnitude

of hardening o f the nonirradiated alloys is significantly lower (Fig 6b) This indicates

the deeper copper separation from the solid solution in the case o f preirradiated

NIKOLAEV AND RYBIN ON RADIATION HARDENING 13

Fig 5 Isochronal annealing recovery of the yield stress (a) and the transition

temperature shift (b) of binary iron-refractory element alloys irradiated at 50~ (

0.44at.%Nb, -0.35at.%Ta, -0.45at.%Ta, -0.9at.%Ti, - 1.1 at.%W)

14 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

Fig 6 Changes in the yield stress of irradiated iron-copper alloys during isochronal

annealing (a), (b) - differential curves (A,~ fi) related to iron and hardening of non-

irradiated alloys during thermal ageing (V | )

NIKOLAEV AND RYBIN ON RADIATION HARDENING 15

16 EFFECTS OF RADIATION ON MATERIALS: t 7TH VOLUME

alloys In fact, it is apparent from a comparison of the curves in Fig 6b that even with

copper content of 0.44 at.% the irradiated and annealed alloy detects noticeably

hardening, while in the nonirradiated condition it does not manifest any signs of

hardening

For Fe-Ni alloys the isochrone A~y(Ta) exhibits a two-stage form (Fig 7) like

for the Fe-N alloys, differing from the latter by more developed first substage whose

share depends on nickel concentration Recovery of the properties ends completely at

an annealing temperature of 425~ This result can designate that radiation-induced

separation of the dissolved component in the Fe-Ni alloys, if it does occur, is

nonequilibrium and is eliminated together with the radiation defects annihilation

Data on the influence of annealing on the yield stress of Fe-Mn alloys also

indicates the two-stage nature of the isochronals (Fig 7b) But in contrast to the Fe-Ni

alloys, increase in manganese concentration results in a rise in specific weight and

temperature boundaries of the second substage In other words, manganese intensifies

the residual admixture (nitrogen) effect and improves its thermal stability, probably

because of the formation of manganese nitrides However, this does not prevent

reaching the complete recovery of the initial strength level at T, = 475~

Changes in T t of the Fe-Mn alloys during annealing in the range 225 - 325~

(Fig 8) are characterized be the effect of radiation-anneal embrittlement, which is not

accompanied by change in the mode of cleavage brittle fracture inherent to these

alloys in the irradiated condition In contrast to a similar effect in Fe-Cu alloys,

radiation-anneal embrittlement of alloy Fe-Mn occurs on the background of yield

stress reduction Special experiments to investigate the temperature dependence of

strength and ductility properties of irradiated and annealed alloy Fe - 2.6% Mn in the

interval of-196 +20~ demonstrate (Fig 9) that the reason for this is most likely

related to a decrease in cleavage fracture stress, Obf (Fig 9) This unpredicted effect,

judging from complete recovery of Y t at annealing temperatures of 450 475~ is also

reversible, and probably caused by some nonequilibrium process whose nature is still

unclear

The influence of annealing on Tt recovery of alloys of the III group was

studied on irradiated samples of alloys Fe-0.5 at.% P and Fe-0.6 at.% Sn (Fig 10)

Experiments showed that after annealing at temperature 400~ the residual T t shift

for alloys is only 20 40 ~ while at the temperature of 450 ~ (0.39 Tin) the values o f T t

are completely restored Consequently, for alloys of this group on the condition that

AU < 0 reversibility of radiation embrittlement also occurs at T~- 0.4 Tin

A rather special behaviour was detected during annealing of alloy Fe-0.5 at.%

Sb (Fig 10), for which the tendency for T t r e t u r n noted at Ta=400 450~ is replaced

by intensification of embrittlement at 500 ~ while embrittlement is only eliminated

after annealing at temperature over 600~ This result, however, does not refuse the

concept regarding intracrystalline nonequilibrium segregation of the antimony atoms,

insofar as cleavage fracture, predominantly characteristic for the brittle fracture of

irradiated alloy, after annealing at temperatures of 450 550~ is replaced by typically

NIKOLAEV AND RYBIN ON RADIATION HARDENING 17

1 8 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

Fig 10 Isochronal annealing recovery o f the transition temperature shift o f irradiated

iron alloys with phosphorus, tin and antimony

Fig 11 Effect o f neutron irradiation on electrical resistivity changes o f iron alloys

with different copper, nickel and manganese contents

NIKOLAEV AND RYBIN ON RADIATION HARDENING 19

intergranular failure The isochrone ATt(Ta) obtained for this alloy consequently

reflects superposition of the radiation embrittlement recovery and the effect of temper

embrittlement, to which this material is prone in contrast to the others

2.5 Electrical Resistance Measurements

Concentration dependence The influence of irradiation on changes in

electrical resistance (p) has been studied on alloys of the series Fe-Cu, Fe-Ni and Fe-

