ML20195H746
| ML20195H746 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/23/1988 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-REGGD-01.099, RTR-REGGD-1.099 GL-88-11, NUDOCS 8812010021 | |
| Download: ML20195H746 (29) | |
Text
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-_____y.---
8 ev y PoAer $ tat on SNcorgger1, PA 1$0770004 wN m 64HMS November 23, 1988 U. S. Nuclear Regulatory Commission Attn Document Control Desk Washington, DC 20555 Reference Beaver Valley Power Station, Unit No. 1 and No. 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 l
NRC Generic Letter 88-11 Gentlement In response to NRC Generic Letter 88-11 "HRC Position on Radiation Embrittlement of Reactor Vessel Materials and Its Impact on
[
Plant Operations," a technical analysis was performed to evaluate the applicability of BVPS Units 1 and 2 Prnssuro-Temperature limit curves using Regulatory Guide 1.99, Revision 2.
l f
Attachment 1
is the technical analysis and impact on plant j,
operations for Unit 1. is the corresponding results for Unit 2.
BVPS Unit 1
is currently evaluating surveillance capsule "W".
This data with prior surveillance results and the P.se of Revision 2 to Regulatory Guido 1.99 resulted in the intermediate shell plate j
(B6607-2) and lower shell plate (B6903-1) being the most limiting l
vessel materials.
New heatup and cooldown curves using Rev. 2 of C
Reg.
Guide 1.99 show the present technical specification curves at l
9.5 EFPY are still conservative and may afford additional operating i
flexibility.
Duquesne Light is currently evaluating new heatup and j
cooldown curves
- and, in the interim, will revise the notations on current technical specification curves for controlling material and RTNDT' The applicability date of BVPS Unit 2 reactor vessel beatup and
[
cocidown curves will change from 10EFPY to SEFPY using Rev. 2 of Reg.
Guide 1.99.
Since SEPPY of operation will not be reached until mid-1990's, Duquesne Light proposes to maintain the present technical l
specification curves with a revision to the stated applicability date f
and RTNDT's' f
e 8812010021 SS11e3 i
PDR ADOCK 05000 334
% i l
P PDC
. Beaver Vallcy Powor Station, Unit Non. 1 & 2 DockOt No. 50-334, License No. DPR-66 Docket No. 50-412, License No. NPF-73 Page 2 If there are any questions concerning this response, please contact my office.
Very truly yours, M.
D. Sieber ice President Nuclear Group I
1 i
g
?
i Enclosure i
l cc:
Mr. J.
Beall, Sr. Resident Inspector f
Mr. W. T. Russell, NRC Region I Administrator i
)
Mr.
P. Tam, Sr. Project Manager Director, Safety Evaluation & Control (VEPCO)
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COMMONWEALTH OF PENNSYLVANIA)
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ss:
COUNTY OF BEAVER
)
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On this aI#fRI.
day of (N
, 1988,
/////4 ///d/4/br, a
Notary Public in and for said before me, 7'
Commonwealth and County, personally appeared J. D. Sieber, who being duly
- sworn, deposed, and said that (1) he is Vice President of Duquesne
- Light, (2) he is duly authorized to execute and file the foregoing submittal on behalf of said Company, and (3) the statements set forth in the submittal are true and correct to the best of his knowledge, information and belief.
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ATTACIIMENT 1 PAGE 1 OF 17 3.
TECHNICAL ANALYSIS 3.1 Identification and Location of Beltline Region Materials Figure 1 identifies and indicates the location of all beltline region materials for the Beaver Valley Unit I reactor vessel.
The beltline region is defined to be "the region of the reactor vessel (shell material including welds, heat affected zones, and platws or forgings) that directly surrounds the effective height of the active core and adjacent regions of the reactor l
~
vessel that are predict,ed to experience sufficient neutron irradiation damage to be considered in the selection of the most limiting material with regard to radiation damage" (2).
