ML20236U345
| ML20236U345 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/25/1987 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20236U347 | List: |
| References | |
| NUDOCS 8712020446 | |
| Download: ML20236U345 (21) | |
Text
t B ALTIMORE GAS AND ELECTRIC I
CHARLES CENTER R O. BOX 1475 BALTIMORE, MARYLAND 21203 l
JOSEPH A.TIERNAN
.l Vict PRESIDENT November 25,1987 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Reauest for Additional Informati. n: Steam Generator Tube Intenrity o
REFERENCES:
(a) Letter from Mr. J. A. Tiernan (BG&E) to Mr. A. C. Thadani (NRC),
dated October 17, 1986, Request for Amendment Gentlemen:
During a meeting with the NRC, additional information concerning steam generator tube degradation mechanisms was requested by the technical reviewer. The enclosed attach-ments discuss estimated corrosion / degradation rates for intergranular attack
- sites, degradation in the upper vertical and diagonal support areas and the secondary water 3
chemistry program. Also provided are corrected inservice inspection tables which supersede those in Reference (a).
As discussed at the meeting, we are requesting a change to Technical Specification 4.4.5.3.a,b as previously submitted (Reference a).
This change eliminates all provisions for extending the inspection interval to 40 months with a C-1 rating on the previous inspection.
Should you have further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, f&
JAT/ PSF / dim Attachments cc:
D. A. Brune, Esquire J. E.
Silberg, Esquire R. A.Capra,NRC 7
S. A.McNeil,NRC j
W. T. Russell, NRC L{0 T. Foley/D. C. Trimble, NRC g
T. Macette. DNR k
B712020446 B71125 PDR ADOCK 05000317 p
ATTACHMENT (1)
INTERGRANULAR ATTACK (IGA)
SUMMARY
BG&E was asked to provide an estimated growth rate for the IGA which exists just above the tube sheet in the sludge pile region. IGA was identified from separate destructive examinations performed on different pulled tubes by two independent organizations.
Other indications in the sludge pile zone exhibit similar eddy current responses and are also suspected to be caused by IGA.
To determine when the attack may have initiated and estimate a through wall growth rate, an extensive review of the Calvert Cliffs Unit 2 Steam Generator (SG) eddy current data was performed. Data tapes from the spring 1984 and fall 1985 inspections were reviewed. Tube locations were chosen which corresponded to areas which showed IGA indications during the spring 1987 inspection. Results from 52 tubes containing IGA indications during the spring 1987 inspection were compared with 50 tubes tested during the spring 1984 inspection and 8 tubes tested during the Fall 1985 inspection. Of the 50 tubes reviewed from the spring 1984 inspection, 35 contained measurable IGA indications. Seven of the eight tubes reviewed from the fall 1985 inspection contained existing measurable IGA indications. Where the review did not detect pre-existing degradation the entire percent degradation measured in 1987 was assumed to occur over that time span, if the review showed pre-existing degradation that was not measurable, that tube's data was not used in the trend analysis.
All of the data reviewed from these inspections was acquired with MIZ-12 or MIZ-18 multi-channel eddy current testers. A digital DDA-4 analyzer was used to re-review the data.
To achieve an estimated annual growth rate, a trend analysis was performed using the spring 1984 and fall 1985 reanalysis compared to the spring 1987 results. From this analysis, the average annual growth rate during this period is estimated to be four or five percent per year. The method used to analyze the data takes into account the differences in analysis techniques used previously with the raw data. However, the data reanalysis does not account for improvements in the eddy current test equipment used to acquire data in the past, and therefore, may not substantiate IGA growth. The following calculation summstizes the analysis:
No.of Average (%)
Time Soan Tubes Annual Rate 12/85 - 3/87 8
5.9 6/84 - 3/87 50 4.3 A weighted annual growth rate is calculated as follows:
Weighted (5.9%)
X 1
+
(4.3%)
IQ 4.6%
=
=
Annual Rate 58 58 l _-_ _ - __-.
_ _ ~ _ _ _.