Mn (one composition) For alloys with copper irradiation at temperature 140~ led to

a decrease in p for all compositions, with the exception of iron and was greater the

higher the copper content (Fig 1 I) Taking into consideration that intensive decrease

in electrical resistance of the supersaturated alloys Fe-Cu is caused by precipitation of

the 5-phase during ageing in the interval of 400 600~ a similar effect during

irradiation could be unequivocally related to the solid solution separation

For electrical resistance of Fe-Ni alloys which were irradiated was conducted

at a temperature of 50~ there is a characteristic drop in the magnitude of the

radiation effect as the concentration increases (Fig 11) Increment in p equal to 9.5%

in iron monotonously diminishes in alloys with 1 and 2% Ni, being replaced as a

result by a negative quantity (- 0.25%) with 3% Ni content It is doubtless that the

radiation defects are also forming in Fe-Ni alloys The corresponding resitometric

effect should be present in alloys of any concentration in completely or partially latent

form because the opposite effect appears due to another mechanism action It is clear

that the integral changes observed for the Fe-Ni alloys indicate a perceptible

development of the process of the nickel atoms redistribution

A similar effect, but even more clearly pronounced was obtained for the Fe-

2.6% Mn alloy (Ap/p = -5.5%)

Annealing In the series of Fe-Cu alloys irradiated at a temperature of 140~

the isochronal (20 min) annealing causes a drop in electrical resistance in the interval

200 - 400~ (Fig 12) This drop is apparently governed by annealing of radiation

defects An explicit trend is observed for rise in the annealing part with higher copper

content This circumstance, if only it is not linked to deepening of the process of

copper precipitation, can be viewed as proof for the increased concentration of the

preserved defects In this case one should take into consideration the effect of a

certain mechanism not discussed above that promotes survival of the defects in the

solid solution This type of mechanism [3] could be based on the effect of the type of

"masking" of the vacancies on the composition of the complex with dissolved atom

because of smaller size of the recombination zone of the bound vacancy as comared

with the recombination zone of isolated defect

The drop in electrical resistance during annealing of the irradiated specimens

of the Fe-Ni series is also observed in all compositions, including the alloy of

maximum Ni concentration (3%) in which irradiation led to a decrease in p (Fig 13)

The simplest type of isochrone is observed for iron whose electrical resistance is

2 0 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

Fig 12 Isochronal annealing changes of the electrical resistivity of Fe-Cu alloy irradiated at 140~

NIKOLAEV AND RYBIN ON RADIATION HARDENING 21

22 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

TABLE PHYSICO-CHEMICAL PROPERTIES OF ELEMENTS IN ALLOYS BASED ON ct-Fe

Fe2Hf 0.96

Fe2Nb 1.37 Fe2Ta 1.47

Fe3Mo 2 1.38

g-Fe** 0.98 ~ -"- 0.89 e(Cu)** 0.69 e(Au)** 0.75 Fe3P

FeZn3 0.065

0.395 X Fe2As

FeSe 0.059 X Fe3Sn 0.43 Fe3Sb2 0.214 x

* For liquid phase

** solid solution

NIKOLAEV AND RYBIN ON RADIATION HARDENING 23 restored at Ta=.~50 ~ o C as a result of defects annealing The nonmonotonous nature of

the isochrones for alloys indicates parallel occurrence of two processes, one of which

is related to the rise in p and definitely governed by the presence of nickel The

amplitude of changes p(Ta) decreases in the interval of 75 350~ as the nickel

concentration rises Together with this fact the return of p at 450~ indicates that

homogeneity of the solid solution disrupted by irradiation is restored as a result of

annealing at mentioned temperature This also confirms the nonequilibrium nature of

the structural changes observed in the Fe-Ni alloys, which is natural for nonsaturated

solutions

A pattern similar in the main features was obtained during annealing of alloy

Fe-2.6% Mn (Fig 13) which makes it possible to use these consideration for it

Conclusion

The results of this experimental study agree with the predictions regarding the

diversity of factors that determine the influence of chemical composition on radiation

hardening and embrittlement of reactor pressure vessel materials

Classification of binary alloys based on the concepts regarding interaction of

point detects with dissolved atoms and analysis of the thermodynamic properties of

the corresponding systems, reflected in the structure of their patterns of state in

experimentally confirmed for model alloys of iron in all the studied aspects: in type of

concentration relationship of radiation hardening, in correlation between the

magnitudes/Xcry and ATt, for ranking of effectiveness of the influence of elements

based on the solidus criterion, in capacity of alloys for return of properties when

defects are eliminated One can see in this not only proof for the important role of

interaction between the point defects and solute atoms in the change in mechanical

properties of alloys under the influence of low-temperature irradiation, but also

confirmation of the correctness of the developed basis for the approach to influence of

solute atoms on the formation of structures of irradiated materials In this case the set

of experimental factors corresponds to the conclusion that vacancy-solute atom

reactions are very important in these processes

It should also be stressed that increase in the number of components in the

alloy significantly complicates the situation, introducing an additional factor of

chemical interaction Therefore it should be kept in mind that the influence of certain

element may not be completely the same in binary alloy and in steel

24 EFFECTS OF RADIATION ON MATERIALS: 17TH VOLUME

3 Alekseenko, N N.; Amaev, A D.; Gorynin, I V.; Nikolaev, V A Radiatsionnoye poverzhdeniye stali korpusov vodo-vodyanykh reaktorov [ Radiation Damage of Steel in Vessels of Water-Moderated Water-Cooled Reactors ], Moscow, Energoizdat,

1981