3.2 Definition of Plant-Specific Material Properties i
i The pcetinent chemical and mechanical properties of the beltine region plate and weld materials of the Beaver Valley Unit 1 reactor vessel are given in I
table 1.
J The "weight percent copper"(Cu) and "weight percent nickel'(Ni) material
[
]
chemistry values and the initial RTNDT (1) values shown in the table are the i
same as those used in prior Beaver Valley Unit 1 pressarized thermal shock l
calculations (5).
The chemistry factor (CF) and "margin" (H) values that are also shown in table
]
1 waru determined in accordance with the Regulatory Guide 1.99 Revisien 2 methods described in section 2.
Chemistry factor and margin values in table 1 that were based upon credible surveillance measurements are also giveh for the baltline region materials where this data was available. Table 2 shows the Beaver Yalley Unit 1 surveillance capsule program results (6).
Table 3 gives further information on the de. termination of the chemistry factors from this data in accordance with the applicable procedure from Revision 2 tc nequlatory l
Guide 1.99.
For those rsatter vessel materials where credible surveillance data exists, the respective chemistry facter and margin terms are lower than l
the respective values based on material chemistry mea;urements beept for the 1
chemistry factor for lower shell plate B6903-1.
3Mh 114e4 'O
ATTACHMENT 1 PAGE 2 OF 17 CIRCUMFERENTIAL SEAMS VERTICAL SEAMS 270' D6607-2 19-714B g
r r-f 8.2" 45 CORE g
180' 0'
CORE 144.0" B6607-1 19-714A 90, y
C g
20.5" 4
11-714
=
n 20-71 B7203-2 Y
y_
/
15' W
6 CORE II 7
180' 0'
.a l
s'. 9.1 '
w l
i 20-714A 90
B6903-1 l
l Figure 1 Identification and Lo'ation of Beltline Region Material for the Beaver Valley Unit 1 Reactor Vessel n n.. w,u,e l
l
ATTACHMENT 1 PAGE 3 OF 17 TABLE 1 BEAVER VALLEY UNIT 1 REACTOR VESSEL BELTLINE REGION MATERIAL PROPERTIES Cu Ni 1(a) y (Wt.%)
(Wt.%)
('F)
('F)
Intermediate Shell Plate
.14
.62 100.5 43 34(b)
B6607-1 Intermediate Shell Plate
.14
.62 100.5 73 34(b) 86607-2 Lower Shell Plate B6903-1
.20
.54 141.8 27 34(b)
(167.9)(d)
(37)
Lower Shell Plate B7203-2
.14
.57 98.65 20 34(b)
Lon itudinal Welds
.28
.63 191.65
-56 65.5(C)
(19 714 A&B)
Weld Wire Heat 305424 Circumferential Weld
.29
.07 132.9
-56 65.5(c) l (11-714)
Weld Wire Heat 90136 2
Lon itudinal welds
.34
.61 210.45
-56 65.5(C)
(20 714 A&B)
(191.4)
(44.05)
Weld Wire Heat 305414 1
(a) The initial RTNDT (I) values for the plates are conservatively measured 1
values whereas the weld values are generic mean values for Linde 1092 and 0091 weld flux types (3).
(b) The standard deviation for the initial RTNDT margin term for these materials is assumed to be zero since the initial RTNDT values were obtained from conservative (i.e., "upeer bound") test results.
(c) These are maximum "margin" (M) values.
The standard deviation for ARTNOT' 'a, is 28'F for welds tacept that o need not exceed 3
0.50 times the mean value of ORT This exception can occur for NDT.
these materials at low fluance values.
4
'f (d) Numbers in ( ) corresponds to surveillance capsule data, me.mese ie
ATTACHMENT 1 PAGE 4 OF 17 TABLE 2 a.