' ATTACHMENT (I)
INTERGRANULAR ATTACK (IGA)
SUMMARY
'i An estimated 24-month cycle growth rate is determined below:
24 Months
- Weighted -
X in_Cysh 10%**
Estimated Cycle
=
Rate (ECR)
Annual Rate 12 Months Assumptions:
Plant running' continuously for 24 months Analysis is accurate to within 10%
Thus:
(4.6% X 2) (
10%)
=
ECR = 10% (
10%)
Review of reported cycle corrosion rates in the industry shows some correlation with this calculation methodology. This ' review was based on data obtained through EPRPs i
Steam Generator Reliability Program.
1 1
l 1
i i
1 i..
j
i 4
ATTACHMENT (2)
UPPER SUPPORT REGION
SUMMARY
l l
During a meeting with the NRC, a slide was shown of an OD surface of a steam generator 1
(SG) tube removed from a vertical middle support area of SG #11 during the October 1983 outage. The tube photograph revealed a wear-fretting indication whert, the OD tubing surface was worn, presumably due to tube motion against the tube support bars. This degradation and some of the other eddy current indications at the upper vertical and i
diagonal support locations are suspected to be caused by this type of wear-fretting l
mechanism. A review of eddy current (ET) data taken since 1982 has been performed on known tube indications in the upper support region for Unit 1 SG #11. A summary of conclusions is provided below:
l l
l
'o A total of three defective tubes (containing a 40% indications) have been l
l plugged. As a precautionary measure, three additional tubes in this region i
i with ET indications less than 40% nominal wall loss were plugged.
l o
ET data trend analysis of seven tubes in the upper vertical and diagonal support area shows no significant growth rate of the indications still in i
service. The average degradation growth rate for these indications is less j
than 3% per year. The data from four outages was reviewed - April 1982, October 1983, April 1985, and October 1986.
Due to the small database of known indications in this region, it i:, difficult to estimate the growth rate indications in the upper vertical and diagonal support areas with a high degree of confidence.
l
\\
I l
t I
6 ATTACHMENT (3)
WATER CHEMLTTRY PROGRAM The Calvert Cliffs Secondary Chemistry Program is an all volatile chemistry treatment with a full flow condensate polishing system.' The history' of the program has been one of continuing improvement. - As the attached graphs indicate, there has been an improve-ment in water chemis.ty with a marked increase in 1982. These improvements can be attributed to the replacement of the condenser, formation and development of a water treatment unit, and an overall increased awareness by the' site of the impact of chemistry on the integrity of the steam generators. From this data, it can be con-cluded - that the initiation of IGA /lGSCC attack probably occurred in 1978-1982 time period with limited growth from 1982 to the present.
+
I i
't e
i i
i e
1 4
W U
O
[
W ad j
g j
N l
4
.I l
m e
I F-=
4 e_s 8
2 4
D y
8 4
m s
g, LL -
L H
~
- g' J
sn U
p 4
J B
4e 4
F-l j
4 k
4 H
- ~
Se e..
_~
6 g
- 4. mq
.o 5
=(4
- p as 4
~"
Sar x
2 a
O
.J I
eat
&Q ce t-ZW g
C EE 2
E
<W 6-l Cf) 1
)
L.
g 80 2.c h
.i M3 4
l f
f f
I f
f f
I h_
O_
O e
9dd qdo x
Hd mIoas vants sanoa j
e
._.g-
~
h s
g CE A
D i
i O
i g
a
?
L V
1 g
ON i
i L
' i f' A
i 1
I T
g T
I N
C N
g O
U S
i i
2 i
A i
F F
I P
L m
E a
S C
TR i
i
=
i i
EVL G
U A
A C
A
)
i W A
T i
i a
Y L
R b
U T
A J
S I
A M
i i
v a V E
i H
i i
i i
W A
C M
g I
N J
A W
O ii D
O L
Y
^
A B
M
'A Y
1 1
i e
i R
O R
T P
A A
R
/
~
EN N
i i f E
i i
G k
g R
M g
A
\\
M A
A E
u.
e e
S T
i i
q 2
B EF e
r u
g 1,
i i
i i
iA F
A hA J
a N.
