Lecture6

Qualitat i v e R adiation E ffects in S tr uctur al M a t e r i a l s

Fig u r e s t ak e n f r o m G . S . W as , “ Fu n d am e n t a ls o f R ad ia t io n M a t e r ials S c ie n c e ” u n le s s o t h e r w is e n o t e d

L ear n in g O b ject ives

• Int ui t i ve l y unde rs t a nd a fe w ra di a t i on e f fe c t s i n str u c tu r a l m a te r ia ls

• P h ase i n st ab i l i t y

• R a di a t i on i nduc e d seg r eg at i o n

• V o id s w e llin g

• D i s l oc a t i on l oops

• H a r de ni ng & e m b rittle m e n t

• U n d er s t an d m at er i al s el ect i o n ch o i ces i n n u cl ear sy ste m s w ith r a d ia tio n p r e s e n t

P h ase In st ab ilit y

• Pre c i pi t a t i on a nd di ss ol ut i on

• R e l a t e d t o poi nt de f e c t m ove m e nt t ow a r ds s i nks

M o v e m e n t o f v a c a n ci e s (V ), i n t e r s t i t i a l s (I ), a n d a t o m s A & B t o w ar d s a d e f e c t s i n k i n a b i n ar y A - B a l l o y

Dir ect io n s o f M o vem en t

A t o m ic siz e h e lp s d et e r m i n e w h et h er a n a t o m w i l l mo v e p r e f e r e n ti a l l y vi a v a c a n c i e s o r i n t e r s ti ti a l s

P r ecip it at io n

[Fig. 9.2 from Gary S. Was . Fundamentals of Radiation Materials Science .

ISBN: 9783540494713] removed due to copyright restrictions.

P r ecip it at io n

22. 14 – Nu clear M ater ials

Slid e 6

Disso lu t io n

22. 14 – Nu clear M ater ials

Slid e 7

E f f ect s o f T em p er at u r e

T (C )

Rem em b er T h is?

W h y d o y o u t h i n k C r mo v e s a w a y f r o m t h e g r ai n b o u n d ar y ?

[Fig. 6.1 from Gary S. Was . Fundamentals of Radiation Materials Science .

ISBN: 9783540494713] removed due to copyright restrictions.

Ir r ad iat io n Cr eep

D 9 st eel at 40 d p a, 520 °C HT 9

0 M P a 146 M P a

I r r ad i at ed at 45 M p a a n d n o m i n a l t em p er at u r e o f 605 °C

~ 6 % u n i f o r m st r ai n

T o p o f t u b e ~3 0 ° C h i g h e r i n t em p er at u r e

A v e r ag e d i am et r al st r ai n o f ~ 8%

M axi m u m st r ai n

~ 25%

Courtesy of Garner, F. A. et al. Used with permission.

V o id S w ellin g

M acr o scale V o id Sw ellin g

S w e l l i n g o f s p i r al w r ap p e d 3 1 6 SS f u e l c l ad d i n g f r o m t h e f as t f l u x t e s t r e ac t o r ( FFT F)

V o id S w ellin g Beh avio r

V oi d S w el l i ng vs . T e m pe r at ur e

[Fig. 8.19 from Gary S. Was . Fundamentals of Radiation Materials Science .

ISBN: 9783540494713] removed due to copyright restrictions.

V oi d S w el l i ng vs . G as P r e s sur e

This graph is in the public domain. This graph is in the public domain.

G. R . Od e tte , T . Y a m a m o to a n d P . W e l l s . M i c hi g an I on B eam W o r k s ho p ( 2014)

V oi d S w el l i ng vs . P r e c i pi t a t e s

• W hy w oul d t e m pe re d m a r te n site r e s is t v o id sw e llin g b e tte r ?

• T hi nk a bout de nsi t y of de fe c t si nks

Courtesy of Garner, F. A. et al. Used with permission.

V oy e v odi n , B r yk , B or odi n, M el n i ch en ko , K al ch en ko , G ar n er , 2012

V o id S w ellin g vs. Cr yst al S t r u ct u r e

EP - 450 at 480 o C and 300 dpa w i thout gas , show i ng s w e l l i ng i s s tr onge s t i n fe r r i te gr ai ns

S u r f ace o f U r an u s 50 d u p l ex al l o y i r r ad i at ed at 625 ° C t o 140 d p a

F er r i t e g r ai n s sw el l l ess t h an au st en i t e g r a i n s d u e t o d i f f e r e n t s w e l l i n g r a t e a n d d i f f er en t t em p er at u r e r eg i m e o f sw el l i n g

W h en Do es V o id S w ellin g Hap p en ?

• V a c a nc y c l us t e ri ng c a n e i t he r form :

• V acan cy cl u st er s ( m i n i - voi ds )

• D i s l oc at i on l oops

E n er g y Balan ce Det er m in es

W h ich O n e Is St ab le?

W h a t c an s t ab i l i z e v o i d s f o r s m a l l s i z e (m )?

• Ga s pr essur e

• Hi g h s t a ck i n g f a u l t e n e r g y ( h ar d e r t o f o r m l o o p )

W h at Ar e T h ese L o o p s?

V . G a v in i , K . B h a t t a c h a ry a , M . O rt i z . P hy s . R e v . B , 76, 180101( R )

V isu aliz in g In t er st it ial L o o p s

d oi : 10. 1038/ s r e p 00190

Reprinted by permission from Macmillan Publishers Ltd: Scientific Reports. Source: Yang, Z. et al, " Dislocation Loop Formation and Growth under In Situ Laser and / or Electron Irradiation ." Scientific Reports 1, Article number: 190 (2011). © 2011.

Har d en in g , E m b r it t lem en t

Rad iat io n Em b r it t lem en t

1. D ef ect s ar e p r o d u ced

2. D e fe c t s c l ust e r , form i ng di sl oc a t i on l oops , pre c i pi t a t e s , a m orphous re gi ons…

3. D islo c a tio n s c a n ’ t m o v e a s e a s ily

4. Bal an ce b et w een s l i p & f r act u r e i s s h i f t ed

E m b r it t lem en t : Discu ss

• Fue l unl oa di ng

• Pre s suri z e d t he rm a l shoc k (PT S)

• F or e i gn M ate r i al E xc l us i on (F M E )

• C u rr en t l y t h e l a rg est so u r ce o f L W R sh u t d o w n s

AP - 1000 M at er ial S elect io n

W h y a r e t he r e o nl y A l l o y 7 1 8 g r i d s o n t h e t o p & bo t t o m o f t h e c o r e ?

This table is in the public domain.

Revisit M at er ial S elect io n

M at er ial S elect io n : Co r e

MIT OpenCourseWare http://ocw.mit.edu

2 2.14 Materials in Nuclear Engineering

Spring 20 1 5

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