4
SUMMARY
OF BEAVER VALLEY UNIT 1 REACTOR VESSEc SURVE!LLANCE CAPSULE CHARPY IMPACT TEST RESULTS (6)
Fluence ART
(.NDT 19 2
Material Capsule (10 n/cm )
7) c Plate B6903-1 V
0.291 130 (Longitudinal)
U 0.654 120 W
0.949 150 Plate B6903-1 V
0.291 140 (Transverse)
U 0.654 135 W
0.949 185 Wald metal V
0.291 150 0
0.654 155 W
0.949 185 HAZ metal V
0.291 0
0 0.654 35 W
0.949 60 n mmeis
i ATTACHMENT 1 PAGE 5 0F 17 t
TABLE 3 CALCULATION,0F CHEMISTRY FACTORS USING BEAVER VALLEY UNIT 1 SURVEILLANCE CAPSULE DATA Material Capsule f
ff 6RT ff x 6RT II NDT NDT 19 2
(10 n/cm )
('F)
Plate B6903-1 V
0.291 0.662 130 86.1 0.438 (Longitudinal)
U 0.654 4.895 120 105.7 0.776 W
0.949 0.985 150 147.8 0.970 Plate B6903-1 V
0.291 0.662 140 92.7 0.438 (Transverse)
U 0.654 0.8*1 135 118.9 0.776 l
W 0.949 0.983 185 182.2 0.970 I=
733.4 4.368 i
i e Chemistry Factor (Plate B6903-1) = I(ff x TNDT)
,;.j,9 Weld Metal V
0.291 0.662 150 99.3 0.438 (Weld Wire Heat U
0.654 0.881 155 136.6 0.776 305424)
W 0.949 0.95:i 185 182.2 0.970 i
I=
418.1 2.184 e Chemistry Factor (weld metal)
- 418.1 t
191,4 2.184 r
i i
Notes:
f = fluence in 10 n/cm
{
19 2
ff = fluence factor new mu,e
t ATTACHMENT 1 PAGE 6 OP 17 l
l 3.3 Neutron Fluence Values l
Fast neutron fluence (E>l MeV) at the inner surface of the Beaver Valley Unit i reactor vessel is given as a function of full power service life in
)
figure 2.
This information is pertinent to the generation of heatup and I
cooldown P/T limits (at the 1/4 T and 3/4 T locations) and in determining l
RTPTS values at the vessel inner surface, f
3.4 Adjusted Reference Tem:eretures Values For Heatup and Cooldown Curves
{
i Using the material property and neutron fluence data from sections 3.2 and 3.3, adjusted reference temperature valuen are calculated to determine the most limiting Beaver Valley Unit I reactor vessel materials using Regulatory i
Guide 1.99 - Revision 2.
Intermediate shell plate B6607-2, lower shell plate B6903-1, and longitudinal welds19-714 A & B have the highest combination of l
chemistry factor, initial RTNDT, and applicable margin term, as can be seen j
from as table 1.
Considering that both shell plates experience the peak
[
neutron fluence exposure and that the longitudinal welds experience the minimum neutron fluence exposure, these materials bound all other materials in f
the Beaver Valley Unit 1 reactor vessel as long as credible surveillance capsule data are used.
i The adjusted reference temperatures for plates B6607-2 and 86903 I and longi-i tudinal welds 19 714 A & B are calculated in tables 4, 5, and 6. respectively, I
at the 1/4T and 3/4T vessel weil locations for 6 EFPY and 9.5 EFPY.
6 EFPY represents the approximate current life of the Beaver Valley Unit 1 plant and
[
9.5 EFPY is the applicability date for the P/T limits (7) in the current
[
Technical Specifications.
l The adjusted reference temperatures (formerly total RTNDT values) from Revision 1 to Regulatory Guide 1.99 (8), which were used to generate the current Beaver Valley Unit 1 P/T limits, are also shonn in tables 4, 5 and 6.