}
0 0
a O
5 s
2 g
!II L
g'
,i
. i a' i@,
m E
a L
'O 1
a a
5 V
a O
N
,i i
a' i
l k
p T
CO a
a
, i i
a' i
^
PE a
S y
a
,i me a'
i g
l O'a L
W t
GU t
A b
/
2 ei i
- a h
m i A
' i h
W L
N' f
i ss U
t J
a e
g e
N A
(
N U
A J
t h
\\
,i i
AI i
A 1
a 1
Y AM Y'
,i ai e~
a n
a a
~
4 a
R l
a P
J
^
A a
a a
a
,i I i
' i A
R A
M
,i ie
' i B
E F
,i
,i
' i Nn A o J
n 0
0 0 0
0 0
0 o
,g 0
0 0
0 8
4 2
0 2
i 4
s s
U 5
y E
0 o
1 1
gs k
1 k
n N8 gE g-
$y*
m CED A
g 8
8 8
8 I
g' 4
i
'6 6
j T.
l VO 3
f 6
^
N g
3 8
4 4
e 1
~
^
T
^
4 T
I C
N O
U a
S 8
I 6
i F
I F
6 I
i I
P L
E 6
g S
C T
R 8
A 4
i EVL GU A
+
A C
T 8
4 A
a Y
.u u
R LU T
J g
S I
'6 A
M i
i E
a H
C a
a g
NUJ NW g
O u
D h
h A '
i t
W O
L YA B
M A
1 1
I i
e R
a O
R T
P A
A R
A a
EN f
I i
i EG R
M AM A
w E
m T,
I l
i i
S 4
BEF erug I
1 I
i i
F 5
N W
AJ 8
0
{",
6 A
0 0
0 0 0
O 0
0 0
0 3
0 M
0 5
0 4
0 1
1 1
0 H
3
6 4
g 6
8 8
8 g a' a
VO
' N q
8 4
8 8
8 b
g T
CO 8
4
- a f
8 t
8 P
,A k
J ES a
6 l
i 8
8 i
7 i
g G
U A
K.
{
1 3
8 8
i 8
4 L 1 l
^
d 4
i l
L 3
U
. L i J 8
I 4
t 8
4 N
U J
I 8
I 6
YA M
8 I
8 I
4 R
P A
I 6
J.
4 M_
h R
'W A
M I
i B
t E
F b '1
' i I
9 N,
A J,
0 5
0 0 0
0, m
0 0
0 0
0 3
0 0
0 3
1 0
g 4
1 2
1 0
o 1
h
{
d 3j
$3
}
Il d
CED s
i i
e i
i VON
'"F i
s i
i i
i i
1 T
T I
C N
G U
^
S
'li i
i i
^
i F
F
^
I P
L b
^
E h
S C
T R
3 i
i 4
i E
V I
L G
m U
A
"~
h A
C A
T i
5
+ i r A
L a
Y A
p L
R U
T J
S 4
I 4
a a
I t
c y
M d
6 e'
i y E
h s
e v
H
!m y
C e
r W
T N
p W
C Y
i n '
e W
e O
D h
^
O n
L h
i' v
u B
W r
1 a
1 i
1 1
i n
e' i
d i
R I
e j
O e
R T
t P
A A
e R
^
e n
E ir E
s N
i e'
i
+
d i
G s
2 R
M l
i i
S p
^
A Q
^
M AE T
a e'
i O
n J
e 6
l B
e EF er u
t i
i i
i g
i
(
F A
n 9
J f
o o
.g 0
0 0
5 l0 3,
0 m m
0 c
s 1
0 4
i o
0 0
1 h
j g
MEb h
s e
e
1 I
i i
i i
a i
i i
i i
i 4
f i g_
l n
N_
t t
!~
(
8 5
m u.g 2
u 4
oa
=
~-
4
_ 7._ _ ~Q l
>-.c j
.," w _
1 7
l l
d b
W.
_~ ~
L
-A a
$4 g
_ )
_ "_I h
b l
~
\\
!_ m o
{
.d
)
Ei!
t d!
l
~
h i
g u;
1 4
g l
o l
{
E i
W
~
m 4
(
g s.
e g
=
+-
a
=
%g z
e
- zn
.e-e n
f f
I f
f 1
I I
f I
t t
o o
9 8
88 8
o 8 8
o 8 8
o d
a e d d
g g
g mo M add qdi qdd g
Hd
- CMD *1Y3 301807 0 HnIDOS V3171S E3Aad
9 e
e h
g
_3I g
1f I_
j*l;l l
4 4
a 4
j n
N
%y d
, _L a
l
/<
4
+3 5
4 g
- [
1 4
O 9
d I_
_1',
g a
i e
4 w
g d
d l
t-J B~
4
~* _
c Q
l i
- L i
J d
m
/
x 5
R za i
g j
S l
5 j
em
==
an.
