ML20056H347
| ML20056H347 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 09/01/1993 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9309090177 | |
| Download: ML20056H347 (10) | |
Text
n
~ Crammonwaelth Edison C
1400 Opus Place O
Downers Grove, Illinois 60515 September 1,1993 i
Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation j
U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk i
Subject:
Zion Station Units 1 and 2 Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events - 10 CFR 50.61 Response to NRC Request for Additional Information NRC Docket Nos. 50-295 and 50-304
References:
(a)
May 22,1992 letter from S.F. Stimac to T.E. Murley.
(b)
December 2,1992 letter from C.Y. Shiraki to T.E. Murley (c)
January 28,1993 letter from S.F. Stimac to T.E. Murley
Dear Dr. Murley:
Reference (a) provided Commonwealth Edison Cr apany's (CECO's) re-assessment of end oflife adjusted reference temperature, pressurized thermal shock (RT
,) values for Zion Units 1 ano 2. ibference (b) transmitted the staffs g
request ir additional information (RAI) related to the reference (a) submittal.
CECO's response to the RAI was transmitted via reference (c).
In a meeting held on June 9,1993, CECO discussed the performance of a modified analysis utilizing improved analytical techniques. The modified analysis necessitated additional testing, which is now complete.
1 The purpose of this letter is to transmit for staff review the summary report' which demonstrates that the Zion reactor vessels do not exceed the end-of-life PTS screening criteria. The report detailing the development of the methodology utilized will be submitted prior to September 30,1993.
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i Dr. Murley September 1,1993 i
Please direct any questions you may have to this office.
j Sincerely, w 3.
l T.W. Simpkin Nuclear Licensing Administrator
)
i Enclosure 1
cc:
J.B. Martin, Regional Administrator - RIII C.Y. Shiraki, Project Manager - NRR J.D. Smith, Senior Resident Inspector - Zion i
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i PRESSURIZED THERMAL SHOCK (PTS) EVALUATION l
FOR ZION UNITS 1 AND 2
-l Introduction i
Commonwealth Edison Company submitted a PTS evaluation on the
'i limiting beltline weld metal, WF-70, for the Zion Unit 1 and~2 reactor vessels on May 22, 1992.
A revised evaluation based on_
further WF-70 weld metal testing has been performed and is
{
described below.
This submittal differs from the previous submittal in (1)' the method for determination of the initial RTm, and (2) the determination of the chemistry factor which is now so)ely based on Zion specific curveillance data.
Previously, the initial RT for WF-70 weld metal was determined m
from the Charpy transition temperature.
An alternative method for I
determination of initial RTm has been developed by the B&WOG which is validated by a direct toughness curve.
The methodology is i
provided in a separate report by B&WOG (BAW-2202).
l i
Evaluation of Initial RTm i
In the BAW-2202
- report, it is demonstrated that the Charpy l
transition temperature based initial RT results in two m
significant problems: it introduces a large scatter in the data and
-l it introduces wide fluctuating values through the thickness of a
'l Midland WF-70 weld metal piece.
However, based on actual fracture 1
tooghness testing, the BAW-2202 report justifies the use of'the
'l drop weight test data for the determination of initial RTm for I
welds made from Heat 72105.
~
w-
f I
All available B&WOG and ORNL drop weight test data on Heat 72105 l
- are listed in Table 1.
From' the available drop weight data, a mean value of -56oF is determined -as the initial RTm for WF-70, with a standard deviation (0 ) of 14.8 F.
The latter value is used in 1
determining the margin term along with the Regulatory Guide 1.99, Revision 2, Positivn 2, recommended 0 standard deviation of 14 F
{
3 (credible surveillance data available).
i Evaluation of Shift of RTm The surveillance data available for the Zion Station Units 1 and 2
{
weld metals fabricated of 72105 include the data from both of their respective reactor vessel surveillance programs.
Seven individual
-(
data sets (seven separate irradiations from surveillance capsules)
{
are presented in Table 2 and constitute all the irradiated
-l surveillance data for Zion Units 1 and 2.available up to the time I
of this report.