Plates B6607-2 and B6903-1 are the most limiting materials in the Beaver Valley Unit I reactor vessel based upon these calculations relative to the generations of heatup and cooldown curves.
nes, muv e
Figure 2 Fast Neutron fluence (E, MeV) As A Function of Full Power Service ife (EFPY) for Beaver Valley Unit 1 [6]
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ATTACHMENT 1 PAGE 8 OF 17 l
TABLE 4 l
CALCULATION OF ADJUSTED REFERENCE TEMPERATURES FOR BEAVER VALLEY UNIT 1 REACTOR VESSEL MATERIAL - INTERMEDIATE SHELL PLATE B6607-2 Regulatory Guide 1.99 - Revisien 2 6 EFPY 9.5 EFFY Parameter 1/4 I 3/4 T 1/4 T 3/4 i Chemistry Factor, CF ('F) 100.5 100.5 100.5 100.5 n/cm)(a) 0.54 0.21 0.81 0.32 19 2
Fluence, f '10 Fluence Factor, ff 0.83 0.58 0.94 0.69 ARTNDT = CF x ff (*F) 83 58 95 68 Initial RTNDT, I ( F) 73 73 73 73 Margin,M(*F) 34 34 34 34 e Revision 2 to Regulatory Guide 1.99 Adjusted Referonce Temperature, 190 165 202 176
)
ART = Initial RTNDT * 'UNOT + Margin e Revision 1 to Regulatory Guide 1.99 274 137 Total RT II
~
~
NDT 19 2
(a) Fluence, f, is based upon fsurf (10 n/cm, E>1 NeV) = 0.871 at 6 EFPV and 1.30 at 9.5 EFPY.
The Beaver Valley Unit 1 reactor vessel wall thickness is 7.875 inches.
(b) The current Beaver Valley Unit 1 heatup and cooldown pressure / temperature limits are based upon these total RTNOT values, ms, mese,e
ATTACHMENT 1 PAGE 9 OF 17 TABLE 5 CALCULATION OF ADJUSTED REFERENCE TEMPERATURES FOR BEAVER VALLEY UNIT 1 REACTOR VESSEL MATERIAL - LOWER SHELL PLATE B6903-1 Regulatory Guide 1.99 - Revision 2 6 EFPY 9.5 EFPY Parameter 1/4 T 3/4 T 1/4 T 3/4 i Chemistry Factor, CF ('F) 167.9 167.9 167.9 167.9 n/cm )(a) 0.54 0.21 0.81 0.32 19 2
Fluence, f (10 Fluence Factor, ff 0.83 0.58 0.94 0.69 ARINDT = CF x ff ('F) 139 97 158 116 Initial RTNDT,I(*F) 27 27 27 27 Margin, M ('F) 17 17 17 17 e Revision 2 to Regalatory Guide 1.99 AdjustedReferenceTemperature 183 141 202 160 ART = Initial RTNDT + aRTNDT + Margin i
e Revision 1 to Regulatory Guide 1.99 274 137 I
Total RTNOT (7
[
19 2
(a) Fluence, f, is based upon fsurf(10 n/cm E>l NeV) = 0.871 et I
The Beaver Valley Unit 1 reactor vessel wall thickness is 7.875 inches.
(b) The current Beaver Valley Unit I heatup and cooldown pressure /t uperature limits are based upon these total RTNOT values.
Y 3 Mle /11106410
ATTACHMENT 1 PAGE 10 OF 17 TABLE 6 CALCULATION OF ADJUSTED REFERENCE TEMPERATURES FOR BEAVER VALLEY UNIT 1 REACTOR VESSEL MATERIAL - LONGITUDINAL WELOS19-714 A & B Regulatory Guide 1.99 - Revision 2 6 EFPY 9.5 EFFY Parameter 1/4 I 3/4 T 1/4 I 3/4 i Chemistr; Factor, CF ('F) 191.65 191.65 191.65 191.65 n/cm )(a) 0.097 0.038 0.147 0.057 2
19 Fluence,f(10 Fluence Factor, ff 0.41 0.25 0.525 0.314 ARTNOT = CF x ff ('F) 79 48 101 60 Initial RTNDT, ! ('F)
-56
-56
-56
-56 Margin,M('F) 65.5 59 65.5 65.5 I
e Revision 2 to Regulatory Guide 1.99 Adjusted Reference Temperature 89 51 111 70 ART = Initial RTNDT + ARTNDT + Margin e Revision 1 to Regulatory Guide 1.99 NDT [7)(b) 274 137 Total RT 19 2
(a) Fluence, f, is based upon fsurf (10 n/cm, E>l MeV) = 0.156 at 6 EFPY and 0.236 at 9.5 EFPY at the longitudinal welds.
