ML20043G671

Review of Upper Shelf Charpy Energy Behavior of Matls in San Onofre Unit 1 Reactor Vessel

ML20043G671
Person / Time
Site:	San Onofre
Issue date:	04/30/1990
From:	Bamford W, Chicots J, Terek E WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML13316A548	List: ML20043G671
References
WCAP-12566, NUDOCS 9006200554
Download: ML20043G671 (57)

Text

--

WESTINGHOUSE CLASS 3 WCAP-12566 i

A REVIEW OF THE UPPER SHELF CHARPY ENERGY BEHAVIOR OF THE MATERIALS IN THE SAN ONOFRE UNIT 1 REACTOR VESSEL April 1990 W. H. Bamford J. Chicots Reviewed by:

E. Terek O

<l

/

lue Approved by:/5. 5. Palusamy,d4& nager Structural Materials Engineering l h. % }L T. A. Meyer, M& nager Structural Materials and Reactor Technology Work Performed Under Shop Order SPSP106 WESTINGHOUSE ELECTRIC CORPORATION Nuclear and Advanced Technology Division P.O. Box 2728 Pittsburgh, Pennsylvania 15230-2728 e 1990 Westinghouse Electric Corp.

Sr06200D34 90061e PdR ADOCK 05000206 PDC

.264s/041290 10

1 e

TABLE ~OF-CONTENTS-l Section Title Page

1.0 INTRODUCTION

1-1 l',1 Current Regulatory Requirements 1-1 1.2 Scope of This Work 1-3 j

2.0 REVIEW 0F SAN ON0FRE UNIT 1 SURVEILLANCE: PROGRAM 2-1 3.0

SUMMARY

OF AVAILABLE DATA ON. IRRADIATION DAMAGE 3-1 3.1 ' Transition Temperature Response 3-1 3.2 Charpy Upper Shelf Energy 3-2 3.3 Orientation Effects 3-5 i

l

-4.0 PRESENT STATUS OF SAN ONOFRE UNIT 1 4-1 4.1 Available Results 4-1 4.2 Trends in Upper Shelf Energy 4-1

'5.0~

SUMMARY

AND CONCLUSIONS

,5-1

6.0 REFERENCES

6-1 f

' APPENDIX A:'

SUMMARY

OF AVAILABLE MATERIAL:: CORE REGION A-1 MATERIALS FOR SAN ONOFRE UNIT'1 42Ms/041100:10 j

I e,y gc l'*

LIST OF TABLES M

-Table' Title Page-

_2-1 Chemistry of Surveillance Materials 2-4 yw

\\

i ' *? ?

. 2 Specimen Identification and' Location in San 2-5 j

Onofre Reactor Irradiation Test Capsules Type I W+ -._

+

2-3' Specimen Ident'fication and Location Reactor 2-6 w O Irradiation Teit Capsules Type II

?3-1 Chemistry of Available Materials 3-6 3-2 Summary of' San Onofre Reactor Vessel Surveillance 3-7 Capsule Charpy Impact Test Results:

Transition' Temperature Increase (8) a,-

q 3-3 Summary of Available Results:

ASTM A302B-3 l Correlation ~ Monitor Material n '.

l 3-4 Summary of Available Results 3-9 c4-1 Summary of Available Upper Shelf Charpy Energy 4 W Results for San Onofre Unit 1 n,

e 1

l i,

1 I3 n'

4240s/041190.10 jj y j;ff

i a

LIST $OFFIGURES Figures-Title Page

' 1-1 Identification and-Location of Beltline Region 1-5 Material for San Onofre Unit 1 s

2. Fast Neutron Fluence (E > 1.0 MeV) as a Function 2-7 of Azimuthal Angle at the Inner Radius of the i

San Onofre Unit 1 Reactor Vessel i

'2-2 Relative Axial Distribution of Fast Neutron 2-8 Fluence (E >'1.0 MeV) at the Inner Radius of the San Onofre Unit-1 Reactor Vessel 3-1 Summary of Saturation in Transition Temperature 3-11 Shift for A3028 Correlation Monitor Material l

a 3-2 ~

Summary of Upper Shelf Charpy Results for A302B 3-12 Correlation Monitor Material'[2]. -3olid Points

. 3 are from San Onofre Unit 1.

]

'3-3 Charpy Upper Shelf Behavior of Heat 19281-2.

3-13 (Solid Point On Vertical Axis is Unirradiated Material) 3.

Charpy Upper Shelf Energy Behavior of Heat BRP, 3-14

-i Showing Evidence of Saturation (Solid Point On Vertical' Axis is Unirradiated Material) 1; i

13.5 Charpy Upper Shelf Energy Behavior of Heat 001 3-15 (Solid Point On Vertical Axis is Unirradiated Material)

.uu,wii o:io w.

hk LIST OF FIGURES-(cont.)

Figures:

Title Page 3-6 Upper Shelf Energy Behavior of Heats A9811 and 3-16 W10201-5, Showing Saturation in Irradiation Damage. Solid Symbols are W10201-5.

and Upper Shelf Charpy Energy Behavior for Heat W10201-6, Showing Saturation.

3-7 Upper Shelf Energy Behavior of Heats W9807-4 and 3-17 W9807-7, Showing Saturation Behavior 3-8 Upper Shelf Charpy Energy Behavior of A302B Steels:

3-18 Heat C1423 (upper figure) and Heat W9807-2 (lower figure). -(Solid Point On Vertical Axis is Unirradiated Material) 3 Upper Shelf-'Charpy Energy Behavior of A302B Modified 3-19

-Materials: Heat DRS3 (upper figure) and Heat QC2 (lowerfigure) 3-10 The Effects of Orientation on the Upper Shelf 3-20

-Charpy Energy of Heat B2803-3 4-1 Charpy Energy Results for Heats W7601-9 and 4-5 W7601-1 [9]

4-2 Charpy Energy Results.for Heat W7601-8 [8]

4 4-3 Charpy Energy Results for A302B ASTM Correlation 4-7 Monitor Material, From San Onofre Unit 1 Surveillance Capsules

• 2"ad """'

iv

~

l u

LIST OF FIGURES (cont.)-

Figures Title Page 4-4 Charpy Upper Shelf Energy Results for San Onofre 4-8 Unit 1 Heat W7601-9 (top) and Heat W7601-8 (bottom)

(Solid Points Plotted on the Vertical Axis are for Unirradiated Material) 4-5 Charpy Upper Shelf Energy Results' for_ San Onofre 4-9 Unit 1 Heat W7601-9-(top) and Heat W7601-1 (bottom, j

(Sclid Points Plotted on the Vertical Axis are l

for Unirradiated Material) i A-1 Archive Lower Shell Plate Material A-2 A-2 Archive Intermediate Shell Plate Material A-3

.- j l

i-l 4260s/041190:10 y

L SECTION

1.0 INTRODUCTION

The San Onofre Unit I reactor vessel.was manufactured by Combustion Engineering, and began service in 1968.

The vessel is composed of a nunber of plates of A302 Grade B steel, welded together.

The overall configuration of

-the vessel, with the identification of all the plates, is shown in figure 1-1.

As may be seen from figure 1-1, the material immediately adjacent to the core is contained-in the intermediate shell, and all three heats of this shell are contained in the surveillance capsule program (1). The material in the nozzle shell and the lower shell are not exposed to the center-most portion of the core region, but are still irradiated, and therefore are of interest.

The purpose of'this report is to provide a review of the status of the core region materials for San Onofre Unit I relative to the upper shelf fracture toughness issue.

This issue resulted from the requirements of 10 CFR 50 Appendix G, as described below.

1.1. Current Regulatory Requirements Federal' regulations require the owners of light-water cooled nuclear power plants to monitor the neutron radiation induced changes in impact toughness

-and mechanical properties of materials comprising the reactor' vessel. The reactor' vessel surveillance programs employed by Southern California Edison meetsLthis requirement.

Test data obtained from the program allow determination of the conditions under which the reactor vessel may be operated to avoid nonductile failure within a prescribed margin of safety.