f E
[c:
d 5
g J
.;l.
m=
m
-m l
e b
i a
9,1 g
l 2
l
" E R
""s 2
5 EB N
"E B
a o.
e a
3 g
g g
- /Sd W
W W
I Hd "IND *.LC 33fE10 mIDOS C r1IS E3ADJ l
i l
_..___.__ ___ _ __ _ J
a t
VON a
t TCO i
pI '
m
M' A
I P
e M, '
m m
ES 0
a g
g e
g ' '
a t
la'
' 'i g
w a
G A
y UA g,
g l
M a
g g
6 I
d' g
L t
a L
e'
=
=
U J
W'a A
a i
g ' '
t g
g a
N h
UJ 4
a g
t ae' 6
A t
a ' '
g g
4 Y
A AM
/
a a
a a ' '
i '
3
N' a
M a.
R a
P a
A i
- i '
M a
[
A'
' 'y.
a a
R a
t N" '
a a
A H
A a
A
- _h L
b I
l, v
a a
B i
a E
F a
a g
a i '
g
A
' 1 4
k' d
M
. f p
3 a
N 8 A 9 J
1 a
g
- g d
- S
'I 0
0 0 0 g2 1
O 0 0
0 N m
0 0
0 0 0
0 O
0 5
4 0
1 9
0 0
0 0
I 1
E g0 0
R 2 1
k k
R E
85 5"
3
1 j
l 100 1983 240 DAYS E
t CD
)
i a
20
^ '
^ '
D 100 I902 80 234 0^IO 00 40 i
l 20 16 DAYS
]
4 DAYS, 2 D\\YS, 1 DAY t t
I D
100 IOUI 80 1
60 153 DAYS 1
l 40
.i 66 DAYS 4
2D 22 DAYS 16 DAYS. 9 DAYS. 5 DAYS, 3 DAYS,
, 3 DAYS, 4 DAYS D
IO I
200 h
~
g m
f u
h
~64 DAYS 2D 33 DAYS 44 DAYS-'
22 DAYS 20 DAYS 18 DAYS 17 DAYS 9 DAYS, 9 DAYS, 7 DAYS l
_1979
~
80 60 i
~66 DAYS
~
20 37 DAYS 34 DAYS 19 DAYS 25 DAYS 14 DAYS 12 DAYS 5 DAYS, 6 DAYS i O
300
_1978 80 CD 127 DAYS 40 20 44 DAYS I 18 DAYS 13 DAYS 7 DAYS 11 DAYS. 4 DAYS, 3 DAYS, 1 DAY D
100 1077 go 60 l
1 40
~/9 DAYS I
61 DAYS
{
2D 36 DAYS
!.15 DAYS 16 DAYS l
5 DAYS, 5 DAYS, 6 DAYS, 4 DAYS,
1 D
[
D.D < 1D 20 < 30 40 < SD 00 < 70 80 < 90 Figure 10 DISTRIBUTION T STEAM GENERATDR SDDIUM CDCDf7RATTDNS AT CALVERT Q.!U3 UNIT 1 P
100 1983 220 DAYS 80 60 40 20 27 DAYS I
^ '
^ '
^ '
D 10D 1982 I
W 160 DAYS 60
~
B6 DAYS 20
^
^ '
D 100 IUOI i
80 so
'34 DAYS 80 DAYS 20 31 DAYS 18 DAYS 11 DAYS. 6 DAYS i 1 DAY, 2 DAYS i 9 UAYE D
IO 100 i
W 80 60 h
D
~
SD DAYS 34 DAYS-2D 17 DAYS 21 DAM j
- 13 DAYS 14 DAYS 8 DAYS 10 DAYS I 12 DAYS O
gg 1979 80 SD
~~
l 2D
-C9 DAYS S4 DAYS 29 DAYS-
,15 DAYS I i 20 DAYS El DAYS 15 DAYS i
r I
i
._1_2 DAYS',12 DAYS 10 DAYS i p
.j i-3978 goo i
80 60
~
~
65 DAYS 44 DAYS 52 DAYS
~
16 DAYS 19 DAYS 24 DAYS ~
3 DAYS
, S DAYS,'S DAYS, 2 DAYS l 0
300 1977 j
W j
40 35 DAYS 39 DAYS 44 DAYS i
2D "l21 DAYS 13 DAYSI j.