The Beaver Valley Unit 1 reacter vessel wall thickness is 7.875 inches.
(b)
The current Beaver Valley Unit I heatup and cooldown prassure/ temperature limits are based upon the:e total RTNDT values, newne.u is
- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -
ATTACHMENT 1 PAGE 11 OF 17 3.5 Aeolicability Date of Current Pressure-Temeerature Limits figure 3 shows a plot of the adjusted reference temperatures, as calculated in section 3.4. from 6 EFPY through 32 EFPY for interrediate shell plate B6607-2 and loaer shell plate B6903-1 in order to cetermine the applicability date of the current Beaver Valley Unit 1 P/T limits.
As can be seen frem figure 3 the applicability date for the current heatup and cooldewn curves appears to be less than the current life of the Beaver Valley Unit 1 plant.
That is, the adjusted reference temperatures per Revision 2 to Regulatory Guide 1.99 at 6 EFPY for the 3/4 T location is well above the respective values used to generate the current P/T limits at 9.5 EFPY using Revision 1 to Regulatory Guide 1.99.
However, the adjusted reference temperature at the 1/4T location is much lower using the new Guide such that the value used to generate the current curves will not be exceeded through end of design life (32 EFPY).
Given these significant changes, an additional assessment was performed.
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ATTACHMENT 1 4.
ESTIMATED IMPACT ON PLANT OPERATIONS PAGE 13 OP 17 Given the potential for significant changes to operating flexibility based upon the adjusted reference temperatures using Regulatory Guide 1.99 - Revision 2, new heatup and cooldown curves were generated for Beaver Valley Unit 1.
These pressure / temperature limits were calculated using the same methods that were used to calculate the current limits (7) with the exception that the new Regulatory Guide 1.99, Revision 2 methods were used and the instrumentation error margins aere deleted.
New curves were generated at 9.5 EFPY in order that a direct comparison could be made with the current operating limits.
Referring to figure 3 and table 4, intermediate shell plate B6607-2 is the limiting material at 9.5 EFPY using Revision 2 to Regulatory Guide 1.99. The 1/4 T and 3/4 T adjust;d reference temperatures (ART's) for this material are 202*F and 176'F, respectively.
Figure 4 shows the cooldown limitations for several cooldown rates using Revision 2 to Regulatory Guide 1.99 ART's (with no instrumentation error margins) against the current cooldown limits for a 100*F per hour rate using Revision 1 totcl RTNOT's (including instrumentation error margins). As expected, the new cooldown limita-tions provide significantly more operating flexibility.
The deletion of instrumen-tation error margins produce the benefit at low indicated temperatures while the majority of the benefit at higher indicated temperatures is caused by the use of Regulatory Guide 1.99, Revision 2.
The reference temperature at the 1/4 T loca-tion, which governs the cooldown limits, is 72'F lower than the value used to generate the current curves.
The heatup limitations are governed by the 3/4 T location because of tensile stresses in the outer wall (caused by heatup) or by the 1/4 T location because of pressure stresses at steady state conditions or during heatup. The current heatup curve for Beaver Valley Unit 1 is controlled by the steady state conditions because of the high reference temperature at the 1/4 1.