Fracture mechanics techniques are.used to quantitatively define plant operating conditions in terms of pressure-temperature limits.

The fracture mechanics

' analysis are performed in accordance with 10CFR50*, Appendix G.

The input information for these analyses included material properties, applied stresses, neutron-fluence, a reference flaw size, and system operatirg considerations.

Title 10, Code of Federal Regulations, Part 50.

- um.munao 1-1

A revision to 10CFR50, Appendices G and H, has been completed by the NRC and became effective on July 26, 1983.

The most significant revisions are to (1)' extend the coverage of Appendix G to include steels with specified minimum yield strengths from 50,000 to 90,000 psi, (2) determine the temperature shift at the 30 f t-lb level (this does not change the 50 f t-lb minimum upper shelf.

energy criterion), (3) satisfy predicted end-of-life fracture toughness requirements using radiation conditions at the " critical location on the crack front of the assumed flaw" and (4) extend Appendix H rules to define the basic requirements of an integrated surveillance p m aram.

At the time the early reactor vessels were fabricated, applicable codes and regulations did not specify minimum C VSE levels.

Even though these y

conditions existed before the current requirements for reactor vessel fracture toughness were established,' it is now required that all reactor vessel materials, regardless of the date of manufacture, must exhibit adequate toughness to prevent nonductile failure. 10CFR50, Appendix G, requires that when significant radiatien induced degradation of material fracture toughness properties occurs, certain corrective actions must be defined three years before-the degradation is predicted to occur (when the C USE drops below the y

50 ft-lb level).

If corrective actions are not addressed in.a timely manner, plant' availability may be severely limited.

Imposition of these restrictions is described in 10CFR50, Appendix G, and the ASME Boiler and Pressure Vessel Code,Section III. Paragraph V.B. of 10CFR50, Appendix G, in part states the following requirements:

Reactor vessels may continue to be operated only for that service period within which the requirements of Section IV of this Appendix aro satisfied using the. predicted value of the adjusted reference temperature and the predicted value of the upper-shelf energy at the end of the service period to account for the effects of radiation on the fracture toughness of the beltline materials.

In the event that these requirements cannot be satisfied as stated in 10CFR50, Appendix G, or by alternative procedures acceptable to the NRC, reactors may continue to be operated provided all the following requirements of 10CFR50, Appendix G, paragraph V.C are satisfied:

um.ma io 1-2

N.

V W

"1.

A volumetric examination of-100 percent of the beltline materials that do not satisfy the requirements of Section V.B of this appendix j

w (Appendix G) is made and any flaws characterized according to j

Section XI of the ASME Code'and as'otherwise specified by the j

Director, Office of Nuclear Reactor Regulation, i

o 2.

Additional evidence of the fracture toughness of the beltline

)

materials after exposure to neutron irradiation is to be obtained from results of supplemental fracture toughness-tests.

3.

A fracture analysis shall be performed that conservatively demonstrates, making appropriate allowances for all uncertainties, j

the existence of equivalent margins of safety for continued operations.

l 1

Paragraph V.D further. states, "If the procedures of Section V.C of this d

4

- appendix do-not indicate the existence of an equivalent safety margin, the Jreactor vessel beltline region may, subject to the approval of the Director,

' Office of Nuclear Reactor Regulation, be given a thermal annealing treatment-

-to recover the fracture toughness of the material." All nuclear plants, l

regardless of the fabrication date, must meet the requirements stated above.

l 1.2. Scope Of This Work

'The key goal of this work is to determine the status of each of the core p

cregion materials relative to the 10CFR50 requirements that the upper shelf

'Charpy energy remain above 50 ft-lb.

g To; accomplish this, a summary of all the available data for the San Onofre l

[K materials has been provided, taken from the surveillance capsule program

-}

results.. To provide further information on the behavior of this class of p

material, all the available data from commercial reactor surveillance programs

=have been collected, and are discussed in Section 3.

Only data which are

{

judged to be equivalent-to the materials of the San Onofre vessel have been considered, for example, there are a few laboratory heats of A302B material whose behavior is much different, and these have not been included.

12 "" " * '

1-3 a

+

This assessment-of the data leads to a series of conclusions relative to the San Onofre vessel, as discussed in Section 5.

Also included is a-recommendation for which surveillance capsule would be most advantageousLto remove at the:next outage.

In addition, should further material' characterizationibe necessary, a summary of the available archive material is included in'an Append'ix.

t t

t

/'I

- um. neo.io 14

ii b

M v76ol-6 6-s60s ke60A 0

0 i

-0

~

180 s'

e 9

g v7601-7 Of sanc] 90 v760s-3' 0

g m 2-s60 v7601-8 v7,o3,9 i

A.

g

=

.+

=

I 0l 00 geo E

4

,,<+

3.875" g 4 1 s60 74,9, 1_

7-860c s

v7601-1 a

h g

v7601-4 I

s-s60A I-s-s60s 0

180 O

\\ ' )** k i v76ol-2 v7601-5 6-860c 0

90 F_igure 1-1, Identification and Location of Beltline Region Material for San Onofre Unit 1 v u. con oo-15

SECTION 2 REVIEW OF SAN ONOFRE UNIT 1 SURVEILLANCE PROGdAM Sections from'the three intermediate shell pictes were provided by Combustion Engineering and used for Charpy, tensile and WOL-type fracture toughness j

specimens in the surveillance test program.

In addition, a weld was provided i

typical of the welds in the vessel, and ASTM correlation monitor A302B matsrial was also inserted. The chemistry of all of these materials is summarized in table 2-1, as obtained from the Lukens Steel material test certificates.

The original surveillance program contained 8 capsules, of two different j

types.. Three of these capsules have been removed and tested, and the results

[

are= discussed herein.

There are five remaining capsules, and the distribution of specimens in each capsule is provided in tables 2-2 and 2-3.

j As may be-seen, the Type I capsules contain fewer tensile specimens and more WOL specimens than the Type 11 capsules, but each capsule t"ce contains the same number of Charpy specimens.

Dosimeters of Al-Co ar'

=nielded Al-Co

.s are secured in holes drilled in spacers at the top, middle and bottom of each o

type of capsule. ' Additional dosimetry is contained in the Type 11 capsules.

4!

-All specimens in the surveillance program, incluuing Charpy, tensile and Wedge T

Opening' Loading fracture specimens, were machined in the longitudinal or strong direction. The only transverse specimens tested for these heats have

[

been in the unirradiated condition, y

q The surveillance program as originally constructed consists of capsules A, B,

-C,-and D, with capsules E, F, G and H held as extra capsules for complementary testing. :This program was subsequently revised:

capsules A, D and F have

-been removedcand tested, and capsule C is scheduled for remosal at 14 effective full power years (EFPY).

Capsule E is scheduled for removal at 23.EFPY, and capsules B, G, and.H remain as spares. Considering the content of the capsules, it is clear that those of type I contain a better mix of the three heats of base metal than the type 11 capsules. Choosing a capsule of type I will yield 8 Charpy specimens from each of the three heats of plate um,an. "

2-1 1

material, and of the correlvtion monitor A302B.

In contrast, the C capsule contains only heat W76014 of the base plate.

Therefore, it is recommended that capsule B, E, G or H be removed at the next outage, to provide the maximum amount of information possible.

Since capsules G and H may be removed without a change in the plant technical specifications, these are the preferred capsules for removal.

The choice then can be made on the basis of irradiation level, and a fluence level greater 19 2

than 2.4 x 10 n/cm and less than or equal to the end of operating life is recommended.

The current fluence values represent best estimate calculatior.s scaled to available measurements and will be applicable to the June 1990 shutdown (approximately12EFPY). The and of life values were projected based on a continuation of the low leakage fuel management strategy implemented during cycle 9 and on continued operation with a reactor inlet temperature of 528'F.

Based on conversations with SCE personnel this mode of operation is the

?a wred approach. All values also assume that the thermal shield is repaired and remains in place throughout the irradiation period.

glMUMVESSELEXPOSURE (fluence (E > 1.0 MeV) (n/cm2))

12 E!7Y 3.68E19 27 EFP) 7.63E19 These peak exposure values occur at an azimuthal location of O' and an axial elevation corresponding to the midplane of the active core.