All of the data have been verified by the B&W Owners Group based on a thorough review of all source documents and the fluence values are based on current re-evaluations of the capsule fluence.
j The irradiated shift data were analyzed using the procedure described in Regulatory Guide 1.99, Revision 2,
Position 2 for i
credible surveillarce data.
This approach calculated a chemistry l
factor of 198 as shown in Table 3, which ie the relationship of l
RT, shif t to fluence that fits the surveillance data of both Zion units combined.
A chemistry factor of 198 will'be used in this report for calculating RTm-Marcin The Margin term was calculated using the following expression from Regulatory Guide 1.99, Revision 2:
i
e i
i o
a'
~
Margin = 2 a
+
where:
a = standard deviation for the initial RTm 2
standard deviation for ARTm a =
3 i
As stated above, the standard deviation for the initial RT,, is i
14.8 F based on the available drop weight data.
Because credible surveillance data is used in che determination of the chemistry i
factor for the WF-70 weld metals, the standard deviation for ART j
c7 t
is 14 F based on Regulatory Guide 1.99, Revision 2,
Position 2.
Using these values in the above expression, the margin factor is
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calculated to be 41 F.
rim Evaluation Using the PTS Rule methodology described in 10CFR50.61, the RTns values were calculated for the weld metal WF-70 at the end-of-life
]
]
(32 EFPY) fluence values for Zion Station Units 1 and 2.
Table 4 presents the results of the RTns eval uation.
j Summarv
- I 1.
Initial RT
- From the results of this evaluation, the m
initial RT value to be used for the Zion Station Units 1 and m
2 WF-70 beltline welds is calculated as:
i Initial RTm = -56 F Standard Deviation (0 )
14.8 F
=
1 2.
Shift of RT
- Using the methodology of Regulatory Guide m
1.99, Revision 2, Position 2, a chemistry factor'of 198 was
. calculated for the seven surveillance data sets with wire heat number 72105.
This chemistry factor is used in the determination of the RTm shift.
,e w-w
i t
t 3.
Marain A margin of 41 F was used instead of the 56 F'in 10CFR50.6] because it takes into account the actual standard deviation of the data set used to determine the initial RTm
~j (Position 2).
1
(
l i
4.
E h Conclusion - This evaluation, based on the preceding t
values of initial RTm,;, RTm shift, and margin, concludes that the RTns at 32 EFPY are as follows:
[
j 4
Zion Unit 1, RTns = 213 F l
Zion Unit 2,.
RTns = 155 F I
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i a
1 b
I a
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1... -.
i Table 1.
! Summary of Available Drop Weight Data for Weld Metals Fabricated with Weld Wire 72105 and Linde 80 Flux t
S.R.
Drop Wt.
Source Material Time, Hrs.
_Tgg Fm Oconee 2-RVSP WF-209-1 33
-20 l
Oconee 3-RVSP WF-209-1 30
-20 Zion 1-RVSP WF-209-1 23
-70 Zion 2-RVSP WF-203-1 30
-70 B&WOG-RVSP WF-70 48
-50 l
l B&W-NBD WF-70 48
-50 HSST-Series 3 WF-70 48
-50 Midland Beltline WF-70 23
-60 Midland Beltline WF-70 23
-60 i
Midland Beltline WF-70 30
-60 v
Midland Beltline WF-70 40
-50 i
i Midland Beltline WF-70 50
-60 ORNL Midland Beltline WF-70 23
-76 ORNL Midland Beltline WF-70 23
-58 ORNL Midland Beltline WF-70 23
-76
]
ORNL Midland Beltline WF-70 23
-58 l
ORNL Midland Beltline WF-70 23
-76 ORNL Midland Beltline WF-70 23
-49 l
f ORNL Midland Beltline WF-70 23
-49 ORNL Midland Beltline WF-70 23
-67 j
ORNL Midland Nozzle Belt WF-70 28
-40 j
ORNL Midland Nozzle Belt WF-70 28
-49 i
ORNL Midland Nozzle Belt WF-70 28
-58 t
ORNL Midland Nozzle Belt WF-70 28
-67 l
(1)
Drop weight temperatures of ORNL data were converted from degrees-centigrade.
l l
4
-,__,_.____m
= =,
e
.+
Table 2.