Figure 5 shows the composite heatup limitations for all conditions using Revision 2 to Regulatory Guide 1.99 ART's at 9.5 EFPY for heatup rates up to 60'F per hour. Given that the 3/4 T ART is 39'F higher than the current value and the 1/4 T ART value is 72'F lower, the 3/4 T location now controls most of the composite heatup curve, except at the highest indicated temperatures.
If the new composite curve is compared to the current heatup limitations, as shown in figure 6. further operating flexibility is also nei wwe i
ATTACHMENT 1 PAGE 14 OP 17 Figure 4 Beaver Valley Unit 1 Coold:an Curves Using Regulatory Guide 1.99 -
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ATTACHMENT 1 PAGE 15 0F 17 Figure 5 Beaver Valley Unit 1. Composite Heatup Curve Development Using Regulatory Guide 1.99 - Revision 2
.500
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ATTACl! MENT 1 PAGE 16 OF 17 Figure 6 Beaver Valley Unit 1 Heatup Curves Using Regulatory Guide 1.99 - Revision 1 and Revision 2 2500 agg:
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ATTACHMENT 1 PAGE 17 OF 17 available during heatup.
Again, the heatup operating margin benefit at low indicated temperatures is due to the deletion of instrumentation error i
margins, while the majority of the cperating margin benefit at higher indicated temperatures is ca'ased by the use of Regulatory Guide 1.99, 1
Revision i, These results show that the current heatup and cooldown curves in the Beaver Valley Unit 1 plant Technical Specifications at 9.5 EFPY are conservative with '
respect to the implementation of Revisien 2 to Regulatory Guide 1.99.
l Since additional cperating flexibilty may be gained using the new version of l
the Guide and deletion of the margin instrumentation errors, Duquesne Light plans to evaluate the implementation of new heatup and cooldown curves.
l Implementation of less restrictive operating limits will assist in maintaining a "clean" record relative to low temperature over pressure event occurrences, in the future, cperating flexibility may be reduced when later pressure /
i l
temperature curves are implemented.
Duquesne Light will monitor this f
situation and address any issues that may develop utilizing industry guidance j
currently being developed as part of the on going EPRI Reactor Vessel l
]
Embrittlement Managtment Program. Plant operating issues are being addressed l
i as part of this industry effort.
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RTTACl! MENT 2 PAGE 1 OP 9 3.
TECHNICAL ANALYSIS e
3.1 Identification and Location of Beltline Region Materials Figure 1 identifies and indicates the locatien of all beltline region materials for the 3eaver Valley Unit 2 reactor vessel.
The beltline,egion is defined to be "the region of the reactor vessel (shell material including welds, heat affected zones, and plates or forgings) that directly surrounds the effective height of the active core and adjacent regions of the reactor vessel that are predicted to experience sufficient neutron irradiatier. damage to be considered in the selection of the most limiting material with regard to radiation damage" (2),
3.2 Definition of Plant-Specific Material Properties The pertinent chemical and mechanical prcperties of the beltine region plate end weld materials of the Beaver Valley U.1it 2 reactor vessel are given in table 1.
The "weight percent cepper" (Cu) and "weight percent nickel" (Ni) material chemistry values and the initial RTNDT (I) values shown in the table are the same as those used in prior Beaver Valley Unit 2 PTS calculations (5).
The chemistry factor (CF) and "margin" (H) values that are also shown in table 1 were determined in accordance with the Regulatory Guide 1.99 Revision 2 methods described in section 2.
The chemistry fcctors and margins are based upon material chemistry neasurement information since credible surveillance data are not yet available for the Beaver Valley Unit 2 reactor vessel materials.
3.3 Neutron Fluence Values Fast neutron fluence (E>l NeV) at the inner surface of Beaver Valley Unit 2 l
reactor vessel is given as a function of full-poner service life in figure 2.
This information is pertinent to the generation of heatup and cooldown P/T limits (at the 1/4 T and 3/4 T locations) and in determining RTPTS values at the vessel inner surface.
The intermediate and lower shell plates and the girth weld that joins them experience the peak neutron fluence exposure.