See figure 1-1 for the location of the core and heats of material at various locations.

2 SURVEILLANCE CAPSULE EXPOSURE (Fluence [E > 1.0 MeV) (n/cm ))

CAPSULE 12 EFPY 27 EFPY A

WITHDRAWN D

WITHDRAWN E

1.03E20 2.14E20

,ow.aneo io 2-2

CAPSULE 12 EFPY 27 EFPY C

7.44E19 1.54E20 F

WITHDRAWN H

6.42E19 1.33E20 B

4.71E19 9.77E19 G

4.71E19 9.77E19

/

The current (12 EFPY) and projected fluence values are depicted as a function of azimuthal angle in figure 2-1.

The data shown on figure 1 represent core midplane values.

The relative axial distribution over the beltline region is shown in figure 2-2.

The data in figure 2-2 have been normalized to a value of 1.0 at the core midplane. Therefore, abso'eute distributions of fast neutron fluence may be obtained by multiplying the data in figure 2-1 by the appropriate data from figure 2-2.

Based on the figures above for the expected fluence at various capsule 4

locations, it appears preferable to remove capsule H at the next outage, since the fluence at either one would be higher than that presently characterized.

I on.wiia io 2-3

TABLE 2-1 CHEMISTRY OF SURVEILLANCE MATERIALS Heat Cu S

C Mn P

Mo Si W7601-9

.18

.0?6

.19 1.36

.014

.47

.23 W7601-1

.17

.025

.22 1.36

.013

.46

.24 W7601-8

.18

.020

.20 1.34

.012

.47

.20 Correlation Monitor

.20

.023

.24 1.34

.011

.51

.23 Wald

.19

.013

.11 1.50

.017

.47

.35 4

42Ms/04116010 2-4

l TABLE 2-2 SPECIMEN IDENYiT! CATION AND LOCATION IN SAN ONOTRE REACTOR 1RRADIAT10N TEST CAPSULES TYPE I Specien Cepsule Capsule Capsule Capsule Location Type B

E G

H 40, 41 Charpy WD-8, YB-B WB-24, YB-24 WB-32, YB-32 WB+40, YB-40 38, 39 2A-8, R-8 2A-24 R-24 ZA-32, R-32 ZA-40, R-40 37 Tensile WB-1 WB-3 WB-4 WB-5 35, 36 Charpy WB-7, YB-7 WB-23, YB-23 WB-31, YB-31 WB-39, YB-39 33, 34 2A-7, R-7 ZA-23, R-23 2A-31, R-31 ZA-39, R-39 32 WOL WB-9 WB-13 WB-15 WB-17 31 WOL WB-8 WB-12 WB-14 WB 16 29, 30 Charpy WB-6, YB 6 WB-22, YB-22 WB-30, YB-30 KB-3B, YB-3B 27, 28 2A-6, R-6 ZA-22, R-22 ZA-30 R-30 ZA-38, R-38 26 WOL YB-9 YB-13 YB-15 YB-17 25 WOL YB-8 YB-12 YB-14 YB-16 23, 24 Charpy WB-5, YB-5 WB-21, YB-21 WB-29, YB-29 WB-37, YB-37 21, 22 ZA-5, R-5 2A-21, R-21 ZA-29, R-29 2A-37, R-37 19, 20 Charpy WB-4, YB-4 WB-20 YB 20 WB-28, YB-28 WB-36, YB-36 17, 18 ZA-4, R-4 2A-20, R-20 ZA-28, R-28 2A-36, R-36 16 WOL 2B-9 2B-13 2B-15 2B-17 1

15 WOL 2B-8 2B-12 2B 2B-16 l

13, 14 Charpy WB-3, YB 3 WB-19, YB-19 WB-27, YB-27 WB-35, YB-35 11, 12 ZA-3, R-3 ZA-19, R-19 2A-27, R-27 2A-35, R-35 9, 10 Tensile YB-1, 28-1 YB-3, 2B-3 YB-4, IB-4 YB-5, ZB-5 7, B Charpy WB-2, YB-2 WB-18, YB-18 WB-26, YB s WB-34, YB-34 5, 6 2A-2, R2 2A-18, R-18 ZA-26, R-26 2A-34, R-34 3, 4 Charpy WB-1, YB-1 WB-17, YB-17 WB-25, Y-25 WB-33, YB-33 1, 2 ZA-1, R-1 2A-17, R-17 2A-25, R-25 2A-33, R-33

• Specieen Locations (Note Sketch) h Soecimen Number Code

[

W (*) Plate (W7601-1)

/

i'j Y (*) Plate (W7601-8) i ;,

2 (*)' Plate (W7601-9)

[

Av 1~B R

Plate (ASTM Correlation Monitor)

L u n.."

2-5

-- 1h"

~

s s

f.

TABLE 2-3 SPECIMEN IDENilFICATION AND LOCATION REACTOR IRRADIATION TEST CAPSULES TYPE 11 Specimen Capsule Location Type C

l 40, 41 Charpy WB-48 R-56 38, 39 D-16, H-16 36, 37 Charpy WB-47, R-55 34, 35 D-15 H-15 32, 33 Tensile WB-6, WB-7 31 WOL WB-21 29, 30 Charpy WB-46, R-54 27, 28 D-14, H-14 I

26 WOL WB-18 24, 25 Charpy WB-45, R-53 22, 23 D-13, H-13 21 Dosimeter 19, 20 Charpy WB-44, R-52 17, 18 D-12, H-12 16 WOL D-4 14, 15 Charpy WB-43, R-51 12, 13 D-11, H-11 11 WOL D-3 1

9, 10 Tensile D-3, D-4 7, 8 Charpy WB-42, Rw0 5, 6 D-10, H-10 3, 4 Charpy WB-41, R-49 1, 2 D-9, H-9 5pecimen Number Code

• Specimen Locations (Note Sketch)

W

• Plate (W7601-1 Plate (W7601-8

[r Y

• Z Plate (W7601-9) i R

Plate (ASTM Correlation Monitor) 3,j D

Weld Metal 6

-3 H

Heat Affected Zone Metal p

n n,mano io 2-6

c

'it

• ? u.

8

..ti,-

f.,

j

[

, !ii9o t jt ;,

,Ig

• tt(,

i

.; g t. g i.

• . *ols 1,

9 l

g

-l

- ii

..,.)s1l*'

.9jtjt i

~

f i

"1 s i.lit4:;

t j

1 yl tt{tr!

+

..t.

• l{T u

r i,

r d

b

-.-.- i e

mq.

-, F,

8i.

+y w.W, ie a N,,I.!!

n 4}

t 1

• 1,

, m J

" ' * - e c

d 9 n.,.

,. a i, ri TTp

.T.'

s : 7:te,,

1p

'; d.

ny 6

,.7 P

I.

i+Fm

-i.

e

. mn

+; c,,

n l.T#h

.g

+'gi.1 h.

l q

f' pa W.@

f#;.

'i

!lmma[%#nh hm. p'}*:

- i o

.l I

t t

"04 ' f -

S,p p.

-?' q

.e Pj

.9.p i.

4,,3, q

, p ] l.i n :1y d

,l

,!l;..

b,. yl!Jr49!l.

' n1q t!6etI I

t:

l*

e t'0 4 /._

y J,i mp.

+

y i o, im,:

ee,

.r t,.

p ;{r t,li t!*.l

-l f-

.it il3I hi!

8t,.

-ti t

.r a

j e '

r!

r Nr, E T.. i '

Lr g '

- ~

t k,, {ff f' !.

,.!3.

1x.

~

1

!i 9

4,

+.

/;

" m:

m!!

m HT 4J i i.,. d t'p :to mPmh Oih, "

p T O'(

d' mf:y

'l i

+t" r

i,

. t f'

.e

,+r.

+

-q;,

g ; ;

,e

l:

lMP1*y i. 1i4 ty,li',,l :(:ng,.U t;

rha:i i "

4q 4 l'

,t

., - !l45' it, i

s 1l'.