l l # U^
^
B DAYS, 8 DAYS. 6 DAYS I
i O
O.00 < D.20 D.40 < D.60 D.80 < 1.00
- 1. 2 < 1. 4 1.6
- 1.8 l
f Figure 11 DISTRisurrDN & STEAM GFKRATM CATION CDN:AX:TrYITY AT CALVERT CUFFS UNIT w
1 i
1 o
j i
i i
J l
i i
i I
g 2
mg
@g
.)a g.
a.
g
. e
{
9 3
U
.a A
i I'
s';
f g
3 3
=
I l
i 3_
_ -g g
+
h k
b I
W i
~:
s_
.o_
cc 8
g_
m l
- m
=
,h.
s) h
',P E
l
%+
. e J
t Q(-
3; l2 _
y
}.f
_ L g
l e
g g,c
. e M
I I
I I
f f
f I
l t
t I
9.
9
.8 8
0 8 8
O
~
g a
os m
a.
=
o-o o-a 9dd 9dd Add
=/sn
=E x
31v m s sola n o xntaas u to 1va maawie 83Aod
.g
R 1
l 5
I I
{,
y g
M
. S If g.
_ -g 1
i, a
=-
=
=
1
~
g
~
W
-g }
_j.
3 4
l i
1
- g-a l
+
l s
1 j
_._ g g
1 F
l
.A
.3 i
3 a
j l
- C 1
4 e
i y
~ ~5 N
a j
n I
.q]
q 4
5
]
1'
.i 4
l S
~
~ ~
T g
a r
cn
/_
7_
gC Y
b a-
~
w-. B.
. e.
8 i
',I
_yg' I
t t
I lec*
t I
I
_I t
g d
dd d
dd d
d d
d-5 ne 9
ne msn x
J aiv.ms aarvna miaos asca iva muus 0
t d
t_.________.__________.____________.__.________________________
=
. g.
CHLDRIDE 1DD
~ BD GD
- 51. B 40 35.9 20 B. 6 l
PD 1,0
. D. 7.,
SULFATE 100
'l]
80 l
s l
g c0 9
- 1 33.4 I
4D 25.3 l
2D 18.8
- 7. 5 j
- 4. 7 g4 i
O. 3 D
SDDIUM 100 80
- 65. D 00 40 I
18.6 g
10.5
- 4. 6
- 0. 5 -.,
- 0. 3 D. 3
- 0. 0 < 2. D
- 4. D < 6. D 8.D < 3D 12 < 14 16 = 18 CONCENTRATIONS, ppb Figure 14 Calvert Cliffs 1 Secondary Water Chemistry - August 1985 to July 1986'
ATTACHMENT (4)
STEAM GENERATORINSPECTION RESUL13 UNIT I STEAM TOTAL # TUBES
- TUBES
- TUBES YEAR GENERATOR INSPECTED DEGRADED DEFECTIVE 1977 11 306' 0
0 12 332 0
0 TOTAL 643 1978 11 614 0
0 1979 12 668 0
0 1980 11 646 0
0 1982 11 886 0
0 12 103_&
0 0
TOTAL.
1924 1983 11 1044 10 1
12 1Q41
.,4 1
TOTAL 2092 16 3
1985 11 8460 59 9
12 8442 R
_I TOTAL 16902 128 16 1
i 1986 11 8488 86 21 12 8494 1Qf it.
TOTAL 16982 192 32
)
i
ATTACHMENT (4)
STEAM GENERATORINSPECTION RESULTS UNrr 2 STEAM TOTAL # TUBES
- TUBES
- TUBES YEAR GENERATOR INSPECTED DEGRADED DEFECTIVE 1978 21 339 0
0 22 14Q 0
0 TOTAL 779 1979 21 667 0
0 1981 22 755 0
0 1982 21 832 5
1 l
22
_8M 2
1 TOTAL 1647 7
2 1984 21 7367 9
4 22
_642.Q H
2 TOTAL 13857 24 6
l 1985 21 2066 24 9
1 22 24M 21
_4 TOTAL 4512 45 13 1987 21 8497 78 29 22
_M11 M
14 TOTAL 17008 133 43
, _ _ _ - - _ _ _ _ _ _ _ - -