The longitudinal nelds experience neutren fluences somewhat less than the peak value, but the difference is not significant, me.mo
ATTACHMENT 2 PA' B 2 OF 9 CIRCUMFERENTIAL SEAMS VERTJCAL SEAM 3 270' B9004-1 101 1248-
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Figure 1 Identification and Location of Beltline Region Material for the Beaver Valley Unit 2 Reactor Vessel i,
I
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,J ATTACHMENT 2 PAGE 3 OF 9 TABLE 1 BEAVER VALLEY UNIT 2 REACTOR VESSEL BELTLINE REGION MATERIAL PROPERTIES Cu Ni
!(8)
M(b)
(Wt.%)
(Wt.%)
('F)
('F)
Interrrediate Shell Plate
.07
.53 44 60 34 B9004-1 I
Intermediate Shell Plate
.07
.59 44 40 34 B9004-2 Lowsr Shell Plate 89005-1
.08
.59 51 28 34 Lower Shell Plate B9005-2
.07
.58 44 33 34 Intermediate to Lower Shall
.08
.07 43.7
-30 56 Girth Weld and All Longitudinal Welds (a) The initial RTNDT (!) values for the plates and welds are conservatively measured values.
(b) These are maximum "margin" (M) values. The standard deviation for the initial RTNDT margin term (og) is assumed to be zero since the initial RTNOT values were obtained frem con:ervative (i.e., "upper bound")testresults. However, the standard deviation fo* ART NOT' c, is 28'F for welds and 17'T for base metal, except that c 3
3 need not exceed 0.50 times the mean value of ART This exception NOT.
occurs for these materials at low fluence values.
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ATTACHMENT 2 PAGE 5 OF 9 3.4 Adjusted Reference Temeeratures Values For Heatuo and Cooldown Curves Using the material property and neutron fluence data from sections 3.2 and 3.3, adjusted reference temperature values are calculated for the limiting Beaver Valley Unit 2 reacter vessel materials using Regulatory Guide 1.99, Revision 2.
When considering the chemistry factor, initial RTNDT, and applicable margin terms and when considering that all materials experience the peak neutron fluence exposure, intermediate shell plate 89004-1 and loner sFell plate B9005-1 bound all other materials.
The adjusted reference tee:eratures for plates 89004-1 and B90051 are calculated in tables 2 and 3, respectively, at the 1/4T and 3/4T vessel wall locations for 5 EFPY and 10
- EFPY, 10 EFPY is the applicability date for the P/T limits in the current Beaver Valley Unit 2 Technical Specificatiens.
5 EFPY is an intermediate point of interest beyond current plant life.
The adjusted reference temperatures (formerly total RTNDT values) from Revision 1 to Regulatory Guide 1.99 (6), which were used to generate the current Beaver Valley Unit 2 P/T limits, are also shown in tables 2 and 3.
Intermediate shell plate B9004-1 is the most limiting material in the Beaver Valley Unit 2 reactor vessel based upon these calculatiens relative to the generation of heatup and cooldown curves.
3.5 Aeolicability Date of Current Pressure-Temperature Limits Figure 3 shows a plot of the adjusted reference temperatures, as calculated in se: tion 3.4, from 2.5 EFPY through 10 EFPY for intermediate shell plate B9:04-1 in order to determine the applicability date of the current Beaver Valley Unit 2 P/T limits.