I'glp3 A

e. r,.

i. i.

8

[

t t

o ;t, 4'.i,;,

+bqi4:: q;Ld[

pp.i,

!I

' !ntjt.

l.l.fh I.;lJ'y li

.s F

3 p

• .c!

.1

!,i t dl-d ii!';

it!f.

i t

i i

tl}f

+

0b'U h@!ej, ti;1 ttu t'

r 'p.

.p l1i r

t b

i f.

i:1!r.

i

!.;"., Ti.g..;l *

{-

i li1.s t

p f *tD 1't, p.

e t

f li:;f a

t I

!l

!itl

!i

{

i!

d m?'tlt M t{i;ls J t.l,

.(I-f

}

Il i !I t

I a)i!i+t?, ;T T

lf 7

T, 4hyU 3p. I j hn _. +. 7 e, t'M;,i,. r lNeI

• ti.
• fi 1l.

s3 ~ flY fl 5 i L n. l - mf- ~ ' ~ ~ : i. .3!q ~ t;.4 f,;.. 4 t 4. t'i I7.. A", ~I"7'1;11 4 1q ' oi7 8

n~.

.ih p p',,h, 11 "q ,; yM o[ I o 8 N' b7 re 1 r,.

iIi.L,31fo g!

i

• t n. j * ~ 3 n i. e, p:

m.1'M -7p" i: -:,9 m!:,. ? dq=m4 !t,th13i "!nh hi! '.:am00 I i M :. '1P M pO1, f: t f IIpH ;t !'r

• T.

l:. .iN ! i - i H- ::'l hj $ , ; y P ii 4t' T...

l l,

j e; t.; I ia,l I -l l tl ilIt>;tm'D r t'

iq.).

jgl.. tyq I? ' i, t fy l',l 8 ~ ' a m. I i e ,p'

o

-t3m' ', it'=- uL f F nm.,U ,H+i '.!' '+t1' f'. mt' h.t 7.m T i ~ .Lc

• 5

+p, .p; t

e.

i:i. ri

• Po

- - i m

a

-c aO t H;: q yaO fii I'+1 m1pl "17 +. ;T {+7}3.;.i, tpTfo ty. 5, T;' t d-pl( ' E f': mP' m fI i pyi. i; e '1 ' nq,!m ;t.z 0 dP., :s h e ..+ i

1

, j lq: o,y i t{! l', tt t1,i 1 I, 44ll p !Y{'- f t i.

3X lQ 1 t

pt-y l; 4 th 1r ot 7pt4'9S!y@a 1 + .jn.: qy$ h:;,,1(fl, ltii 1! 4 iT ; t . p,.,.1h i I 4 's tli;j e i !l! ii. i f!.. l 8!!. t; t pn tt

, '; ; i lt;16 t

1t'l. 'l, li

• j TI1! t f

ljlggtI' i i q + 7 'I 3i 'j,{* }tI4,}# ~ L {i g. e ~ o S 4A DO g g C>2O ),,, g2@J vgdd [ b .3 * ~ ;*' - ue**#ze_3gL0cgy.cogv"A - O Z >^ =e.e w3cupeoC Op 4 4*63wce 4cayg.* g_* mCC L Meu $ o. #c.* )ec OcOpm, 4 u e c 3c*+* ge*u+eog .*.e- ,O*e%:L. N*n

M I'8 >r X i x I I /- \\ o.9 - 7 x 1 1 j f. n 8.6 \\, l I \\ = 0.1 l I 3 I.. -i- -- i A i -/- 1- - - 0.G _j 3 1 y i \\; ~ I

e.s 1

i g $ 0.4 i i I i d I a3 i-I. t -\\ 0.2 1 l t-0.) t .y .g 9 5 3, .) 6 ) 5. O N E b Dt1YAWE P90M C0AI H2* LAME III\\ 9 Figure 2-2. Relative Axial Distribution of fast Neutron Fluence (E > 1.0 MeV) at the inner Radius of the San Onofre Unit 1 Reactor Vessel cu.<meno 2-8

\\ SECTION 3

SUMMARY

OF AVAILABLE DATA ON 1RRADIAT10N DAMAGE The A302B plate steels used in the San Onofre Unit I reactor vessel were also used in at least six other commercial reactor vessels, in the original specified condition. In later years, nickel was purposely added to enhance ductility, and this material was referred to as A302B modified steel. This type of steel was later redesignated A533B, and remains the steel of choice for reactor vessels today. Studies have shown that nickel has an important detrimental impact on the transition temperature shift, but it probably has little or no effect on upper shelf behavior, as will be seen later. Data have been collected on ten heats of 302B material which are contained in on going surveillance programs, as well as the ASTM correlation monitor reference material which was inserted in nearly all the early surveillance l programs. Three additional heats of A302B modified steel were also included for comparison, All neutron fluence values were measured in neutrons per square centimeter for energies greater than 1 MeV. All the irradiations were in commercial reactors, with the exception of some of the specimens of A302B reference material. A compilation of the chemistry of the materials contained in.this study is provided in table 3-1. 4 There have been many studies of the effects of irradiation on A302B and A533B materials, and additional work continues in this subject. In this space an attempt will be made to briefly summarize the observations which have been made on the upper shelf Charpy behavior of these materials, with emphasis on

A302B, 3.1 Transition Temperature Response It has long been known that irradiation elevates the transition temperature of both ASTM A302B and A533B class 1 materials.

After a relatively rapid elevation in the first few increments of exposure, the rate of damage accumulation tends to decrease, and a general tendency of the material to saturate is seen. The fluence at which saturation is observed is about 19 2 l'x 10 n/cm for A3028 steel, based on studies by Hawthorne (2) and nu,+nn a 33

Yanichko and Chirigos (3). Further discussion of saturation effects in these steels is found in references 4 and 5. Such behavior is not observed in A533B class 1 steels, primarily because the higher nickel level contributes to additi'nal damage mechanisms. An example of this saturation in transition o temperature shift for A302B is found in a compilation by Yanichko, which appears in figure 3-1. This figure is a compilation of transition temperature shift results for the ASTM A302B correlation monitor material. In this figure the three heats of A3028 plate contained in the San Onofre surveillance program have also been plotted, showing that these materials also display a saturation in transition temperature shift. The data from the San Onofre capsules are summarized in table 3-2. 3.2 Charpy Upper Shelf Energy A summary of the available irradiation results on upper shelf Charpy energy of A3023 materials appears in table 3-3. These results were taken from surveillance capsules in a large number of commercial operating reactors. The upper shelf energy was in all cases taken as the average of the results at l which 100 percent shear was recorded. A summary of the upper shelf data available for the A302B correlation monitor + naterial is presented in 'igure 3-2. The results shown are all for specimens taken in the longitudinal or strong direction. The data are from a compilation by Hawthorne (2), but the correlation monitor results from the San Onofre Unit I capsules have been included. The unirradiated upper shelf energy for the correlation monitor material ranged from 67 to 86 ft-lb, for the longitudinal, or strong direction. There is a dearth of transverse or weak direction data, but available results range from 45-46 ft-lb for the unirradiated condition [2]. Figure 3-2 demonstrates 19 2 that after irradiation to fluences as high as 5.1 x 10 n/cm, the upper shelf energy for the longitudinal direction ranges from 53 to 69 ft-lb, about the same range (16 ft-lb) as for the unirradiated material. The data show 19 2 that the irradiation damage saturates at about 1 x 10 n/cm, about the same levei at which the transition temperature shift saturates. Hawthorne (2) L .m.* nem 3 l l