Zion Units 1 and 2 Surveillance Transition Temeerature Data (Data available through 8/27/93) 30 ft-lb Transition 3
Capsule Weld Fluence Temperature.
- F t
Plant Ident.
Metal n/cm2 Initial Irradiated Channe Zion Unit 1 T
WF-209-1D 2.53E+18
+4 116 112
- i Zion Unit 1 U
WF-209-1D 8.49E+18
+ 4 203 199 Zion Unit 1; X
WF-209-1D 1.26E+19
+4 203 199 Zion Unit 1 Y
WF-209-1D 1.56E+19
+4 209 205 Zion Unit 2 U
WF-209-1E 2.57E+18
-23 122 145 Zion Unit 2 T
WF-209-1E 8.04E+18
-23 168 191 Zion Unit 2 Y
WF-209-1E 1.48E+19
-23 208 231 r
I
_-__-.-----.-s--.-,-v w
+-~-
-on-
.m
--er-m w-m -
e
,w,,-w. oee w-.s,,
-w
<me-e w-ww--v w-e,-o,m aemer-m,*=.-wmew, ens
-ew--n-+ev=~s-e-me + w v
v e-n-a---we+ve--wwm-<er--
,,-mo
i si t
x Table 3.
Calculation of Chemistry Factor Usino Zion Units 1 and 2 Surveillanceh apsule Data C
Capsule Fluence Fluence Measured Plant Ident.
n/cm2 Factor ART ff*6RTm_
(f f) ^2 m_
Zion Unit 1 T
2.53E+18 0.627 112 70.224 0.393 Zion Unit 1 U
B.49E+18 0 954 199 189.846 0.910 4
- Zion Unit 1 X
1.26E+19 1.064 199 211.736 1.132 Zion Unit 1 Y
1.56E+19 1.123 205 230.215 1.261 Zion Unit 2 U
2.57E+18 0.631 145 91.495 0.398 Zion Unit 2 T
8.04E+18 0.939 191 179.349 0.882 Zion Unit 2 Y
1.48E+19 1.109 231 256.179 1.230 1229.044 6.206 Chemistry Factor 1229.004 198.04
=
=
6.206 l
L l
4 e~w-e-4 we+e et+---e->=tm*--'w
?-Mw*'m'
- - -r-T
+-'+---h-e---+-s ibW='me+4 e
b> ewe d-esieni
-e1.-a--.2-w e->++mtavMvm ew ve e ge--"-*+YM5 d eeen"4'h-m.
EAtre enWW Ms6 m-$w*t-a mm.-'e.,4*ee.%
--+y,,
_.. ewes.-w e-m ena e
- w,twuaanac d_m---w sme-M+
t.
l; 1
+
l.
Table 4.
Evaluation of Zion Unit 1 and 2 Pressurized Thermal Shock Criterien for 32 EFPY l
i l
l Per 10CFR50.61 (May 1991) with RG 1.99. Rev.
2.
Pos.
2.
Chemistry Factor and Marctin Chemical Estimated f
Composition, IS Fluence 32 EFPY PTS Evaluation Peactor Vessel Heat w/o 3 32 EFPY Initial RTea Screening Beltline Peqion Location Number Tyre
.-Cu Ni-n/cm' E,:n F Shift Marcin RTm Criterion Zion Unit 1 WF-70 ASA/L!nde 80 0.35 0.59 1.73E+19
-56 228 41 213 300 IS to LS Circum. Weld (100%)
Zion Unit 2
.WF-70 ASA/Linde 80
- 9., 5 0.59 6.04E+18
-$6 170 41 155 270 In+erm. Longit. Weld (100%)
- o
_..m___-____=_.mm-,,..-......---.,,~4,
.-mm,.
--v,.-. - -. _..-s-..---e
--.,m,-..-,
-~
4
. - - ~ --
.~--~------.~,,--.m.
o-.<.
--.--.--.,,-..-._.m.
--