2.5 EFPY is just another intermediate lifetime beycnd current life.
As can be seen from figure 3 the applicability date based on the adjusted reference temperatures per Revision 2 to Regulatory Guide 1.99 at the 3/4T 1c:stien is 5 EFPY for the current heatup and cooldown curves rather than 10 EFPY as determined using Revision 1 to Regulatory Guide 1.99.
nei.n:ue a
ATTAC!! MENT 2 PAGE 6 oF 9 TABLE 2 CALCULATION OF ADJUSTED REFERENCE TEMPERATURES FOR BEAVER VALLEY UNIT 2 REACTOR VESSEL MATERIAL -
INTERMEDIATE SHELL PLATE B9004-1 Regulatory Guide 1.99 - Revision 2 5 EFPY 10 EFPY Parameter 1/4 T 3/4 T 1/4 T 3/47 Chemistry Factor, CF ('F) 44 44 44 44 19 n/cm )(a) 0.63 0.25 1.27 0.49 2
Fluence, f (10 Fluence Factor, ff 0.87 0.62 1.07 0.80 ARTNDT = CF x ff ('F) 38 27 47 35 Initial RTNDT, I ('F) 60 60 60 60 Margin, M (*F) 34 27 34 34 e Revision 2 to Regulatory Guide 1.99 Adjusted Referen:e Temperature, 132 114 141 129 ART = Initial RTNDT + ARTNDT + Margin o Revision 1 to Regulatory Guide 1.99 (b) 139 114 Total RT NDi 1
I (a)
Fluence, f, is based upon fsurf (10 n/cm, E>l Mov) = 1.01 at 5 EFPY 19 2
and 2.03 at 10 EFPY, The Beaver Valley Unit 2 reactor vessel wall thickness is 7.875 inches at the beltline region.
(b)
The current Seaver Valley Unit 2 heatup and cooldown pressure /terparature i
limits are based upon these total RTNOT values.
l f
m..,, :..
ATTACliMENT 2 PAGE 7 OP 9 TABLE 3 CALCULATION OF ADJUSTED REFERENCE TEMPERATURES FOR BEAVER VALLEY UNIT 2 REACTOR VESSEL MATERIAL -
LOWER SHELL PLATE 89005-1 Regulatery Guide 1.99 - Revision 2 5 EFPY 10 EFPY Parameter 1/4 I 3/4 T 1/4 I 3/4 T Chemistry Factor, CF (*F) 51 51 51 51 n/cm )(a) 0.63 0.25 1.27 0.49 18 2
Fluence,f(10 Fluence Factor, ff 0.87 0.62 1.07 0.80 ARTNDT = CF x ff ('F) 45 32 55 41 Initial RTNDT, I ('F) 28 28 28 28 Margin,M('F) 34 32 34 34 e Revision 2 to Regulatory Guide 1.99 Adjusted Reference Temperature, 107 92 117 103 ART = Initial RTNDT + ARTNDT + Margin i
l e Revision 1 to Regulatory Guide 1.99 Total RT (b)
NDT 339 334 19 2
(a) Fluence, f, is based upon fsurf (10 n/cm, E>l Nev) = 1.01 at 5 EFPY and 2.03 at 10 EFPY.
The Beaver Valley Unit 2 reactor vessel wall thickness i
is 7.?.75 inches at the belt? ira region.
1 (b) The current Beaver Valley Unit 2 heatup and cooldoan pressure / temperature limits are based upon these total RTNDT values.
t mwm.,.
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Figure 3 Adjusted Reference Temperature versus ETPY for Beaver Valley Unit 2 Rer.ctor Vessel Shell Plate B9304-1 Using Regulatory Guide 1.99 - Revision 2 l$
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i ATTACHMENT 2 PAGE 9 OF 9 4.
ESTIMATED IMPACT ON PLANT OPERATIONS l
Based on the results given in this report, the applicability date of the Beaver Valley Unit 2 reactor vessel heatup and cooldean curves will be changed from 10 EFPY to 5 EFPY in the plant Technical Specifit.itions.
5 EFPY of operation should be reached during the mid-1990's.
j l
Operating flexibility may be reduced when new pressure / temperature curves are implemented in the future.
Duquesne Light will monitor this situation and f
address any issues that,may develop utilizing industry guidance currently i
being developed as part of the on going EPRI Reactor Vessel Embrittlement Management Program.
Plant operating limits issues are being addressed as part f
of this industry effort.
f i
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l t
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n.wm,.
- - _ _ -