L l further states that his analysis of the limited available data for the weak (transverse) plate orientation suggests a similar trend toward saturation, but at a lower Charpy level. The Charpy shelf is strongly dependent on the yield strength of the material, and this property also shows a saturation at a fluence of 1 x 10 n/cm2 (2), providing further support for this fluence 19 as a key value. Review of the other heats of A302B revealed a range of initial upper shelf energies, primarily dependent on the bulk sulfur content of the material. The initial upper shelf of these materials also tends to correlate with the year of manufacture of the steel, and tends to increase for heats with a later manufacturing date. This is because the steel making practice was improved aith time, resulting in cleaner heats and generally lower sulfur and phosphorous contents. Thus, the A302B reference heat has some of the lowest properties, because it was produced before any of the other materials considered here, in 1959. In the discussion to follow, the materials will be discussed in accordance with their Charpy upper shelf behavior. Except as noted, all the data are for longitudinal or strong direction properties. The first heat to be discussed is number 19281-2, which began with an upper 19 shelf average value of 76.9 ft-lb. Irradiation levels exceeding 5 x 10 2 n/cm have been characterized, and the upper shelf Charpy energy appears to have stabilized in the range of 46-62 ft-lb. This result is shown in l figure 3-3. Note that the untrradiated Charpy upper shelf energy is shown as a point on the Y-axis. A great deal of data are available for heat BRP, shown in figure 3-4. Here we see that the upper shelf energy has clearly saturated in the range of 61 to 20 nje,2 The material had an 72 ft-lb, even at a fluence exceeding 10 upper shelf Charpy energy of 81 ft-lb in the unirradiated condition, as shown by the plotted point on the vertical axis. A heat which shows similar behavior to that of BRP is heat QC1, shown in figure'3-5. This heat has an average unirradiated upper shelf energy of 106'ft-lb, and the irradiated upper shelf energy ranges from 73 to 85 ft-lb. l j ou,$ n.o io 33

Note that this heat was made from A302B modified steel, and therefore has a higher nickel content than those discussed above. This does not appear to have any bearing on the irradiation behavior, however, as may be seen from the figure. The lowest value obtained for this heat is 69 percent of the unirradiated value, while the corresponding value for heat BRP is 75 percent. It may be premature to conclude that saturation has occurred for heat 001, based on the sparse data. Heats A9811 and W10201-5 have very similar behavior, even though the two heats began with slightly different upper shelf energies (107.5 vs. 97.1 ft-lb). The two data sets are combined in figure 3-6, and reveal that saturation in damage appears to occur in both materials. The range of irradiation shelf values for the two heats is nearly the same as the range of unirradiated shelf values. Heat W10201-6 has a similar initial upper shelf to that of A9811 and W10201-5, so it is portrayed at the bottom of the same figure, 3-6, Unlike the othar j heats, however, W10201-6 shows very little drop in the upper shelf ene,rgy, 19 2 even at fluences near 5 x 10 /cm, Figure 3-7 provides a summary of the upper shelf behavior of two similar heats of A3028, heats W9807-4 and W9807-7. The unirradiated Charpy upper shelf energy ranged from 121 to 126 ft-lb, while the irradiated behavior showed saturation in damage with shelf values ranging from 109 to 124 ft-lb. Since i 19 the fluence reached as high as 2.2 x 10, no further degradation is expected. Further examples of the behavior of heats with higher initial toughness are provided in figures 3-8 and 3-9. Heat C1423 showed little or no degradation in the upper shelf energy, with the irradiated values of shelf energy within a bend which contains the initial value. Heat W9807-2 shows a small change in the upper shelf energy with irradiation, with the irradiated shelf energy l ranging from 116 to 130 ft-lb, as shown in figure 3-8. s F 4m, woo io 34

r Heat DRS3 is shown in figure 3-9, and for this case the shelf energy ranges from 106 to 115 ft-lb. This heat is A302B modified, and therefore has higher nickel values, but again this fact seems to have no bearing on the shelf behavior in the irradiated condition. Heat 0C2 shows similar behavior to that of DRS3, with an irradiated shelf energy ranging from 119 to 123 ft-lb. The behavior of these two heats of A302B modified shows less scatter than that for the A302B steel, shown in figure 3 8, presumably because the new steel making practice used for the A302B modified material resulted in lower levels of sulfur and phosphorous, and more uniform properties. 3.3 Orientation Effects The trends of the strong and weak direction properties after irradiation are similar for A302B steels, with the weak direction properties being lower, as expected. One heat of A302B modified material (B2803-3) was found with both longitudinal and transverse properties, and these results are shown in figure 3-10. Several important trends are revealed from study of this figure. First, the scatter in data is higher fo the strong direction properties, with a band of 72-96 ft-lb, as opposed to a rather narrow band for the weak direction properties, ranging from 56-64 ft-lb. Considering the weak direction after irradiation, the band is even more narrow, with energies ranging from 56-5B ft-lb. Hawthorne [2] pointed out similar behavior for the A3028 correlation monF ~ material. He further observed that the weak direction properties did not j degrade as much as the strong direction properties. Therefore, based on Hawthorne's observations and the data in figure 3-10, the lower shelf energy expected for the weak direction of any given heat of A302B after irradiation 'can be conservatively predicted by using the ratio of the transverse to longitudinal unirradiated properties, and multiplying this value by the' strong direction irradiated properties. This is the approach followed for the San Onofre shell materials, in the sections to follow. e ommwo 35

TABLE 3-1 CHEMISTRY OF AVAILABLE MATERIALS i Heat Cu S C Mn P Mo Si Ni Correlation Monitor 0.20 0.023 0.24 1.34 0.011 0.51 0.23 0.18 W7001-9 0.18 0.026 0.19 1.36-0.014 0.47 0.23 t W7601-1 0.17 0.025 0.22 1.36 0.013 0.46 0.24 W7601-8 0.18 0.020 0.20-1.34 0.012 0.47 0.20 W9807-2 0.10 0.014 0.20 1.42 0.010 0.47 0.26 W9807-4 0.12 0.021 0.20 1.37 0.010 0.47 0.19 W9807-7 0.12 0.010 0.20 1.46 0.013 0.48 0.22 BRP 0.10 0.018 0.30 1.42 0.016 0.51 0.25 A0811 0.19 0.020 0.19 1.42 0.010 0.48 0.75 C1423 '0.11 0.019 0.21 1.37 0.014 0.46 0.25 sW10201-5 0.10 0.021 0.20 1,29 0.010 0.46 0.22 W10201-6 0.09 0.015 0.19 1.32 0.010 0.49 0.19 0.18' 19281-2 0.18 0.028 0.20 1.27 0.020 0.48 0.21 0.18 DRS3* 0.12 0.013 0.25 1.59 0.011 0.47 0.27 0.54 QC2* 0.10 0.009 0.26 1,64 0.007 0.47 0.35 0.54 QCl* 0.20 0.020 0.25 1.48 0.009 0.50 0.27 0.55 B2803-3* 0.24 0.024 0.22 1.30 0.012 0.45 0.28 0.52

• A302B Modified

.t \\ un.mn.o io 3-6

TABLE 3-2

SUMMARY

OF SAN ONOFRE REACTOR VESSEL SURVEILLANCE CAPSULE CHARPY IMPACT TEST RESULTS: TRANSITION TEMPERATURE INCREASE [8] 30 f t-lb 50 ft-lb () Transition Transition Fluence Temp Increase Temp Increase 19 2 Material 10 n/cm (.p) (.7) g W7601-1' 3.4 140 110 W7601-8 3.4 110 85 W7601-8 4.9 120 110 W7601-9 1.8 100 85 W7601-9 3.4 130 125 Weld metal 1.8 80 95 Weld metal 4.9 145 165 p ( HAZ metal 1.8 80 85 HAZ netal 4.9 115 130 ASTM correlation 1.8 120 130 monitor 3.4 150 175 4.9 130 135 (8) Currcnt update fluences from Surveillance Capsule A, D and F data ?( \\y .( on. nwuo 37 y

i TABLE 3-3

SUMMARY

OF AVAILABLE RESVLTS: ASTM A3028 CORRELATION MONITOR MATERIAL Upper Shelf Fluence Energy Level l Material (E>1MeV) (ft-lb) i 302BREF 67.0 0.20E19 81.0 0.70E19 >66.0 1.10E19 69.0 1.50E19 57-0 1.70E19 55.0 2.10E19 >60.0 2.30E19 69.0 3.00E19 65.0 3.10E19 63.0 3.10E19 59.0 3.10E19 61.0 3.10E19 60.0 3.40E19 54.0 4.80E19 64.0 l 2.60E19 66.0 4.10E19 >65.0 l

• 1'.80E19
• 56.0
• 3.4 E19
• 53.0
• 4.90E19
• 62.0 Correlation monitor material in San Onofre Unit I capsules l

l uw.54nso in 3-8 4 1 '?'

TABLE 3-4

SUMMARY

OF AVAILABLE RESULTS Upper Shelf Fluence Energy Level Material (E>1MeV) (ft-lb) A9811 107.5 3.58E18 90.0 7.05E18 92.0 2.11E19 95.0 2.22E19 100.0 C1423 119.5 3.58E18 121.0 7.05E18 131.0 2.11E19 136.0 1 2.22E19 134.0 W10201-5 97.1 i ,o 3.69E18 87.5 5.84E18 100.0 W10201-6 107.1 3.69E18 108.5 4.11E19 105.0 i W9807-2 135.0 2.39E18 117.0 4.71E18 124.0 1.58E19 130.0 i W9807-4 126.0 4.71E18 124.0 l 1.58E19 122.0 2.22E19 110.0 W9807-7 120.0 4.71E18 108.0 1.58E19 117.0 BRP 81.0 1.50E18 81.0 '7.10E18 72.0 2.27E19 67.0 2.30E19 61.0 10.7E19 69.0 i ow. ann.ie 39

TABLE 3-4.(cont.)

SUMMARY

OF AVAILABLE RESULTS Upper Shelf Fluence Energy Level Mt 93tr. (E>1MeV) (ft-lb) 19281-2 76.9 2.50E18 62.0 5.00E19 46.0 ORS 3 135.0 9.25E18 115.0 1.02E19 112.0 2.06E19 106.0 0C2 135.0 1.27E19 123.0 4.14E19 119.0 0C1 106.0 1.19E19 85.0 4.04E19 73.0 B2803-3 (Transverse) 57.0-64.0 2.92E18 58.0 8.05E18 57.0 1.07E19 56.0 B2803 (Longitudinal) 72.0-80.0 2.92E18 96.0 1.07E19 82.0 on.uu oio 3 10

l 5 I 5 e l 0 a 1 i = 5 re ta M ro t 5 1 in 4 o M no i ta 0 l 1 e 4 rro C 820 5 ) 3 1 3 V A L E A M ro 0 I f RE 1 t T f E M 0 i ( hS 1 E 3 C M e N C r E / u R M t E a F 9 r 1 e E o R 5 0 p m 1, i e B 2 2 E T 0 C 3 N no A v E i U t L i F s 0 n I a 2 r T n i L L n T T O o AE 5 i MR M I t O 1 a F r .O FN F u t EO E a R R e S N BA B f 2S 2 o M.p 0 0 0 o I 3N 3 y 1 r AI A am g O mu S 189 111 5 000 8 666 777 1 WWW 3 AO# e= r 1 u. 1 0 g i. g 0 0 0 F. 0 0 3 2 1 _ S u _b aa x w.

l' r. 150 140 130 120 110 O 100 h 90 .3 g 80 J3 gy y %!RRADIAT10N VAltES W 70 C-G O O a g 60 D E os 3o - D 40 30 i i i i i i i i i s. i .i i 0.20 0.32 0.50 0.79 1.26 2.00 3,16 5.01 Fluence (x 10E19) Figure-3-2. Sumary of Upper Shelf Charpy Results for A302B Correlation Monitor Material (2). Solid Points are from San Onofre Unit 1 . 4in.mim.io 3 12

t 150 140 130 12o - 110 p 100 15 so - i 8 vo - so _ So - a ~, 4o - 30 i i i i i i i i i i i i i 0.20 0.32 0.50 0.79 1.26 2.00 3.16 5.01 nuence (x locis) Figure 3-3. Charpy Upper Shelf Behavior of Heat 19281-2 (Solid Point on Vertical Axis is Unirradiated Material) um.mino io 3-13

ISO 140 - 130 120 110 - ,= e 90 30 a lO E 70 a 30 - 80 40 30 i 0.13 0.20 0.32 0.80 0.79 1.25 2.00 3.16 8.01 7.94 12.89 Phonee (a 10C19) Figure 3-4. Charpy Upper Shelf Energy Behavior of Heat BRP, Showing Evidence of Saturation (Solid Point on Vertical Axis is UnirradiatedMaterial) um.mm oio 3-14

ISO 140 1.',0 120 110 Il 100 5 90 c 80 G 70 60 50 40 30 i e i i i 1.00 1,as 2.51 3.98 Piuence (a 10t19) Figure 3-5. Charpy Upper Shelf Energy Behavior of Heat QC1 (Solid Point on Vertical Axis is Unirradiated Ksterial) .m.mi4.o io 3-15

s' 100 140 = 130 - 180 - 110 g = ee D D D 90 - CL 80 - g 70 - to - 80 40 i i i i i i i 0.31 0 80 0.79 1.26 2.00 nwones (a 10t19) 190 -- 140 = .130 - 180 = 110 - = Il 30 80 g 70 - 80 90 - 40 - 30 9.31 0.80 0.79 1.86 SAO 8.16 BA) Mpense (s 19t19) Figure 3-6. (topfigure) Upper Shelf Energy Behavior of Heats A9811-and W10201-5, Showing Saturation In Irradiation Damage. Solid Symbols are W10201-5. (bottom figure) Upper Shelf Charpy Energy Behavior for Heat W10201-6. Showing Saturation. .in.e..o io 3-16 E

ISO 140 - 12 81 5 120 # 3 5 D D c ? 110 m 100 90 ] a0 70 60 = 50 40 3) i i i i i i i 0.40 0.63 1.00 1.58 2.51 Fluence (x 10t19) Figure 3-7. Upper Shelf Energy Behavior of Heats W9807-4 and W9807-7, showing Saturation Behavior. Note That The Solid Points are 3 for Heat W9807-4. .im.*"'" " 3-17 dUdl

O' .'t. ISO 140 - "O D 1M. D 120 110 - 100 - s 1 .0 - 3 0 70 n0 90 - 40 - a0 i i i i i i 0.32 0.60 0.79 1.26 a.oD Fluesies (x 10C19) 190 i40 II 130 m O IE ~ D n 110 y 100 E so. l a0 70 80 - a0 40 - a0 i i o.a0 a.aa o.a0 e.7s i.as am m (a 10C19) Figure'3-8. Upper Shelf Charpy Energy Behavior of A302B Steels: Heat C1423 (upper figure) and Heat W9807-2 (lower figure). (Solid Point on Vertical Axis is Unirradiated h terial) .ix.e.,o in 3-18

100 140 - 0 130 - 120 0 0 110 - 100 E o0 - 80 = 70 - 40 - l i no - 40 30 i i i i i i 0 89 1.12 1.41 1.78 a24 Pluence (a 10C19) ISO 140 - 11 130 120 e 110 - k toO g } ~ a0 70 e0 - a0 - 40 30 i i i.as a.oo a.1s s.oi Namee (a tot 19) 'j ' Figure 3-9. Upper Shelf Charpy Energy Behavior of A302B Modified Materials: Heat DRS3 (upper figure) and Heat 0C2 (lower figure). eim.wowe io 3 39 i j

180 140 130 120 l 110 100 b 90 }3 80 l D g) 70 60 l i 50 - 40 30 i i i i i i 0.25 0.40 0.63 1.00 Fluence (x 10C19) [ Figure 3-10. The Effects of Orientation on the Upper Shelf Charpy Energy of Heat B2803-3. nw.mo io 3-20 .)

g SECTION 4.0 PRESENT STATUS OF SAN ONOFRE UNIT 1 The results snd trends discussed in the previous section will be used, along with the presently available data for San Onofre, to predict the present and future status of the San Onofre Unit i vessel materials in this section. -4.1 Available Results 4 The Charpy results for the three heats of A302B in the intermediate shell course are presented in figures 4-1 and 4-2. These results have been reproduced from the two most recent surveillance capsule test reports (8,9). The upper shelf energy values are tabulated as a function of neutron fluence in table 4-1. Only specimens from the strong direction are available in the surveillance specimens, but both directions were tested in the unirradiated cor.dition. The unirradiated results for the weak (transverse) direction are included in table 4-1. t The Charpy results for the A302B ASTM correlation monitor material contained =in the San Onofre Unit 1 surveillance capsules are summarized in figure 4-3. This figure clearly shows the saturation which occurs for this material in l both the transition shift and upper shelf drop, as discussed earlier in section 3. 4.2 Trends in Upper Shelf Energy The general behavior studied and discussed in section 3 can be used to predict the future trends expected for the San Onofre core region materials. We have seen that saturation of the irradiation effects on the upper shelf is expected 19 2 to occur at a fluence level of 1.0 x 10 n/cm. Since each of the intermediate shell materials has been irradiated to a fluence exceeding this value, no further damage is expected. 4 The Charpy ::helf energy behavior of two of the heats in the intermediate shell of the vessel is provided in figure 4-4. All available irradiated results are i 42ewo41190 to 4.}

.. 7 ^ for longitudinally criented specimens. Heat W7601-9 is shown at the top of figure 4-4, and'shows very clear saturation, with data available at fluences 19 2 up to 3.4 x 10 n/cm.- The range of results is from 70,0 to 78.75 f t-lb for this heat, and this same range has been plotted on the figure showing l results for heat W7601-8. This heat shows less scatter than that of W7601-9, but the wider band has been used to provide a realistic prediction of the l range of future results. The results for heat W7601-8 provide very strong evidence of saturation, since results are available at a fluence of 4.9 x 19 10 and the Charpy shelf is slightly higher at this fluence than at the lorer fluence value. j The Charpy results from the third heat of the intermediate shell are provided j 1 in figure 4-5. Unfortunately, only one data point is available for this heat, L W7601-1, but to compensate for the lack of data, the scatter band from heat W7601-9 has been reproduced here as well. The scatter band has been set with i the single data point at the bottem end of the range, to match the observed behavior of the other two heats. Considering the original average upper shelf energy for each of the materials, as shown in table 4-1, the maximum observed drop in shelf was calculated as a fraction of this value. For heat W7601-9, the lowest value was found to be 75 percent of the original (70/92.3), while the iowest result for heat W7601-8 i was 70 percent of the original value. Using the lowest value of the'above two results, the bottom end of the scatter band was set at 61 ft-lb, or 70 percent of the original shelf value for heat W7601-1. This corresponds precisely to the actual data point. A separate study was made of the collective upper shelf behavior'of the three heats of the San Onofre core region material, to determine whether the irradiation effects on the upper shelf Charpy energy are reaching saturation. l Plott were made of the data with.two different approaches. The results of both approaches are shown in figure 4-6. Both approaches show very clearly that the damage is saturating, when the three plates are considered as a class of material. . uu,m mo.* 4-2 h. s

'To determine the trend the i radiated behavior of the transverse or weak direction properties, the longitudinal properties were used and corrected by the ratio of the transverse to longitudinal unirradiated properties. When this is done,-the following values result. p L PROJECTED LOWER BOUND RESULTS - SAN ONOFRE UNIT 1 L heat . longitudinal transverse L W7601-9 70 ft-lb 54 ft-lb l W7601-8 69 ft-lb -54 ft-lb W7601-1 61 ft-lb 53 ft-lb The projected results above are expec+ed to be conservative, because the observed behavior for the transverse orientation for both the ASTM correlation i 1 monitor material, and heat B2803-3 has been that the transverse orientation shows a smaller drop, and a narrower scatter band, b 1 l-l l-l l.- nu.iuna.io 4-3

'i L' TABLE 4-1

SUMMARY

OF-AVAILABLE UPPER SHELF CHARPY ENERGY RESULTS FOR SAN ONOFRE UNIT 1 Upper Shelf Fluence. Energy Level 2 Material (E>1MeV, n/cm )- (ft-lb) W7601-1 86.3/75.0* 3.4E19 60.9 W7601-9 92.3/71.5 1.8E19 78.75/70.4** 3.4E19 70.4 W7601-8 94.3/75.9 3.4E19 69.4 4,9E19 71.8 C 'l n Values given are for longitudinal / transverse orientations.

• • 70.4 ft-lbs based on average upper shelf energy.

4-4

I I PLATE W76014 40 0 g Unirradicted 1,8' g gp nvt> 1 MeV I ie $M 'n 6 g a 3 3 /,/ 80 /i i d / [,3,7 xgg'nyt>l MeV 2 so @ /. I20 / 6 130'b3,[ 'r U / '5 c 8 o ico too soo 4m TEST TEMPERATURE (*F) I ] cun m.oi.i j100 ,g Unirradicted Y %.0 __ t 3 E j ,4icxid'nyt>iMev Iu j in 2.0 a b' 0 0 100 200 300 400 TEST TEMPERATURE (*F)

• CURRENT UPDATE FLUENCES FROM SURVEILLANCE CAPSULE lhTA Figure 4-1.

Charpy Energy Results for Haats W7601-9 and W7601-1 [9] 4130s/G2029010

.. ~. -.. .l + 14.420 3 'l 120 l l l l L iOO l-3 3 $- 60 er h60 ,b 0 100 g C % iRRA0iaTED AT 550'F -l ) 9 N/Ch 2 4.9* X 10 i 20 Se 2 g 80 5 g .60 t E ilo D IRRADIATED AT 550'F 4,9' X 1 N/Ch 0 '~ 120 100 e e 7 so e - A -Q _ 7 s-UNIRRADIATED r 60 l100 g IRRADIATED AT 660*F l-g 19 L ise' O 3.4* x 10 N/CM o'4,9* x 10 N/C 2 20 7 I I I I I O -100 0 100 200 300-Il00 500 TEMPERATURE ('F) L

• CURRENT UPDATE FLUENCES FROM SURVEILLANCE CAPSULE DATA Figure 4-2.

Charpy Energy Results for Heat W7601-8 [8] ? t I u m.S a m to 4-6 L

9 t 14,4204 120 I I I I I e i00 lanAciAfte AT 550*F 4,9' x 1019 N/CM 60 3 2 is0' g Y 60 - 1 2 20 2 n_ 80 5 g 60 e r o v gn n N ~ gggo WE inaAciaTED A1 6500r g 5 2 2 4.9* x 1019 N/CM 0 ~~ 120 lana 01ATED AT 550'F 0 1.8* x 1019 N/CE 100 19 O 3.4* x 10 N/CM y 80- /-- o 4.9* x 1019 N/CM t 4 A - [' #4 a g uninaA0 LATED 1350 ge 130' 20 IW" I -0 -100 0 100 200 300 460 0 500 TDFERATURE ('F)

• CURRENT UPDATE FLUENCES FROM SURVEILLANCE CAPSULE DATA Figure 4-3.

Charpy Energy Results for A302B ASTM Correlation Monitor l.- Material, from San Onofre Unit 1 Surveillance Capsules L um.mamao 4-7

2 6 r 150' 140 -' 130 120 110 - p-100 - i6 90 d' } 3 a0 -_o h 70 - U* 'I 60 - 30 i' 40 - 30 i i i i i i i.i .I 1.74' 1,91 2.09 2.29 2.51 2,75 3.02 3.31 -I nu,once (x,10E19). ~s -150 t 140 - 130 - 120- - 110 - i 100,, E M - 1 3 .o f' O .[ 70 - 60 - i 50 - 40 - 30 i i i i e i i a 3 8 8 8 3.39 3.55 3.72 3.89 4.07-4.27 4.47 4.68 4.90 nuance (x 10E19) Figure-4-4.- Charpy' Upper Shelf Enomy 4ults for San Onofre Unit 1 Heat W7601-9-(top) and Hea!.u o04 8 (bottom) (Solid Points Plotted on.-the Vertical Axis are im Unirradiated Material) ein.e4.co 4-8

-u .~ - 140 130 .) 120 - p 110 I' 100 90 JI h 80 - 70 - i c. 60 - j SO. - i i 40 - I I i i i a a a s a i i i i - 1.74. 1.91 2.09 2.29 2.51 2.75 3.02 3.31 nuence (x 1009) \\ 150 .i 140 - 130 120 110 - 100 - go _ Il 80 --_________ D 70 - ,o __. _ _ _ _ _. _ _ _. _ _ _ _ _ _. _ _,. 50 - 40 - 30 2.00 -2.19 2.40 2.63 2.88 3.16 3.47 Mu; ece (x 1009) ) Figure 4-5. Charpy Upper Shelf Energy Results for San Onofre Unit 1 Heat W7601-9'(top) and Heat W7601-1 (bottom) (Solid Points Plotted on the Vertical Axis are for Unirradiated Material) . p w.<osi m io. 49

e ioo-1 90 - I . Q: so - 3, 70~ b e:- 1 I 3o - b i g 4o - s Wy so - t 20 - 10 - ^ i o. 1' 2 3 4 5 ioo-90 - j so. -

70 -

,r 60 - .al so - 'E I w 40 - W E so - 3 g n 20 - 10 - o i i a i 1 2 3 4 5 FLUENCE (X 10E19). Figure'4-6 Results of a study of the irradiation damage saturation of the three heats of plate in'the i San Onofre Unit-1 Raactor Vessel. Above: Irradiated upper shelf percentage as a function of fluence. 'Below: Percentage drop in shelf vs. fluence. um.eweio 4-10 t , + s

s SECTION 5,0

SUMMARY

AND CONCLUSIONS Charpy upper shelf energy behavior after irradiation has been studied for a number of heats of A302B steel, to provide a reliable prediction for the j behavior of the San Onofre Unit 1 core region materials. The surveillance program for San Onofre Unit 1 contains all three heats of steel found in the ' intermediate-shell (immediately adjacent to the core), so data are directly i available. l Data-trends from the heats studied show a common pattern of irradiation effects behavior. The irradiation damage affects the Charpy transition f temperature, Charpy upper shelf energy and yield strength of these materials, and saturation in all three of these properties for A302B appears to occur at 19 2 a fluence of 1 x 10 n/cm. This saturation in damage has been observed I in all the heats of A302B studied here. The data patterns exhibited by longitudinal (strong) and transverse (weak) orientations are very similar, The transverse properties tend to show a smaller drop in. upper shelf energy,'and a narrower scatter band than the longitudinal properties. Therefore the use of longitudinal trending behavior -will be-conservat'ive, t -This study has-resulted in the conclusion that.the upper shelf energy q properties of the San Onofre Unit 1 core region materials have already 3 saturated, and are unlikely to drop further with additional service. The Charpy upper shelf properties of the materials are projected to be as follows: longitudinal transverse heat W7601 70 ft-lb 54 ft-lb W7601-8 69 ft-lb 54 ft-lb f W7601-1 61 ft-lb 53 ft-lb. i The properties of other irradiated core region materials are expected to fall within this range of properties, even though only these three heats are the - - m.,m m o 5-1

~ m f ..= l ? only ones characterized. 'The welds are expected to have superior properties.. s ito.!those listed.above. Therefore it may be concluded that the core region.

• T materials-~of the San Onofre Unit I reactor-vessel are unlikely to fall ~below the.50 ft-lb requirement of'10 CFR 50, for the entire operating life of the

Tplant, i

(c _n. g, I 'f t l', s-e i I s, l 4 s I i: -l (4 a l ' t i'; j t I r e: y [' , 42Ms/04119010 5-2

4 SECTION 6.0 i-REFERENCES- .1. Yanichko, S. E., " San Onofre Reactor Vessel Radiation Surveillance Program," Westinghouse Electric Corp. WCAP-2834, Rev. 1, November 1966. 2. Ha'wthorne, J. R., " Trends in Charpy-V Shelf Energy Degradation and Yield 5 Strength Increase of Neutron-Embrittled Pressure Vessel Steels," in Nuclear Engineering and Design, Vol. 11, 1970, pp. 427-446. L J-3. Yanichko, S. E. and Chirigos, S. N., " Observations on a Steady State l Effect Limiting Radiation Damage in Reactor Vessel Steels," Nuclear Engineering and Design Vol. 56, 1980, pp. 297-307. -4. Steine', R. H., and Steele, L. E., " Steels for Commercial Nuclear Power Reactor Pressure Vessels," in Nuclear Engineering and Design, Vol. 10,. i 1969, pp. 259-307. 1 5. Stahlkopf, K.', Odette, G. R., and Marston, T. V., " Radiation Da n ge Saturation in Reactor Pressure Vessel Steel: Data and Preliminary L Model," Institution of Mechanical Engineers, London,.1980. l -6. . Anderson, S. L., " Fast Neutron Fluence Evaluation for San Onofre Unit 1," Westinghouse Electric Corp. letter PSE-REA-835/90, Feb. 2, 1990. i L, 7. H'awthorne, J. R., and Potapovs. V., " Initial Assessments of Notch-i Ductility Behavior of A533B Pressure Vessel Steel With Neutron Irradiation," ASTM Special Technical Publication 457 (1969). L 8.- Yanichko, S. E., Anderson, S. L. and Kaiser, W. T., " Analysis of Capsule- [ F from the Southern California Edison Co. San Onofre Reactor Vessel L ~ Radiation Surveillance Program," Westinghouse Electric Corp. WCAP-9520, May 1979. 9. Norris, E. B., " Analysis of Second Surveillance Material Capsule from San E Onofro Unit 1," Southwest Research Institute Project 07-2892, June'1972. ca.*"a:io 6-1

+]$4 y, ,\\, 3, bi -\\]. v;. 7 r g [-, ' \\ ...-.','i__%a APPENDIX A:

SUMMARY

OFJAVAILABLE MATERIAL: CORE REGION? _ s mg' v NATERIALS FOR SAN ONOFRE UNIT 1

l

.n 1 o y [d[ EM. N;, .\\, ; 5- ~ lThis Appendix.contains sketches of the archive materials from San Onofre t ' Unit 1 maintained by Westinghouse -These' sketches.are provided for 1[ ~ e '?informationTonly. and are not to scale.1 4 -l\\ [. y

i N'

ij 2, M\\} }j{. q N k; r ) i i q \\- l 1 t-e, t! t \\ \\ l' f 1 T 1 s e h .'\\. ; ' \\r s .s - x\\ a s 'T i i 4 \\ (' sI v4

3; i

a g. s k' i A $ * " " i A-1 ' n. ~.. 3 q .u

N:[ k=W. :., - x E M e y r . 1 t. t. sg. \\ s,.., [, t 3 r e .i if .j i ) \\\\ i e % J-. (.

r

\\ \\; 8 e W601-4 i' '(1 PItCE) \\\\x [ +- g< 4 .i t-x '\\.. ~ k s,*( s, / e (N. 'J 4 .\\ n 4 /,, = , 1,, .j' 1 1 r. s s y N \\ y 'l YY

1 r

-e 4 M)T T0 m .s y ). i N /,, + i ,p> 1 + ) Nh/ 1 m j [N ,J t x i i-Q \\ t \\ v .} , o-9 J Figure A-1. Archive Lower Shell Plate Material i-N;. \\.:, e A-2 j .immotio so s-D j i' y,\\ "S-g f'!,[.' ' --- 3 'l .k _. ;.,. ' {.y

e. b* 6 r W601-1 t

• [

y' \\/ Y L k W601-8 (1 PIECE) Ab eF% v V N* \\ 9 i +k. t \\' Li _ / e L'p, / Q,

i 1

p,< 2! 7 / y N /- W601-9: y ' #*/ (2 PIECES) E-10 S' ALE ' ,I w& w6q s k, =:, i :. n

,. y Figure A-2.

Archive Intertwd\\ ate Shell Plate Waterial [ .5-t ~ ' }W ) D. A-3 ..o 4 _) af - t, ' ' - ~ ~ ~ ~ ., x... ...r.}}